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IMAT 2024 Answers & Worked Solution | LOCOMOTIVE
IMAT 2024 · Answers & Worked Solution

IMAT 2024 Answers & Worked Solution

All 60 answers, solved and explained — General Knowledge, Logical Reasoning, Biology, Chemistry, Physics & Mathematics. Verified line by line by the LOCOMOTIVE academic team.

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General Knowledge & Logical Reasoning

Current affairs, history, culture, logical and critical-thinking problems · 9 questions
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Who is the author of the famous novel To the Lighthouse?

  • AJane Austen
  • BMary Shelley
  • CEmily Dickinson
  • DVirginia Woolf
  • EAgatha Christie
Correct answer: D Virginia Woolf

Full explanation

To the Lighthouse was written by Virginia Woolf, published in 1927 as one of the defining works of modernist, stream-of-consciousness fiction. Woolf is also behind Mrs Dalloway, Orlando, The Waves, and the essay A Room of One’s Own – so option D is correct.

Each wrong option names a real, well-known author, just not the right one. Mary Shelley (option B) is the author of Frankenstein; or, The Modern Prometheus, not To the Lighthouse. Emily Dickinson (option C) worked almost entirely in poetry rather than the novel form – her Complete Poems is her signature body of work. Jane Austen (option A) wrote Pride and Prejudice, and Agatha Christie (option E) is remembered for detective novels such as The Murder of Roger Ackroyd. None of these four wrote To the Lighthouse, which leaves only option D.

Summary to learn

Modernist, stream-of-consciousness fiction is associated with specific authors and specific signature works: Virginia Woolf wrote To the Lighthouse, Mrs Dalloway and Orlando; Mary Shelley is remembered for the Gothic novel Frankenstein; Jane Austen for novels of manners like Pride and Prejudice; Emily Dickinson almost entirely for poetry; and Agatha Christie for detective fiction. Matching a described literary style to the right author means knowing which author actually pioneered that style, not just recognising a famous name.

Based on historical records, we can say that many ancient societies devised symbols to represent numbers and solutions to mathematical problems.

Although thinkers began to take the first steps towards mathematics early on, it can be asserted that only with Greek civilisation did this discipline acquire the abstract and general characteristics that render it distinct and render it a unique science. It is noteworthy that mathematics evolved into an abstract and general science at a deliberate pace. Documents from pre-Greek civilisations indicate that solutions to mathematical problems were confined to specific, tangible cases. These documents convey the impression that mathematical concepts were communicated sporadically and non-methodically (occasionally even fortuitously), and were treated as useful information geared towards practical outcomes.

MANARA, LUCCHINI Momenti del pensiero matematico – Mursia Which of the following CANNOT be inferred from the text?

  • ASince antiquity, mathematics has been characterized by abstractness and generality.
  • BIn antiquity, mathematical notions were not communicated in a methodical manner.
  • CSymbols representing numbers had already been adopted in antiquity.
  • DIn antiquity, mathematical notions were geared towards practical outcomes.
  • EThe evolution of mathematics has been an extremely slow process.
Correct answer: A Since antiquity, mathematics has been characterized

Full explanation

To answer this question, break down the paragraph into different parts.

The first sentence indicates that symbols for numbers existed in ancient times. (This rules out option C)

The second one suggests that the abstractness and generality were specific to the Greek era, not ancient time.

Then, it expresses that mathematics evolved slowly and deliberately. (This rules out option E)

After that, it suggests that earlier mathematics lacked generality and abstraction. and pre-greek mathematics were not communicated in a structured or methodical way. (This rules out option B)

And Lastly, it presumed that ancient mathematics was practical and application-focused. (This rules out option D)

Thus, the only option that cannot be inferred from the text is the option A.

Summary to learn

An inference question asks which statement a passage does NOT support — meaning every other option is directly backed by something the passage actually states, while the credited answer typically isn’t false so much as simply never addressed. This distinction (unsupported vs. directly contradicted) is the core skill critical-reading inference questions test: a statement can be wrong to select as “supported” not because the passage argues against it, but because the passage is silent on it.

The Hundred Years’ War was principally a conflict between which of the following kingdoms?

  • AThe Kingdom of Aragon and The Kingdom of Castile
  • BThe Kingdom of Aragon and the Kingdom of France
  • CThe Kingdom of France and the Kingdom of England
  • DThe Kingdom of Castile and the Kingdom of Portugal
  • EThe Kingdom of England and the Kingdom of Portugal
Correct answer: C The Kingdom of France and the Kingdom of England

Full explanation

The Hundred Years’ War (1337-1453) was fought between the Kingdom of France and the Kingdom of England over rival claims to the French throne and control of French territory. France ultimately prevailed, pushing the English out of nearly all their continental holdings except Calais, which held out until 1558. That makes option C the correct pairing.

The other four options all pair kingdoms that were never the war’s protagonists. Aragon and Castile (option A) were both Iberian kingdoms whose rivalries and eventual union belong to Spanish, not Anglo-French, history. Aragon and France (option B) weren’t opposing sides in this conflict either – Aragon’s political entanglements at the time were centred on the Mediterranean and Iberia. Castile and Portugal (option D) were Iberian neighbours whose own wars (such as the War of the Castilian Succession) are a separate story entirely. And England and Portugal (option E) is the most misleading pairing of all, because those two kingdoms weren’t enemies at all – the Anglo-Portuguese Alliance of 1373 made them allies, one of the oldest alliances in European history and still formally in force today.

Summary to learn

The Hundred Years’ War (1337-1453) was fought between the Kingdom of France and the Kingdom of England over rival claims to the French throne, ending with France pushing England out of nearly all its continental territory except Calais. It is easy to confuse with separate, contemporaneous European conflicts – the Anglo-Portuguese Alliance of 1373 made England and Portugal allies, not enemies, while the Aragon/Castile/Portugal rivalries belong to a different set of Iberian wars entirely.

In which of the following is the verb passive?

  • AIn the Iliad, Homer sings the deeds of the Pelide Achilles.
  • BMany students read Greek tragedies in high school.
  • CIn the Gallic Wars, Julius Caesar described in detail his military campaign to conquer Gaul.
  • DIn one of his works, Plato associates solid forms to the four elements: octahedron to air, tetrahedron to fire, cube to earth, and icosahedron to water.
  • EThe deeds of Aeneas were sung by Virgil.
Correct answer: E The deeds of Aeneas were sung by Virgil.

Full explanation

A passive verb follows the pattern “to be” + past participle, with the receiver of the action as the grammatical subject and the doer (if named at all) tucked into a “by…” phrase. Everything else in this list is active: the subject performs the verb directly.

In option A, “Homer sings the deeds” – Homer is the subject and does the singing. In option B, “students read Greek tragedies” – the students are the ones doing the reading. Option C works the same way: “Julius Caesar described…his military campaign” – Caesar is the subject performing the verb. Option D follows suit: “Plato associates solid forms to the four elements” – Plato is doing the associating.

Option E flips that structure around: “The deeds of Aeneas were sung by Virgil.” Here the deeds – the thing being acted upon – sit in the subject slot, the verb is the auxiliary “were” plus the past participle “sung,” and Virgil, the actual performer of the singing, is demoted to a “by” phrase. That’s the passive voice, which makes E the answer.

Summary to learn

A verb is passive when the grammatical subject is the receiver of the action rather than the one performing it, following the pattern “to be” + past participle, with the actual doer (if named) tucked into a “by…” phrase. Every other sentence structure, where the subject directly performs the verb, is active – the test is always which noun is doing the acting, not just which noun comes first in the sentence.

The following table shows the results of a test:

mark012345678910
frequency14462112210

To pass the test, a mark of higher than 5 is needed. What percentage of the candidates passed the test?

  • A25%
  • B24%
  • C20%
  • D30%
  • E50%
Correct answer: A 25%

Full explanation

Reading the frequency table, everyone who scored higher than 5 falls in the mark-6-through-mark-10 columns: 1 student got a 6, 2 got a 7, 2 got an 8, 1 got a 9, and nobody managed a perfect 10. That’s 1 + 2 + 2 + 1 + 0 = 6 students who passed.

To turn that into a percentage you need the whole class, which comes from adding every column in the table, not just the passing ones: 1 + 4 + 4 + 6 + 2 + 1 + 1 + 2 + 2 + 1 + 0 = 24 candidates sat the test in total.

So the pass rate is 6 out of 24, which simplifies to 1/4, or 25% – option A.

Summary to learn

Reading a frequency table means treating each column as a (value, count) pair: the top row lists every value that occurred, and the row below it lists how many times each value occurred. To find a subgroup total (such as everyone scoring above a cutoff), add up only the frequencies for the qualifying columns; to turn that into a percentage, divide by the sum of every column’s frequency, not just the qualifying ones.

Shelly is one of 1500 participants in a Latin contest. 12% of the participants will receive as a prize either a silver-plated or gold-plated pen. If the number of silver-plated pens is twice the number of gold-plated ones, what is the probability that Shelly will receive a gold-plated one?

  • A6 %
  • B33 %
  • C8 %
  • D67 %
  • E4 %
Correct answer: E 4%

Full explanation

Start with how many pens are being handed out at all: 12% of the 1500 participants receive one, which is 0.12 × 1500 = 180 pens in total.

Those 180 pens split between silver and gold in a 2:1 ratio, so it helps to think of them as 3 equal shares: 180 ÷ 3 = 60 pens per share. That gives 120 silver pens (two shares) and 60 gold pens (one share) – gold is the rarer prize.

Shelly’s chance of walking away with a gold pen specifically is just the number of gold pens divided by the total number of participants: 60/1500 = 4% – option E.

Summary to learn

When a group is split by a ratio (such as 2:1 between two prize types), the total splits into that many equal shares – a 2:1 ratio makes three equal shares, two going to one category and one to the other. The probability of drawing a specific sub-category is then just that category’s share of the count divided by the total population, not divided by the smaller prize-winning group alone.

Two consecutive discounts of 10% and 20% are equal to a single discount of:

  • A25%
  • B28%
  • C30%
  • D18%
  • E15%
Correct answer: B 28%

Full explanation

Model the original price as x, and apply the two discounts one after the other rather than adding their percentages together – successive discounts don’t simply add up, because the second one is taken off an already-reduced price, not off the original.

After the first 10% discount, the price drops to 0.9x. Apply the second, 20% discount to that new, smaller price: 0.9x − 0.2(0.9x) = 0.9x × 0.8 = 0.72x.

So the final price is 72% of the original, which means the combined discount is 100% − 72% = 28% – option B. That’s short of the 30% you’d get by just adding 10% + 20% (option C), which overstates the saving because it ignores that the second cut applies to a smaller base than the first one did.

Summary to learn

Successive percentage discounts do not add together – each discount is applied to the price that’s already been reduced by the previous one, not to the original price. Multiplying the surviving fractions together (e.g. 0.9 × 0.8) gives the true combined effect, which is always a little less favourable than naively adding the two percentages, because the second cut is taken from a smaller base.

Stacie builds a cube using 343 blocks of wood. She decides to paint the cube green. How many of the wooden blocks will have at least one side painted green?

  • A105
  • B238
  • C245
  • D125
  • E218
Correct answer: E 218

Full explanation

Since 343 = 7³, picture the big cube as a 7×7×7 stack of unit blocks – six painted faces on the outside, and a solid core buried inside where the paint never reaches.

The efficient move is to find that unpainted core first, then subtract it from the total, rather than trying to count painted blocks directly – a corner block has 3 painted faces, an edge block has 2, a face block has 1, and keeping those categories straight gets messy fast. Peel away the painted outer layer on every side and what’s left is a smaller cube, one unit shorter in each direction: 7 − 2 = 5, so the interior is 5×5×5 = 125 blocks that see no paint at all.

Every block that isn’t in that untouched interior has at least one painted face, so the answer is 343 − 125 = 218 – option E.

Summary to learn

For a solid cube built from unit cubes and painted on the outside, the fastest way to count painted pieces is to find the unpainted interior first and subtract it from the total. Peeling away one layer of unit cubes from every face of an n×n×n cube leaves an (n−2)×(n−2)×(n−2) interior that the paint never reaches – everything outside that interior has at least one painted face.

“When he takes the train, Marco always arrives at work on time.” Which of the following statements can be deduced from the preceding proposition?

  • AMarco arrived late; therefore he took the train.
  • BMarco arrived late; therefore he did not take the train.
  • CMarco arrived on time; therefore he missed the train.
  • DMarco did not take the train; therefore he arrived late.
  • EMarco took his car; therefore he arrived on time.
Correct answer: B Marco arrived late; therefore he did not take the train.

Full explanation

Start by pinning down exactly what the sentence claims: “When he takes the train, Marco always arrives at work on time” is the conditional Train → On Time. It says nothing at all about what happens when Marco doesn’t take the train – he might still be on time some other way, or he might not be. The only thing you’re logically entitled to derive from a conditional is its contrapositive: if the consequent fails, the antecedent must have failed too. Here that’s Late → Not Train – exactly option B.

Every wrong option tries to run the logic in a direction the original statement doesn’t support. Option A (“arrived late, therefore he took the train”) asserts Late→Train, which is nowhere near what was said. Option C (“arrived on time, therefore he missed the train”) assumes the converse – that being on time somehow requires having missed the train – which the statement never claims; being on time is consistent with having taken the train just fine. Option D (“did not take the train, therefore he arrived late”) is the denial of the antecedent, a classic invalid move: not taking the train tells you nothing about whether he was late. And option E (“took his car, therefore he arrived on time”) introduces a mode of transport the original statement never mentions at all, so nothing can be concluded about it either way.

Only the contrapositive holds up, which is why B is the answer.

Summary to learn

A conditional statement “If A, then B” only licenses one further deduction with certainty: its contrapositive, “If not B, then not A.” It says nothing about what happens when A doesn’t hold (that’s the inverse, “if not A then not B”, which doesn’t follow) and nothing that lets you run the logic backwards from B to A (that’s the converse, “if B then A”, which also doesn’t follow) – only the contrapositive preserves the original statement’s truth.

Biology

Cell biology, genetics, molecular biology & human physiology · 23 questions
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Which process occurs within mitochondria?

  • ACellular respiration
  • BGlycolysis
  • CPhotosynthesis
  • DThe methylation of sugars
  • EThe formation of microbodies
Correct answer: A Cellular respiration

Full explanation

Option A Explanation:

Cellular respiration has 4 stages which are Glycolysis, Pyruvate oxidation (formation of acetyl CoA), the citric acid cycle and the oxidative phosphorylation. The first stage occurs in the cytoplasm while the latter three stages occur in the mitochondria. Thus, this option is correct.

Option B Explanation:

Glycolysis is an anaerobic process that takes place in the cytoplasm and does not require oxygen.

Option C Explanation:

Photosynthesis takes place in chloroplasts, where sunlight, water, and carbon dioxide are converted into glucose and oxygen.

Option D Explanation:

The methylation of polysaccharides mainly occurs in the Golgi apparatus, where sugars are modified before being transported or secreted.

Option E Explanation:

Microbodies are a category of organelle that includes peroxisomes. Thus, synthesis of vesicles and organelles like microbodies mostly originates from Endoplasmic reticulum and Golgi apparatus. It is not a function of mitochondria and does not exist in the mitochondria.

Summary to learn

Cellular respiration runs through four stages: glycolysis happens in the cytoplasm and needs no oxygen, while pyruvate oxidation, the citric acid (Krebs) cycle, and oxidative phosphorylation all take place inside the mitochondria. Photosynthesis, by contrast, is a plant-cell process confined to chloroplasts, and has no place in an animal cell’s mitochondria at all.

What is a Hydrogen Bond?

  • AIt is a covalent bond between hydrogen and oxygen.
  • BIt is a bond between a hydrogen atom and another strongly electronegative atom (such as oxygen or nitrogen) which is present in another molecule.
  • CIt is a strong bond which allows bonding between non-polar molecules.
  • DIt is the bond which occurs between hydrogen and oxygen within a water molecule.
  • EIt is the bond between hydrogen and ionised atoms (such as phosphorus).
Correct answer: B It is a bond between a hydrogen atom and another strongly electronegative atom (such as oxygen or nitrogen) which is present in another molecule.

Full explanation

Option A Explanation:

Hydrogen bond is an intermolecular (Secondary) bond, not a covalent bond. Intermolecular forces are the forces of attraction or repulsion between molecules. They are weaker than chemical bonds but crucial for determining physical properties like boiling point, melting point, and solubility.

Option B Explanation:

Hydrogen bond is an intermolecular bond and It can be found between Hydrogen and other electronegative atoms which can be F, N, or O, present in another molecule as stated. Thus, this option is correct.

Option C Explanation:

In general, intermolecular bonds, including hydrogen bonds, are much weaker than intramolecular bonds, which are the strong covalent or ionic bonds that hold atoms together within a molecule. Hydrogen bonds occur only between polar molecules and do not form between non-polar molecules.

Option D Explanation:

Within the water molecule, bond between hydrogen and oxygen is a covalent bonds, not a hydrogen bond. If it said the bond is between hydrogen and oxygen between water molecules, it could be true.

Option E Explanation:

Hydrogen bonds form when a hydrogen atom, covalently bonded to a highly electronegative atom like nitrogen, oxygen, or fluorine, is attracted to a lone pair of electrons on another nitrogen, oxygen, or fluorine atom in a different molecule. This requires a polar molecule with a hydrogen attached to N, O, or F and another nearby molecule with available lone pairs on these atoms.

Summary to learn

A hydrogen bond is a relatively weak, non-covalent attraction between a hydrogen atom already covalently bonded to a highly electronegative atom (like O, N, or F) and a lone pair on a nearby electronegative atom. Because water molecules form extensive networks of hydrogen bonds with each other, hydrogen bonding is the reason water has an unusually high boiling point, high melting point, and strong ability to dissolve polar and ionic substances compared to similarly-sized molecules that can’t hydrogen-bond.

In eukaryotic cells, Krebs cycle reactions occur:

  • AIn the mitochondrial matrix
  • BOn the internal membrane of the mitochondria
  • CIn the cytoplasm
  • DIn the large ribosomal subunit
  • EClose to the plasma membrane
Correct answer: A In the mitochondrial matrix

Full explanation

Option A is correct: the Krebs cycle, also called the citric acid cycle (CAC), is an aerobic stage of cellular respiration that occurs in the mitochondrial matrix of eukaryotic cells.

Option B is false: the electron transport chain, not the Krebs cycle, occurs on the inner mitochondrial membrane.

Option C is false for eukaryotic cells: in prokaryotic cells (which lack mitochondria), the Krebs cycle occurs in the cytoplasm, but the question specifically asks about eukaryotic cells, where it takes place in the mitochondrial matrix.

Option D is false: ribosomes (including the large ribosomal subunit) are responsible for translation, where proteins are produced – not for the Krebs cycle.

Option E is false: the Krebs cycle occurs only in the mitochondrial matrix, where the needed enzymes are present and the electrons produced can directly enter the electron transport chain – not close to the plasma membrane.

Hence, the correct answer is (A).

Summary to learn

The Krebs (citric acid) cycle is one of the aerobic stages of cellular respiration, and in eukaryotic cells it takes place specifically in the mitochondrial matrix – the fluid-filled space enclosed by the inner mitochondrial membrane. That’s distinct from the electron transport chain, which runs along the inner membrane itself, and from glycolysis, which happens out in the cytoplasm before either mitochondrial stage begins.

What kind of monosaccharide is glucose?

  • ATetrose
  • BPentose
  • CTriose
  • DHexose
  • ENonose
Correct answer: D Hexose

Full explanation

Option A Explanation:

Tetroses are monosaccharides with four carbon atoms. They include aldotetroses like erythrose and ketotetroses like erythrulose. Tetroses are less common but play roles in some metabolic pathways.

Option B Explanation:

Glucose is a hexose sugar with 6 carbon atoms, while pentoses have 5 carbon atoms. Examples of pentoses include ribose, found in RNA, and deoxyribose, found in DNA.

Option C Explanation:

Trioses are simple sugars with 3 carbon atoms, such as glyceraldehyde and dihydroxyacetone, important in energy metabolism. Glyceraldehyde and dihydroxyacetone are the intermediates in the glycolysis process.

Option D Explanation:

Hexoses are monosaccharides with six carbon atoms, like glucose, fructose, and galactose. They are important energy sources and building blocks in metabolism.

Option E Explanation:

Nonoses are monosaccharides with nine carbon atoms. An example is sialic acid (N-acetylneuraminic acid), which is important in cell signaling and found on the surfaces of animal cells.

Summary to learn

Monosaccharides are classified by how many carbon atoms they contain: trioses have three, tetroses have four, pentoses have five, hexoses have six, and nonoses have nine. Glucose, with six carbon atoms, is a hexose – the same class as fructose and galactose – while ribose and deoxyribose (five carbons each) are pentoses, and glyceraldehyde (three carbons) is a triose.

Which pentose sugar is present in RNA nucleotides?

  • AFructose
  • BGlucose
  • CRibose
  • DGlycerol
  • ELactose
Correct answer: C Ribose

Full explanation

Option A Explanation:

Fructose is a hexose sugar with six carbon atoms and is classified as a ketose due to its ketone group. It occurs naturally in fruits, honey, and some vegetables and is sweeter than glucose. Unlike ribose, fructose is not part of RNA structure.

Option B Explanation:

Glucose is a hexose monosaccharide with six carbon atoms, classified as an aldose because it has an aldehyde group. It is a primary source of energy for cells and is found in many foods. Glucose is also a building block of polysaccharides like starch, glycogen, and cellulose.

Option C Explanation:

The monomer found in RNA is the nucleotide, which consists of ribose as the sugar unit, a phosphate group, and a nitrogenous base. Ribose is a five-carbon aldopentose sugar. Unlike RNA, DNA contains deoxyribose, a similar sugar that lacks one oxygen atom.

Option D Explanation:

Glycerol is a three-carbon alcohol with three hydroxyl groups, making it highly water-soluble. It serves as the backbone of triglycerides and phospholipids, where fatty acids attach. Glycerol is not present in the structure of RNA molecules.

Option E Explanation:

Lactose is a disaccharide composed of glucose and galactose linked by a β-1,4-glycosidic bond. It is naturally found in milk and dairy products and is broken down in the body by the enzyme lactase into its monosaccharide components for absorption.

Summary to learn

RNA’s sugar backbone is built from ribose, a five-carbon (pentose) aldose sugar; DNA uses deoxyribose, which is identical except for missing one oxygen atom. Other common sugars serve different roles entirely: fructose and glucose are six-carbon hexoses (glucose being the primary cellular fuel and a building block of starch, glycogen and cellulose), glycerol is a three-carbon alcohol that forms the backbone of fats and phospholipids, and lactose is a glucose-galactose disaccharide – none of which appear in RNA’s structure.

What are carrier proteins?

  • AThey are proteins that transport mRNA in the nucleus.
  • BThey are proteins that phosphorylate enzymes in the plasma membrane.
  • CThey are proteins that break down phospholipids in the plasma membrane.
  • DThey are the proteins that transfer molecules and ions across the plasma membrane
  • EThey are proteins that transport tRNA in the nucleolus.
Correct answer: D They are the proteins that transfer molecules and ions

Full explanation

Option A Explanation:

Carrier proteins are a kind of transport proteins that exist on the plasma membrane, and mRNA is transported by different mechanisms, not by carrier proteins.

Option B Explanation:

Proteins that phosphorylate enzymes in the plasma membrane are the kinase enzymes. Carrier proteins only carry materials across the membrane.

Option C Explanation:

Proteins that break down phospholipids in the plasma membrane is the phospholipidase enzyme. Carrier proteins only carry materials across the cell membrane.

Option D Explanation:

Correct. Carrier proteins are membrane proteins that transport specific molecules or ions across the cell membrane by binding to them and changing shape to move them across.

Option E Explanation:

Carrier proteins do not transport tRNA or any RNA molecules, which are moved by different nuclear export mechanisms.

Summary to learn

Carrier proteins are integral membrane proteins that move specific molecules or ions across the cell membrane by binding to them and changing shape – a conformational change that shuttles the bound molecule from one side of the membrane to the other. That function is distinct from enzymes that phosphorylate or break down membrane components, and distinct from the separate cellular machinery (nuclear export mechanisms) that moves RNA out of the nucleus.

What is the cell’s energy currency?

  • AATP
  • BFADH2
  • CNADH
  • DCreatine
  • ENADPH
Correct answer: A ATP

Full explanation

Option A Explanation:

Cells harvest the chemical energy stored in organic molecules and use it to generate ATP, the molecule that drives most cellular work. Thus, this option is correct.

Option B Explanation:

FAD+ is an energy carrier molecule produced during the Krebs cycle which donates the electrons to the electron transport chain, contributing to the production of ATP. FADH2 is the reduced form of FAD+.

Option C Explanation:

NADH is an energy carrier molecule produced during glycolysis, the Krebs cycle, and other metabolic pathways. NADH is an electron carrier, not the direct energy currency.

Option D Explanation:

Creatine is a compound derived from amino acids. It serves as an energy storage and transfer in the tissues. However, it is not the energy currency of the cell.

Option E Explanation:

NADPH is an electron carrier mainly involved in anabolic (biosynthetic) reactions, such as fatty acid synthesis and the Calvin cycle in photosynthesis.

Reference Image

IMAT 2024 question 16 figure
Summary to learn

ATP is the cell’s direct energy currency: cells harvest chemical energy from organic molecules (via cellular respiration) and store it in ATP’s high-energy phosphate bonds, which are then broken to power most cellular work. NADH and NADPH are electron carriers rather than direct energy currency – NADH mainly feeds electrons into the electron transport chain during catabolism, while NADPH mainly powers biosynthetic (anabolic) reactions like fatty acid synthesis and the Calvin cycle. FAD/FADH2 is a similar electron-carrying pair generated in the Krebs cycle, and creatine is a separate energy-storage compound in tissue, not the cell’s primary currency.

Which kind of reaction is ATP hydrolysis?

  • ALipolysis
  • BEndergonic
  • CCondensation
  • DOxidation-reduction
  • EExergonic
Correct answer: E Exergonic

Full explanation

Option A Explanation:

Lipolysis is the process of breaking down triglycerides into glycerol and fatty acids; it is not related to ATP hydrolysis.

Option B Explanation:

Endergonic reactions require an input of energy, but ATP hydrolysis is exergonic because it releases energy.

Option C Explanation:

Condensation is a reaction where two molecules join together with the release of water, while ATP hydrolysis is the opposite—it uses water to break a bond.

Option D Explanation:

Oxidation-reduction reactions involve the transfer of electrons, but ATP hydrolysis does not involve electron transfer.

Option E Explanation:

One ATP molecule releases approximately 7.3 kcal/mol (~30.5 kJ/mol) of energy upon hydrolysis, which can be used for cellular work or dissipated as heat, depending on the process. Thus, this option is true.

Summary to learn

ATP hydrolysis – breaking the bond to a terminal phosphate group with the addition of water – releases roughly 7.3 kcal/mol (about 30.5 kJ/mol) of energy, making it an exergonic reaction (one that releases energy) rather than an endergonic one (which would require an energy input). It’s a hydrolysis reaction, the opposite of a condensation reaction that joins two molecules while releasing water, and it involves no transfer of electrons, so it isn’t an oxidation-reduction reaction either.

The presence of intercellular compartmentalisation is a characteristic of which organisms?

  • AOf eukaryotes
  • BOf viruses
  • COf bacteria
  • DOf prokaryotes
  • EOnly of algae
Correct answer: A Of eukaryotes

Full explanation

Option A Explanation:

Intercellular compartmentalization involves the organization of different cell types into specialized functions that collectively support the organism’s physiological processes. Since it involves multiple cell types to organize into specific tissues, it only occurs in multicellular organisms. Thus, this option is true.

Option B Explanation:

Viruses lead a type of borrowed life, relying entirely on host cells for replication, and are not considered true cells. As a result, they lack cellular structures and do not possess intercellular compartmentalization.

Option C Explanation:

Bacteria, which are prokaryotes, are typically unicellular organisms.

Therefore, they lack intercellular compartmentalization, as they consist of a single cell without internal membrane-bound compartments.

Option D Explanation:

Prokaryotes are typically unicellular organisms. Therefore, there is no intercellular compartmentalisation.

Option E Explanation:

Algae can be both unicellular and multicellular. However, multicellular algae usually lack true tissue differentiation. Therefore, there is no intercellular compartmentalization.

Summary to learn

Compartmentalisation – dividing a cell’s interior into distinct membrane-bound regions – lets incompatible chemical processes happen simultaneously without interfering with each other, and lets each organelle maintain its own optimal internal environment (pH, enzyme concentration, ion levels) for the specific reactions that occur there. This is a defining feature that distinguishes eukaryotic cells, with their many membrane-bound organelles, from prokaryotic cells, which lack this internal compartmentalisation.

Which intracellular structure is composed of microtubules?

  • AThe nucleus
  • BThe centriole
  • CThe Golgi apparatus
  • DThe nucleolus
  • EThe endoplasmic reticulum
Correct answer: B The centriole

Full explanation

Option A Explanation:

The nucleus is supported by the nuclear lamina, made of intermediate filaments, not microtubules. Microtubules are part of the cytoskeleton outside the nucleus and do not form part of its structure.

Option B Explanation:

Centrioles are cylindrical cellular structures composed primarily of microtubules. They are typically arranged in a characteristic “9+0” pattern, where nine triplets of microtubules are arranged in a circle. Thus, this option is true.

Option C Explanation:

The Golgi apparatus is not composed of microtubules; it is made of stacks of flattened membrane-bound sacs called cisternae. However, microtubules help position and transport vesicles to and from the Golgi, but they are not part of its structure.

Option D Explanation:

The nucleolus is not composed of microtubules. It is a dense region inside the nucleus made of RNA, DNA, and proteins, where ribosome subunits are assembled. Microtubules are not part of its structure.

Option E Explanation:

The endoplasmic reticulum (ER) is not composed of microtubules. It is made of a network of membrane-bound tubules and sacs. While microtubules help position and organize the ER within the cell, they are not part of the ER’s structure itself.

Summary to learn

Microtubules are hollow cytoskeletal filaments built from tubulin, and centrioles are cylindrical structures made almost entirely of microtubules, characteristically arranged in nine triplets around a circle. Other structures that might seem related aren’t built from microtubules at all: the nuclear lamina (supporting the nucleus) is made of intermediate filaments, the Golgi apparatus and endoplasmic reticulum are membrane-bound sac/tubule systems that microtubules merely help position, and the nucleolus is a dense RNA/DNA/protein region where ribosomal subunits are assembled.

Mitochondria have:

  • AA very selective membrane in which no proteins are present
  • BOnly a very selective outer membrane
  • CAn outer membrane, an intermediate membrane, and a very selective inner membrane
  • DAn outer membrane consisting of a phospholipid monolayer
  • EAn outer membrane and a very selective inner membrane
Correct answer: E An outer membrane and a very selective inner

Full explanation

Option A Explanation:

“A very selective membrane” part is correct for inner membrane but the latter part of the sentence is incorrect. On the inner membrane, there are proteins that take part in the electron transport chain.

Option B Explanation:

Mitochondria have two membranes: an outer membrane, which is smooth and not very selective, but the inner membrane is more selective.

Option C Explanation:

Mitochondria have two membranes: an outer membrane, which is smooth and encloses the organelle, and an inner membrane, which is folded into cristae to increase the surface area for energy production. Between these two membranes is the intermembrane space, which plays a role in cellular respiration.

Option D Explanation:

Mitochondria typically have two membranes: outer membrane and inner membrane. Each membrane is composed of phospholipid bilayer. Thus, this option is false.

Option E Explanation:

Mitochondria have an outer membrane, which is permeable to small molecules, and a very selective inner membrane, which controls the passage of ions and molecules and is folded into cristae to enhance energy production. Thus, this option is true.

Summary to learn

Mitochondria have two membranes with very different properties: a smooth, relatively permeable outer membrane that encloses the organelle, and a highly selective inner membrane folded into cristae, which dramatically increases surface area for the electron transport chain and ATP synthesis. Between the two lies the intermembrane space, itself important for building the proton gradient that drives ATP production – the inner membrane’s selectivity, not the outer membrane’s, is what lets mitochondria carefully control which ions and molecules cross into the matrix.

What is an anticodon?

  • AThe sequence of three nucleotides found on the tRNA corresponding to a codon on the mRNA.
  • BA sequence of three nucleotides transcribed from the mRNA and translated by rRNA
  • CA part of the DNA that codes for a specific amino acid
  • DA terminal triplet of rRNA that binds a specific amino acid
  • EThe sequence of three mRNA nucleotides corresponding to a DNA codon
Correct answer: A The sequence of three nucleotides found on the tRNA corresponding to a codon on the mRNA.

Full explanation

Option A Explanation:

Correct. Anticodon is a sequence of three nucleotides on a tRNA molecule that is complementary to a codon on mRNA. During translation, the anticodon pairs with the mRNA codon, ensuring the correct amino acid is added to the growing polypeptide chain.

Option B Explanation:

A sequence of three nucleotides transcribed from the mRNA is a codon, not an anticodon.

Option C Explanation:

This option describes a DNA codon.

Option D Explanation:

rRNA has neither codon nor anticodon. Anticodon is on tRNA and does not directly bind amino acids (amino acids bind to the other end of tRNA).

Option E Explanation:

Sequence of three mRNA nucleotides is a mRNA codon.

Summary to learn

An anticodon is a three-nucleotide sequence on a tRNA molecule that is complementary to a specific codon on mRNA; during translation, the anticodon base-pairs with its matching mRNA codon so that the amino acid carried by that tRNA (attached at tRNA’s opposite end, not at the anticodon itself) gets added to the growing polypeptide chain in the correct order. A codon, by contrast, is the three-nucleotide sequence on mRNA (transcribed from DNA) that the anticodon pairs with – the two terms name complementary sequences on two different molecules.

What are ribosomes made of?

  • ARNA and DNA
  • BDNA and proteins
  • CDNA and lipids
  • DRNA and proteins
  • ERNA, DNA and proteins
Correct answer: D RNA and proteins

Full explanation

A ribosome is built from two subunits, a large one and a small one, and each subunit is itself a mix of ribosomal RNA (rRNA) and ribosomal proteins folded together. There’s no DNA anywhere in that structure, and no membrane, so no lipid either.

That’s the flaw shared by three of the four wrong options: A (RNA and DNA), B (DNA and proteins), and E (RNA, DNA and proteins) all smuggle DNA into the ribosome, which simply isn’t there – DNA stays in the nucleus (or, in prokaryotes, the nucleoid), while the ribosome itself is assembled from RNA and protein alone. Option B additionally drops RNA entirely, which is just as wrong in the other direction, since rRNA makes up roughly two-thirds of a ribosome’s mass and does the actual catalytic work of peptide-bond formation. Option C (DNA and lipids) misses on both counts: no DNA, and no lipid either, because ribosomes aren’t membrane-bound organelles.

Only option D – RNA and proteins, nothing else – matches what a ribosome is actually made of.

Summary to learn

A ribosome is built entirely from ribosomal RNA (rRNA) and ribosomal proteins, assembled into a large and a small subunit – there is no DNA and no lipid anywhere in that structure. DNA stays inside the nucleus (or the nucleoid in prokaryotes), and lipids belong to membrane-bound structures, which ribosomes are not.

The cell membrane consists of:

  • AA double layer of triglycerides and cholesterol
  • BCholesterol and phospholipid molecules enclosing a protein layer
  • Ca double phospholipid layer with hydrophobic tails facing inward and the presence of integral and peripheral proteins
  • DA glycoprotein layer containing phospholipids and cholesterol
  • EA layer of fatty acids and globular proteins containing phospholipids and cholesterol
Correct answer: C a double phospholipid layer with hydrophobic tails facing inward and the presence of integral and peripheral proteins

Full explanation

Option A Explanation:

The Cell membrane is composed of double layer of phospholipids embedded by proteins and cholesterol. Triglyceride is involved as a component of phospholipid, and cholesterol is found wedged between phospholipid molecules. Both of these molecules do not exist as a layer. Thus, this option is false.

Option B Explanation:

Membrane proteins are embedded in the fluid matrix of the lipid bilayer. They do not exist as a separate layer. Thus, this option is false.

Option C Explanation:

Correct. The cell membrane consists of a double phospholipid layer (bilayer) with hydrophobic tails facing inward and hydrophilic heads facing outward, along with integral and peripheral proteins embedded or attached to the membrane.

Option D Explanation:

There is not a glycoprotein layer in the latest fluid mosaic model of plasma membrane. Glycoproteins and glycolipids can be found on the surface of the cell membrane toward the ECF. Thus, this option is false.

Option E Explanation:

Fatty acids and globular proteins do not exist as a separate layer. Fatty acids can be found as a component of phospholipid in the phospholipid bilayer and globular proteins are embedded in the fluid matrix of the lipid bilayer. Thus, this option is false.

Summary to learn

The cell membrane’s phospholipid bilayer and its embedded/associated proteins are two structurally distinct components, each forming its own continuous layer rather than mixing into one shared layer – phospholipids arrange themselves tail-to-tail as a bilayer because of their amphipathic nature, while membrane proteins are separate molecules that sit within or on that bilayer rather than forming a layer of their own alongside the lipids.

In protein synthesis, what is translation?

  • AIt is the process of transcribing the mRNA sequence into a corresponding DNA molecule.
  • BIt is the process by which mRNA is read and converted into a specific sequence of amino acids.
  • CIt is the process of specific recognition of rRNA by amino acids.
  • DIt is the process in which DNA is read and the corresponding mRNA produced.
  • EIt is the process of pairing between DNA codons and tRNA anticodons
Correct answer: B It is the process by which mRNA is read and converted into a specific sequence of amino acids.

Full explanation

Option A Explanation:

This option describes the process of reverse transcription. Reverse transcription is the process where RNA is converted into DNA using the enzyme reverse transcriptase. This occurs in some viruses, like retroviruses (e.g., HIV), allowing their RNA genome to be integrated into the host’s DNA.

Option B Explanation:

This option correctly describes the process of translation. Translation is the process of protein synthesis, where the ribosome reads mRNA codons and uses tRNA to bring matching amino acids, forming a polypeptide chain. It takes place in the cytoplasm.

Option C Explanation:

This option does not describe the process of translation.

Option D Explanation:

This option describes the process of transcription, not translation. Transcription is the process where DNA is used as a template to produce messenger RNA (mRNA). This occurs in the nucleus of eukaryotic cells and is carried out by the enzyme RNA polymerase, which builds the mRNA strand complementary to the DNA template.

Option E Explanation:

tRNA anticodons pair only with codons on mRNA during translation, but this alone does not fully explain the entire process of protein synthesis.

Summary to learn

Translation is the process by which the genetic code carried on an mRNA molecule is read by ribosomes, three nucleotides (a codon) at a time, to assemble a specific sequence of amino acids into a polypeptide chain – the step that actually converts genetic information into protein. It follows transcription (where mRNA itself is first synthesised from a DNA template) and depends on tRNA molecules to physically deliver the correct amino acid for each codon.

What are the principal components of the cytoskeleton?

  • AMicrotubules, microfilaments, and intermediate filaments
  • BMicrotubules, myosin, and filamin
  • CMicrotubules, dynein, and myosin
  • DActin, myosin and dynein
  • ECollagen fibres and reticular fibres
Correct answer: A Microtubules, microfilaments, and intermediate

Full explanation

Option A Explanation:

The cytoskeleton is a network of fibers extending throughout the cytoplasm. The eukaryotic cytoskeleton is composed of three types of molecular structures: microtubules, microfilaments, and intermediate filament. Thus, this option is correct.

Option B Explanation:

Microtubule is a component of the cytoskeleton but myosin and filamin are not.

Option C Explanation:

Microtubule is a component of the cytoskeleton but dynein and myosin are not.

Option D Explanation:

All of these mentioned proteins are not principal components of the cytoskeleton.

Option E Explanation:

Mentioned fibres are not the principal components of the cytoskeleton.

Summary to learn

The eukaryotic cytoskeleton is built from three types of protein filaments, each with a distinct diameter and role: microtubules (the thickest, built from tubulin, involved in structural support and transport), microfilaments (the thinnest, built from actin, involved in cell shape and movement), and intermediate filaments (built from various proteins depending on cell type, providing mechanical strength). Motor proteins like myosin and dynein move along these filaments but are not filament components themselves.

The term “allele” defines:

  • AA hereditary trait only found in haploid cells
  • BA coding DNA base for a specific amino acid
  • Cone of several alternative forms of a gene
  • DThe phenotypic manifestation of a given gene
  • EA set of coding DNA triplets for a specific amino acid
Correct answer: C one of several alternative forms of a gene

Full explanation

An allele is one of the alternative versions of a gene that can sit at a given chromosomal locus – the reason two people can carry different versions of, say, the gene for eye colour. That’s exactly option C.

Each wrong option is actually describing a different piece of genetics vocabulary, mislabelled as “allele.” Option A restricts alleles to haploid cells, but that’s backwards – the concept of two different alleles at a locus is most meaningful in diploid organisms, which carry one allele from each parent, and ploidy has nothing to do with what an allele is. Option B – “a coding DNA base for a specific amino acid” – describes something smaller than an allele: a single amino acid is specified by a triplet of three bases (a codon), not one base, and a codon isn’t an allele either. Option D describes the phenotype, not the allele – the allele is the underlying genetic variant, which can exist and be inherited whether or not it’s actually expressed (a recessive allele hiding behind a dominant one in a heterozygote produces no phenotypic trace at all, but it’s still very much there). Option E – “a set of coding DNA triplets for a specific amino acid” – is closer to describing a gene (or over-describes a single amino acid, which needs only one triplet, not a set), not an allele, which is a variant form of that gene rather than the gene itself.

Summary to learn

An allele is one of the alternative versions of a gene that can occupy a given chromosomal locus, which is why two individuals can carry different genetic variants at the same gene. This is distinct from a codon (a triplet of DNA/mRNA bases coding for a single amino acid, smaller than a gene), a gene (the full coding sequence an allele is a version of), and a phenotype (the observable trait that results from which allele is actually expressed).

In a heterozygous condition, an allele can certainly express itself when:

  • AAssociated
  • BRecessive
  • CMutated
  • DMultiple
  • EDominant
Correct answer: E Dominant

Full explanation

Option A Explanation:

In associated genes, the expression of one allele is associated by another allele. Thus, it is evident that an allele cannot certainly express itself in any condition.

Option B Explanation:

For a recessive allele to be able to express itself, it needs to be in a homozygous condition.

Option C Explanation:

Mutated alleles mean the allele is not in its normal state to be expressed. Thus, it cannot express itself.

Option D Explanation:

If a character is determined by the expression of multiple genes, it is not possible that one allele certainly expresses itself.

Option E Explanation:

According to the third concept of Mendel’s model, it is described that, if the two alleles at a locus differ (in heterozygous condition), then one, the dominant allele, determines the organism’s appearance; the other, the recessive allele, has no noticeable effect on the organism’s appearance. Thus, for a allele to be certainly expressed, it needs to be a completely dominant allele.

Summary to learn

Mendel’s model of dominance says that in a heterozygous individual (two different alleles at one locus), the dominant allele determines the organism’s observable trait while the recessive allele produces no visible effect – so an allele is guaranteed to express itself in a heterozygote only if it is completely dominant. A recessive allele needs a homozygous condition to show up, a mutated allele may no longer function normally enough to express as usual, and any allele whose expression depends on other genes (epistasis) or that is genetically linked to another allele’s expression cannot be guaranteed to express on its own.

What are mutations?

  • AAlterations in the mechanism of cell division.
  • BAlteration in the energy metabolism of a cell
  • CAlterations in enzyme functionality during zygote formation
  • DAlterations in the active transport system of biological membranes
  • EAlterations in the genetic information of a cell
Correct answer: E Alterations in the genetic information of a cell

Full explanation

Option A Explanation:

This refers to changes in how cells divide, such as errors in mitosis or meiosis, but this is not the definition of mutation itself.

Option B Explanation:

Changes in how the cell produces or uses energy, which might be a result of a mutation, but this is not the definition of mutation itself.

Option C Explanation:

Changes in enzymes during fertilisation or early development; this is not what defines a mutation.

Option D Explanation:

Changes in how substances are actively transported across membranes, which is not related to mutations directly.

Option E Explanation:

Correct. Mutations are permanent changes in the DNA sequence, altering the genetic information of a cell, which can affect proteins and traits.

Summary to learn

A mutation is a permanent change in an organism’s DNA sequence – altering the underlying genetic information itself, which can then go on to affect the proteins built from that DNA and the traits those proteins produce. Related but distinct cellular events (errors in cell division, changes in energy metabolism, enzyme changes during development, or changes in membrane transport) may sometimes result from a mutation, but none of them define what a mutation actually is.

Translation is a process which:

  • Aleads to the synthesis of polypeptide chains from mRNA
  • Boccurs in the nucleus of eukaryotic cells
  • Cleads to the synthesis of RNA from DNA
  • Dis very similar to transcription
  • EIs exclusively eukaryotic
Correct answer: A leads to the synthesis of polypeptide chains from mRNA

Full explanation

Option A Explanation:

This option correctly describes the process of translation. Translation is the process that leads to the synthesis of polypeptide chains from mRNA, where ribosomes read the mRNA codons and tRNA brings the corresponding amino acids to build the protein.

Option B Explanation:

In eukaryotic cells, the translation process occurs in the cytoplasm. Thus, this option is false.

Option C Explanation:

Translation leads to the synthesis of proteins from RNA. The process mentioned in which RNA molecules are synthesised from DNA is known as the transcription process.

Option D Explanation:

Transcription is a process in which mRNA is synthesised from DNA. Translation is the process that comes after transcription that leads to the synthesis of proteins from RNA. Thus, it can be seen that these two processes are not similar to each other.

Option E Explanation:

Translation occurs in both eukaryotic and prokaryotic cells. This is one of the fundamental processes of gene expression in organisms.

Summary to learn

Transcription and translation are two distinct steps of gene expression that use different templates, occur in different locations, and produce different products: transcription copies DNA into mRNA inside the nucleus, while translation reads that mRNA to build a protein at the ribosome, in the cytoplasm. Treating them as the same process, or mixing up which nucleic acid is being read versus produced at each step, is the core error these kinds of questions test for.

If the sequence CCGTTATTGA is found on a strand of DNA helix, what sequence will be found on the complementary strand?

  • AGGCAATAACT
  • BAGTTATTGCC
  • CGGACATCCCT
  • DCGCACCTCCT
  • EGGCAATTAAT
Correct answer: A GGCAATAACT

Full explanation

DNA base-pairing is fixed: A pairs with T, and G pairs with C. Reading straight down the given strand, C-C-G-T-T-A-T-T-G-A, and swapping each base for its partner gives G-G-C-A-A-T-A-A-C-T – which is option A.

The other four options are worth checking individually, because two of them are traps that mimic mistakes it’s easy to make by hand. Option B, AGTTATTGCC, isn’t a complement at all – it’s the original sequence CCGTTATTGA simply written back to front, with no base-pairing applied. That’s the error you get if you remember that DNA strands run antiparallel and reverse the sequence, but forget the actual point of the exercise: swapping each base for its partner. Option E, GGCAATTAAT, is closer to the truth – it matches the correct answer at every position except two, where a T and an A have been swapped near the end (…TAACT becomes …TTAAT) – the kind of transposition slip that creeps in when carrying a ten-letter sequence across by hand. Options C (GGACATCCCT) and D (CGCACCTCCT) don’t follow any recognisable pattern against the original strand at all; they’re simply incorrect base-pairings.

Summary to learn

DNA base-pairing is fixed and predictable: adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C). Finding a complementary strand means substituting each base in the given strand for its partner, one position at a time, in the same left-to-right order – not reversing the sequence (which looks superficially similar but isn’t the same operation) and not transposing letters partway through, both of which are easy hand-copying slips that produce a plausible-looking but wrong answer.

Replication is the process through which:

  • ADNA is used as a template to synthesise new RNA molecules
  • BDNA is used as a template to synthesise new DNA molecules
  • CDaughter cells are formed from a mother cell
  • DRNA is used as a template to synthesise proteins
  • ERNA is used as a template to synthesise new RNA molecules
Correct answer: B DNA is used as a template to synthesise new DNA

Full explanation

Option A Explanation:

This option describes the Transcription process, not replication.

Option B Explanation:

DNA replicates typically in the semiconservative model, in which the two strands of the parental DNA molecule separate, and each functions as a template for synthesis of a new, complementary DNA strand. Thus, this option is true.

Option C Explanation:

This option describes Mitosis or Meiosis process, not replication.

Option D Explanation:

This option describes the Translation process, not replication.

Option E Explanation:

RNA does not generally replicate itself in most biological systems.

Summary to learn

DNA replication follows the semiconservative model: the two strands of the parental double helix separate, and each original strand serves as a template for building one new, complementary strand, so every resulting DNA molecule ends up with one old strand and one newly synthesised strand. This is distinct from transcription (DNA to mRNA), translation (mRNA to protein), and mitosis/meiosis (which distribute already-replicated chromosomes, rather than copying the DNA itself).

The prokaryotic operon is:

  • Aa protein complex that catalyses the process of protein synthesis
  • BA group of adjacent genes independent from each other
  • CA functional unit composed of a group of adjacent genes, co-ordinately controlled, and of DNA sequences with regulatory functions.
  • DAn RNA complex that is involved in the replication of DNA
  • EA DNA sequence element without any type of regulatory function
Correct answer: C A functional unit composed of a group of adjacent genes, coordinately controlled, and of DNA sequences with regulatory functions

Full explanation

Option A Explanation:

Together, the operator, the promoter, and the genes they control (the entire stretch of DNA required for expression of a specific gene) constitute an operon. Thus, it does not contain proteins.

Option B Explanation:

The group of genes involved in operon unit are dependent on each other. For example, in trp repressor, if a repressor binds to the operator, it blocks attachment of RNA polymerase to the promoter and thereby prevents transcription of the genes.

Option C Explanation:

It correctly describes the structure and function of operon unit.

Option D Explanation:

Operon unit is discovered as a basic mechanism for the control of gene expression in bacteria, in the transcription stage, by interfering with the transcription of DNA genes. Thus, the operon unit solely consists of DNA segments.

Option E Explanation:

This option describes the opposite of the function of Operon unit which is to adjust the production level of certain enzymes.

Summary to learn

A prokaryotic operon is a stretch of DNA consisting of a promoter, an operator, and the structural genes they jointly control, functioning as a single coordinated unit – genes in an operon are transcribed together and regulated together, for example when a repressor protein binds the operator and blocks RNA polymerase from reaching the promoter, shutting down transcription of every gene in that operon at once. An operon is purely a DNA-level arrangement (no proteins are part of its physical structure), and its regulatory role is to adjust how much of an enzyme or gene product gets made, not to prevent gene expression outright.

Chemistry

General, inorganic, organic & biochemistry · 15 questions
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A mixture of 0.3 mol of N₂, 0.5 mol of CO₂, and 0.4 mol of O₂ exerts a pressure of 2.4 atm on the walls of the vessel that contains it. What is the pressure exerted by the nitrogen?

  • A0.3 atm
  • B0.5 atm
  • C0.6 atm
  • D0.75 atm
  • E0.8 atm
Correct answer: C 0.6 atm

Full explanation

Dalton’s Law says the total pressure of a gas mixture is just the sum of what each gas would exert on its own – so nitrogen’s slice of that 2.4 atm is exactly proportional to nitrogen’s slice of the total moles in the container.

Add up every gas present: 0.3 mol N₂ + 0.5 mol CO₂ + 0.4 mol O₂ = 1.2 mol total. Nitrogen’s mole fraction is its own share of that total: 0.3/1.2 = 0.25 – one quarter of every gas particle bouncing around in the container is nitrogen.

Since each gas contributes to the total pressure in exactly the same proportion as its share of the moles, nitrogen accounts for exactly a quarter of the total pressure: P(N₂) = 0.25 × 2.4 atm = 0.6 atm – option C.

Summary to learn

Dalton’s Law of Partial Pressures says the total pressure of a gas mixture equals the sum of each individual gas’s partial pressure, and each gas’s share of the total pressure is exactly proportional to its mole fraction (its share of the total moles present) – a gas making up a quarter of all the particles in a container contributes a quarter of the total pressure, regardless of what the other gases are.

A gas, confined in a rigid cylinder and maintained at a temperature of -3 °C exerts a pressure of 9 atm. What pressure would the same gas exert if it were heated to 27 °C?

  • A-81 atm
  • B8.1 atm
  • C9.6 atm
  • D10 atm
  • E12.5 atm
Correct answer: D 10 atm

Full explanation

This is a question about the ideal gas law equations, specifically Gay-Lussac’s law.

Gay-Lussac’s Law states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas, when the volume is kept constant.

Given: the phrase “a gas confined in a rigid cylinder” means that the gas has constant volume. Temperature is −3°C. Pressure is 9 atm.

T₁ = −3 + 273 K = 270 K, P₁ = 9 atm

T₂ = 27 + 273 K = 300 K, P₂ = ?

According to Gay-Lussac’s law,

P₁/T₁ = P₂/T₂

P₂ = (P₁ × T₂) / T₁ = (9 atm × 300 K) / 270 K = 10 atm

Summary to learn

Gay-Lussac’s Law describes a fixed-volume gas: at constant volume, a gas’s pressure is directly proportional to its absolute temperature (in kelvin), so P₁/T₁ = P₂/T₂. Because the relationship uses absolute temperature, any Celsius value must first be converted to kelvin (by adding 273) before it can be plugged into the equation.

Which of the following compounds forms a hydroxide when reacting with water?

  • AN₂O₃
  • BSiO₂
  • CSO₃
  • DCl₂O
  • EBaO
Correct answer: E BaO

Full explanation

N₂O₃, SO₃, and Cl₂O are acidic oxides. They are oxides of non-metals that are placed on the top right part of the periodic table. Thus, they react with water to form acid solutions.

N₂O₃ + H₂O ⟶ 2HNO₂ SO₃ + H₂O ⟶ H₂SO₄ Cl₂O + H₂O ⟶ 2HOCl SiO₂ is a metalloid oxide and it is not soluble in water and does not react easily with water.

BaO is a basic oxide. It is the oxide of a group II alkaline earth metal.

Thus, reaction of BaO with water gives barium hydroxide.

BaO + H₂O ⟶ Ba(OH)₂

Summary to learn

Metal oxides and non-metal oxides react with water in opposite ways: a basic oxide (from a metal, such as an alkaline earth metal like barium) reacts with water to form a metal hydroxide (a base), while an acidic oxide (from a non-metal sitting toward the upper-right of the periodic table, such as nitrogen, sulfur, or chlorine) reacts with water to form an oxoacid. A metalloid oxide like SiO₂ sits in between and is essentially insoluble, reacting with water only under much more forcing conditions than a typical acidic or basic oxide.

Given the theoretical reaction yield of 4 FeS₂ + 11 O₂ ⟶ 2 Fe₂O₃ + 8 SO₂ which of the following statements is correct?

  • AFrom 4 mol of O₂ and 11 mol of FeS₂, 8 mol of SO₂ can be obtained.
  • BFrom 2 mol of FeS₂ and 11 mol of O₂, 1 mol of Fe₂O₃ can be obtained.
  • CTo obtain 1 mol of Fe₂O₃, 2 mol of FeS₂ and 5 mol of O₂ are necessary.
  • DFrom 10 mol of O₂ and 1 mol of FeS₂, 3 mol of SO₂ can be obtained.
  • ETo obtain 1 mol of Fe₂O₃ and 6 mol of SO₂, 2 mol of FeS₂ and 9 mol of O₂ are necessary.
Correct answer: B From 2 mol of FeS₂ and 11 mol of O₂, 1 mol of Fe₂O₃ can be obtained.

Full explanation

This is a simple stoichiometric question that involves identifying the correct mole ratio between the reactants and products.

According to the given equation, 4 moles of FeS₂ reacts with 11 moles of O₂ to give 2 moles of Fe₂O₃ and 8 moles of SO₂.

Option A has the mole ratio of the reactants reversed.

Option C has 2 moles of FeS₂ which would require 5½ mole of Oxygen instead of 5 moles.

Option D has 1 mole of FeS₂ which would require 2¾ mole of Oxygen and forms 2 moles of SO₂, not 3 mole.

Option E has 2 moles of FeS₂ and enough O₂ and forms 1 mol of Fe₂O₃ and 4 mol of SO₂ instead of 6 mole.

Option B says it has 2 moles of FeS₂ and enough O₂ and forms 1 mol of Fe₂O₃. Thus, this is the only correct option.

Summary to learn

Reading a balanced chemical equation’s coefficients gives the exact mole ratios between every reactant and product – scaling any one substance up or down by a factor scales every other substance in the equation by that same factor. Checking whether a proposed set of amounts is consistent means picking one substance as a reference, working out what every other substance’s amount should be from the equation’s ratios, and comparing that to what’s actually claimed.

How many mL of water must be added to 15 mL of a 0.25 M solution of H₂SO₄ to obtain a 0.05 M solution?

  • A120 mL
  • B30 mL
  • C60 mL
  • D75 mL
  • E50 mL
Correct answer: C 60 mL

Full explanation

Dilution doesn’t destroy any solute – it just spreads the same amount of H₂SO₄ across more water – so the product of concentration and volume stays constant before and after: M₁V₁ = M₂V₂.

Plug in what’s known: 0.25 M × 15 mL = 0.05 M × V₂, so V₂ = (0.25 × 15)/0.05 = 75 mL. That 75 mL is the total volume of the diluted solution – not the amount of water poured in on top of what was already there.

Since the original 15 mL of solution is still part of that 75 mL, the water actually added is the difference: 75 mL − 15 mL = 60 mL – option C.

Summary to learn

Diluting a solution never changes how much solute is present – it only spreads that same amount through more solvent – so concentration times volume stays constant before and after dilution: M₁V₁ = M₂V₂. The volume that formula solves for is always the total volume of the diluted solution, so finding how much solvent was actually added requires one further step: subtracting the original volume back out.

How many Na+ ion moles can be found in 250 mL of a 1.2 M solution of Na₂SO₄?

  • A0.3
  • B0.4
  • C0.6
  • D1.2
  • E1.8
Correct answer: C 0.6

Full explanation

Start with what happens when Na₂SO₄ dissolves: it splits completely into ions, Na₂SO₄ → 2Na⁺ + SO₄²⁻, so every mole of the salt that dissolves releases two moles of sodium ions – an easy detail to overlook if you stop counting at the moles of salt itself.

Find how much salt is actually present: with a 250 mL (0.25 L) sample at 1.2 mol/L, moles of Na₂SO₄ = volume × molarity = 0.25 L × 1.2 mol/L = 0.3 mol.

Since each mole of Na₂SO₄ hands over two moles of Na⁺, the sodium-ion count is double that: 2 × 0.3 mol = 0.6 mol – option C.

Summary to learn

When an ionic compound dissolves in water, it dissociates completely into its component ions in whatever ratio its formula specifies – a compound like Na₂SO₄ releases two Na⁺ ions for every formula unit that dissolves, not one. Converting a solution’s concentration and volume into moles of a specific ion therefore takes two steps: first find the moles of the compound itself (volume × molarity), then multiply by that ion’s own coefficient in the formula.

In the reaction NH₃ + BF₃ ⇄ NH₃BF₃ the ammonia behaves as a:

  • ALewis acid
  • BLewis base
  • CBrönsted acid
  • DBrönsted base
  • EArrhenius base
Correct answer: B Lewis base

Full explanation

The given acid-base reaction cannot be categorised in Bronsted Acid and Base definitions because there is not hydrogen transfer between the reactants. It does not increase the concentration of H+ or OH- either, so, this also cannot be categorised in Arrhenius’s definition. But we can use the Lewis theory of acids and bases, which explains acid-base reactions based on the transfer of electron pairs. According to this theory, a Lewis acid is defined as a substance that accepts an electron pair, while a Lewis base is a substance that donates an electron pair. This definition focuses on electron movement rather than protons, making it more general and applicable to a wider range of reactions.

NH₃ has lone pairs of electrons and BF₃ has available place for electrons in its p subshell. Thus, during the given reaction, NH₃ donates its lone pair to BF₃, making NH₃ the Lewis base.

Summary to learn

The Lewis theory of acids and bases defines an acid as an electron-pair acceptor and a base as an electron-pair donor – a broader definition than the Bronsted-Lowry (proton transfer) or Arrhenius (H⁺/OH⁻ concentration) theories, which can’t classify reactions where no proton or hydroxide ion changes hands at all. A molecule with an available lone pair of electrons (like the nitrogen in NH₃) acts as a Lewis base, while a molecule with an empty orbital able to accept that pair (like the boron in BF₃) acts as a Lewis acid.

Zinc nitrate, nitrogen dioxide, and water are obtained from the reaction of metallic zinc and nitric acid in an aqueous solution. What is the reducing species?

  • AHNO₃(aq)
  • BZn(NO₃)2(aq)
  • CH⁺(aq)
  • DZn²⁺ (aq)
  • EZn(s)
Correct answer: E Zn(s)

Full explanation

Start by writing a balanced equation for what’s actually happening: Zn + HNO₃ → Zn(NO₃)₂ + NO₂ + H₂O.

Now track oxidation states across that reaction. Zinc goes from 0 (as the free metal) to +2 in Zn(NO₃)₂ – it loses electrons, so it’s being oxidised. Nitrogen, meanwhile, starts at +5 in HNO₃ and ends up split between +5 (in the nitrate ion that stays in solution) and +4 (in the NO₂ gas that’s given off) – some of the nitrogen gains an electron, so it’s being reduced.

The reducing agent is whatever gets oxidised – it’s the species that hands electrons over, enabling something else to be reduced. Since zinc is the one losing electrons here, metallic zinc, Zn(s), is the reducing species: option E.

Summary to learn

A reducing agent is the species that gets oxidised (loses electrons), enabling something else to be reduced; an oxidising agent is the species that gets reduced (gains electrons). Identifying which is which in a redox reaction means writing a balanced equation and tracking each element’s oxidation state from reactants to products – whichever element’s oxidation number increases is being oxidised, and whichever element’s oxidation number decreases (or splits between two products at different oxidation states) is being reduced.

Which of the following compounds contains the most hydrogen atoms?

  • A2-Hexanol
  • B1,2-Dimethylcyclobutane
  • C2,3-Dimethylpentane
  • DCyclohexane
  • E2,3-Dimethyl-2-butene
Correct answer: C 2,3-Dimethylpentane

Full explanation

The fastest way through a question like this is to build each molecular formula from its structure rather than trying to count hydrogens off a drawing, because branching and rings both remove hydrogens compared to a plain, unbranched chain.

2-Hexanol is hexane (six carbons, no rings or double bonds) with one hydrogen swapped for an -OH group – swapping H for OH doesn’t change the total hydrogen count here, since the OH group brings its own H back. That gives C₆H₁₄O, 14 hydrogens.

IMAT question 41 figure

1,2-Dimethylcyclobutane has a four-carbon ring (which already costs two hydrogens relative to an open chain) plus two methyl branches, for six carbons total and one ring: C₆H₁₂, 12 hydrogens.

IMAT question 41 figure

2,3-Dimethylpentane is a fully saturated, acyclic, unbranched-in-effect skeleton once you count all seven carbons (five in the pentane chain, two in the methyl branches) with no ring and no double bond to cost any hydrogens: C₇H₁₆, 16 hydrogens – more than any of the others, because it’s the only one with seven carbons and zero rings or double bonds.

IMAT question 41 figure

Cyclohexane and 2,3-dimethyl-2-butene both land on C₆H₁₂ (12 hydrogens) too – the ring costs cyclohexane exactly what the double bond costs the alkene, so both tie with the dimethylcyclobutane above, well short of the pentane derivative.

IMAT question 41 figure
IMAT question 41 figure

With 16 hydrogens against 14 or 12 everywhere else, 2,3-dimethylpentane wins – option C.

Summary to learn

A molecular formula’s hydrogen count follows directly from its degree of unsaturation: a fully saturated, acyclic (chain, no rings) molecule follows CₙH₂ₙ₊₂ (plus any heteroatom needed for a functional group, which doesn’t change the hydrogen count if it simply replaces one H), while each ring or each double bond in the structure costs exactly two hydrogens relative to that fully saturated baseline. Comparing molecules with different numbers of carbons, rings and double bonds means applying this rule to each one individually rather than trying to estimate hydrogen count by eye from a drawing.

A carbon-oxygen double bond is NOT present in which of the following molecules?

  • ADimethyl ether
  • BAcetaldehyde
  • CAcetone
  • DAcetic acid
  • EMethyl acetate
Correct answer: A Dimethyl ether

Full explanation

Four of these five molecules are built around a carbonyl group, C=O, just wearing different disguises. Acetaldehyde is an aldehyde (a carbonyl with a hydrogen attached), acetone is a ketone (a carbonyl flanked by two carbon groups), acetic acid is a carboxylic acid (a carbonyl paired with a hydroxyl), and methyl acetate is an ester (a carbonyl next to an oxygen that links to another carbon chain). Every one of those functional groups has that double bond to oxygen baked in by definition.

Dimethyl ether breaks the pattern. It’s built as R-O-R′ – two methyl groups joined by a single bond to one oxygen atom, with no carbonyl anywhere in the structure. That single C-O-C bridge is the whole story, which is why option A is the one without a carbon-oxygen double bond.

Summary to learn

A carbonyl group (C=O) is the defining feature shared by several organic functional groups that otherwise look quite different: an aldehyde (carbonyl plus H), a ketone (carbonyl between two carbon groups), a carboxylic acid (carbonyl plus hydroxyl), and an ester (carbonyl next to an oxygen bridging to another carbon chain) all contain it. An ether, by contrast, is built as a simple R-O-R′ single-bond bridge between two carbon groups, with no carbon-oxygen double bond anywhere in its structure.

Various units of measurement can be used to express the value of pressure. Which of the following values of pressure does NOT correspond to 1 atm?

  • A101325 Pa
  • B1013 millibar
  • C1013.25 kPa
  • D760 mmHg
  • E760 torr
Correct answer: C 1013.25 kPa

Full explanation

The standard atmosphere is defined as exactly 101325 Pa, and from there the other common pressure units all check out: 760 mmHg and 760 torr are the same thing under two different names (both essentially measure the height of a mercury column), and since 1 bar = 100000 Pa, 101325 Pa works out to 1.01325 bar, or 1013.25 millibar – which rounds to the “1013 millibar” you’ll recognise from weather forecasts. So options A, B, D and E all check out.

Option C is where the trap sits. Since 1 kPa = 1000 Pa, converting 101325 Pa into kilopascals means dividing by 1000, not 100: 101325 Pa ÷ 1000 = 101.325 kPa. The figure “1013.25” is real – it’s just the millibar (equivalently, hectopascal) value from option B, misapplied to the wrong unit. Mixing up kPa with mbar/hPa this way is an easy slip, because the two units differ by only a factor of ten and the number “1013” is genuinely correct for one of them. In kPa, 1 atm is 101.325 kPa, not 1013.25 kPa, which is why option C is the one that does NOT correspond to 1 atm.

Summary to learn

The standard atmosphere (1 atm) has several exactly-equivalent expressions across different pressure units: 101325 Pa, 101.325 kPa, 1013.25 mbar (or hPa), and 760 mmHg/torr. Because kPa and mbar/hPa differ by only a factor of ten, and the same digit string “1013” is correct for one of them but not the other, converting between pressure units carefully – dividing by exactly the right power of ten – is where these conversions usually go wrong.

Given that the relative atomic mass of nitrogen is 14 u, how many nitrogen atoms are present in 0.7 g of gaseous nitrogen?

  • A2.01 x 10⁻²³
  • B1.51 x 10²²
  • C3.01 x 10²³
  • D6.02 x 10²²
  • E3.01 x 10²²
Correct answer: E 3.01 x 10²²

Full explanation

To find the quantity of nitrogen atoms present in 0.7g of N₂ , the given mass must be converted to mole first. Then, using Avogadro’s number, the answer can be calculated.

Molar mass of N₂ = 2 x 14 g/mol = 28 g/mol

Mole of 0.7 g of N₂ =massmolar mass=0.7 g28 g/mol= 0.025 mol

Number of molecules of N₂ = 0.025mole x 6.023 x 10²³ = 0.15 x 10²³ molecules

Since one molecule of N₂ contains 2 nitrogen atoms, Number of nitrogen atoms = 2 x 0.15 x 10²³ = 0.3 x 10²³ = 3 x 10²²

Summary to learn

Converting a mass of a substance into a number of individual atoms or molecules is a two-step chain: first divide the given mass by the substance’s molar mass to get moles, then multiply the moles by Avogadro’s number (6.022 × 10²³) to get the number of particles. When the question asks for atoms of one specific element within a molecule (rather than molecules of the compound itself), a final multiplication by how many atoms of that element each molecule contains is needed too.

Carbon and oxygen can react at high temperatures to form CO₂. Assuming that the relative atomic mass of the carbon is 12 u, the relative atomic mass of the oxygen is 16 u and the yield of the reaction is 100%, what happens when 9 g of carbon reacts with 36 g of oxygen?

  • A33 g of CO₂ are produced.
  • B45 g of CO₂ are produced.
  • C9 g of oxygen remain.
  • D4 g of oxygen remain.
  • E18 g of oxygen remain.
Correct answer: A 33 g of CO₂ are produced.

Full explanation

Start with a balanced equation: C + O₂ → CO₂ – one mole of carbon reacts with exactly one mole of oxygen gas to give one mole of carbon dioxide.

Convert both masses to moles before comparing them, since grams can’t be compared directly against a 1:1 mole ratio. Carbon: 9 g ÷ 12 g/mol = 0.75 mol. Oxygen: 36 g ÷ 32 g/mol = 1.125 mol.

Because the equation needs C and O₂ in a 1:1 ratio, whichever one runs out first sets the limit on how much CO₂ can form. Here there’s only 0.75 mol of carbon against 1.125 mol of oxygen, so carbon is the limiting reagent – the reaction can only go as far as that 0.75 mol allows, using up 0.75 mol of O₂ along the way and leaving 1.125 − 0.75 = 0.375 mol of oxygen (12 g) unreacted.

That 0.75 mol of carbon becomes 0.75 mol of CO₂ (the same 1:1 ratio from the equation). CO₂’s molar mass is 12 + 2(16) = 44 g/mol, so the mass produced is 0.75 mol × 44 g/mol = 33 g – option A.

The three “leftover oxygen” options (C, D and E: 9 g, 4 g and 18 g) are all wrong for the same reason – none of them matches the actual 12 g of oxygen genuinely left over once the reaction runs out of carbon.

Summary to learn

In a limiting-reagent problem, converting every given mass into moles and comparing those mole amounts against the balanced equation’s required ratio reveals which reactant runs out first – that reactant is the limiting reagent, and it alone determines the maximum amount of product that can form, regardless of how much excess the other reactant has left over.

How much water needs to be added to 1 mL of an HCI solution with a pH of 2 to obtain a solution with a pH of 4?

  • A24 mL
  • B2 mL
  • C1 mL
  • D99 mL
  • E49 mL
Correct answer: D 99 mL

Full explanation

pH measures concentration on a log scale: [H⁺] = 10−pH. So the starting solution, at pH 2, has [H⁺] = 10−2 mol/L, and the target solution, at pH 4, has [H⁺] = 10−4 mol/L – one hundred times more dilute, since each whole pH unit represents a tenfold change in concentration.

Dilution doesn’t remove or add any H⁺ ions, it only spreads the same amount through more volume, so M₁V₁ = M₂V₂ holds throughout: (10−2 mol/L)(1 mL) = (10−4 mol/L)(V₂), which rearranges to V₂ = 10−2/10−4 mL = 100 mL.

That 100 mL is the total volume of the diluted solution, not the water added on top of what’s already there. Since the original 1 mL of acid is still part of that 100 mL, the water actually needed is the difference: 100 mL − 1 mL = 99 mL – option D. It’s an easy trap to stop at the 100 mL figure and reach for a nearby wrong option instead of subtracting the starting volume back out.

Summary to learn

pH is a logarithmic scale: [H⁺] = 10−pH, so each single-unit change in pH corresponds to a tenfold change in hydrogen-ion concentration. Since dilution conserves the total amount of H⁺ while spreading it through more volume, M₁V₁ = M₂V₂ converts a target pH change into the required total volume – and, as with any dilution problem, that total volume must have the original volume subtracted back out to find how much diluting liquid was actually added.

According to the Bronsted−Lowry theory:

  • Aa base is a compound which can donate OH– ions
  • Bthe conjugate acid is the product of the bonding of the base with an OH– ion
  • Cthe conjugate base is formed by an acid that has acquired an OH– ion
  • Da strong acid forms a conjugate with a weak base
  • Ean acid is a substance which can provide a pair of electrons
Correct answer: D a strong acid forms a conjugate with a weak base

Full explanation

Bronsted-Lowry theory defines an acid as a proton (H⁺) donor and a base as a proton acceptor – nothing about hydroxide ions or electrons belongs in that definition, which is exactly where four of these five options go wrong.

Option A describes a base by its ability to donate OH⁻ ions – that’s the Arrhenius definition of a base, not the Bronsted-Lowry one. Options B and C both build their conjugate pair around the wrong ion: a conjugate acid forms when a base picks up an H⁺ (not an OH⁻, as B claims), and a conjugate base forms when an acid gives away an H⁺ (not “acquires an OH⁻”, as C claims) – a conjugate acid-base pair always differs by a single proton, never by a hydroxide ion. Option E describes a substance that donates a pair of electrons, which is the definition of a Lewis base, not an acid – the option mislabels it.

Option D survives all of this: a strong acid is, by definition, one that dissociates almost completely, handing away its proton readily. That means whatever’s left behind – its conjugate base – has very little pull left to grab that proton back, which is exactly what makes something a weak base. So a strong acid genuinely does pair with a weak conjugate base, which is why D is the correct statement.

Summary to learn

Bronsted-Lowry theory defines an acid strictly as a proton (H⁺) donor and a base as a proton acceptor – hydroxide ions and electron pairs belong to different theories (Arrhenius and Lewis, respectively) and don’t factor into the Bronsted-Lowry definition at all. A strong acid, which dissociates almost completely, leaves behind a conjugate base with very little tendency to reclaim that proton – which is exactly why a strong acid’s conjugate base is reliably weak.

Physics & Mathematics

Mechanics, electricity, thermodynamics, algebra & geometry · 13 questions
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The expression (5121/3)1/2 is equivalent to:

  • A2√2
  • B√2
  • C3√4
  • D6√2
  • E26√2
Correct answer: A 2√2

Full explanation

Start by collapsing the double exponent: raising something to the 1/3 power and then to the 1/2 power is the same as raising it once to their product, (1/3)×(1/2) = 1/6. So (5121/3)1/2 = 5121/6.

Now break 512 into a clean base to work with – since 512 = 2⁹, 5121/6 = (2⁹)1/6 = 29/6 = 23/2, which is far easier to simplify than the sixth root of 512 directly.

A fractional exponent of 3/2 splits neatly into a whole-number part and a leftover half: 23/2 = 21 × 21/2 = 2√2 – option A.

The other four options are the kind of result you get from mismanaging that exponent arithmetic along the way – combining the fractional powers incorrectly, or losing track of which root and which power apply to 512 versus to the simplified base of 2 – rather than reducing the exponents cleanly as above.

Hence, the correct answer is (A).

Summary to learn

Nested exponents combine by multiplying: raising a quantity to the power m and then to the power n is the same as raising it once to the power m×n. Once a large base like 512 is rewritten as a power of a small prime (512 = 2⁹), that combined exponent often reduces to a simple whole-number-plus-fraction form, like 23/2 = 2 × √2, that’s much easier to evaluate than working with the original large number’s roots directly.

If f(x) = log₂(x² + 12), what is the reciprocal of f(2)?

  • A½
  • B4
  • C2
  • D¼
  • E6
Correct answer: D ¼

Full explanation

Work from the inside out. First evaluate f(2): substitute x = 2 into f(x) = log₂(x² + 12), giving f(2) = log₂(4 + 12) = log₂16.

Since 16 is a power of 2 – specifically 2⁴ – log₂16 is asking “what power of 2 gives 16”, and the answer is just that exponent: 4. So f(2) = 4.

The question asks for the reciprocal of that result, not f(2) itself – an easy detail to skim past. The reciprocal of 4 is 1/4, which is option D. (Options B and C, 4 and 2, are what you’d land on if you stopped at f(2) or mis-simplified the logarithm instead of taking that extra inverting step.)

Hence, the correct answer is (D).

Summary to learn

Evaluating a composite expression works from the inside out: substitute the given value into the innermost function first, simplify that result completely, and only then apply whatever operation the question asks for on the outside (here, taking a reciprocal). Skipping that last outer step – stopping at the inner function’s value instead of finishing the operation the question actually asked for – is one of the most common ways to land on a wrong-but-plausible answer.

In a bag are 3 red balls and 7 green balls, indistinguishable by touch. Two extractions are made, with the first ball being returned to the bag before the second extraction. What is the probability of extracting 2 green balls?

  • A51/100
  • B42/90
  • C7/10
  • D49/100
  • E9/100
Correct answer: D 49/100

Full explanation

Since the ball is put back before the second draw, the bag is identical for both extractions – 3 red and 7 green every time – so the two draws are independent, and the probability of green on a single draw is always 7/10.

For two independent events to both happen, multiply their probabilities: P(green, then green) = 7/10 × 7/10 = 49/100 – option D.

It’s worth seeing where a couple of the other options come from. Option E, 9/100, is what you’d get from (3/10)² – the probability of drawing two red balls instead, an easy question-reading slip. Option B, 42/90, comes from forgetting the replacement altogether and calculating as if the first ball stayed out of the bag: 7/10 × 6/9 = 42/90. Option C, 7/10, is just the single-draw probability, never squared for two draws at all.

Hence, the correct answer is (D).

Summary to learn

When an item is returned to a pool before a second draw (sampling with replacement), the two draws are independent events, and the probability of both happening is simply the product of each individual probability. Forgetting the replacement and calculating as if the pool had shrunk after the first draw (sampling without replacement) is the most common mistake in this kind of question, and produces a different, wrong fraction.

Which of the following is the solution of the inequality [x² + |4x + 3|] / [4 − 3x] ≥ 0?

  • Aeach real x with x > 4/3
  • Beach real x with x ≠ −3/4 and x ≠ 0
  • Ceach real x with x ≥ 4/3
  • Deach real x with x < 4/3
  • Eeach real x with x ≤ 4/3
Correct answer: D each real x with x < 4/3

Full explanation

Look at the numerator: x² is non-negative for every real x, and |4x + 3| is non-negative for every real x (it’s a modulus/absolute value). So their sum, the numerator, is always non-negative (≥ 0) for every real x.

Since the numerator is always non-negative, the sign of the whole fraction is determined by the denominator alone (and the denominator must not be zero, or the fraction is undefined).

So we need 4 − 3x > 0. Solving: −3x > −4, and dividing both sides by −3 (which reverses the inequality): x < 4/3.

So the inequality holds for every real x with x < 4/3, i.e. x ∈ (−∞, 4/3).

Hence, the correct answer is (D).

Summary to learn

A sum of squares and absolute values (like x² + |4x+3|) is always non-negative for every real number, which means the sign of a fraction with that kind of numerator is controlled entirely by the denominator. Solving an inequality that reduces to just a denominator condition (here, 4 − 3x > 0) still requires care with the algebra – dividing or multiplying an inequality by a negative number always flips its direction.

Let θ be the acute angle formed between the tangent at point A to a circle and one of its chords, AB. Considering any point D on the larger of the arcs AB, denoted by φ as the angle ADB, what relationship exists between the angles θ and φ?

  • AThey are complementary.
  • BThey are explementary.
  • CThere is no relationship between the two angles.
  • DThey are equal.
  • EThey are supplementary.
Correct answer: D They are equal.

Full explanation

θ sits between the tangent line at A and the chord AB – a sort of boundary case where the “inscribing” point has slid all the way around to A itself. φ, meanwhile, is a genuine inscribed angle, measured from a separate point D sitting on the far arc and looking back at that same chord AB.

The Tangent-Chord (Alternate Segment) Theorem is exactly the rule connecting these two: the angle between a tangent and a chord at the point of tangency always equals the inscribed angle subtended by that chord from the alternate segment – the arc lying on the other side of the chord from the tangent. That’s precisely the setup described here.

So θ = φ – the two angles are equal, which is option D. None of the other relationships fit this pairing: complementary (summing to 90°) and supplementary (summing to 180°) describe angles that share a straight line or a right angle, and explementary (summing to 360°) describes angles completing a full turn – none of which is what a tangent-chord angle and its alternate inscribed angle actually do; they’re simply equal.

Hence, the correct answer is (D).

Summary to learn

The Tangent-Chord (Alternate Segment) Theorem states that the angle between a tangent line and a chord, measured at their point of tangency, always equals the inscribed angle that the same chord subtends from any point on the arc on the far side of the chord (the alternate segment). This lets an angle at a tangency point be found without any extra construction, simply by finding the matching inscribed angle instead.

Given a cylinder with a base radius of 5 cm and a height of 7 cm, what is its volume?

  • A245π cm³
  • B175π cm³
  • C70π cm³
  • D105π cm³
  • EThis cannot be calculated with these data
Correct answer: B 175π cm³

Full explanation

The volume of a cylinder only ever needs two measurements — the base radius and the height — because V = πr²h, and both are handed to you directly here: r = 5 cm, h = 7 cm. There’s no missing piece, which rules out option E (“cannot be calculated”) before you even reach for a calculator.

Substituting in: V = π(5 cm)²(7 cm) = π(25 cm²)(7 cm) = 175π cm³.

Hence, the correct answer is (B).

Summary to learn

A cylinder’s volume depends on exactly two measurements – its base radius and its height – through the formula V = πr²h. Whenever both are given directly, the volume can always be calculated; there’s no scenario where a cylinder’s radius and height are both known but its volume supposedly “cannot be calculated.”

In a right triangle, let a and b represent the legs and c the hypotenuse. If α is the angle opposite a, which of the following relations is true?

  • Ac = a cos(α)
  • Ba = c cos(α)
  • Cc = a sin(α)
  • Da = c sin(α)
  • Ea = b cos(α)
Correct answer: D a = c sin(α)

Full explanation

By definition, sin(α) = opposite/hypotenuse. The side opposite α is a, and the hypotenuse is c, so sin(α) = a/c, which rearranges to a = c·sin(α) — option D.

Two of the wrong options can be ruled out on principle alone, without even thinking about which side is which: options A and C both require cos(α) = c/a or sin(α) = c/a. But c is the hypotenuse, always the longest side of a right triangle, so c/a is always greater than 1 — and neither sine nor cosine can ever exceed 1. Those two are impossible before you plug in a single value.

Options B and E fail for a different reason: they pair the wrong side with the wrong function. Cosine relates α to its adjacent side, which is b, not a — so cos(α) = b/c, giving b = c·cos(α), not a = c·cos(α) as option B claims. Option E, a = b·cos(α), makes a similar mix-up: relating a and b validly would go through the tangent (a = b·tan(α)), not the cosine.

Hence, the correct answer is (D).

Summary to learn

In a right triangle, the three trigonometric ratios each relate a specific pair of sides to a chosen angle: sine is opposite over hypotenuse, cosine is adjacent over hypotenuse, and tangent is opposite over adjacent. Because the hypotenuse is always a right triangle’s longest side, any proposed ratio that would make sine or cosine exceed 1 (such as hypotenuse divided by a leg) can be ruled out immediately, without needing to check which side is actually opposite the given angle.

A boat is moving in a uniform straight motion at a certain speed v. If a braking force of 210 N is applied for a distance of 5 m, how much power is developed by the braking force?

  • A420 W
  • B105 W
  • C1050 W
  • D8.4 W
  • E210 W
Correct answer: N/A None of the options is correct — this is a defective question in the original source paper

Full explanation

This question is flawed in the original source material — the source itself states “THIS WAS AN INCORRECT QUESTION. So, none of the given options are correct,” and LOCOMOTIVE is publishing that acknowledgement rather than force-fitting one of the five listed options as if it were right.

Power is the rate at which work is done: P = W/t. Work done by a force is W = F × d, so P = (F × d)/t = F × (d/t) = F × v, since speed v = d/t.

Substituting the given braking force F = 210 N: P = F × v = 210v watts.

Since the boat’s speed v is never given a numerical value in the question, the power cannot be reduced to any single number — it can only be expressed as 210v W. None of the five fixed numerical options (420 W, 105 W, 1050 W, 8.4 W, 210 W) can therefore be correct for every possible v, which is exactly why the source itself withdraws this question.

Summary to learn

Power is the rate at which work is done, P = W/t, and since work is W = F×d, power can also be written as P = F×(d/t) = F×v, where v is speed. This means that for a constant force, power depends directly on how fast the object is moving – the same braking force produces different amounts of power at different speeds, which is exactly why a braking-force question that never specifies the boat’s speed cannot be reduced to one single numerical answer.

An ideal gas is in a container placed on a thermostat at temperature T and occupies volume V at pressure P. If the volume occupied by the gas is tripled while keeping the temperature constant, its pressure…

  • Abecomes P/2
  • Bdoes not change
  • Cbecomes 3P
  • Dbecomes P/3
  • Echanges, depending on T
Correct answer: D becomes P/3

Full explanation

Boyle’s Law governs exactly this situation – same gas, same temperature, only the volume changing – and it says pressure and volume move in opposite directions so that their product stays fixed: P₁V₁ = P₂V₂.

Starting at P₁ = P, V₁ = V, tripling the volume gives V₂ = 3V, so solving for the new pressure: P₂ = P₁V₁/V₂ = PV/(3V) = P/3 – option D.

That inverse relationship is the whole idea behind Boyle’s Law: squeeze a gas into a smaller space and the same number of molecules collide with the container walls more often, raising pressure; let it expand and those collisions become rarer, dropping pressure by the same factor the volume grew. Since the volume tripled, the pressure has to fall to a third of what it was – not stay unchanged (option B, which would only hold if the gas weren’t actually being compressed or expanded) and not grow (option C, which has the relationship backwards).

Hence, the correct answer is (D).

Summary to learn

Boyle’s Law describes a fixed-temperature gas: at constant temperature, a gas’s pressure and volume are inversely proportional, so their product stays constant, P₁V₁ = P₂V₂. Compressing a gas into a smaller volume packs its molecules together more tightly, so they collide with the container walls more often and pressure rises; letting it expand has the opposite effect, and pressure falls by exactly the same factor the volume grew.

In a conductor, when a current of 10 A flows, 2922 W are dissipated. What is the resistance value of the conductor?

  • A2922 Ω
  • B29.22 Ω
  • C2.922 Ω
  • D292.2 Ω
  • E29 220 Ω
Correct answer: B 29.22 Ω

Full explanation

Power dissipated in a resistor follows P = I²R, so solving for resistance gives R = P/I² = 2922 W / (10 A)² = 2922/100 = 29.22 Ω — option B.

The other four options are all built from the same four digits, 2-9-2-2, just with the decimal point in a different place, which is the tell that they come from a slip in the division rather than a genuinely different method. Option A, 2922 Ω, is what you get if you forget to divide by I² at all and just report the power. Option D, 292.2 Ω, comes from dividing by I (10) instead of I² (100) — forgetting to square the current. Option E, 29 220 Ω, is the power multiplied by the current rather than divided by its square — the inverse of the right operation. Option C, 2.922 Ω, overshoots the correct division by an extra factor of ten, as if dividing by 1000 rather than 100.

Hence, the correct answer is (B).

Summary to learn

For a resistor, power, current and resistance are linked by P = I²R, which rearranges to R = P/I². Because current is squared in this relationship, forgetting to square it – or dividing by the wrong power of ten – is the most common way to land on an answer built from the right digits but the wrong decimal placement.

An electron in motion with a constant velocity v, enters a uniform magnetic field B perpendicularly. Given that me, e, v represent the mass, charge, and magnitude of the electron’s velocity respectively, which of the following statements is false?

  • AThe electron continues to move with a constant velocity v
  • BThe trajectory of the electron is a circle with a radius of mev/(eB)
  • CThe motion of the electron is uniformly circular with a period of 2πme/(eB)
  • DThe motion of the electron is circular with constant angular velocity
  • EThe motion of the electron is uniformly circular with a frequency eB/(2πme)
Correct answer: A The electron continues to move with a constant velocity v

Full explanation

When a charged particle like an electron enters a magnetic field perpendicularly, it feels the Lorentz force F = evB, always directed perpendicular to its velocity. This force changes the electron’s direction continuously but never its speed, so the electron moves in a circle at constant speed (uniform circular motion).

Equating the magnetic force to the centripetal force: evB = mev²/r, giving r = mev/(eB) — this confirms option B.

The period is T = circumference/speed = 2πr/v = 2πme/(eB) — this confirms option C. Since the motion is uniform circular motion, the angular velocity is constant — this confirms option D. The frequency is f = 1/T = eB/(2πme) — this confirms option E.

Option A is the false statement: although the electron’s speed stays constant, its velocity (a vector) is continuously changing direction, so the velocity is not constant.

Hence, the correct answer is (A).

Summary to learn

A charged particle moving perpendicular to a uniform magnetic field feels a magnetic (Lorentz) force that is always perpendicular to its velocity – such a force can change the particle’s direction but never its speed, since a force perpendicular to motion does no work on the particle. The result is uniform circular motion: constant speed, but continuously changing velocity (a vector, which depends on direction as well as magnitude), with a radius, period, and frequency all derivable by equating the magnetic force to the centripetal force required for that circular path.

A point particle moves along a given x-axis with the law of motion x(t) = 4cos(ωt) where x is in metres, t in seconds and ω = 2π rad/s. The velocity of the point particle at the instant t* = ½ s equals:

  • Aapproximately −4 m/s
  • Bapproximately 25.1 m/s
  • Capproximately 8.5 m/s
  • Dapproximately 4.2 m/s
  • E0 m/s
Correct answer: E 0 m/s

Full explanation

Velocity is how position changes over time, so differentiate x(t) = 4cos(ωt) with respect to t: v(t) = dx/dt = −4ωsin(ωt).

Substitute the given values, ω = 2π rad/s and t* = ½ s: v(½) = −4(2π)sin(2π × ½) = −8πsin(π). Since sin(π) = 0 exactly, the whole expression collapses to zero: v(½) = 0 m/s – option E.

That’s not a coincidence of the numbers – it’s built into how simple harmonic motion works. At t* = ½ s, the particle sits at x = 4cos(π) = −4 m, right at the far extreme of its swing (its maximum displacement in the negative direction). Any oscillating particle has to momentarily stop at each extreme before reversing course, exactly like a pendulum hanging still for an instant at the top of its arc – so zero velocity there is exactly what you’d expect physically, not just what the derivative happens to produce.

Hence, the correct answer is (E).

Summary to learn

In simple harmonic motion, velocity is the time-derivative of position, so for x(t) = A cos(ωt), the velocity is v(t) = −Aωsin(ωt) – and since sine and cosine are 90° out of phase, velocity is exactly zero at the instants when position is at its maximum displacement (±A), and velocity is at its maximum when position passes through zero. That’s a general feature of oscillating systems: a particle always comes to a momentary stop at each extreme of its swing before reversing direction, just like a pendulum pausing at the top of its arc.

A pendulum rod moves from the vertical position. Which of the following statements is false?

  • AIn the absence of friction, the pendulum tends to come to a stop after a certain time.
  • BIn the absence of friction, the motion is simple harmonic oscillation.
  • CIn the presence of friction, oscillatory motion is damped.
  • DThe pendulum stops after reaching a certain height and then swings back.
  • EThe pendulum describes a circular arc during its motion.
Correct answer: A In the absence of friction, the pendulum tends to come to a stop after a certain time.

Full explanation

Option A is false: without friction, no dissipative forces remove energy from the pendulum, so its mechanical energy is conserved and it keeps oscillating indefinitely — it never “tends to come to a stop.”

Option B is true (for small angular displacements, at least, which is the standard idealised treatment): the restoring force is proportional to displacement, giving simple harmonic motion.

Option C is true: friction (air resistance, pivot friction) damps the oscillation, decreasing its amplitude over time.

Option D is true: at each extreme of its swing, the pendulum momentarily stops before swinging back.

Option E is true: the pendulum bob traces a circular arc, determined by the length of the rod/string.

Hence, the correct answer is (A).

Summary to learn

A frictionless pendulum conserves mechanical energy, so it keeps oscillating indefinitely without ever coming to rest, tracing a repeating circular arc and momentarily pausing at each extreme of its swing before reversing – that’s simple harmonic motion for small angular displacements. Introducing friction (air resistance, pivot friction) removes energy from the system over time, which is what actually damps the oscillation and eventually brings a real-world pendulum to rest.

Frequently Asked Questions

Right here — every question from the IMAT 2024 exam (General Knowledge, Logical Reasoning, Biology, Chemistry, Physics and Mathematics) is solved and explained on this page, for free, with no sign-up required.

Yes. Every calculation, chemical and biological fact was independently re-derived and checked by the LOCOMOTIVE academic team before publishing.

The IMAT is a single 100-minute test made up of General Knowledge & Logical Reasoning, Biology, Chemistry, Physics & Mathematics questions. Correct answers score +1.5, unanswered questions score 0, and incorrect answers score −0.4 (the exact weighting has varied slightly by year — always check the official rules for the year you are sitting).

The overall syllabus (General Knowledge, Logical Reasoning, Biology, Chemistry, Physics & Maths) has stayed broadly the same, but the exact number of questions, section weighting and question style have changed over the years — this 2024 paper is a great way to build core knowledge, but always pair it with recent past papers to get used to the current format.

Yes — the underlying subject knowledge and reasoning skills are directly transferable, which makes older papers like this one useful extra practice once you’ve worked through the most recent papers.

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