IMAT 2025 Worked Solution

Full explanation

Key points

- Yellowing of skin/eyes → liver damage/jaundice

- Fever, rash, kidney enlargement → severe kidney inflammation

- Sometimes accompanied by painful urination and lower back pain → may progress to kidney failure

Analysis of the given options

Option A: Incorrect. Text says "may" occur, frequency unknown → not always.

Option B: Correct. Text explicitly mentions kidney enlargement, inflammation, and potential kidney failure.

Option C: No mention of the pancreas in the excerpt.

Option D: Text mentions painful urination, so this statement is false.

Option E: The text does not mention any benefit for patients with kidney failure.

Full explanation

Key points

- Apulian ICT sector recovering after 2020 decline

- Growth hindered by shortage of trained professionals

- Exprivia revenue ↑ 5.4%, profitability ↑

- Gianni Sebastiano: "The more digitalization you put into processes, the more you impact efficiency and costs: this is the great lesson of the pandemic"

- Companies are revising processes; pandemic highlighted importance of digitalization

Analysis of the given options (We need to choose incorrect statement)

Option A: Correct: text explicitly mentions process revision improving efficiency and profitability.

Option B: Correct: text mentions shortage of professionals but also reports profitability growth.

Option C: Not correct: the pandemic highlighted the importance of digitalization, but it did not directly ensure growth or transform companies automatically. Growth was due to process revision and other factors.

Option D: Correct: text says "this is the great lesson of the pandemic," implying the pandemic pushed companies to digitalize.

Option E: Correct: process digitalization improves efficiency and profitability → contributes to growth.

Full explanation

Key points

- The animal kills a man, then weeps for him with tears and lamentation, then devours him.

- Leonardo uses it as a metaphor for hypocrisy: outward tears, inward cruelty.

Analysis of the given options

Option A: Crocodile — correct. "Crocodile tears" = idiom for fake or hypocritical sorrow. Matches the description perfectly: outward weeping, inward cruelty.

Option B: Lions kill prey but don't weep afterward; no known association with hypocrisy.

Option C: Panther - No cultural or historical reference to crying after killing.

Option D: Tigers are fierce predators but do not weep after killing.

Option E: Boas constrict prey silently; no tears or lamentation.

Full explanation

Key points

- Kuru, discovered by Vincent Zigas in 1955, is caused by eating the brains of deceased relatives.

- Creutzfeldt-Jakob Disease (CJD) resembles kuru, not limited to New Guinea, and is sometimes confused with Alzheimer's.

- Both kuru and CJD are caused by prions, infectious proteins present even after death.

Analysis of the given options

Option A: Incorrect. Alzheimer's is a distinct disease, sometimes confused with CJD, but not a progression of it.

Option B: Incorrect. Zigas discovered the cause (practice of eating brains), not a cure.

Option C: Incorrect: CJD is not limited to New Guinea; only kuru is linked to that practice.

Option D: Incorrect: prion = infectious protein, not a bacterium.

Option E: Correct. Text: CJD "is sometimes confused with diseases like Alzheimer's." Kuru and CJD have overlapping symptoms → diagnostic confusion is possible.

Logical reasoning and problem-solving

Full explanation

Given statement: "The number two is a prime number."

The statement asserts the existence of at least one prime number: 2. Nothing in the statement says anything about other numbers. (We know there are other prime numbers but in solving questions like this, we only consider what is written in the question. )

Exclusion of other options

Option B: Contradicted by the given statement. So, incorrect.

Option C: Not deducible: the statement says nothing about numbers other than 2.

Option D: Contradicted by 2 being prime.

Option E: Not deducible; statement only mentions 2.

Excluding the other options, the correct option is A.

Full explanation

Given statements

1. If today is Saturday, then I am a philosopher.

2. I am not a philosopher.

So, deduction would be that today is not Saturday (Option B - correct); it could be any day of the week except Saturday (Option A and C - incorrect). Statement 2 says explicitly that I am not a philosopher. Therefore, option D can be excluded.

Full explanation

Given :

- Square table → 4 sides → 4 people.

- People: Alberto (A), Beatrice (B), Carlo (C), Daniela (D).

- Alberto (A) is to the left of Beatrice (B).

- Alberto is not to the right of Carlo (C).

If we draw an image out of the given information, it would be as follows.

Analysis of the given options

Option A: Correct.

Option B: Incorrect because Carlo is seated across from Alberto.

Option C: Incorrect because Daniela is seated to the left of Alberto.

Option D: Incorrect. Alberto is seated to the left of Beatrice.

Option E: Incorrect. Beatrice is seated across from Daniela.

Full explanation

Given:

There are 3 colored pills placed in 3 colored boxes. No pill is in the box of its own colour (derangement).

- Blue pill is NOT in the green box. It also cannot be in blue box according to the rule. So, blue pill must be in the red box.

- Green pill cannot be in the green box. And red box is occupied by blue pill, So, so green pill must be in the blue box.

- That leaves the red pill to go to the green box

Result (pill → box):

- Blue pill → red box

- Green pill → blue box

- Red pill → green box

This matches option E.

Full explanation

Clock shows 3:00 PM (hour hand at 3, minute hand at 12).

One full rotation of the minute hand = 60 minutes = 1 hour. So, 1.75 rotations = 1 hour 45 minutes.

3:00 PM + 1 h 45 min = 4:45 PM

Full explanation

During lactic acid fermentation, pyruvic acid is reduced directly by NADH to form lactate as an end product, regenerating NAD+ with no release of CO2. Thus, the correct option is option A.

Pearson Chapter 10 cellular respiration

Full explanation

Glycolysis is a 10-step pathway that occurs in the cytoplasm. Overall, for 1 glucose molecule, 2 ATP molecules, 2 NADH molecules, and 2 pyruvates are formed.

Analysis of the given options

Option A: Incorrect. Phosphofructokinase catalyses the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate (Kinase in the enzyme name refers to adding a phosphate group to a substrate). No step directly converts fructose-1,6-diphosphate to dihydroxyacetone phosphate (DHAP).

Option B: Incorrect. Triose phosphate isomerase catalyses the conversion of DHAP to glyceraldehyde-3-phosphate, which are isomers of each other.

Option C: Correct. During the steps of the glycolysis of one glucose molecule, 2 NAD+ are reduced into NADH, transferring high-energy electrons for later ATP production in cellular respiration.

Option D: Incorrect. The glycolysis pathway does not contain a carbon reduction step. Glucose, a 6-carbon molecule, is converted into 2 pyruvates (3-carbon molecules) without any CO2 release.

Option E: Incorrect. No FADH2 production occurs in the glycolysis pathway.

Full explanation

For each acetyl-CoA molecule that enters the Kreb cycle, the cycle produces 2 molecules of CO2, 3 molecules of NADH, 1 molecule of FADH2, and 1 molecule of ATP (or GTP), along with regenerating the starting molecule oxaloacetate. Therefore, the correct option is option A.

Full explanation

Generally, there are 2 types of phosphorylation: substrate-level phosphorylation and oxidative phosphorylation. Substrate-level phosphorylation involves the direct transfer of a phosphate group from a phosphorylated intermediate (a substrate) to ADP, forming ATP. Oxidative phosphorylation occurs in the inner mitochondrial membrane, and generally it is a process that uses reduced coenzymes to make ATP. Oxidative phosphorylation involves oxidation of NADH and FADH2 and movement of electrons through coenzymes and storing electrochemical gradient energy, which is then used by ATP synthase to produce ATP through chemiosmosis.

Analysis of the given options

Option A: Incorrect. The process mentioned is β-oxidation, where fatty acids are oxidized into 2-carbon molecules (acetyl-CoA), not oxidative phosphorylation. Option B: Incorrect. The process mentioned is the deamination and the urea cycle. Oxidative phosphorylation does not directly involve biomolecules like carbohydrates or proteins. Option C: Correct. This option correctly describes oxidative phosphorylation. Option D: Incorrect. Oxidative phosphorylation is the final stage of catabolism, not anabolism. Option E: Incorrect. Fatty acid synthesis occurs in the cytosol, not in the mitochondria, and it is an anabolic process.

Full explanation

Cytochromes are electron carrier proteins between ubiquinone and oxygen in the electron transport chain. Their prosthetic group, called a heme group, has an iron atom that accepts and donates electrons. The electron transport chain has several types of cytochromes, each named "cyt" with a letter and number to distinguish it as a different protein with a slightly different electron-carrying heme group.

Analysis of the given options Option A: Correct. Cytochromes are part of the respiratory chain. Option B: Incorrect. They only move electrons, not whole hydrogen atoms (that's NAD and FAD which carry whole hydrogen atoms) Option C: Incorrect. ATP synthase makes ATP, not cytochromes Option D: Incorrect. They are essential participants of oxidative phosphorylation, not inhibitors. Option E: Incorrect. Glycolysis happens in the cytosol and does not use cytochromes.

Full explanation

Collagen is the most abundant structural protein in the body. It forms extracellular fibers in connective tissue (bone, cartilage, skin, tendons). It is secreted by cells (like fibroblasts) and functions outside the cell, not inside or in membranes.

Analysis of the given options Option A: Incorrect — collagen functions outside the cell, not inside. Option B: Incorrect — collagen is not part of the membrane. Option C: Correct — collagen is a major component of the extracellular matrix. Option D: Incorrect — Think filaments are composed of myosin, not collagen.  Option E: Incorrect — collagen is not found in the nucleus.

Full explanation

In skeletal muscle, contraction is regulated by calcium ions (Ca²⁺).

Key steps: - Ca²⁺ is released from the sarcoplasmic reticulum. - Calcium binds to troponin on the thin filament. - Troponin changes shape → moves tropomyosin, exposing actin binding sites for myosin → contraction occurs.

Note: Vimetin is an intermediate filament, unrelated to muscle contraction.

Full explanation

Muscle contraction relies on the sliding filament model: actin (thin filament) and myosin (thick filament). ATPase activity is on the myosin head. Key steps - ATP binds to myosin → myosin releases actin (dissociation). - ATP is hydrolyzed → myosin head "cocks." - Calcium binds to troponin → tropomyosin moves → actin binding sites exposed → myosin can bind actin. - Power stroke occurs - As ATP binds to the myosin head, the crossbridge detaches and the cycle repeats.

Analysis of the given options Option A: Correct --- ATP binding causes myosin to release actin.  Option B: Incorrect — ATP actually triggers dissociation, not formation. Option C: Incorrect — Calcium allows binding, not dissociation. Option D: Incorrect --- myosin has ATPase activity, actin does not.  Option E: Incorrect — tropomyosin blocks actin sites; it doesn't hydrolyze ATP.

Full explanation

The Bohr effect describes how increased CO₂ and H⁺ (lower pH) in tissues reduces hemoglobin's affinity for oxygen. This enhances oxygen release where it's most needed (active tissues).

Key point: oxygen delivery increases, but oxygenated hemoglobin decreases in the blood.

Analysis of the given options Option A: Incorrect — Bohr effect is about hemoglobin function, not RBC count. Option B: Incorrect — affinity decreases, so fewer hemoglobin molecules are oxygenated. Option C: Correct — low pH and high CO2 promote oxygen release, lowering oxygenated hemoglobin. Option D: Incorrect — it is a shift in oxygen binding, not denaturation. Option E: Incorrect — Irrelevant.

Full explanation

The text describes catalyst Option D. A catalyst is a substance that:

1. Increases the rate of a chemical reaction

2. Is not consumed during the reaction

Enzymes are biological catalysts.

Analysis of the given options Modulator: usually refers to a molecule that alters enzyme activity, not a general catalyst. Effector: Often used in allosteric regulation — changes enzyme activity indirectly. Cofactor: They are non-protein helpers for enzymes. Cholesterol: A lipid molecule, unrelated to catalysis.

Full explanation

Competitive inhibition occurs when an inhibitor that resembles the substrate competes for binding to the enzyme's active site. - Can be overcome by increasing substrate concentration. - Does not change Vmax, but increases Km.

Analysis of the given options Option A: Correct --- this is exactly the definition of competitive inhibition.  Option B: Incorrect — the inhibitor binds to the enzymes, not the substrate. Option C: incorrect — that describes non-competitive pr allosteric inhibition, not competitive. Option D: Incorrect — Not competitive inhibition. Option E: Incorrect — not relevant here.

Full explanation

Analysis of the given options

Lipase: Breaks down fats (triglycerides), not proteins. Amylase: Breaks down starch/carbohydrates into sugars. Peptidase: Correct. It hydrolyzes peptide bonds in proteins. Isomerase: Catalyzes structural rearrangements of molecules, not digestion. Transaminase: Catalyzes amino group transfer in amino acid metabolism, not digestion.

Full explanation

Oxidative phosphorylation occurs in the inner mitochondrial membrane. It involves: - Integral membrane proteins --- complexes I--IV of the electron transport chain and ATP synthase. - Mobile molecules --- coenzyme Q (ubiquinone) and cytochrome c, which shuttle electrons between complexes. So it's a combination of membrane-bound proteins and mobile electron carriers.

Full explanation

During biological oxidation (glycolysis, Krebs cycle, β-oxidation), electrons are transferred to coenzymes: NAD⁺ → NADH and FAD → FADH₂. These reduced coenzymes must be reoxidized to keep metabolism running. This happens in the electron transport chain (respiratory chain), where electrons are passed through complexes and ultimately reduce oxygen to water. In anaerobic conditions, the fermentation process reoxidizes the reduced enzymes.

Analysis of the given options Option A: Incorrect. Fatty acid beta-oxidation generates reduced coenzymes; it does not reoxidize them. Option B: Correct. NADH and FADH2 are oxidized in the ETC, releasing energy for ATP synthesis. Option C: Incorrect. Electrons do not go directly to oxygen; they pass through ETC complexes first. Option D: Incorrect. Reduced enzymes are not reoxidized in ATP synthase. Also, ATP synthase uses the proton gradient, not direct electron transfer. Option E: Incorrect. Hormone synthesis is unrelated to reoxidizing coenzymes.

Full explanation

The high-energy reserve compound that is present in muscles is creatine phosphate (phosphocreatine), which can provide immediate energy before glycolysis or oxidative phosphorylation kicks in.

A common point of confusion is creatinine phosphate, but this is actually a waste product of creatine and does not serve as an energy reserve.

Creatine phosphate: Creatine is involved in fatty acid transport into mitochondria, not high-energy phosphate storage.

Glucose-1-phosphate: Intermediate in glycogen breakdown, not a direct high-energy ohosphate donor.

Phosphofructokinase: That's an enzyme in glycolysis, not an energy-storage compound.

Full explanation

The liver is the central metabolic hub: detoxification, amino acid metabolism, gluconeogenesis, and the urea cycle. Processes like glycolysis, beta-oxidation, and the Krebs cycle happen in many tissues, but the urea cycle occurs exclusively in the liver, spanning both the mitochondria and the cytoplasm of hepatocytes, because the liver is the only organ that contains all the necessary enzymes for the complete urea cycle. In the case of transamination, significant activity can be seen not only in the liver, but also in the kidneys, heart, and skeletal muscle cells.

Therefore, the correct option is option A.

Full explanation

Humans mainly store long-term energy as triglycerides (fats) as a more compact reservoir of fuel because they are highly reduced molecules with minimal water.

Analysis of the given options Option A: Incorrect. Triglycerides have more calories and less water. Option B: Incorrect. More calories. Option C: Correct. This is why fat is the most efficient energy store. Option D: Incorrect. Less water. Option E: Fats contain less oxygen than proteins or carbohydrates.

Full explanation

A lysosome is a membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest (hydrolyze) macromolecules. These enzymes work best in an acidic environment (pH < 7). Lysosomes are formed by budding from the golgi apparatus. Function: Phagocytosis (Digest materials taken into the cell) and Autophagy (Recycle intracellular material) Malfunction is linked to many diseases (e.g, Tay-Sachs)

Analysis of the given options Option A: Incorrect. Lysosomal storage diseases are well documented. Option B: Incorrect. Enzymes work best at acidic pH, not alkaline. Option C: Incorrect. Lysosomes form from the Golgi, not the smooth ER. Option D: Correct. This correctly describes how lysosomes originate. Option E: This is the role of ribosomes on the rough ER, not lysosomes.

Full explanation

In eukaryotes, DNA is mainly in the nucleus, but also in mitochondria (animals + plants) and chloroplasts (plants + algae). Mitochondria and chloroplasts are semi-autonomous and have their own circular DNA + ribosomes. Other organelles (ER, Golgi, lysosomes, etc.) do not contain DNA. Prokaryotes do not have a nucleus — their DNA is in the cytoplasm, in the nucleoid.

Analysis of the given options Option A: Correct. All three organelles do contain DNA. Option B: Incorrect. Mitochondria and chloroplasts also contain DNA, not just RNA. Option C: Incorrect. Most organelles do not have DNA. Option D: Incorrect. Protein synthesis does happen in the rough endoplasmic reticulum, but DNA is not located in the RER. Option E: Incorrect. Prokaryotes lack a nucleus. Their DNA is in the nucleoid region.

Full explanation

The plasma membrane is a phospholipid bilayer with proteins. Its main role is selective permeability: it controls what enters and leaves the cell, maintaining homeostasis.

Analysis of the given options

Option A: Incorrect. The plasma membrane does not synthesize proteins. It is ribosomes.

Option B: Incorrect. It is the mitochondria that produce energy via the electron transport chain.

Option C: Correct. This is the plasma membrane's core function: transport of ions, nutrients, signalling molecules, and waste.

Option D: Incorrect. That's the nucleus in eukaryotes or the nucleoid region in prokaryotes.

Option E: Incorrect. Movements involves cytoskeleton, cilia, flagella, not the plasma membrane itself.

Full explanation

Exergonic reactions are reactions with a negative Gibbs free energy. They release energy and can occur spontaneously.

Analysis of the given options Option A: Incorrect. The mentioned process is the photosynthetic light reactions. Option B: Incorrect. The mentioned processes are endothermic reactions. Option C: Correct. This is the exact definition of exergonic reactions. Option D: Incorrect. In exergonic reaction, energy must come from transforming reactants. Option E: Incorrect. Some exergonic reactions involve the synthesis of new compounds (like ATP hydrolysis driving biosynthesis), but not always.

Full explanation

Bones have 2 main active cell types:

- Osteoblasts — "builders" of bone, they make the bone matrix (collagen + minerals), crucial for bone formation and mineralization.

- Osteoclasts — "chewers" of bone, they break down/resorb bone.

Analysis of the given options Option A: Correct. This is the main function of osteoblasts. Option B: Incorrect. This is the job of osteoclasts, not osteoblasts. Option C: Incorrect. Bones can buffer pH a little by absorbing/releasing ions (bone buffering), but this is not the direct role of osteoblasts. Option D: Incorrect. This is the osteoclast function. Option E: Incorrect. Nutrients are transported by blood vessels, not osteoblasts.

Full explanation

Insulin is a peptide hormone secreted by the beta-cells of the pancreas (Islets of Langerhans). Its main role is to promote storage of nutrients — glucose, fatty acids, and amino acids — after a meal.

Analysis of the given options

Option A: Correct. Insulin promotes transcription of GLUT4 in muscle cell membranes, stimulating glucose uptake. Option B: Incorrect. Insulin promotes synthesis; glucagon/epinephrine stimulates glycogen breakdown. Option C: Incorrect. It's a peptide hormone composed of two polypeptide chains linked by 2 disulfide bonds. Steroid hormones are like cortisol, aldosterone, sex hormones. Option D: Incorrect. Insulin stimulates fatty acid synthesis (lipogenesis) Option E: Incorrect. Insulin comes from the pancreas, not the adrenal.

Full explanation

There are two equations that students need to know and could be confused.

The ideal gas equation is PV = nRT

The combined gas law equation is (P₁V₁)/(T₁) = (P₂V₂)/(T₂)

Where:

- P = pressure

- V = volume

- n = number of moles

- R = gas constant

- T = temperature

Option A exactly matches the ideal gas law.

Full explanation

Recall the rules H = +1, O = -2 Sum of oxidation numbers = 0 for neutral molecule

Analysis of each compound Option A: Cl₂ : Diatomic element → oxidation number = 0

Option B: HClO₂ (chlorous acid) Let Cl = x +1+x+(−4) = 0 ⟹ x = +3 (Correct)

Option C: HCl +1+x = 0 ⟹ x=--1

Option D: HClO (hypochlorous acid) +1+x+(−2) = 0 ⟹ x = +1

Option E: HClO₃ (chloric acid) +1+x+(−6) = 0 ⟹ x = +5

Full explanation

Analysis of the given options Option A: Oxidation numbers can be negative. Examples: Cl⁻ in NaCl (--1), O²⁻ in H₂O (--2). Option B: Oxidation numbers can be positive. Examples: Na⁺ in NaCl (+1), Fe³⁺ in Fe₂O₃ (+3). Option C:  the average oxidation number can be fractional so, can be a number with a decimal point. In Pb3O4, the average oxidation number of lead is +8/3 which is +2.67. Option D: Correct. Oxidation numbers are never irrational. Option E: Oxidation number can be 0 for elements in their standard state. Example: O₂, H₂, N₂ all have oxidation number 0.

Full explanation

Analysis of the given options Option A: Correct. NaCl = Na⁺ + Cl⁻ ions arranged in a crystal lattice. Held together by strong electrostatic forces (ionic bonds). Option B: Incorrect. Molecular solids = discrete molecules held by van der Waals forces, dipole-dipole, or H-bonds. Example: ice (H₂O), dry ice (CO₂). NaCl is not made of molecules. Option C: Incorrect. Metallic solids = metal atoms in sea of delocalized electrons. Example: Fe, Cu, Al. NaCl is ionic, not metallic. Option D: Incorrect. Covalent network solids = atoms covalently bonded in a continuous network. Example: diamond, SiO₂. NaCl has ionic bonds, not covalent network. Option E: Incorrect. Amorphous solids = no long-range order (non-crystalline). Example: glass, gels. NaCl forms a regular crystalline lattice, so it's not amorphous.

Full explanation

In the periodic table, the atomic radius increases going: Across a period (left → right): - Atomic number ↑ → more protons → nuclear charge ↑ → electrons pulled closer → radius decreases. Down a group (top → bottom): - New electron shells are added → electrons are farther from the nucleus → radius increases.

Full explanation

A pure covalent bond is a bond that forms between two atoms of the same element. Same element → same electronegativity → ΔEN = 0 → pure covalent Examples: H₂, O₂, N₂.

Exclusion of the other options Option A: Two atoms with quite similar electronegativity could still have some electronegativity difference. So, this could not be said to be a pure covalent bond. Option C: This forms ionic or polar covalent bonds, not pure covalent. Option D: Electronegativity is a property of atoms. There is no atom without the electronegativity property. Option E: Ions form ionic bonds, not covalent bonds.

Full explanation

Monoprotic weak acid, K_a = 1.0×10⁻⁵, concentration C=0.001 M. HA ⇌ H⁺+ A⁻

Let x be the amount of HA dissociated:

----------------------------------------------------------------------- Species Initial Change Equilibrium ----------------- ----------------- ----------------- ----------------- HA 0.001 -x 0.001-x

H+ 0 +x x

A- 0 +x x -----------------------------------------------------------------------

Ka expression K_a = (\left\lbrack H⁺ \right\rbrack\lbrack A^-\rbrack)/(\lbrack HA\rbrack) = (x × x)/(0.001 - x) = (x² )/(0.001 - x)

Assuming: 0.001−x ≈ 0.001

K_a = (x²)/(0.001) x = \sqrt{\left( 1 × 10^{- 5} \right)\left( 1 × 10^{- 3} \right) } = \sqrt{1 × 10^{- 8}} = 1 × 10^{- 4}M

So, pH = - \log\left\lbrack H⁺ \right\rbrack = - \log\left\lbrack 1 × 10^{- 4} \right\rbrack = 4

Correct answer: D (4)

Full explanation

KBr = salt of strong acid (HBr) + strong base (KOH). Such salts dissociate completely: KBr → K⁺(aq) + Br⁻(aq) Neither K⁺ nor Br⁻ hydrolyzes in water. So the solution is neutral. Neutral solution at 25 °C → pH = 7. Concentration (0.7 M) doesn't matter here, because ions don't affect water's neutrality.

Full explanation

Heat + 2FeCl₃ (s) ⇌ 2FeCl₂ (s) + Cl₂ (g)

Key points: Heat on the left → reaction is endothermic forward. Solids (FeCl₃, FeCl₂) do not affect equilibrium position by changing their amount (their activities are constant). Only gases and aqueous species appear in the equilibrium constant. Thus, Cl₂(g) and temperature changes are relevant.

Analysis of the given options Option A: Incorrect. Adding/removing a solid does not shift equilibrium. Option B: Incorrect. Again, solids don't matter in Le Chatelier's principle for equilibrium shifts. Option C: Incorrect. Cooling removes heat → system shifts to the left (exothermic direction) to produce more heat. To shift right, we'd need to heat (since forward is endothermic). Option D: Correct. Increasing a product (Cl₂ gas) → equilibrium shifts left to consume Cl₂. Option E: Incorrect. Same issue: solids don't change equilibrium position.

Full explanation

Analysis of the given options Option A: Correct. Activation energy (Ea) = minimum energy required to reach the transition state. It's the "hurdle" reactants must overcome before products can form. Option B: Incorrect. That's the ΔH (enthalpy change), not activation energy. Option C: Incorrect. No such definition exists in chemical kinetics. a is about the energy barrier, not a KE--PE comparison. Option D: Incorrect. Energy released = related to ΔH, not Ea. Option E: Incorrect. activation energy is absorbed (input), not released.

Full explanation

The benzene molecule (C₆H₆) has a planar, hexagonal ring structure of six carbon atoms. Every carbon in benzene bonds to two neighbouring carbons and one hydrogen (three σ bonds). That requires three sp² orbitals (formed from 1 s + 2 p) arranged trigonal-planar (≈120°). Therefore, the correct answer is E.

Full explanation

Analysis of the given options Option A: Correct. Glycogen is made only of glucose monomers → a homopolysaccharide. Option B: Incorrect. Heteropolysaccharides contain different monomers (e.g., hyaluronic acid with N-acetylglucosamine + glucuronic acid). Glycogen = glucose only → not hetero. Option C: Incorrect. Disaccharides = 2 monomers (e.g., maltose, sucrose, lactose). Glycogen = many glucose → polysaccharide. Option D: Incorrect. In animals: storage polysaccharide = glycogen. In plants: storage polysaccharide = starch. So glycogen is not shared by both. Option E: Incorrect. Polypeptide = chain of amino acids. Glycogen = carbohydrate, not protein.

Full explanation

There are two important oxidation states for iron: Ferrous — Iron II (Fe2+) and Ferric — Iron III (Fe3+)

CO₃²⁻ is the carbonate ion with a -2 charge.

In FeCO₃, to balance, Fe must be +2, not +3 → so not ferric.

The correct name is iron(II) carbonate, aka ferrous carbonate.

Exclusion of other options Iron pentacarbonyl:  Fe(CO)₅, a coordination compound with CO ligands, not carbonate. Iron oxide: Oxide means a compound with O²⁻ only (e.g., FeO, Fe₂O₃).

Full explanation

An orbital can hold a maximum of two electrons. According to Pauli's exclusion principle, no two electrons in an atom can have the same set of four quantum numbers, meaning a maximum of two electrons can occupy an orbital, and they must have opposite spins. One must have a spin of +1/2 and the other -1/2.

Therefore, the correct answer is B. Two with antiparallel spins

Full explanation

The basic structure of an amino acid is composed of a central carbon surrounded by one amine group (-NH2), one carboxyl group (-COOH), one hydrogen group, and one side chain R group. Side chain R defines the type of amino acid.

Analysis of the given options

Option A: Correct. The key point to notice here is that the amine group and the amino group can be used interchangeably in amino acids because the amino group refers to the primary amine group.

Option B: Incorrect. The solubility of amino acids mainly depends on the side chain R attached to the central carbon. If the side chain is largely hydrophobic, e.g., in Isoleucine, the amino acids would be insoluble in water. If the side chain is hydrophilic, e.g., serine, the amino acids would be soluble in water.

Option C: Incorrect. Hexane, being a nonpolar solvent, nonpolar amino acids like isoleucine would be soluble in that solvent, not all amino acids.

Option D: Incorrect. Carbohydrates are made of monosaccharides (sugars), not amino acids. Amino acids are building blocks of proteins.

Option E: Incorrect. Acidity and basicity largely depend on the side chain R of amino acids. It is incorrect to say that they have no acid/base activity. As an example, Aspartate and glutamate, having a carboxyl group as a side chain, show acidic properties.

Full explanation

Step 1 — find the domain: √(2x) is only defined when the expression inside is non-negative, so 2x ≥ 0, giving x ≥ 0.

Step 2 — since both sides of √(2x) < 1 + x are non-negative for x ≥ 0, we can square both sides without flipping the inequality: (√(2x))² < (1 + x)², so 2x < 1 + 2x + x².

Subtracting 2x from both sides: 0 < 1 + x², i.e. x² + 1 > 0.

Step 3 — interpret: x² + 1 is always positive for every real x (since x² ≥ 0), so this simplified inequality is true for every real number. But we must still respect the domain restriction x ≥ 0 found in Step 1.

So the solution is ∀x ≥ 0.

Hence, the correct answer is (B).

Full explanation

Test each option by substituting u = sin x or v = cos x and checking whether the resulting quadratic inequality holds for the whole valid range [−1, 1].

Option A: with u = sin x, u² + u − 2 ≤ 0. The quadratic u² + u − 2 = 0 has roots u = 1 and u = −2 (opens upward, so ≤ 0 between its roots): −2 ≤ u ≤ 1. Since sin x always lies in [−1, 1], which is entirely inside [−2, 1], this inequality is always satisfied.

Option B: with v = cos x, v² − v − 2 ≥ 0 holds for v ≤ −1 or v ≥ 2. Taking cos x = 0 gives 0 − 0 − 2 = −2 < 0, which fails ≥ 0 — not always true.

Option C: tan²x − 2tan x + 1 = (tan x − 1)² > 0 fails exactly when tan x = 1 (e.g. x = 45°) — not always true.

Option D: with u = sin x, 2u² − u − 1 > 0 holds for u < −½ or u > 1. Taking sin x = 0 gives 0 − 0 − 1 = −1 < 0, which fails — not always true.

Option E: with v = cos x, 2v² + v − 1 < 0 holds for −1 < v < ½. Taking cos x = 1 gives 2 + 1 − 1 = 2, which is not < 0 — not always true.

Only option A is satisfied for every real x.

Hence, the correct answer is (A).

Full explanation

The Cartesian product of two sets A and B, denoted A × B, is the set of all ordered pairs (a, b) where a ∈ A and b ∈ B.

For example, if A = {1, 2} and B = {3, 4}, then A × B = {(1,3), (1,4), (2,3), (2,4)}.

Hence, the correct answer is (C).

Full explanation

This trinomial fits the perfect-square pattern (x − y)² = x² − 2xy + y².

Here a² is the square of a, 4b² is the square of 2b, and the middle term −4ab equals −2 × a × 2b.

So a² − 4ab + 4b² = (a − 2b)².

Hence, the correct answer is (A).

Full explanation

Let the height BC = h, so the base AB = (5/4)h.

Perimeter P = 2(AB + BC): 72 = 2((5/4)h + h) = 2((9/4)h) = (9/2)h.

So h = 72 × 2/9 = 144/9 = 16 cm.

Then AB = (5/4) × 16 = 20 cm.

So AB = 20 cm, BC = 16 cm.

Hence, the correct answer is (B).

Full explanation

A linear equation is "determined" if it has a unique solution. Solving for x: 3x + a = 3, so 3x = 3 − a, giving x = (3 − a)/3.

The coefficient of x is 3, which is never zero, so we can always isolate x and find a unique solution regardless of the value of a.

Hence, the correct answer is (C).

Full explanation

A linear equation is impossible when the coefficient of x is zero but the constant term is non-zero, giving a false statement (a contradiction) with no solution.

Here, if a + 3 = 0, i.e. a = −3, the equation becomes (0)x = 5, i.e. 0 = 5, which is false — there is no solution. For any other value of a, the equation can be solved for x normally.

Hence, the correct answer is (B).

Full explanation

Convert speeds to m/s: v₁ = 120 km/h = 100/3 ≈ 33.33 m/s; v₂ = 80 km/h = 200/9 ≈ 22.22 m/s.

The relative speed at which A closes the gap on B is v₁ − v₂ = 100/3 − 200/9 = (300 − 200)/9 = 100/9 m/s.

In 60 seconds, the distance closed is (100/9) × 60 = 6000/9 ≈ 666.67 m.

Since 666.67 m > the initial 500 m gap, car A has not only caught up to car B but overtaken it within that one minute.

Hence, the correct answer is (D).

Full explanation

Resistors in series add directly, so each branch's resistance is R_series = 10R.

The 100 identical branches (each 10R) are in parallel, so 1/R_eq = 100 × (1/10R) = 10/R, giving R_eq = R/10.

Hence, the correct answer is (D).

Full explanation

Conventional current is defined as the direction of flow of positive charge, so for current flowing left to right, the conventional current direction is left to right.

In a metal wire, current is actually carried by electrons (negative charges). Since electrons are negative, their movement in one direction is equivalent to positive charge moving in the opposite direction. So for the conventional current to be left to right, the electrons must physically move right to left.

Protons are fixed in the metal lattice and do not move; only electrons are mobile.

Hence, the correct answer is (E).

Full explanation

Gravitational acceleration at distance r from a planet's centre is g' = GM/r².

If R is the Earth's radius, a distance of 3R from the surface means a distance of R + 3R = 4R from the centre.

So g' = GM/(4R)² = GM/(16R²) = (1/16)(GM/R²) = (1/16)g, since g = GM/R² at the surface.

Hence, the correct answer is (E).

Full explanation

Segment 1 (constant speed): acceleration is zero, so net force is zero. The engine force forward must exactly balance friction: F1 = F_friction = 2000 N.

Segment 2 (accelerating at a = 2.0 m/s²): the net force is ΣF = ma = 2000 kg × 2.0 m/s² = 4000 N. This net force is the engine force minus friction: F2 − 2000 N = 4000 N, so F2 = 4000 + 2000 = 6000 N.

Hence, the correct answer is (A).

Full explanation

A fluid at rest cannot sustain shear stresses, so it can only exert forces perpendicular (normal) to any surface it contacts. This perpendicular force per unit area is what's called pressure.

The force is not "in any direction" (option B rejected) and not "parallel" (option C rejected, since that would require a shear force, which a static fluid cannot exert). It isn't "no forces, only pressure" (option D rejected, since pressure is precisely the mechanism by which the force is exerted) and the forces are certainly not zero (option E rejected).

Hence, the correct answer is (A).