Q1. Microtubules are absent in
Correct Answer: (a)
Microtubules form the structure of centrioles, flagella, and spindle fibers, but are not a structural component of mitochondria.
Microtubules form the structure of centrioles, flagella, and spindle fibers, but are not a structural component of mitochondria.
Q2. Which of the following statements is correct?
Correct Answer: (a)
Lenticels are essential for gas exchange in the bark of most woody perennials. Cortex and pith are part of ground tissue, not vascular tissue.
Lenticels are essential for gas exchange in the bark of most woody perennials. Cortex and pith are part of ground tissue, not vascular tissue.
Q3. A patient with a pituitary tumor exhibits fatigue, weight loss, and low blood sugar. This is probably due to a lack of production of
Correct Answer: (b)
Adrenocorticotropic hormone (ACTH) triggers the adrenal cortex to release glucocorticoids like cortisol. Cortisol is vital for maintaining blood glucose levels. A lack of ACTH leads to low cortisol, causing hypoglycemia (low blood sugar) and chronic fatigue.
Adrenocorticotropic hormone (ACTH) triggers the adrenal cortex to release glucocorticoids like cortisol. Cortisol is vital for maintaining blood glucose levels. A lack of ACTH leads to low cortisol, causing hypoglycemia (low blood sugar) and chronic fatigue.
Q4. Which of the following is a key difference between inducible operons and repressible operons?
Correct Answer: (c)
(C) In inducible operons, repressor proteins can bind to the operator without the assistance of a corepressor. In repressible operons, the presence of a corepressor is required in order for the repressor protein to bind to the operator sequence. Choice (A) is incorrect because both inducible and repressible operons have promoter sequences. Operator sequences are present in both inducible and repressible operons, so choice (B) is incorrect. RNA polymerase does not require a corepressor in order to bind to the promoter in both inducible and repressible operons, so choice (D) is incorrect.
(C) In inducible operons, repressor proteins can bind to the operator without the assistance of a corepressor. In repressible operons, the presence of a corepressor is required in order for the repressor protein to bind to the operator sequence. Choice (A) is incorrect because both inducible and repressible operons have promoter sequences. Operator sequences are present in both inducible and repressible operons, so choice (B) is incorrect. RNA polymerase does not require a corepressor in order to bind to the promoter in both inducible and repressible operons, so choice (D) is incorrect.
Q5. You have identified a calcium storage disease in rats. How would this inability to store Ca2+ affect muscle contraction?
Correct Answer: (b)
During muscle contraction, calcium ions bind to troponin. This binding causes tropomyosin to shift away from actin’s myosin-binding sites, allowing cross-bridge formation. If Ca2+ cannot bind to troponin, the binding sites remain blocked, preventing muscle contraction.
During muscle contraction, calcium ions bind to troponin. This binding causes tropomyosin to shift away from actin’s myosin-binding sites, allowing cross-bridge formation. If Ca2+ cannot bind to troponin, the binding sites remain blocked, preventing muscle contraction.
Q6. In non-cyclic photophosphorylation, there is photolysis of 12 water molecules. How many H+ are formed ?
Correct Answer: (a)
Each molecule of water (H2O) split releases 2 protons (H+). Therefore, 12 molecules of water release 24 protons.
Each molecule of water (H2O) split releases 2 protons (H+). Therefore, 12 molecules of water release 24 protons.
Q7. Which hormone is used to induce rooting from cut end of the stem?
Correct Answer: (b)
Auxins like IBA and NAA are commonly used in horticulture to promote root formation on stem cuttings.
Auxins like IBA and NAA are commonly used in horticulture to promote root formation on stem cuttings.
Q8. In a food web, each successive trophic level has
Correct Answer: (b)
Following the 10% law of energy transfer, energy always decreases at each successive trophic level.
Following the 10% law of energy transfer, energy always decreases at each successive trophic level.
Q9. In respiration, largest amount of energy is produced in:
Correct Answer: (b)
The Krebs cycle coupled with the ETS (aerobic respiration) produces significantly more ATP (36-38) compared to glycolysis or fermentation (2).
The Krebs cycle coupled with the ETS (aerobic respiration) produces significantly more ATP (36-38) compared to glycolysis or fermentation (2).
Q10. Match the items given in column-I with their examples given in column-II and choose the correct answer.
| Column-I | Column-II |
|---|---|
| A. Free living aerobic nitrogen fixers | I. Anabaena and Nostoc |
| B. Anaerobic nitrogen fixers | II. Pseudomonas and Thiobacillus |
| C. Nitrogen fixing cyanobacteria | III. Nitrosomonas and Nitrococcus |
| D. Denitrifying bacteria | IV. Azotobacter and Beijernickia |
| E. Nitrifying bacteria. | V. Rhodospirillum |
Correct Answer: (a)
A-IV (Azotobacter), B-V (Rhodospirillum), C-I (Nostoc), D-II (Pseudomonas), E-III (Nitrosomonas).
A-IV (Azotobacter), B-V (Rhodospirillum), C-I (Nostoc), D-II (Pseudomonas), E-III (Nitrosomonas).
Q11. A scientist at a pharmaceutical company wants to create bacteria that will synthesize human growth hormone.
The scientist has successfully created a plasmid that contains the DNA code for the human growth hormone gene. Which technique should the scientist use to insert the plasmid into a cell?
The scientist has successfully created a plasmid that contains the DNA code for the human growth hormone gene. Which technique should the scientist use to insert the plasmid into a cell?
Correct Answer: (a)
Bacterial transformation inserts naked, foreign DNA into a bacterial cell. CRISPR-Cas9 is used for gene editing, not inserting plasmids into a cell, so choice (B) is incorrect. Choice (C) is incorrect because gel electrophoresis is used to separate DNA fragments according to their size. Polymerase chain reaction is used to amplify the number of copies of a specific DNA sequence, so choice (D) is incorrect.
Bacterial transformation inserts naked, foreign DNA into a bacterial cell. CRISPR-Cas9 is used for gene editing, not inserting plasmids into a cell, so choice (B) is incorrect. Choice (C) is incorrect because gel electrophoresis is used to separate DNA fragments according to their size. Polymerase chain reaction is used to amplify the number of copies of a specific DNA sequence, so choice (D) is incorrect.
Q12. Assertion: Baculoviruses are excellent for integrated pest management (IPM).
Reason: They have no negative impacts on non-target insects, mammals, or birds.
Correct Answer: (a)
Their species-specific nature makes them safe for beneficial organisms in an IPM program.
Their species-specific nature makes them safe for beneficial organisms in an IPM program.
Q13. The chromosomes in which centromere is situated close to one end are:
Correct Answer: (a)
In an acrocentric chromosome, the centromere is located near one end, resulting in one very short and one very long arm.
In an acrocentric chromosome, the centromere is located near one end, resulting in one very short and one very long arm.
Q14. Gills are found in
Correct Answer: (d)
Gills are the primary respiratory organs for most aquatic organisms. They are found in all fish, many aquatic invertebrates (such as crustaceans and mollusks), and the larval stages (or some adult forms like the axolotl) of many amphibians.
Gills are the primary respiratory organs for most aquatic organisms. They are found in all fish, many aquatic invertebrates (such as crustaceans and mollusks), and the larval stages (or some adult forms like the axolotl) of many amphibians.
Q15. Prezygotic isolating mechanisms include all of the following except
Correct Answer: (a)
Prezygotic isolating mechanisms are those that prevent the formation of a zygote. Courtship rituals (behavioral), habitat separation (ecological), and seasonal reproduction (temporal) all act before fertilization. Hybrid sterility occurs after a zygote has formed and developed into an adult, making it a postzygotic isolating mechanism.
Prezygotic isolating mechanisms are those that prevent the formation of a zygote. Courtship rituals (behavioral), habitat separation (ecological), and seasonal reproduction (temporal) all act before fertilization. Hybrid sterility occurs after a zygote has formed and developed into an adult, making it a postzygotic isolating mechanism.
Q16. If a drug inhibits the release of acetylcholine (ACh), what will happen?
Correct Answer: (b)
Acetylcholine is released at the neuromuscular junction to stimulate muscle fiber depolarization. If ACh release is inhibited, the nerve impulse cannot trigger muscle contraction, even though the neuron itself may still fire action potentials.
Acetylcholine is released at the neuromuscular junction to stimulate muscle fiber depolarization. If ACh release is inhibited, the nerve impulse cannot trigger muscle contraction, even though the neuron itself may still fire action potentials.
Q17. If the two genes in the previous question showed complete linkage, what would you predict for an F2 phenotypic ratio?
Correct Answer: (d)
With complete linkage, the alleles on the same chromosome are inherited as a unit. If Red (R) is linked with Tall (T) and White (W) with Short (t), the F1 (RT/Wt) produces only RT and Wt gametes. The cross (RT, Wt) × (RT, Wt) yields 1 RRTT (red tall), 2 RWTt (pink tall), and 1 WWtt (white short).
With complete linkage, the alleles on the same chromosome are inherited as a unit. If Red (R) is linked with Tall (T) and White (W) with Short (t), the F1 (RT/Wt) produces only RT and Wt gametes. The cross (RT, Wt) × (RT, Wt) yields 1 RRTT (red tall), 2 RWTt (pink tall), and 1 WWtt (white short).
Q18. Convergent evolution
Correct Answer: (b)
Convergent evolution occurs when unrelated or distantly related organisms independently evolve similar traits because they are subjected to similar selective pressures in their environments, such as the streamlined bodies of dolphins (mammals) and sharks (fish).
Convergent evolution occurs when unrelated or distantly related organisms independently evolve similar traits because they are subjected to similar selective pressures in their environments, such as the streamlined bodies of dolphins (mammals) and sharks (fish).
Q19. What property of DNA causes it to move toward the positive electrode in gel electrophoresis?
Correct Answer: (d)
The phosphates in the backbone of the DNA double helix have a slight negative charge and are attracted to the positive electrode. The nitrogen atoms in the nitrogenous bases are not charged, so choice (A) is incorrect. Hydrogen bonds between the base pairs do not result in a net negative charge, so choice (B) is incorrect. The oxygen atoms in the deoxyribose sugars are not charged, and thus choice (C) is incorrect.
The phosphates in the backbone of the DNA double helix have a slight negative charge and are attracted to the positive electrode. The nitrogen atoms in the nitrogenous bases are not charged, so choice (A) is incorrect. Hydrogen bonds between the base pairs do not result in a net negative charge, so choice (B) is incorrect. The oxygen atoms in the deoxyribose sugars are not charged, and thus choice (C) is incorrect.
Q20. Inorganic catalyst work efficiently at _______temperature and ________ pressure.
Correct Answer: (d)
Unlike organic enzymes which denature at high heat, inorganic catalysts often require and operate efficiently at high temperatures and pressures.
Unlike organic enzymes which denature at high heat, inorganic catalysts often require and operate efficiently at high temperatures and pressures.
Q21. Swimming underwater using forelimbs for propulsion is similar to flying through the air because
Correct Answer: (d)
Both swimming and flying rely on generating lift by pushing against a fluid medium (water or air). By exerting a downward force on the surrounding fluid, an upward lift force is generated, allowing the organism to remain suspended or move efficiently against gravity.
Both swimming and flying rely on generating lift by pushing against a fluid medium (water or air). By exerting a downward force on the surrounding fluid, an upward lift force is generated, allowing the organism to remain suspended or move efficiently against gravity.
Q22. Assertion: Hormone releasing IUDs make the cervix hostile to sperms.
Reason: They alter the quality of cervical mucus.
Correct Answer: (a)
Hormonal changes directly affect the mucus barrier at the cervix.
Hormonal changes directly affect the mucus barrier at the cervix.
Q23. Which of the following statement regarding the process of glycolysis is correct?
Correct Answer: (d)
Glycolysis is the partial oxidation of one molecule of glucose (6C) into two molecules of pyruvic acid (3C).
Glycolysis is the partial oxidation of one molecule of glucose (6C) into two molecules of pyruvic acid (3C).
Q24. Vernalization induces flowering following exposure to
Correct Answer: (c)
Vernalization is the acquisition of a plant's ability to flower in the spring by exposure to the prolonged cold of winter. This ensure that reproductive development occurs at an appropriate time.
Vernalization is the acquisition of a plant's ability to flower in the spring by exposure to the prolonged cold of winter. This ensure that reproductive development occurs at an appropriate time.
Q25. The phenomenon of Alternation of Generation is shown by:
Correct Answer: (d)
Alternation of generations is fundamental to the life cycle of all sexually reproducing plants.
Alternation of generations is fundamental to the life cycle of all sexually reproducing plants.
Q26. The bacteria which oxidize various inorganic substances and use the released energy for the synthesis of food are called _______________.
Correct Answer: (d)
Chemosynthetic autotrophs obtain energy by oxidizing inorganic substances like nitrates, nitrites, and ammonia, and use this energy for ATP production.
Chemosynthetic autotrophs obtain energy by oxidizing inorganic substances like nitrates, nitrites, and ammonia, and use this energy for ATP production.
Q27. From evolutionary point of view, retention of the female gametophyte with developing young embryo on the parent sporophyte for some time, is first observed in:
Correct Answer: (c)
This is a precursor to the seed habit, first seen in heterosporous pteridophytes.
This is a precursor to the seed habit, first seen in heterosporous pteridophytes.
Q28. Match the MTP legality grounds (2017 Amendment):
| Ground | Requirement |
|---|---|
| A. Up to 12 weeks | (I) Opinion of one doctor |
| B. 12 to 24 weeks | (II) Opinion of two doctors |
Correct Answer: (a)
Legal requirements for MTP in India (Page 46).
Legal requirements for MTP in India (Page 46).
Q29. Which of the following statement(s) is/are correct regarding class aves?
(i) The forelimbs are modified into wings and the hindlimbs generally have scales and are modified for walking, swimming or clasping the tree branches.
(ii) Heart is completely four-chambered.
(iii) They are warm-blooded (homoiothermous) animals i.e., they are able to maintain a constant body temperature.
(iv) They are oviparous and development is direct.
(i) The forelimbs are modified into wings and the hindlimbs generally have scales and are modified for walking, swimming or clasping the tree branches.
(ii) Heart is completely four-chambered.
(iii) They are warm-blooded (homoiothermous) animals i.e., they are able to maintain a constant body temperature.
(iv) They are oviparous and development is direct.
Correct Answer: (d)
All statements correctly describe Class Aves.
All statements correctly describe Class Aves.
Q30. Which of the following pair is correctly matched ?
Correct Answer: (a)
Anaphase I specifically involves the separation and poleward movement of homologous chromosomes.
Anaphase I specifically involves the separation and poleward movement of homologous chromosomes.
Q31. If the cells of root in wheat plant have 42 chromosomes, then the no. of chromosome in the cell of pollen grain is
Correct Answer: (b)
Root cells are diploid (2n = 42). Pollen grains are products of meiosis and are haploid (n), so 42 / 2 = 21.
Root cells are diploid (2n = 42). Pollen grains are products of meiosis and are haploid (n), so 42 / 2 = 21.
Q32. In IVF (In Vitro Fertilisation), where does the fertilisation occur?
Correct Answer: (b)
In vitro fertilisation (IVF–fertilisation outside the body in almost similar conditions as that in the body).
In vitro fertilisation (IVF–fertilisation outside the body in almost similar conditions as that in the body).
Q33. How do the muscles move your hand through space?
Correct Answer: (d)
Muscles generate movement by contracting and by being attached to bones across joints. When a muscle contracts, it pulls one bone toward another, resulting in movement of the hand through space. Muscles do not actively lengthen; they relax.
Muscles generate movement by contracting and by being attached to bones across joints. When a muscle contracts, it pulls one bone toward another, resulting in movement of the hand through space. Muscles do not actively lengthen; they relax.
Q34. With reference to double stranded DNA, The following ratio is always constant for all species
Correct Answer: (d)
According to Chargaff's rule, the ratio of Purines (A+G) to Pyrimidines (T+C) is always equal to one ($1:1$) in double-stranded DNA of all species.
According to Chargaff's rule, the ratio of Purines (A+G) to Pyrimidines (T+C) is always equal to one ($1:1$) in double-stranded DNA of all species.
Q35. Which is the important site of formation of glycoproteins and glycolipids in eukaryotic cells?
Correct Answer: (b)
The Golgi apparatus is the primary site for glycosylation in the cell.
The Golgi apparatus is the primary site for glycosylation in the cell.
Q36. Which one of the following combination is mismatched?
Correct Answer: (b)
Pili and fimbriae are surface appendages for attachment; pili can be involved in conjugation (genetic transfer) but not reproduction in the sense of multiplication.
Pili and fimbriae are surface appendages for attachment; pili can be involved in conjugation (genetic transfer) but not reproduction in the sense of multiplication.
Q37. The experiments with nutritional mutants in Neurospora by Beadle and Tatum provided evidence that
Correct Answer: (d)
Beadle and Tatum used X-rays to create mutations in Neurospora crassa and observed that these mutations caused deficiencies in specific metabolic pathways. Their work established the 'one gene-one enzyme' hypothesis, demonstrating that the primary function of a gene is to dictate the production of a specific enzyme.
Beadle and Tatum used X-rays to create mutations in Neurospora crassa and observed that these mutations caused deficiencies in specific metabolic pathways. Their work established the 'one gene-one enzyme' hypothesis, demonstrating that the primary function of a gene is to dictate the production of a specific enzyme.
Q38. Suppose that your research mentor has decided to do a project on the filtering capabilities of Malpighian tubules. Which of the following creatures will you be spending your summer studying?
Correct Answer: (a)
Malpighian tubules are the primary excretory structures found in insects. Ants, being insects, possess Malpighian tubules, whereas birds, mammals, and earthworms use different excretory mechanisms.
Malpighian tubules are the primary excretory structures found in insects. Ants, being insects, possess Malpighian tubules, whereas birds, mammals, and earthworms use different excretory mechanisms.
Q39. Which of the following structures is not found in a prokaryotic cell?
Correct Answer: (d)
Prokaryotes lack membrane-bound organelles, including a nuclear envelope.
Prokaryotes lack membrane-bound organelles, including a nuclear envelope.
Q40. Cytisus scoparius, also known as Scotch broom, was introduced into California from England in the mid-1800s as an easy-to-grow plant that helped stabilize soil on the hillsides. One Scotch broom plant can produce over 12,000 seeds a year. Scotch broom forms a dense shade canopy that prevents seedlings of other plants from growing. There are no natural predators for Scotch broom in California since its leaves are toxic to most animal species. Which of the following most accurately describes Scotch broom’s role in the California ecosystem?
Correct Answer: (b)
(B) Scotch broom is not native to California. It outcompetes other plants and has no natural predators in California, so it is an invasive species. Choice (A) is incorrect because if a keystone species is removed, the entire ecosystem may collapse. Removing Scotch broom would most likely help the ecosystem, not cause it to collapse. Scotch broom does not benefit other organisms in this ecosystem; therefore, it is not a mutualistic species and choice (C) is incorrect. Choice (D) is incorrect because Scotch broom is not native to California.
(B) Scotch broom is not native to California. It outcompetes other plants and has no natural predators in California, so it is an invasive species. Choice (A) is incorrect because if a keystone species is removed, the entire ecosystem may collapse. Removing Scotch broom would most likely help the ecosystem, not cause it to collapse. Scotch broom does not benefit other organisms in this ecosystem; therefore, it is not a mutualistic species and choice (C) is incorrect. Choice (D) is incorrect because Scotch broom is not native to California.
Q41. Which of the following could not be considered an ecosystem?
Correct Answer: (b)
An ecosystem must include both biotic communities and their abiotic environment. 'All the fish' represents only a part of the biotic component without the abiotic surroundings.
An ecosystem must include both biotic communities and their abiotic environment. 'All the fish' represents only a part of the biotic component without the abiotic surroundings.
Q42. If genomics found that the same mutation was present in all cancer patients that failed to respond to a particular treatment, what might be concluded?
Correct Answer: (a)
A consistent correlation between a specific genetic mutation and a physiological outcome (like drug resistance) strongly suggests a causative link. Identifying such mutations is the basis for pharmacogenomics, allowing doctors to tailor treatments to a patient's specific genetic profile.
A consistent correlation between a specific genetic mutation and a physiological outcome (like drug resistance) strongly suggests a causative link. Identifying such mutations is the basis for pharmacogenomics, allowing doctors to tailor treatments to a patient's specific genetic profile.
Q43. What causes a green plant exposed to the light on only one side, to bend toward the source of light as it grows?
Correct Answer: (c)
Phototropism is caused by the accumulation of auxin on the darker side of the stem, which stimulates cells on that side to elongate more than cells on the lighted side.
Phototropism is caused by the accumulation of auxin on the darker side of the stem, which stimulates cells on that side to elongate more than cells on the lighted side.
Q44. Regarding 'Methanogens', which statements are true?
(i) They grow anaerobically on cellulosic material.
(ii) They produce a large amount of methane.
(iii) They are found in the rumen of cattle and anaerobic sludge.
(i) They grow anaerobically on cellulosic material.
(ii) They produce a large amount of methane.
(iii) They are found in the rumen of cattle and anaerobic sludge.
Correct Answer: (a)
Full description of methanogens from section 8.4.
Full description of methanogens from section 8.4.
Q45. Generally, which type of data is considered most reliable when constructing phylogenies?
Correct Answer: (d)
(D) The DNA sequence of an organism is not affected by its environment or geological events, so it provides reliable evidence for ancestry of organisms. Fossils do not necessarily show when a species originated, so choice (A) is incorrect. Habitats and morphological characteristics can change during an organism’s lifetime, so choices (B) and (C) are incorrect.
(D) The DNA sequence of an organism is not affected by its environment or geological events, so it provides reliable evidence for ancestry of organisms. Fossils do not necessarily show when a species originated, so choice (A) is incorrect. Habitats and morphological characteristics can change during an organism’s lifetime, so choices (B) and (C) are incorrect.
Q46. A stage in cell division is shown in the figure. Select the answer which gives correct identification of the stage with its characteristics.
Correct Answer: (d)
The diagram shows two nuclei forming at the poles with the nuclear envelopes reappearing, which is the definitive event of telophase.
The diagram shows two nuclei forming at the poles with the nuclear envelopes reappearing, which is the definitive event of telophase.
Q47. Which one of the following promotes the abscission of older mature leaves and fruits?
Correct Answer: (a)
While auxins prevent abscission of young parts, they promote the abscission of older, mature leaves and fruits. (Wait, checking Key: 50(a). Indole compounds = Auxins).
While auxins prevent abscission of young parts, they promote the abscission of older, mature leaves and fruits. (Wait, checking Key: 50(a). Indole compounds = Auxins).
Q48. Match the androecium formula (given in column II) with their family (given in column I) and choose the correct combination from the options given below.
| Column-I (Family) | Column-II (Androecium formula) |
|---|---|
| A. Brassicaceae | I. A3 + 3 |
| B. Fabaceae | II. A(5) |
| C. Solanaceae | III. A(9) + 1 |
| D. Liliaceae | IV. A2 + 4 |
Correct Answer: (a)
Brassicaceae is tetradynamous (2+4). Fabaceae is diadelphous ((9)+1). Solanaceae has 5 stamens. Liliaceae has 6 stamens in two whorls (3+3).
Brassicaceae is tetradynamous (2+4). Fabaceae is diadelphous ((9)+1). Solanaceae has 5 stamens. Liliaceae has 6 stamens in two whorls (3+3).
Q49. In eukaryotes, the regulation of gene expression occurs
Correct Answer: (c)
Eukaryotic gene expression is highly complex and regulated at multiple stages. This includes chromatin remodeling, the regulation of transcription initiation, and extensive post-transcriptional mechanisms such as alternative splicing, mRNA degradation, and translational control.
Eukaryotic gene expression is highly complex and regulated at multiple stages. This includes chromatin remodeling, the regulation of transcription initiation, and extensive post-transcriptional mechanisms such as alternative splicing, mRNA degradation, and translational control.
Q50. Which of the following is not concern with cyclic photophosphorylation?
Correct Answer: (a)
Oxygen is only liberated during non-cyclic photophosphorylation because that is where the water-splitting PSII is active.
Oxygen is only liberated during non-cyclic photophosphorylation because that is where the water-splitting PSII is active.
Q51. You experience a longer period than normal between meals. Your body’s response to this will be to produce
Correct Answer: (b)
During periods of fasting (between meals), blood glucose levels drop. The pancreas responds by secreting glucagon, which stimulates the liver to break down glycogen into glucose and release it into the blood, thereby raising blood sugar levels back to homeostatic levels.
During periods of fasting (between meals), blood glucose levels drop. The pancreas responds by secreting glucagon, which stimulates the liver to break down glycogen into glucose and release it into the blood, thereby raising blood sugar levels back to homeostatic levels.
Q52. The ____ cannot be controlled by conscious thought.
Correct Answer: (c)
The autonomic nervous system regulates involuntary physiological processes such as heart rate, blood pressure, respiration, and digestion. In contrast, the somatic nervous system is associated with the voluntary control of body movements via skeletal muscles.
The autonomic nervous system regulates involuntary physiological processes such as heart rate, blood pressure, respiration, and digestion. In contrast, the somatic nervous system is associated with the voluntary control of body movements via skeletal muscles.
Q53. According to the 2011 census report, the population growth rate in India was:
Correct Answer: (c)
According to the 2011 census report, the population growth rate was less than 2 per cent.
According to the 2011 census report, the population growth rate was less than 2 per cent.
Q54. Auxin regulates cell growth by which of the following mechanisms?
Correct Answer: (b)
The 'Acid Growth Hypothesis' suggests auxins increase cell wall plasticity (extensibility) by triggering the pumping of H$^+$ ions into the wall.
The 'Acid Growth Hypothesis' suggests auxins increase cell wall plasticity (extensibility) by triggering the pumping of H$^+$ ions into the wall.
Q55. Proteins perform many physiological functions. For example some proteins function as enzymes. One of the following represents an additional function that some protein discharge
Correct Answer: (d)
Many vital hormones, such as insulin and growth hormone, are chemically proteins or polypeptides.
Many vital hormones, such as insulin and growth hormone, are chemically proteins or polypeptides.
Q56. Respiratory organs of invertebrates and vertebrates are similar in that
Correct Answer: (c)
Regardless of the specific structure (gills, lungs, or tracheae), all respiratory organs have evolved to maximize the surface area (A) available for gas exchange. A larger surface area allows more molecules to diffuse across the respiratory membrane simultaneously.
Regardless of the specific structure (gills, lungs, or tracheae), all respiratory organs have evolved to maximize the surface area (A) available for gas exchange. A larger surface area allows more molecules to diffuse across the respiratory membrane simultaneously.
Q57. Consider the given statements:
(1) Amino acids can be classified as alpha, beta, gamma, delta based on functional group.
(2) Only L-amino acids are obtained on hydrolysis of proteins.
(3) Glycine shows high optical activity
Which of the statement(s) given above is/are correct?
(1) Amino acids can be classified as alpha, beta, gamma, delta based on functional group.
(2) Only L-amino acids are obtained on hydrolysis of proteins.
(3) Glycine shows high optical activity
Which of the statement(s) given above is/are correct?
Correct Answer: (d)
Proteins consist only of L-amino acids. Amino acids are classified based on the position of the amino group relative to the carboxyl group. Glycine is achiral and thus optically inactive.
Proteins consist only of L-amino acids. Amino acids are classified based on the position of the amino group relative to the carboxyl group. Glycine is achiral and thus optically inactive.
Q58. Identify the wrong statement about meiosis
Correct Answer: (d)
Meiosis involves two cycles of nuclear division but only a single cycle of DNA replication.
Meiosis involves two cycles of nuclear division but only a single cycle of DNA replication.
Q59. Most carbon dioxide is
Correct Answer: (c)
Once carbon dioxide enters red blood cells, the enzyme carbonic anhydrase rapidly catalyzes the reaction between CO2 and H2O to form carbonic acid (H2CO3), which is a key intermediate step in the formation of bicarbonate for transport.
Once carbon dioxide enters red blood cells, the enzyme carbonic anhydrase rapidly catalyzes the reaction between CO2 and H2O to form carbonic acid (H2CO3), which is a key intermediate step in the formation of bicarbonate for transport.
Q60. Which of the following is NOT a component of a flower?
Correct Answer: (d)
A typical flower is composed of four whorls: sepals, petals, stamens, and carpels. A bract is a modified leaf that may be associated with a flower or inflorescence, but it is technically not part of the flower itself.
A typical flower is composed of four whorls: sepals, petals, stamens, and carpels. A bract is a modified leaf that may be associated with a flower or inflorescence, but it is technically not part of the flower itself.
Q61. Contraction of the smooth muscle layers of the arterioles
Correct Answer: (a)
Contraction of arteriole smooth muscle causes vasoconstriction, narrowing the lumen and increasing resistance to blood flow. It generally reduces, rather than increases, blood flow to an organ and decreases heat loss through the skin.
Contraction of arteriole smooth muscle causes vasoconstriction, narrowing the lumen and increasing resistance to blood flow. It generally reduces, rather than increases, blood flow to an organ and decreases heat loss through the skin.
Q62. Match the following and choose the correct option.
| Column - I | Column - II |
|---|---|
| A. Pioneer community on lithosphere | I. Crustose lichens |
| B. Ecological succession | II. Mesophytes |
| C. Climax community | III. Ecosystem development |
| D. Ecological pyramid | IV. Elton |
Correct Answer: (c)
Pioneers on rock are Lichens (I). Succession is overall ecosystem development (III). Climax species are often Mesophytes (II). Elton described ecological pyramids (IV).
Pioneers on rock are Lichens (I). Succession is overall ecosystem development (III). Climax species are often Mesophytes (II). Elton described ecological pyramids (IV).
Q63. How does maternal inheritance of mitochondrial genes differ from sex linkage?
Correct Answer: (c)
Mitochondria are found in the cytoplasm and are passed to offspring through the egg, not the sperm. Consequently, every child (male or female) inherits their mitochondria exclusively from their mother. In contrast, sex-linked traits show different inheritance ratios between sons and daughters.
Mitochondria are found in the cytoplasm and are passed to offspring through the egg, not the sperm. Consequently, every child (male or female) inherits their mitochondria exclusively from their mother. In contrast, sex-linked traits show different inheritance ratios between sons and daughters.
Q64. Imagine that you are doing an experiment on the movement of ions across neural membranes. Which of the following plays a role in determining the equilibrium concentration of ions across these membranes?
Correct Answer: (d)
The electrochemical gradient is the combined force of the chemical concentration gradient and the electrical gradient (charge difference) across a membrane. Together, these factors determine the direction and equilibrium of ion movement.
The electrochemical gradient is the combined force of the chemical concentration gradient and the electrical gradient (charge difference) across a membrane. Together, these factors determine the direction and equilibrium of ion movement.
Q65. FISH analysis of a breast tumor biopsy for HER2 gene reveals two spots of fluorescence in cells. What conclusion do these data support about the tumor?
Correct Answer: (d)
Fluorescence In Situ Hybridization (FISH) is used to visualize specific DNA sequences. Normal diploid cells have two copies of every gene. Since the analysis shows only two spots of fluorescence, the HER2 gene has not been duplicated or amplified. Because targeted therapies like Herceptin are only effective in tumors where the gene is amplified and overexpressing protein, these treatments would not be suitable for this patient.
Fluorescence In Situ Hybridization (FISH) is used to visualize specific DNA sequences. Normal diploid cells have two copies of every gene. Since the analysis shows only two spots of fluorescence, the HER2 gene has not been duplicated or amplified. Because targeted therapies like Herceptin are only effective in tumors where the gene is amplified and overexpressing protein, these treatments would not be suitable for this patient.
Q66. Which of the metabolites is common to respiration mediated breakdown of fats, carbohydrates and proteins?
Correct Answer: (c)
Acetyl CoA is the universal convergent point. Fats enter as acetyl CoA or DHAP, proteins as pyruvate/acetyl CoA/cycle intermediates, and carbohydrates as pyruvate then acetyl CoA.
Acetyl CoA is the universal convergent point. Fats enter as acetyl CoA or DHAP, proteins as pyruvate/acetyl CoA/cycle intermediates, and carbohydrates as pyruvate then acetyl CoA.
Q67. Read the given statements and answer the question.
(i) It includes unicellular as well as multicellular fungi.
(ii) In multicellular forms, hyphae are branched and septate.
(iii) Conidiophore produces conidia (spores) exogenously in chain.
(iv) Sexual spores are ascospores produced endogenously in chain.
(v) Fruiting body is called ascocarp.
Identify the correct class of fungi which have all the above given characteristics.
(i) It includes unicellular as well as multicellular fungi.
(ii) In multicellular forms, hyphae are branched and septate.
(iii) Conidiophore produces conidia (spores) exogenously in chain.
(iv) Sexual spores are ascospores produced endogenously in chain.
(v) Fruiting body is called ascocarp.
Identify the correct class of fungi which have all the above given characteristics.
Correct Answer: (b)
Sac fungi (Ascomycetes) produce ascospores in asci (endogenous) and conidia exogenously on conidiophores.
Sac fungi (Ascomycetes) produce ascospores in asci (endogenous) and conidia exogenously on conidiophores.
Q68. In which populations is genetic drift more likely to occur?
Correct Answer: (b)
(B) Genetic drift, the random loss of alleles, is more likely in small populations because in small populations, fewer individuals would have the opportunity to pass on a rare allele to the next generation than in a large population. Choice (A) is incorrect because it is the opposite of the correct answer. Greater diversity does not influence the chances of genetic drift, so choice (C) is incorrect. Choice (D) is incorrect because gene flow, or migration, does not necessarily cause genetic drift.
(B) Genetic drift, the random loss of alleles, is more likely in small populations because in small populations, fewer individuals would have the opportunity to pass on a rare allele to the next generation than in a large population. Choice (A) is incorrect because it is the opposite of the correct answer. Greater diversity does not influence the chances of genetic drift, so choice (C) is incorrect. Choice (D) is incorrect because gene flow, or migration, does not necessarily cause genetic drift.
Q69. Lactational amenorrhea is effective as a contraceptive for a maximum period of ______ months following parturition.
Correct Answer: (b)
Lactational amenorrhea... has been reported to be effective only upto a maximum period of six months following parturition.
Lactational amenorrhea... has been reported to be effective only upto a maximum period of six months following parturition.
Q70. Which of the following statements is accurate for DNA replication in your cells, but not PCR?
Correct Answer: (c)
During in vivo DNA replication, the lagging strand is synthesized in short Okazaki fragments that must be joined together by the enzyme DNA ligase. In PCR, the target sequence is typically small enough that the polymerase completes the entire strand from a single primer, and there are no fragments to seal. Furthermore, PCR uses heat-stable Taq polymerase, whereas human cells use heat-labile polymerases.
During in vivo DNA replication, the lagging strand is synthesized in short Okazaki fragments that must be joined together by the enzyme DNA ligase. In PCR, the target sequence is typically small enough that the polymerase completes the entire strand from a single primer, and there are no fragments to seal. Furthermore, PCR uses heat-stable Taq polymerase, whereas human cells use heat-labile polymerases.
Q71. Why do we need to be repeatedly vaccinated for influenza viruses?
Correct Answer: (b)
Influenza viruses frequently undergo antigenic variation by altering their surface proteins, allowing them to evade immune memory and necessitating repeated vaccination.
Influenza viruses frequently undergo antigenic variation by altering their surface proteins, allowing them to evade immune memory and necessitating repeated vaccination.
Q72. Sieve tubes are suited for translocation of food because they possess
Correct Answer: (c)
Sieve tube elements have perforated end walls (sieve plates) and a continuous lumen which allows for the efficient mass flow of nutrients.
Sieve tube elements have perforated end walls (sieve plates) and a continuous lumen which allows for the efficient mass flow of nutrients.
Q73. A student was given a specimen to identify on the basis of the characteristics given below.
(i) They are metamerically segmented.
(ii) They have closed circulatory system.
(iii) They have circular and longitudinal muscles for locomotion.
Identify the specimen.
(i) They are metamerically segmented.
(ii) They have closed circulatory system.
(iii) They have circular and longitudinal muscles for locomotion.
Identify the specimen.
Correct Answer: (b)
Description fits earthworms (Pheretima).
Description fits earthworms (Pheretima).
Q74. You study a gene known to be important in the early stages of heart development. Loss of the gene is also suspected to play a role in triggering lung cancer. What kind of transgenic mouse would you use to study your gene in vivo?
Correct Answer: (c)
A traditional knockout mouse lacks the gene from conception, which would likely result in embryonic lethality if the gene is essential for heart development. A conditional knockout allows the researcher to delete the gene at a specific time or in a specific tissue (such as the lungs of an adult mouse), allowing the study of its role in cancer without stopping development.
A traditional knockout mouse lacks the gene from conception, which would likely result in embryonic lethality if the gene is essential for heart development. A conditional knockout allows the researcher to delete the gene at a specific time or in a specific tissue (such as the lungs of an adult mouse), allowing the study of its role in cancer without stopping development.
Q75. The presence of a predatory species
Correct Answer: (b)
Predators can indirectly benefit certain prey species by reducing populations of their competitors, a phenomenon known as a trophic or indirect effect.
Predators can indirectly benefit certain prey species by reducing populations of their competitors, a phenomenon known as a trophic or indirect effect.
Q76. Which of the following describes 'Secondary Sewage Treatment' correctly?
(i) It is primarily a physical process.
(ii) Useful aerobic microbes grow into flocs.
(iii) It continues until the BOD of the effluent is reduced.
(i) It is primarily a physical process.
(ii) Useful aerobic microbes grow into flocs.
(iii) It continues until the BOD of the effluent is reduced.
Correct Answer: (a)
Primary treatment is physical; secondary is biological.
Primary treatment is physical; secondary is biological.
Q77. Two food chains are given below.
(i) Tree → aphid → insectivorous bird → prey feed on bird
(ii) Phytoplankton → zooplankton → plankton feeding fish → carnivorous fish
Which diagram is a pyramid of energy representing both food chains?
(i) Tree → aphid → insectivorous bird → prey feed on bird
(ii) Phytoplankton → zooplankton → plankton feeding fish → carnivorous fish
Which diagram is a pyramid of energy representing both food chains?
Correct Answer: (a)
Ecological pyramids of energy (a) are always upright, regardless of whether the ecosystem is terrestrial or aquatic.
Ecological pyramids of energy (a) are always upright, regardless of whether the ecosystem is terrestrial or aquatic.
Q78. A molecule of CO₂ that is generated in the cardiac muscle of the left ventricle would not pass through which of the following structures before leaving the body?
Correct Answer: (b)
CO₂ produced in the left ventricle enters the coronary circulation, returns to the right atrium, then passes through the right ventricle and lungs before being exhaled. It does not re-enter the left atrium before leaving the body.
CO₂ produced in the left ventricle enters the coronary circulation, returns to the right atrium, then passes through the right ventricle and lungs before being exhaled. It does not re-enter the left atrium before leaving the body.
Q79. Transition state structure of the substrate formed during an enzymatic reaction is.
Correct Answer: (b)
The transition state is a high-energy, very brief (transient) intermediate that exists only during the reaction process and is inherently unstable.
The transition state is a high-energy, very brief (transient) intermediate that exists only during the reaction process and is inherently unstable.
Q80. Which of the following is correct?
(i) Fertilisation is the fusion of sperm and ovum.
(ii) Zygote is diploid.
(iii) Insemination leads to fertilisation.
(i) Fertilisation is the fusion of sperm and ovum.
(ii) Zygote is diploid.
(iii) Insemination leads to fertilisation.
Correct Answer: (a)
Sequence of early reproductive events.
Sequence of early reproductive events.
Q81. G protein–coupled receptors are involved in the nervous system by
Correct Answer: (d)
G protein–coupled receptors (metabotropic receptors) act as postsynaptic receptors that, upon binding neurotransmitters, initiate complex intracellular signaling cascades. These are distinct from ionotropic receptors, which are ligand-gated ion channels themselves.
G protein–coupled receptors (metabotropic receptors) act as postsynaptic receptors that, upon binding neurotransmitters, initiate complex intracellular signaling cascades. These are distinct from ionotropic receptors, which are ligand-gated ion channels themselves.
Q82. Cytotoxic T cells are characterized by the
Correct Answer: (b)
Cytotoxic T cells express the CD8 co-receptor, which allows them to recognize antigens presented on MHC-I molecules of infected or abnormal cells and directly kill those cells.
Cytotoxic T cells express the CD8 co-receptor, which allows them to recognize antigens presented on MHC-I molecules of infected or abnormal cells and directly kill those cells.
Q83. In the Irish Setter, the overall red coat color is controlled by the melanocortin receptor. When this receptor is bound by MSH, dark eumelanin is produced. When bound by an antagonist, red pheomelanin is made. The red color is likely due to a mutation in the
Correct Answer: (b)
If the red coat color is caused by the antagonist successfully out-competing MSH or MSH failing to bind, a mutation that prevents the receptor from binding MSH would leave the receptor constantly available to the antagonist, leading to the permanent production of red pigment.
If the red coat color is caused by the antagonist successfully out-competing MSH or MSH failing to bind, a mutation that prevents the receptor from binding MSH would leave the receptor constantly available to the antagonist, leading to the permanent production of red pigment.
Q84. Bone develops by one of two mechanisms depending on the underlying scaffold. Which pairing correctly describes these mechanisms?
Correct Answer: (d)
Intramembranous ossification occurs when bone forms directly from embryonic mesenchymal tissue (common in flat bones of the skull). Endochondral ossification occurs when bone replaces a pre-existing hyaline cartilage model (common in long bones like the femur).
Intramembranous ossification occurs when bone forms directly from embryonic mesenchymal tissue (common in flat bones of the skull). Endochondral ossification occurs when bone replaces a pre-existing hyaline cartilage model (common in long bones like the femur).
Q85. You are designing a pesticide to disrupt the endocrine systems of arthropods without harming mammals. Which of the following substances should be the target of your investigations?
Correct Answer: (c)
Juvenile hormone is a crucial regulator of development, molting, and metamorphosis specifically in insects and other arthropods. Because mammals do not utilize this hormone, targeting it allows for a pesticide that is highly specific to pests with minimal risk to humans.
Juvenile hormone is a crucial regulator of development, molting, and metamorphosis specifically in insects and other arthropods. Because mammals do not utilize this hormone, targeting it allows for a pesticide that is highly specific to pests with minimal risk to humans.
Q86. “G0” state of cells in eukaryotic cell cycle denotes
Correct Answer: (d)
Cells that do not divide further exit the G1 phase to enter an inactive stage called quiescent stage (G0) of the cell cycle.
Cells that do not divide further exit the G1 phase to enter an inactive stage called quiescent stage (G0) of the cell cycle.
Q87. Leaves of dicotyledonous plants possess _________ venation, while _________ venation is the characteristic of most monocotyledons.
Correct Answer: (a)
Reticulate venation (network) is common in dicots; parallel venation is characteristic of monocots.
Reticulate venation (network) is common in dicots; parallel venation is characteristic of monocots.
Q88. Column-I contains organisms and column-II contains their excretory structures. Choose the correct match form the options given below.
| Column- I (Organism) | Column -II (Excretory structures) |
|---|---|
| A. Cockroach | I. Nephridia |
| B. Cat fish | II. Malpighian tubules |
| C. Earthworm | III. Kidneys |
| D. Balanoglossus | IV. Flame cells |
| E. Flatworm | V. Proboscis gland |
Correct Answer: (d)
A-II; B-III; C-I; D-V; E-IV.
A-II; B-III; C-I; D-V; E-IV.
Q89. As you sit quietly reading this sentence, the part of the nervous system that is most active is the
Correct Answer: (c)
The parasympathetic nervous system is the 'rest and digest' division of the autonomic nervous system. It predominates during periods of relaxation and low stress, maintaining homeostatic functions and conserving energy.
The parasympathetic nervous system is the 'rest and digest' division of the autonomic nervous system. It predominates during periods of relaxation and low stress, maintaining homeostatic functions and conserving energy.
Q90. Match column I (containing fungus name) with column II (common name) and choose the correct options.
| Column-I (Fungus name) | Column-II (Commonly called) |
|---|---|
| A. Puccinia | I. Yeast |
| B. Ustilago | II. Mushroom |
| C. Agaricus | III. Smut fungus |
| D. Saccharomyces | IV. Rust fungus |
Correct Answer: (d)
Puccinia - Rust; Ustilago - Smut; Agaricus - Mushroom; Saccharomyces - Yeast.
Puccinia - Rust; Ustilago - Smut; Agaricus - Mushroom; Saccharomyces - Yeast.