IMAT 2020 Worked Solution

Full explanation

The argument states that allowing prisoners to receive books as gifts may discourage them from working, which is important for their self-esteem and work ethic. It concludes that prisoners should only access books through the prison library instead of receiving them from relatives or friends.

To strengthen this argument, we need a statement that further justifies why preventing book parcels is beneficial---either by supporting the idea that prisoners should work or that library access is sufficient.

Option A Explanation:

A\) Many parcels of books sent by relatives or friends have been found to contain illegal drugs.

Correct. This strengthens the argument by adding a security concern---if book parcels can be used to smuggle drugs, banning them becomes more reasonable.

Option B Explanation:

B\) Prisoners often read detective stories which may encourage them to glamorise crime.

Irrelevant. The argument is about discouraging work, not book content.

Option C Explanation:

C\) The range of books available in prison libraries is limited.

Weakens the argument. If the library selection is limited, banning book parcels reduces prisoners' access to books, making the policy less justified.

Option D Explanation:

D\) Many prisoners have difficulty finding work when they are released because of their low level of literacy.

Irrelevant. The argument is about prison work ethic, not literacy levels after release.

Option E Explanation:

E\) Prisoners have to purchase a range of items from their wages, including a television licence.

Irrelevant. This does not support the idea that banning book parcels encourages work.

Full explanation

The argument states with a point that say that optimistic, happy people tend to be healthier, more physically active and more successful. Then, that point is contradicted by the third statement which says that positivity could result in negative results if not used properly. Then, examples come. So, it implies that positivity mindset might not always give positive results. We have to choose the conclusion that resembles this the most.

Option A Explanation:

A\) Positive thinking is not always helpful.

This directly summarizes the argument: positivity has both benefits and downsides.

Option B Explanation:

B\) Negative thinking about health can be beneficial.

Too specific. This is one example, but not the main conclusion.

Option C Explanation:

C\) People who think positively live longer.

This is mentioned as a potential benefit but is not the argument's main point.

Option D Explanation:

D\) Being overly positive can damage our relationships with friends.

This is one consequence but not the overall conclusion.

Option E Explanation:

E\) Research into positivity has so far ignored its potential downsides.

The passage cites research showing the negative effects, so this is inaccurate.

Full explanation

This is a simple visualization question. We'll look only at the first fold.

1st fold: Left side over right → dot on center of that left face.

the paper is unfolded in the reverse sequence and is then turned over, the dot appears on the right side, centered on the right half of the paper.

Among the options, only option B satisfies this condition.

Therefore, the correct answer is option B.

Full explanation

To answer this question, we have to count the children who has more than 2 siblings.

Rajiv, Emily and Fatima each have 1 brother and 1 sister.

Candice and Marvin have 1 brother and 2 sisters.

Aruna has 2 sisters.

Phoebe has 1 brother and 3 sisters.

Leroy and Gemma have 2 brothers.

Paul has 2 brothers and 1 sister.

Callum has 3 brothers.

So, in total, 11 families have a total of 3 or more children.

Full explanation

Let's say that a tin of sweets has 100 g.

36% is eaten, which means 36 g is eaten. So, 64g of sweets remain.

Then, 25% of the remaining sweets is eaten.

25% of 64g would be 16g.

So, 64g - 16g = 48g of sweets remain.

The same number of sweets will be eaten on each of the following two days.

Remaining sweets = 48g - 16g - 16g = 16g which is the same as 16% because we use 100g as original content of the tin.

Thus, the correct answer is option C) 16

Full explanation

Zoom is double concentrate, meaning it needs only half the amount of powder that Zap or Own Brand needs for the same amount of washing. So, to compare fairly, work out the price per "effective" kilogram of washing power: for Zoom, effective kg = actual kg × 2 (since each kg goes twice as far); for Zap and Own Brand, effective kg = actual kg.

Box A has the lowest price per effective kilogram (£1.20), so it represents the best value for money.

Hence, the correct answer is (A).

Full explanation

The passage states that Mondrian chose London over a rural area because he loved its diverse and vibrant culture. It then concludes that London has more artists than any other city in England, implying that other artists must also prefer London for similar reasons.

For the argument to hold, it assumes that other artists also choose London for the same reasons as Mondrian---this connects the premise (Mondrian's preference) to the conclusion (London has the most artists).

Option A Explanation:

A\) London is a big city because all the artists who live there boost its size and population.

Incorrect. The passage does not say that artists make London big, just that it attracts many artists.

Option B Explanation:

B\) There is less inspiration for artists in rural areas.

The passage suggests that Mondrian preferred city life, but it does not state that rural areas lack inspiration.

Option C Explanation:

C\) Artists can only create great works if they are happy and relaxed.

This is too extreme; the passage does not claim this as a requirement.

Option D Explanation:

D\) Other big cities in England have the same attractive features as London.

The passage does not compare London to other cities in England.

Option E Explanation:

E\) Other artists make the same choice as Mondrian for the same reasons.

Correct answer. The passage assumes that London has more artists because, like Mondrian, they are drawn to its diverse and vibrant culture.

Full explanation

Premise: People who take their holidays in Las Vegas love to gamble.

- (If X → Y) → If someone goes to Las Vegas, they must love gambling.

Premise: Gerry is going to France for his holiday.

- (Not X) → Gerry is not going to Las Vegas.

Conclusion: Therefore, Gerry must not like gambling.

- (Not X → Not Y) → Since Gerry is not going to Las Vegas, he must not love gambling.

Option A Explanation:

A\) People who eat a lot of sweets have rotten teeth. You eat a lot of sweets, so your teeth must be rotten.

- (X → Y, X is true → Y is true)

- Not a match.

Option B Explanation:

B\) People who live in the city hate traffic jams. You live in the country so you must like traffic jams.

- (If X → Y, then Not X → Not Y)

- Exact parallel reasoning!

Option C Explanation:

C\) You have to find the password to complete the game. You haven't finished the game yet so you can't have found the password.

- (If X → Y, then Not Y → Not X) (Contrapositive, which is valid reasoning)

- Not a match.

Option D Explanation:

D\) You always walk when you are visiting your sister. You are not visiting your sister so that's why you are taking the car.

- (If X → Y, then Not Y → Not X)

- Not a match

Option E Explanation:

E\) In England cars are driven on the left side of the road. We are driving on the left, so we must be in England.

- (If X → Y, then Y → X) (Affirming the consequent, another fallacy, but not the same one)

- Not a match.

Full explanation

Criteria to buy a new car is to buy the cheapest car to use for one year, a total annual mileage of 20,000.

For autogas car, total fuel charge is \30 × 100\ (full tank can be used for 200 miles) = 3000

Total cost = 10,000 (car cost) + 3000 = 13,000

For diesel car, total fuel charge is \50 × 40\ (full tank can be used for for 500 miles) = 2000

Total cost = 12,000 (car cost) + 2000 = 14,000

For petrol car, total fuel charge is \50 × 50\ (full tank can be used for 200 miles) = 2500

Total cost = 10,000 (car cost) + 2500 = 12,500

For hydrogen car, total fuel charge is \50 × 100\ (full tank can be used for 200 miles) = 5000

Total cost = 9,500 (car cost) + 5000 = 14,500

For electric car, total fuel charge is \5 × 100=500\

Total cost = 12,500 (car cost) + 500 = 13,000

So, petrol car cost the lowest.

Full explanation

The paragraph discusses about the driverless vehicle development and complications. Conclusion is explicitly stated in the second sentence "But we are so engrossed in the technology that we are ignoring the legal implications — and legislating for new scenarios takes time." This is followed by the examples that point out the need for new legislation.

Thus, the conclusion that is best suited to this paragraph is Option C) New laws are needed to determine liability for accidents involving driverless cars.

Full explanation

In 1961, the Soviet Union sent the first human into space, completing an orbit around Earth.

Option A Explanation:

A\) Valentina Tereshkova

First woman in space (1963), but not the first to orbit.

Option B Explanation:

B\) Yuri Gagarin

Correct answer. He flew aboard Vostok 1 on April 12, 1961, becoming the first person to orbit Earth.

Option C Explanation:

C\) Neil Armstrong

First person on the Moon (1969), not the first in orbit.

Option D Explanation:

D\) John Glenn

First American to orbit Earth (1962), but after Gagarin.

Option E Explanation:

E\) Buzz Aldrin

Second person on the Moon, not the first to orbit Earth.

Full explanation

Carl Friedrich Gauss (1777--1855) was a German mathematician known for his contributions to statistics, number theory, and physics.

Option A Explanation:

A\) the normal distribution curve

Correct answer. Also called the Gaussian distribution, it is a key concept in statistics and probability.

Option B Explanation:

B\) the sine function

While Gauss worked on trigonometry, the sine function predates him.

Option C Explanation:

C\) the law of supply and demand

An economic principle, not related to Gauss.

Option D Explanation:

D\) Bayes' theorem

Developed by Thomas Bayes, not Gauss.

Option E Explanation:

E\) the uncertainty principle

Formulated by Werner Heisenberg in quantum mechanics.

Full explanation

The sharing economy involves peer-to-peer access to goods/services rather than ownership (e.g., Airbnb, Uber).

Option A Explanation:

A\) Unused value is wasted value.

Key principle---sharing prevents waste.

Option B Explanation:

B\) Competition is dangerous.

The sharing economy still thrives on competition (e.g., Uber vs. Lyft).

Option C Explanation:

C\) Stranger danger can be overcome.

Trust-building mechanisms (reviews, IDs) reduce risks.

Option D Explanation:

D\) Access is preferable to ownership.

Central idea---why own when you can share?

Option E Explanation:

E\) Transparent and open data increases innovation.

Open data fosters efficiency in sharing platforms.

Correct answer is option B) competitive is dangerous.

Full explanation

Amarcord (1973) is a famous Italian film known for its nostalgic and surreal style. It was directed by Federico Fellini.

Option A Explanation:

A\) Stanley Kubrick

Known for 2001: A Space Odyssey, The Shining, not Amarcord.

Option B Explanation:

B\) Francis Ford Coppola

Directed The Godfather series, not Amarcord.

Option C Explanation:

C\) François Truffaut

A major French director, known for The 400 Blows.

Option D Explanation:

D\) Alfred Hitchcock

Master of suspense, directed Psycho, Vertigo, not Amarcord.

Option E Explanation:

E\) Federico Fellini

Fellini was an Italian director known for surreal, dreamlike films, including Amarcord.

Full explanation

The Romance languages evolved from Latin and include Spanish, French, Italian, Portuguese, and Romanian.

Option A Explanation:

A\) Bulgarian

Correct answer. Bulgarian is a Slavic language, not Romance.

Option B Explanation:

B\) Spanish

Romance language, derived from Latin.

Option C Explanation:

C\) Romanian

Though geographically in Eastern Europe, it is a Romance language.

Option D Explanation:

D\) Catalan

Spoken in Spain, a Romance language.

Option E Explanation:

E\) French

A major Romance language.

Full explanation

Each country has an official currency

Option A Explanation:

A\) Peso — Argentina

Correct. The Argentine peso (ARS) is the national currency.

Option B Explanation:

B\) Baht — Thailand

Correct. The Thai baht (THB) is used in Thailand.

Option C Explanation:

C\) Rand — South Africa

Correct. The South African rand (ZAR) is the official currency.

Option D Explanation:

D\) Euro — Hungary

Incorrect. Hungary uses the Hungarian forint (HUF), not the Euro.

Option E Explanation:

E\) Rupee — India

Correct. The Indian rupee (INR) is India's currency.

Full explanation

The Fields Medal is often considered the "Nobel Prize of Mathematics," awarded every four years to outstanding mathematicians under 40.

Thus, the correct option is C) Mathematics

Full explanation

The Nobel Prize in Literature is awarded to writers who have made significant contributions to literature.

Option A Explanation:

A\) Pablo Neruda

Won in 1971. Chilean poet.

Option B Explanation:

B\) Bob Dylan

Won in 2016. American singer-songwriter.

Option C Explanation:

C\) Thomas Mann

Won in 1929. German novelist (The Magic Mountain).

Option D Explanation:

D\) Charles Dickens

Did NOT win. Despite being a famous 19th-century writer (Oliver Twist, A Christmas Carol), he never received the Nobel Prize.

Option E Explanation:

E\) Harold Pinter

Won in 2005. British playwright.

Full explanation

Primo Levi was an Italian Jewish writer known for his works on the Holocaust and survival.

Option A Explanation:

A\) The Truce

Written by Levi. Sequel to "If This Is a Man".

Option B Explanation:

B\) If This Is a Man

Written by Levi. His famous memoir about Auschwitz.

Option C Explanation:

C\) The Drowned and the Saved

Written by Levi. Reflections on the Holocaust.

Option D Explanation:

D\) Beyond Good and Evil

Not written by Levi. This is a philosophy book by Friedrich Nietzsche.

Option E Explanation:

E\) If Not Now, When?

Written by Levi. A novel about Jewish resistance fighters.

Full explanation

An archipelago is a group of islands. Some belong to specific countries.

Option A Explanation:

A\) Hawaii — United States of America

Correct. Hawaii is a U.S. state.

Option B Explanation:

B\) Azores — Portugal

Correct. The Azores are an autonomous region of Portugal.

Option C Explanation:

C\) Cape Verde — Brazil

Incorrect. Cape Verde is an independent country, not part of Brazil.

Option D Explanation:

D\) Canary Islands — Spain

Correct. They are an autonomous community of Spain.

Option E Explanation:

E\) Galapagos Islands — Ecuador

Correct. They belong to Ecuador.

Full explanation

In Italy, direct universal suffrage means that all eligible citizens vote directly for the representatives. The Chamber of Deputies and the Senate of the Republic are the two houses of Parliament, both elected by the people.

Option A Explanation:

A\) President of the Council of Ministers

(Prime Minister) — Not directly elected by the people; appointed by the President of the Republic.

Option B Explanation:

B\) High Council of the Judiciary

Not elected by the public; it consists of judges and members appointed by different institutions.

Option C Explanation:

C\) Government

The government is formed by the Prime Minister and ministers, but they are not directly elected by the people.

Option D Explanation:

D\) Senate of the Republic

Correct answer. Senators are elected by the Italian people through direct universal suffrage.

Option E Explanation:

E\) President of the Republic

Elected by Parliament and regional representatives, not directly by the people.

Full explanation

The World Heritage Sites are places of outstanding cultural or natural importance, recognized and protected under the UNESCO World Heritage Convention.

Option A Explanation:

A\) WTO

World Trade Organization — Focuses on international trade regulations and agreements, not heritage protection.

Option B Explanation:

B\) WHO

World Health Organization — Concerned with global public health, not cultural or natural sites.

Option C Explanation:

C\) OECD

Organisation for Economic Co-operation and Development — Works on economic policies and development, not heritage conservation.

Option D Explanation:

D\) UNICEF

United Nations Children's Fund — Focuses on children's rights, education, and welfare, not World Heritage Sites.

Option E Explanation:

E\) UNESCO

United Nations Educational, Scientific and Cultural Organization — The correct answer. It maintains the World Heritage List and works to protect and preserve cultural and natural heritage worldwide.

Full explanation

Escherichia coli (1) contains circular DNA because it is a prokaryote (a bacterium), and prokaryotic cells have a single, circular chromosome instead of linear chromosomes.

Saccharomyces cerevisiae (yeast) (2) is a eukaryotic organism, and like other eukaryotes, its nuclear DNA is linear; however, it also contains mitochondria, which have circular DNA, so yeast cells do have some circular DNA.

Human liver cells (3) are also eukaryotic with linear nuclear DNA, but they too contain mitochondria, which have their own circular DNA. Therefore, all three --- Escherichia coli, yeast, and human liver cells --- contain circular DNA, though for different reasons: in E. coli it's the main genome, and in yeast and human cells it's mitochondrial DNA.

Full explanation

The general structure of amino acid has a central carbon attached to amino group (-NH₂), carboxyl group (-COOH), Hydrogen and side chain R. In Asparagine, the side chain R has the structure -CH₂CONH₂.

Thus, image X correctly enclose the part that is common to all amino acids. Image Y correctly enclose the side chain R group of Asparagine.

The correct option is option B) row 5.

Full explanation

DNA replication is the process of synthesizing DNA from DNA.

Transcription is the process of synthesizing RNA from DNA.

Analysis of the given statements

1. The breaking of hydrogen bonds: Both DNA replication and transcription requires the breaking of hydrogen bonds to expose the sequence for the synthesis of new DNA strands or RNA strand.

2. The formation of hydrogen bonds: Complementary base pairing and formation of hydrogen bonds occur in both processes. In DNA replication, new DNA strands form hydrogen bonds with the template strand. In transcription, mRNA forms temporary hydrogen bonds with the DNA template strand before detaching.

3. The formation of phosphodiester bonds: Phosphodiester bonds form in both processes to synthesize a new strand of nucleic acids. Thus, this is also a shared feature, not a distinguishing one.

Thus, none of the given information can distinguish between DNA replication and transcription.

Full explanation

Rods detect light intensity and motion in low-light conditions but not color or detail, and are mainly found at the retina's edge.

Cones detect color (red, green, blue) and fine detail, concentrated in the center, with the fovea centralis containing only cones.

When light reaches a photoreceptor, it triggers the breakdown of rhodopsin, a molecule made of opsin and retinal. Light causes retinal to change shape and separate from opsin, initiating an action potential in the receptor cell. Retinal's structure is similar to Vitamin A, and a deficiency in Vitamin A can lead to vision problems, particularly in low-light conditions.

Full explanation

The diagram represents the fluid mosaic model of a cell membrane.

Label 1 indicates the carbohydrate molecule attaching the external surface of the cell membrane. It is a polar molecule

Label 2 indicates the phospholipid head which is hydrophilic and face outside.

Label 3 indicates the phospholipid tail which is made up of hydrophobic fatty acid chains and face inside. This shows the hydrophobic region of a molecule.

Label 4 indicates a part of the membrane protein which is facing outside in exposure to water. This is hydrophilic.

Label 5 indicates a part of peripheral protein which face the outside in exposure to water. This is another hydrophilic part.

Thus, the correct option is option D) 3.

Full explanation

A cell from an organism with a haploid number of 4 have 8 homologous chromosomes.

Option A Explanation:

Diagram does not have a correct description because in Meiosis I, homologous chromosomes separate, not sister chromatids.

Option B Explanation:

Diagram does not have a correct description because in Mitosis, all 8 homologous chromosomes align in metaphase plate during mitosis and then separate in Anaphase. The diagram mentions only 4 chromosomes.

Option C Explanation:

Diagram does not have a correct description because in Mitosis, sister chromatids separate, not homologous chromosomes.

Option D Explanation:

Diagram does not have a correct description because in Mitosis, all 8 homologous chromosomes align in metaphase plate during metaphase, not 4.

Option E Explanation:

Diagram has a correct description. The cell is in prophase, there are 8 chromosomes, in condensed shape without mitotic spindles.

Full explanation

Speciation

There are 2 main types of speciation :

1. Allopatric Speciation ("Geographical Isolation")

2. Sympatric Speciation ("No Physical Barrier", A new species evolves within the same geographical area.) - This is not the case here because the two parents are from different species and different region. Therefore, the first term illustrated in the question is incorrect.

Isolation

Isolation prevents gene flow between populations, allowing genetic differences to accumulate. In this case, the new species no longer mates with the original parent generation, so reproductive isolation is happening. (The 2nd term illustrated in the question is correct).

There are two main types of reproductive isolation that contribute to speciation:

3. Pre-zygotic Isolation (Before Fertilization)

4. Post-zygotic Isolation (After Fertilization)

In this case, the success of the new species is due to the pre-zygotic isolation because the reproductive barrier here is behavioral (pre-zygotic) --- through song differences and large bill and body size, leading to mate choice preferences before fertilization. (Mating doesn't happen with original parent generation). So, it is not post-zygotic. (The 3rd term illustrated in question is wrong)

Thus, the only correct term for the success of new species is 2. Reproductive isolation.

Full explanation

A single base mutation (point mutation) can have different effects on the protein, depending on the type of mutation that occurs.

These are

- Missense mutation is a type of point mutation where a single base change in the DNA sequence leads to the substitution of one amino acid for another in the protein. This can result in a change in the protein's tertiary structure, potentially altering its function.

- Nonsense mutation is a type of point mutation where a single base change converts a codon into a premature stop codon, causing early termination of translation and producing a shorter, usually nonfunctional protein.

- Silent mutation is a type of point mutation where a single base change occurs but does not alter the amino acid sequence of the protein, due to the redundancy (degeneracy) of the genetic code.

Thus, all of the mentioned effects are the possible effects on a single base mutation.

Full explanation

Catabolism refers to the breakdown of molecules to release energy. It is the destructive phase of metabolism, in contrast to anabolism, which involves building complex molecules.

Option A Explanation:

A\) formation of RuBisCo

(Anabolic) RuBisCo (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is an enzyme involved in the Calvin cycle(photosynthesis), which is an anabolic process. Humans do not synthesize RuBisCo.

Option B Explanation:

B\) replication of DNA

(Anabolic) DNA replication builds new DNA strands, requiring nucleotides and ATP, making it an anabolic process.

Option C Explanation:

C\) oxidation of NADH

(Catabolic) NADH is oxidized to NAD⁺ in the electron transport chain (ETC) during cellular respiration. This process releases energy to drive ATP production, making it a classic example of catabolism.

Option D Explanation:

D\) ATP made during glycolysis

ATP synthesis itself is not catabolic; rather, it is a result of catabolic reactions (like glycolysis).

Option E Explanation:

E\) attachment of tRNA to mRNA

(Anabolic) This occurs during translation, which is an anabolic process because it builds proteins from amino acids.

Full explanation

Analysis of the given functions

1. They stimulate cell division in cotton plant seeds.

- Agrobacterium tumefaciens is known for causing tumors in plants by inserting its tumor-inducing plasmid into plant cells.

- This stimulates uncontrolled cell division, leading to tumor formation, which is used here to grow genetically modified cotton plants.

2. They supply the plasmid vector.

- The plasmid from Agrobacterium tumefaciens is used as a vector to transfer the insect toxin gene (from Bacillus thuringiensis) into cotton plant cells.

3. They are the source of the gene for the production of the insect toxin.

- Incorrect because the insect toxin gene comes from Bacillus thuringiensis, not Agrobacterium tumefaciens.

4. They are the source of the gene for antibiotic resistance.

- Incorrect because the antibiotic resistance gene is artificially inserted into the plasmid, not naturally provided by Agrobacterium tumefaciens.

Thus, TWO correct functions of the Agrobacterium tumefaciens bacteria in this process are 1 and 2.

Full explanation

In a developing human fetus, the lungs are non-functional because the fetus gets oxygen from the placenta through the umbilical cord. To bypass the lungs, the fetal circulation has two key shunts:

1. Foramen ovale — A hole in the atrial septum that allows blood to flow from the right atrium to the left atrium, bypassing the lungs.

2. Ductus arteriosus — A vessel that connects the pulmonary artery to the aorta, further bypassing the lungs.

Since the foramen ovale is an opening in the septum, blood from the right atrium can directly enter the left atrium, skipping the pulmonary circulation and being pumped to the rest of the body.

Option A Explanation:

A\) Blood entering the right atrium can bypass the lungs and go to the rest of the body.

This statement is correct.

Option B Explanation:

B\) Blood in the right atrium may return directly to the vena cava.

Blood does not flow backward into the vena cava; it moves forward into the left atrium through the foramen ovale.

Option C Explanation:

C\) The atrioventricular node will not cause ventricular systole.

The atrioventricular (AV) node remains functional, and ventricular systole still occurs normally, even in a fetus.

Option D Explanation:

D\) Blood in the pulmonary artery will go directly to the aorta.

This describes the function of the ductus arteriosus, not the hole in the septum (foramen ovale).

Option E Explanation:

E\) The maximum pressure in the aorta is the same as the maximum pressure in the contracting atrium.

The aortic pressure is much higher than atrial pressure because the aorta supplies systemic circulation, which has high resistance.

Full explanation

Bile is a digestive fluid produced by the liver and stored in the gallbladder. It plays a crucial role in fat digestion by emulsifying large lipid droplets into smaller ones, increasing their surface area for enzymes like lipase to act on, which enhances fat breakdown and absorption in the small intestine.

Analysis of the given statements

1. It emulsifies fat globules. Bile contains bile salts, which break large fat globules into smaller droplets  (emulsification). This increases the surface area for lipase to act on, aiding in fat digestion. Fat globules are large, spherical droplets of fat that form when lipids are released into the digestive system. They are hydrophobic and tend to clump together in water-based environments like the small intestine.

2. It dilutes the contents of the small intestine. When released into the duodenum, it dilutes chyme (partially digested food) and facilitates digestion.

3. It lowers the activation energy of lipase. Bile does not function as an enzyme.

4. It helps to reduce the acidity of the contents leaving the stomach. Bile contains bicarbonate (HCO₃⁻), which neutralizes acidic chyme from the stomach.

Thus, the correct statements are 1, 2 and 4

Full explanation

Immediately after acetylcholine binds to postsynaptic receptors of a muscle fibre, Na+ channels open, leading to depolarization of the membrane and the generation of an action potential. The action potential travels along the T-tubules and reaches the sarcoplasmic reticulum (SR). This causes voltage-gated Ca²⁺ channels in the SR to open, releasing Ca²⁺ ions into the sarcoplasm. Ca²⁺ binds to troponin, which causes a conformational change. This moves tropomyosin away from the myosin-binding sites on the actin filament, allowing myosin to bind to actin and initiate contraction.

Thus, the correct order is 2,3,1

Full explanation

Features of HIV

- HIV (Human Immunodeficiency Virus) is an enveloped virus, and like all viruses, it has a protein capsid that encloses its genetic material.

- It is a retrovirus, meaning its genetic material is single-stranded RNA (ssRNA), not DNA. HIV carries three essential enzymes: reverse transcriptase, integrase and protease.

- Viruses do not have ribosomes. They rely entirely on the host cell's ribosomes for protein synthesis because they cannot make proteins on their own.

Thus, the correct option is option E) 1 only.

Full explanation

Option A Explanation:

A\) distal convoluted tubule

Reabsorbs water under the influence of aldosterone and ADH and plays a role in fine-tuning ion and fluid balance. Remember, ADH has effect on both DCT and collecting duct, but it has an even stronger effect, allowing much more water reabsorption depending on body hydration.

Option B Explanation:

B\) collecting duct

Regulates final water reabsorption under the influence of antidiuretic hormone (ADH), concentrating urine when necessary.

Option C Explanation:

C\) proximal convoluted tubule

Reabsorbs about 65-70% of water by passive transport, along with glucose, amino acids, and ions, through active and passive transport mechanisms.

Option D Explanation:

D\) glomerulus

The glomerulus is responsible for filtration, not reabsorption.

Option E Explanation:

E\) loop of Henle

Specifically, the descending limb is permeable to water, allowing further water reabsorption via osmosis, while the ascending limb is impermeable to water.

Full explanation

The Y chromosome consists of tightly packed nucleosomes, which are fundamental units of chromatin. Each nucleosome is composed of a core of eight histone proteins, around which DNA is wrapped twice, ensuring efficient packaging and regulation of genetic material. Thus, the structure should be ordered in Y chromosome → nucleosome → histone (from largest to smallest).

X chromosome is bigger than Y chromosome.

Thus, the correct option would be option A) row 1

Full explanation

Living organisms are defined by several fundamental characteristics. They are composed of one or more cells, the basic units of life. They perform metabolism, carrying out chemical reactions to obtain and use energy. Living things maintain homeostasis, keeping internal conditions stable. They undergo growth and development, increasing in size and complexity. Reproduction ensures the continuation of their species, either sexually or asexually. Organisms also respond to stimuli from their environment and exhibit heredity, passing genetic information (typically DNA) to their offspring. Together, these features distinguish living organisms from non-living matter.

Analysis of each statement

1. They are made up of one or more cells. This is a fundamental principle of cell theory: all living organisms consist of one or more cells. Unicellular organisms (like bacteria) have a single cell, while multicellular organisms (like humans) have many.

2. They have DNA as the genetic material. DNA (deoxyribonucleic acid) is the universal genetic material in known living organisms.

3. They use energy to stay alive when their surroundings change. Organisms require energy (from food, sunlight, or chemical sources) to maintain homeostasis and survive environmental changes.

4. They undergo phases of growth. Growth is a characteristic of all living organisms. Cells divide and increase in size, allowing unicellular organisms to expand and multicellular organisms to develop and mature.

Full explanation

Diagram 1 describes a chloroplast. The size is \\(4 × 10\^-2)/(4000)=1 × 10\^-5m\

Diagram 2 describes a bacteria. The size is 0.5 micro-meter which is \5 × 10\^-7m\

Diagram 3 describes a mitochondria. The size is \\(6 × 10\^-2)/(20000)=3 × 10\^-6m\

Diagram 4 describes possibly a cell. The size is 0.14 mm which is \1.4 × 10\^-4m\

Diagram 5 describes a neuron. The size is \\(3 × 10\^-2)/(400)=7.5 × 10\^-5m\

Comparing all the structures, the smallest one is bacteria.

Thus, the correct option is option E) 2.

Full explanation

Br₂ consists of two bromine (Br) atoms covalently bonded.

Bromine is a diatomic element, meaning it naturally exists as a molecule of two atoms.

Br₂ is not a compound because it contains only one type of element (bromine).

Option A Explanation:

A\) a compound of the element bromine

A compound consists of two or more different elements. Br₂ contains only bromine, so it is not a compound.

Option B Explanation:

B\) two separate atoms of the element bromine

Br₂ is a single molecule where two bromine atoms are covalently bonded. It does not represent two separate bromine atoms.

Option C Explanation:

C\) a molecule of the element bromine

Br₂ is a molecule because it consists of two atoms chemically bonded. Since it contains only bromine atoms, it is a molecule of the element bromine.

Option D Explanation:

D\) a molecule of the compound bromine

Br₂ is not a compound because it contains only one type of element. A compound must have two or more different elements.

Option E Explanation:

E\) two bromide ions

Br₂ is neutral, not charged. Bromide ions (Br⁻) are negatively charged and exist as separate entities in ionic compounds like NaBr.

Full explanation

Atomic number (Z) = x

Mass number (A) = 2x+6

Number of neutrons = A - Z = (2x+6)-x = x+6

Full explanation

As a general rule, if a metal reacts with cold water, the metal hydroxide and hydrogen is produced. If it reacts with steam, the metal oxide and hydrogen is formed. This is because the metal hydroxides thermally decompose to the oxide and water.

Option A Explanation:

A\) Mg + 2H₂O → Mg(OH)₂ + H₂

Reaction of Magnesium with cold water produce magnesium hydroxide (Mg(OH)₂) and Hydrogen gas. This equation correctly describes the reaction happened and it is balanced.

Option B Explanation:

B\) Mg + H₂O → Mg(OH)₂ + H₂

The equation is not balanced.

Option C Explanation:

C\) 2Mg + 2H₂O → 2MgOH + H₂

MgOH is not a valid compound. MgOH would have an unbalanced charge (+2 from Mg and --1 from OH), so it's chemically invalid.

Option D Explanation:

D\) Mg + H₂O → MgO + H₂

Magnesium reacts very slowly with cold water, producing only small amounts of magnesium hydroxide and hydrogen gas, a reaction often considered negligible. However, when exposed to steam, magnesium reacts much more readily, forming magnesium oxide (MgO) and hydrogen gas. The reaction with steam is faster and more complete, favoring the formation of the oxide rather than the hydroxide, which is typical in the slower reaction with cold water.

Option E Explanation:

E\) 2Mg + H₂O → Mg₂O + H₂

wrong stoichiometry and product

Full explanation

Intermolecular forces (IMFs) are the attractive forces between molecules. They determine properties like boiling point, solubility, and state of matter.

The main types of intermolecular forces are :

- London dispersion forces (weakest) among all types of molecules, but the only type of intermolecular forces between the non-polar molecules.

- Dipole-dipole interactions, between the polar molecules.

- Hydrogen bonding (strongest), between the polar molecules which are able to donate and accept hydrogen bonds.

Option A Explanation:

A\) H₂O (Water)

- Highly polar molecule.

- Forms hydrogen bonds (H attached to O).

Option B Explanation:

B\) CH₄ (Methane)

- Nonpolar molecule (tetrahedral symmetry cancels dipoles).

- Only London Dispersion Forces.

Option C Explanation:

C\) HF (Hydrogen Fluoride)

- Very polar molecule.

- Strong hydrogen bonding (H attached to F).

Option D Explanation:

D\) NH₃ (Ammonia)

- Polar molecule.

- Forms hydrogen bonds (H attached to N).

Option E Explanation:

E\) CO₂ (Carbon Dioxide)

- Nonpolar (linear symmetry cancels dipoles).

- Only London Dispersion Forces but more electrons than CH₄ → slightly stronger IMFs than CH₄.

The molecule with the weakest overall intermolecular forces is CH₄ (methane) because:

It is nonpolar and it only has weak London Dispersion Forces .

Thus, the correct option is option B) CH₄

Full explanation

Sucrose, C₁₂H₂₂O₁₁ , is added to water at 20 °C until no more sucrose will dissolve.

Analysis of the given statements

1. A saturated solution of sucrose is produced. (Correct) A solution is saturated when no more solute (sucrose) can dissolve at a given temperature. Since the problem states that sucrose is added until no more dissolves, a saturated solution is formed.

2. The freezing point of the solution is 0 °C. (Incorrect) When a solute (sucrose) is dissolved in water, the freezing point decreases due to freezing point depression. The solution will freeze at a temperature lower than 0°C, depending on the concentration of sucrose.

3. Sucrose is a non-polar substance. (Incorrect) Sucrose is polar due to its numerous OH (hydroxyl) groups, which allow it to dissolve in water (a polar solvent). If sucrose were non-polar, it wouldn't dissolve in water.

4. Sucrose is the solute. (Correct) In a solution, the solute is the substance that dissolves, and the solvent is the substance that does the dissolving. Here, sucrose is dissolved in water, making it the solute.

Thus, the correct option is option E) 1 and 4 only

Full explanation

The first pair of molecules are cyclopentane and pentene.

- Cyclopentane has the molecular formula C₅H₁₀.

- Pentene refers to a group of alkenes with the molecular formula C₅H₁₀.

Since they have the same molecular formula but different connectivity, they are structural (constitutional) isomers.

The second pair of molecules are 3-chloro-3-methylheptane and 3-chloro-3-methylheptane.

- Both molecules have the same molecular formula (C₈H₁₇Cl) and the same connectivity of atoms.

However, They differ in spatial arrangement (e.g., due to chirality), they are stereoisomers, not structural isomers.

The third pair of molecules are butanenitrile and 2-buten-1-amine

- Both molecules have the same molecular formula (C₄H₇N)

- One has a nitrile (-CN) functional group. The other has an amine (-NH₂) functional group and a C=C double bond.

Since they have the same molecular formula but different connectivity, they are structural (constitutional) isomers.

Thus, the correct option is option A) 1 and 3 only

Full explanation

Equilibrium Constant Expression:

Means that the reaction is exothermic.

We need to determine which factor increases Kc.

Option A Explanation:

A\) an increase in pressure

Pressure affects equilibrium position but not the equilibrium constant Kc.

Option B Explanation:

B\) use of a suitable catalyst

A catalyst only speeds up reaction rates without affecting the position of equilibrium or Kc.

Option C Explanation:

C\) a decrease in temperature

Since the reaction is exothermic, decreasing the temperature shifts equilibrium towards the products (favoring P), increasing Kc.

This option is correct.

Option D Explanation:

D\) a decrease in pressure

Pressure affects equilibrium position but not the equilibrium constant Kc.

Option E Explanation:

E\) an increase in temperature

If temperature increases, the equilibrium shifts towards the reactants \\\\(favoring Q and R), decreasing Kc.

Full explanation

To determine which molecule has a permanent overall dipole moment, we need to analyze molecular geometry and bond dipoles. A molecule has a permanent dipole moment if:

1. It has polar bonds (atoms with different electronegativities).

2. The geometry does not cancel out the dipoles.

Option A Explanation:

A\) NF₃

Shape: Trigonal pyramidal (like NH₃).

Bond Polarity: N-F bonds are polar (F is more electronegative than N).

Dipole Moment: The dipoles do not cancel due to the lone pair on N, leading to an asymmetric charge distribution. NF₃ has a permanent dipole moment.

Option B Explanation:

B\) PCl₅

Shape: Trigonal bipyramidal.

Bond Polarity: P-Cl bonds are polar.

Dipole Moment: The molecular symmetry cancels out the dipoles. No overall dipole moment.

Option C Explanation:

C\) SF₆

Shape: Octahedral.

Bond Polarity: S-F bonds are polar.

Dipole Moment: The symmetry causes the dipoles to cancel. No overall dipole moment.

Option D Explanation:

D\) CCl₄

Shape: Tetrahedral.

Bond Polarity: C-Cl bonds are polar.

Dipole Moment: The symmetry cancels the dipoles. No overall dipole moment.

Option E Explanation:

E\) CO₂

Shape : Linear.

Bond Polarity: C=O bonds are polar.

Dipole Moment: The two bond dipoles are equal and opposite, canceling out. No overall dipole moment.

Full explanation

In the given cysteine structure, carboxyl group (-COOH) and amino group (-NH) can be identified on each end of the molecule. Thiol group (-SH) can be identified as side chain (R) of this amino acid; cysteine.

Full explanation

To determine which pair of species contains vanadium (V) in the same oxidation state, we need to calculate its oxidation number in each compound.

Option A Explanation:

A\) VO₂ and VO₃⁻

Let the oxidation state of V be x.

For VO₂,

x+2(-2)=0

x-4=0

x=+4

For VO₃⁻,

x+3(-2)=-1

x=-1+6=+5

\Different oxidation states.\

Option B Explanation:

B\) VO₂ and V₂O₅

For VO₂ ,

(calculated above) → x=+4

For V₂O₅,

2x+5(-2)=0

x= 10/2 =+5

\Different oxidation states.\

Option C Explanation:

C\) VCl₄ and VO₂⁺

For VCl₄,

x+4(-1)=0

x=+4

For VO₂⁺,

x+2(-2)=+1

x=+1+4=+5

\Different oxidation states.\

Option D Explanation:

D\) VCl₄ and VO₃⁻

For VCl₄,

(calculated above) → x=+4

For VO₃⁻,

(calculated above) → x=+5

\Different oxidation states.\

Option E Explanation:

E\) V₂O₅ and VO₂⁺

For V₂O₅ ,

(calculated above) → x=+5

For VO₂⁺,

(calculated above) → x=+5

\Same oxidation state.\

Full explanation

pH = -log [H⁺]

X : pH = 2, [H⁺] = 10\^{-2}

Y : pH = 4, [H⁺] = 10\^{-4}

Comparing the two solution, H⁺ concentration of X is 100 times greater than that of Y.

Full explanation

Given :

Volume of NaOH = 40 cm³

Concentration of H₂SO₄ = 25 cm³ = 0.025 L (1 L = 1000 cm³)

Volume of H₂SO₄ = 0.40 mol L⁻¹

To find the concentration of NaOH, we first need to find the mole of H₂SO₄ reacted.

mole of H₂SO₄ = concentration x volume = 0.4 mol/L x 0.025 L = 0.01 mol

From the balanced equation, 2 moles of NaOH react with 1 mole of H₂SO₄.

moles of NaOH = 2×0.01 = 0.02 moles

Thus, concentration of NaOH = mole/volume = 0.02 mol/0.04L = 0.5 mol/L

To convert the unit molL⁻¹ to g L⁻¹,

We are given the molar mass of NaOH:

Mr of NaOH=40 g/mol

Concentration in g/L = 0.5×40 = 20 g/L

Full explanation

Rationalise the denominator by multiplying numerator and denominator by the conjugate of (2 + √3), which is (2 − √3): 2/(2 + √3) × (2 − √3)/(2 − √3) = 2(2 − √3) / [(2 + √3)(2 − √3)].

Numerator: 2(2 − √3) = 4 − 2√3. Denominator (difference of squares): (2 + √3)(2 − √3) = 2² − (√3)² = 4 − 3 = 1.

So the expression simplifies to (4 − 2√3)/1 = 4 − 2√3.

Hence, the correct answer is (B).

Full explanation

For y = ax² + bx + c, the turning point's x-coordinate is x = −b/2a. Here a = 2, b = 5, c = −2, so x = −5/(2×2) = −5/4.

Substitute x = −5/4 back into the equation to find the y-coordinate: y = 2(−5/4)² + 5(−5/4) − 2 = 2(25/16) − 25/4 − 2 = 25/8 − 25/4 − 2 = 25/8 − 50/8 − 16/8 = −41/8.

So the turning point is (−5/4, −41/8).

Hence, the correct answer is (B).

Full explanation

Two forces act on the rocket: the upward thrust T and the downward weight mg. By Newton's second law, net force = mass × acceleration, so acceleration = net force / m = (T − mg)/m = T/m − g.

Hence, the correct answer is (A).

Full explanation

Express every term as a power of 2: 8 = 2³, so 8^2x+3 = 2^3(2x+3) = 2^6x+9. Also 4 = 2², so 4^3x = 2^6x, meaning 1/4^3x = 2^−6x.

The left side becomes 2^6x+9 × 2^−6x = 2^6x+9−6x = 2⁹.

Setting exponents equal (since the bases match): 9 = x + 3, so x = 6.

Hence, the correct answer is (C).

Full explanation

The overall mean of a combined group is the weighted average of the two sub-groups' means, weighted by their sizes: (39 × 2 + 36 × x) / (39 + 36) = 3⅓ = 16/5.

Total students = 39 + 36 = 75. So 78 + 36x = 75 × 16/5 = 240.

36x = 240 − 78 = 162, so x = 162/36 = 4.5 = 4½.

Hence, the correct answer is (A).

Full explanation

Total thermal energy supplied = power × time = 100 W × 1600 s = 160 000 J.

This energy converts 200 g of liquid to vapour. Specific latent heat of evaporation L = energy / mass = 160 000 J / 200 g = 800 J/g.

Hence, the correct answer is (D).

Full explanation

Statements 1 and 2 describe the two standard reflection properties that define the principal focus of a parabolic concave mirror: rays parallel to the axis reflect through F (statement 1), and by the reversibility of light, rays through F reflect out parallel to the axis (statement 2). Both are always true, by definition of the focus.

Statements 3, 4 and 5 are not always true: a concave mirror can produce an upright, virtual, magnified image when the object is placed between the mirror and its focal point (e.g. as in a shaving/makeup mirror), so the image is not always inverted, not always real, and not always larger than the object.

Hence, the correct answer is (D).

Full explanation

The boat's own velocity (4.0 m/s, directly across the river) and the river's flow velocity (3.0 m/s, parallel to the banks) are perpendicular, so they combine as vectors at right angles.

The resultant (ground) speed is found with Pythagoras' theorem: √(4.0² + 3.0²) = √(16 + 9) = √25 = 5.0 m/s.

The angle θ from the line at 90° to the bank (i.e. from the boat's own heading direction) satisfies cosθ = adjacent/hypotenuse = 4.0/5.0, so θ = cos⁻¹(4.0/5.0).

Hence, the correct answer is (A).