1. The Royal Botanic Garden, Kew, and the National Botanical Research Institute (NBRI) are located respectively in:
Correct Answer: A (England and Lucknow)
The Royal Botanic Garden is in Kew (England), the Indian Botanical Garden is in Howrah (Kolkata), and the National Botanical Research Institute (NBRI) is in Lucknow.
The Royal Botanic Garden is in Kew (England), the Indian Botanical Garden is in Howrah (Kolkata), and the National Botanical Research Institute (NBRI) is in Lucknow.
2. Which photosynthetic protist group features two flagella and acts mixotrophically as autotrophs in sunlight and heterotrophic predators in darkness?
Correct Answer: C (Euglenoids)
Euglenoids possess an anterior pocket with one long and one short flagellum, photosynthesizing in sunlight but predating smaller organisms when light is absent (mixotrophy).
Euglenoids possess an anterior pocket with one long and one short flagellum, photosynthesizing in sunlight but predating smaller organisms when light is absent (mixotrophy).
3. The rust fungus Puccinia graminis and the loose smut fungus Ustilago belong to the class:
Correct Answer: C (Basidiomycetes)
Basidiomycetes (club fungi) produce basidiospores exogenously and include mushrooms (Agaricus), rust fungi (Puccinia), and smut fungi (Ustilago).
Basidiomycetes (club fungi) produce basidiospores exogenously and include mushrooms (Agaricus), rust fungi (Puccinia), and smut fungi (Ustilago).
4. Prions, which cause bovine spongiform encephalopathy (Mad Cow disease) and Creutzfeldt-Jakob disease (CJD) in humans, are:
Correct Answer: B (Abnormally folded infectious proteinaceous agents)
Prions are infectious neurological agents composed solely of abnormally folded proteins lacking nucleic acids.
Prions are infectious neurological agents composed solely of abnormally folded proteins lacking nucleic acids.
5. The plant body in brown algae (Phaeophyceae) is attached to the substratum by a ______ and possesses a stalk called ______ and a leaf-like photosynthetic organ called ______:
Correct Answer: A (Holdfast; Stipe; Frond)
In Phaeophyceae (e.g., Fucus, Laminaria, Dictyota), the thallus is anchored by a basal holdfast, supported by a stem-like stipe, and carries a photosynthetic frond.
In Phaeophyceae (e.g., Fucus, Laminaria, Dictyota), the thallus is anchored by a basal holdfast, supported by a stem-like stipe, and carries a photosynthetic frond.
6. The independent, photosynthetic, cordate (heart-shaped) gametophytic thallus of a homosporous fern is the:
Correct Answer: B (Prothallus)
Fern spores germinate into a small, multicellular, free-living, photosynthetic thalloid gametophyte called a prothallus that bears antheridia and archegonia.
Fern spores germinate into a small, multicellular, free-living, photosynthetic thalloid gametophyte called a prothallus that bears antheridia and archegonia.
7. Mycorrhizal roots that form an obligate symbiotic association with soil fungi are a diagnostic feature of:
Correct Answer: B (Pinus)
Pinus roots feature an obligate mycorrhizal association; its seeds cannot germinate and establish without fungal symbionts. Cycas has coralloid roots with cyanobacteria.
Pinus roots feature an obligate mycorrhizal association; its seeds cannot germinate and establish without fungal symbionts. Cycas has coralloid roots with cyanobacteria.
8. Alternation of generations between an asexual sessile polyp and a sexual free-swimming medusa (Metagenesis) occurs in:
Correct Answer: C (Obelia)
Obelia exhibits metagenesis where polyps produce medusae asexually, and medusae reproduce sexually to form new polyps.
Obelia exhibits metagenesis where polyps produce medusae asexually, and medusae reproduce sexually to form new polyps.
9. Parapodia with lateral setae used for swimming and locomotion are found in which aquatic annelid?
Correct Answer: B (Nereis)
Nereis is a dioecious aquatic annelid possessing unjointed lateral muscular appendages called parapodia that aid in swimming and gas exchange.
Nereis is a dioecious aquatic annelid possessing unjointed lateral muscular appendages called parapodia that aid in swimming and gas exchange.
10. Sea squirts like Ascidia and Salpa belong to which subphylum of Chordata?
Correct Answer: A (Urochordata)
Urochordata (Tunicata) organisms have notochords restricted to the larval tail stage. Cephalochordates (Branchiostoma/Amphioxus) retain notochords from head to tail throughout life.
Urochordata (Tunicata) organisms have notochords restricted to the larval tail stage. Cephalochordates (Branchiostoma/Amphioxus) retain notochords from head to tail throughout life.
11. A modified petiole that expands, turns green, and carries out photosynthesis in plants with reduced or short-lived leaflets (e.g., Australian Acacia) is a:
Correct Answer: C (Phyllode)
In Australian Acacia, the bipinnate leaflets drop early, and the petiole flattens into a green photosynthetic structure called a phyllode.
In Australian Acacia, the bipinnate leaflets drop early, and the petiole flattens into a green photosynthetic structure called a phyllode.
12. In family Brassicaceae (Cruciferae, e.g., Mustard), the tetradynamous stamen condition consists of:
Correct Answer: B (6 stamens: 2 short outer and 4 long inner)
Tetradynamous androecium (2 + 4 arrangement) features two shorter outer lateral stamens and four longer inner median stamens, characteristic of crucifers.
Tetradynamous androecium (2 + 4 arrangement) features two shorter outer lateral stamens and four longer inner median stamens, characteristic of crucifers.
13. Free-central placentation where ovules are borne on a central axis and unilocular ovaries lack septa is observed in:
Correct Answer: C (Dianthus and Primrose)
In free-central placentation, ovules arise along a central column within a single-chambered ovary devoid of dividing partitions/septa (Dianthus, Primula).
In free-central placentation, ovules arise along a central column within a single-chambered ovary devoid of dividing partitions/septa (Dianthus, Primula).
14. Sieve tube elements in angiosperm phloem are living conducting cells that:
Correct Answer: B (Peripheral cytoplasm and large vacuole, but lack a nucleus at maturity)
Mature sieve tube elements lack a nucleus; their cellular functions are governed by the nucleus of adjoining companion cells through plasmodesmata.
Mature sieve tube elements lack a nucleus; their cellular functions are governed by the nucleus of adjoining companion cells through plasmodesmata.
15. In dorsiventral (dicotyledonous) leaves, palisade parenchyma consists of vertically elongated, parallel cells located toward the:
Correct Answer: A (Adaxial upper epidermis)
Dicot leaf mesophyll is differentiated into adaxial columnar palisade parenchyma packed with chloroplasts and loosely arranged abaxial spongy parenchyma with air cavities.
Dicot leaf mesophyll is differentiated into adaxial columnar palisade parenchyma packed with chloroplasts and loosely arranged abaxial spongy parenchyma with air cavities.
16. Specialized fat-storing connective tissue located beneath the skin and around internal visceral organs like kidneys is:
Correct Answer: B (Adipose tissue)
Adipose tissue is a modified loose connective tissue where adipocytes store neutral lipid droplets for energy reserve, cushioning, and thermal insulation.
Adipose tissue is a modified loose connective tissue where adipocytes store neutral lipid droplets for energy reserve, cushioning, and thermal insulation.
17. In frogs, the digestive stomach wall secretes hydrochloric acid (HCl) and gastric juices from:
Correct Answer: B (Oxyntic and peptic gastric glands)
The frog gastric mucosa contains glands secreting HCl (oxyntic cells) and pepsinogen (peptic cells) to convert swallowed prey into acidic chyme.
The frog gastric mucosa contains glands secreting HCl (oxyntic cells) and pepsinogen (peptic cells) to convert swallowed prey into acidic chyme.
18. The systemic arterial trunk arising from the single ventricle of a frog’s heart that branches into three pairs of aortic arches is the:
Correct Answer: B (Truncus arteriosus)
Blood from the frog ventricle enters the ventral truncus arteriosus, which splits into paired carotid, systemic, and pulmo-cutaneous arches.
Blood from the frog ventricle enters the ventral truncus arteriosus, which splits into paired carotid, systemic, and pulmo-cutaneous arches.
19. In male frogs, the functional connection linking the testes to Bidder’s canal in the kidneys comprises:
Correct Answer: A (10 to 12 Vasa efferentia)
About 10–12 vasa efferentia emerge from each testis, pass through the mesorchium, and open into Bidder’s canal within the kidney.
About 10–12 vasa efferentia emerge from each testis, pass through the mesorchium, and open into Bidder’s canal within the kidney.
20. The sensory touch organs (tangoreceptors) in a frog’s skin are termed:
Correct Answer: B (Sensory papillae)
Frogs have sensory papillae for touch (tangoreceptors), taste buds (gustatoreceptors), nasal epithelium (olfactoreceptors), eyes (photoreceptors), and tympana (audioreceptors).
Frogs have sensory papillae for touch (tangoreceptors), taste buds (gustatoreceptors), nasal epithelium (olfactoreceptors), eyes (photoreceptors), and tympana (audioreceptors).
21. Plasmodesmata in plant tissues are specialized structures that:
Correct Answer: B (Connect cytoplasm of adjacent cells through channels traversing cell walls)
Plasmodesmata are microscopic symplastic channels containing desmotubules (derived from ER) that allow direct cytoplasmic transport of ions and signaling molecules between plant cells.
Plasmodesmata are microscopic symplastic channels containing desmotubules (derived from ER) that allow direct cytoplasmic transport of ions and signaling molecules between plant cells.
22. Rough Endoplasmic Reticulum (RER) is observed in high abundance in cells actively engaged in:
Correct Answer: C (Protein synthesis and secretion)
RER is studded with 80S ribosomes on its cytosolic face and predominates in cells specialized for export protein synthesis (e.g., digestive enzymes, antibody secretion).
RER is studded with 80S ribosomes on its cytosolic face and predominates in cells specialized for export protein synthesis (e.g., digestive enzymes, antibody secretion).
23. In chloroplasts, the flat, membranous sacks arranged in stacks like piles of coins within the stroma are called:
Correct Answer: C (Thylakoids arranged as Grana)
Thylakoids are disc-shaped sacs stacked into grana that contain photosynthetic pigments, photosystems, and ATP synthases in their membranes.
Thylakoids are disc-shaped sacs stacked into grana that contain photosynthetic pigments, photosystems, and ATP synthases in their membranes.
24. The primary protein subunit that polymerizes to form eukaryotic microfilaments involved in amoeboid movement and cleavage furrow formation is:
Correct Answer: B (Actin)
Microfilaments are helical filaments of globular G-actin that drive cytoplasmic streaming, pseudopod extension, and the contractile ring during cytokinesis.
Microfilaments are helical filaments of globular G-actin that drive cytoplasmic streaming, pseudopod extension, and the contractile ring during cytokinesis.
25. Which of the following is a non-reducing disaccharide composed of glucose and fructose linked by an alpha-1,beta-2-glycosidic bond?
Correct Answer: C (Sucrose)
Sucrose is a non-reducing sugar because the anomeric carbons of both glucose (C1) and fructose (C2) participate in the glycosidic bond, leaving no free aldehyde or ketone group.
Sucrose is a non-reducing sugar because the anomeric carbons of both glucose (C1) and fructose (C2) participate in the glycosidic bond, leaving no free aldehyde or ketone group.
26. Collagen is the most abundant protein in the animal world, while the most abundant protein in the whole of the biosphere is:
Correct Answer: B (RuBisCO)
Collagen is the primary structural protein in animals, while RuBisCO in chloroplasts constitutes the most abundant protein on Earth.
Collagen is the primary structural protein in animals, while RuBisCO in chloroplasts constitutes the most abundant protein on Earth.
27. Malonate acts as a competitive inhibitor of the enzyme succinate dehydrogenase because it:
Correct Answer: B (Closely resembles the substrate succinate in structure)
Malonate is a structural analog of succinate that competes for the catalytic active site of succinate dehydrogenase without yielding fumarate.
Malonate is a structural analog of succinate that competes for the catalytic active site of succinate dehydrogenase without yielding fumarate.
28. In human somatic cells undergoing mitosis, if the cell has 46 chromosomes at G1, what will be the chromosome number and chromatid number at Metaphase?
Correct Answer: A (46 chromosomes and 92 sister chromatids)
DNA replicates in S-phase without changing chromosome number (2n = 46). Each metaphase chromosome consists of two sister chromatids joined at the centromere (92 total chromatids).
DNA replicates in S-phase without changing chromosome number (2n = 46). Each metaphase chromosome consists of two sister chromatids joined at the centromere (92 total chromatids).
29. Complete morphological disappearance of the nucleolus and disintegration of the nuclear envelope occur by the end of:
Correct Answer: A (Prophase)
Late prophase is marked by chromatin condensing into visible chromosomes, spindle assembly, nucleolus disappearance, and nuclear envelope breakdown.
Late prophase is marked by chromatin condensing into visible chromosomes, spindle assembly, nucleolus disappearance, and nuclear envelope breakdown.
30. During which stage of Meiosis I do homologous chromosomes separate to opposite poles while sister chromatids remain attached at their centromeres?
Correct Answer: B (Anaphase I)
In meiotic Anaphase I, homologous chromosome pairs disjoin and move to opposite poles without centromere division (reducing ploidy from 2n to n). Centromeres divide in Anaphase II.
In meiotic Anaphase I, homologous chromosome pairs disjoin and move to opposite poles without centromere division (reducing ploidy from 2n to n). Centromeres divide in Anaphase II.
31. The primary photosynthetic pigment that appears bright or blue-green on a paper chromatogram is:
Correct Answer: A (Chlorophyll a)
Paper chromatography reveals Chlorophyll a as blue-green, Chlorophyll b as yellow-green, Xanthophylls as yellow, and Carotenoids as yellow to yellow-orange.
Paper chromatography reveals Chlorophyll a as blue-green, Chlorophyll b as yellow-green, Xanthophylls as yellow, and Carotenoids as yellow to yellow-orange.
32. The enzyme responsible for primary atmospheric CO2 fixation in C3 chloroplasts is:
Correct Answer: B (RuBisCO)
In C3 plants, RuBisCO catalyzes the carboxylation of 5-carbon ribulose-1,5-bisphosphate (RuBP) to yield two 3-carbon molecules of 3-phosphoglycerate (3-PGA).
In C3 plants, RuBisCO catalyzes the carboxylation of 5-carbon ribulose-1,5-bisphosphate (RuBP) to yield two 3-carbon molecules of 3-phosphoglycerate (3-PGA).
33. In C4 plants, the initial 4-carbon acid Oxaloacetate (OAA) is reduced in mesophyll cells to form ______ before transport into bundle sheath cells:
Correct Answer: B (Malic acid or Aspartic acid)
OAA formed in mesophyll cells is converted into malate (or aspartate) and moved through plasmodesmata into bundle sheath cells for decarboxylation.
OAA formed in mesophyll cells is converted into malate (or aspartate) and moved through plasmodesmata into bundle sheath cells for decarboxylation.
34. Photorespiratory loss of carbon occurs because RuBisCO fixes oxygen instead of carbon dioxide, leading to the release of CO2 in the:
Correct Answer: C (Mitochondria during conversion of glycine to serine)
In photorespiration, two glycine molecules condense into one serine molecule inside the mitochondrion, releasing one molecule of CO2 and NH3.
In photorespiration, two glycine molecules condense into one serine molecule inside the mitochondrion, releasing one molecule of CO2 and NH3.
35. Glycolysis breaks down 1 molecule of Glucose (6C) into 2 molecules of:
Correct Answer: A (Pyruvic acid)
Glycolysis consists of 10 sequential enzymatic steps that convert 1 six-carbon glucose molecule into 2 three-carbon pyruvic acid molecules.
Glycolysis consists of 10 sequential enzymatic steps that convert 1 six-carbon glucose molecule into 2 three-carbon pyruvic acid molecules.
36. The step in cellular respiration that couples glycolysis in the cytoplasm to the Krebs cycle in the mitochondrial matrix is catalyzed by:
Correct Answer: B (Pyruvate dehydrogenase complex)
The link reaction oxidatively decarboxylates pyruvate into 2-carbon Acetyl-CoA, reducing NAD+ to NADH and releasing CO2 inside the matrix.
The link reaction oxidatively decarboxylates pyruvate into 2-carbon Acetyl-CoA, reducing NAD+ to NADH and releasing CO2 inside the matrix.
37. In the mitochondrial Krebs cycle, the 6-carbon Citric acid is formed by condensing Acetyl-CoA with:
Correct Answer: B (Oxaloacetic acid)
Citrate synthase combines 2-carbon Acetyl-CoA with 4-carbon Oxaloacetic acid (OAA) and water to generate 6-carbon Citric acid.
Citrate synthase combines 2-carbon Acetyl-CoA with 4-carbon Oxaloacetic acid (OAA) and water to generate 6-carbon Citric acid.
38. In the mitochondrial electron transport system, protons (H+) are pumped from the matrix into the intermembrane space by:
Correct Answer: A (Complexes I, III, and IV)
Complexes I, III, and IV pump protons into the intermembrane space as electrons pass through, creating an electrochemical gradient that drives ATP synthesis through Complex V.
Complexes I, III, and IV pump protons into the intermembrane space as electrons pass through, creating an electrochemical gradient that drives ATP synthesis through Complex V.
39. The plant hormone responsible for initiating rooting in stem cuttings, promoting flowering in pineapples, and preventing premature fruit drop is:
Correct Answer: A (Auxin)
Auxins (such as indole-3-butyric acid and naphthalene acetic acid) induce adventitious root initiation in vegetative propagation and prevent premature leaf/fruit drop.
Auxins (such as indole-3-butyric acid and naphthalene acetic acid) induce adventitious root initiation in vegetative propagation and prevent premature leaf/fruit drop.
40. The plant hormone that breaks seed and bud dormancy, initiates peanut seed germination, and promotes rapid internode elongation in deep-water rice plants is:
Correct Answer: B (Ethylene)
Ethylene breaks seed/bud dormancy, promotes root hair development, and drives rapid petiole/internode elongation in submerged deep-water rice to keep leaves above water.
Ethylene breaks seed/bud dormancy, promotes root hair development, and drives rapid petiole/internode elongation in submerged deep-water rice to keep leaves above water.
41. Respiratory disorder Asthma is clinically characterized by difficulty in breathing and wheezing caused by:
Correct Answer: B (Inflammation and bronchospasm of bronchi and bronchioles)
Asthma is an allergic inflammatory disorder of the lower airways marked by smooth muscle spasm in bronchi and bronchioles, mucosal edema, and wheezing.
Asthma is an allergic inflammatory disorder of the lower airways marked by smooth muscle spasm in bronchi and bronchioles, mucosal edema, and wheezing.
42. About what percentage of oxygen is transported bound to hemoglobin as oxyhemoglobin, and what percentage is carried dissolved in plasma?
Correct Answer: B (97% bound to hemoglobin and 3% dissolved in plasma)
About 97% of oxygen binds reversibly to iron in hemoglobin within RBCs to form oxyhemoglobin, while the remaining 3% dissolves in plasma water.
About 97% of oxygen binds reversibly to iron in hemoglobin within RBCs to form oxyhemoglobin, while the remaining 3% dissolves in plasma water.
43. Which white blood cells are phagocytic granulocytes that form the first line of defense against invading bacterial pathogens?
Correct Answer: C (Neutrophils)
Neutrophils (polymorphonuclear leukocytes) are the most abundant circulating leukocytes (60–65%), rapidly migrating to infection sites to phagocytose pathogens.
Neutrophils (polymorphonuclear leukocytes) are the most abundant circulating leukocytes (60–65%), rapidly migrating to infection sites to phagocytose pathogens.
44. The Sinoatrial Node (SAN) initiates electrical impulses in the human heart because it:
Correct Answer: B (Generates action potentials spontaneously at the highest rate)
The SAN is the natural pacemaker located in the upper right wall of the right atrium because its auto-rhythmic nodal cells discharge at the highest inherent frequency (70–75 bpm).
The SAN is the natural pacemaker located in the upper right wall of the right atrium because its auto-rhythmic nodal cells discharge at the highest inherent frequency (70–75 bpm).
45. High blood osmolarity sensed by hypothalamic osmoreceptors stimulates the posterior pituitary (neurohypophysis) to release:
Correct Answer: B (Antidiuretic Hormone)
Dehydration or elevated blood osmolarity stimulates hypothalamic osmoreceptors to trigger ADH release from the posterior pituitary, inserting aquaporins into collecting ducts to conserve water.
Dehydration or elevated blood osmolarity stimulates hypothalamic osmoreceptors to trigger ADH release from the posterior pituitary, inserting aquaporins into collecting ducts to conserve water.
46. The presence of excess urea in the blood resulting from acute or chronic renal failure is termed:
Correct Answer: A (Uraemia)
Kidney dysfunction prevents adequate nitrogenous filtration, leading to toxic urea accumulation in blood (uraemia), which requires hemodialysis or renal transplantation.
Kidney dysfunction prevents adequate nitrogenous filtration, leading to toxic urea accumulation in blood (uraemia), which requires hemodialysis or renal transplantation.
47. The total number of vertebrae in the adult human vertebral column is 26, arranged in the formula:
Correct Answer: A (C7 T12 L5 S1 Co1)
The adult vertebral column comprises 7 cervical, 12 thoracic, 5 lumbar, 1 fused sacrum (from 5), and 1 fused coccyx (from 4), totalling 26 skeletal units.
The adult vertebral column comprises 7 cervical, 12 thoracic, 5 lumbar, 1 fused sacrum (from 5), and 1 fused coccyx (from 4), totalling 26 skeletal units.
48. Rapid, wild muscle spasms (Tetany) occur due to:
Correct Answer: B (Hypocalcemia)
Hypocalcemia (low extracellular ionized calcium) increases neuronal membrane permeability to sodium, causing spontaneous depolarization and sustained, painful muscle spasms (tetany).
Hypocalcemia (low extracellular ionized calcium) increases neuronal membrane permeability to sodium, causing spontaneous depolarization and sustained, painful muscle spasms (tetany).
49. The protective meninges covering the brain from outside to inside consist of:
Correct Answer: A (Dura mater -> Arachnoid mater -> Pia mater)
Cranial meninges comprise the tough outer Dura mater, the web-like middle Arachnoid mater, and the vascular inner Pia mater in direct contact with brain tissue.
Cranial meninges comprise the tough outer Dura mater, the web-like middle Arachnoid mater, and the vascular inner Pia mater in direct contact with brain tissue.
50. Diabetes insipidus differs from Diabetes mellitus because Diabetes insipidus is caused by:
Correct Answer: B (ADH hyposecretion causing excretion of dilute urine without sugar)
Diabetes insipidus results from ADH deficiency, preventing water reabsorption in collecting ducts and causing extreme polyuria and polydipsia with normal glucose levels.
Diabetes insipidus results from ADH deficiency, preventing water reabsorption in collecting ducts and causing extreme polyuria and polydipsia with normal glucose levels.
51. The inner wall layer of the pollen grain (intine) is composed of:
Correct Answer: B (Cellulose and Pectin)
The outer exine is composed of resistant sporopollenin, while the thin, continuous inner intine is made of cellulose and pectin.
The outer exine is composed of resistant sporopollenin, while the thin, continuous inner intine is made of cellulose and pectin.
52. A false fruit (pseudocarp) is one where floral parts other than the ovary contribute to its formation, as seen in:
Correct Answer: B (Apple, Strawberry, and Cashew)
In false fruits like apple, pear, and strawberry, the fleshy edible portion develops from the floral thalamus rather than the ovary wall.
In false fruits like apple, pear, and strawberry, the fleshy edible portion develops from the floral thalamus rather than the ovary wall.
53. Apomictic seeds are commercially valuable in agriculture primarily because they:
Correct Answer: B (Maintain hybrid vigor across generations without segregation)
Apomixis produces clonal seeds without meiosis or fertilization, allowing farmers to save and replant hybrid seed without losing hybrid vigor.
Apomixis produces clonal seeds without meiosis or fertilization, allowing farmers to save and replant hybrid seed without losing hybrid vigor.
54. In the human male reproductive system, the glans penis is covered by a loose retractable fold of skin called the:
Correct Answer: A (Foreskin / Prepuce)
The enlarged distal end of the penis is the glans penis, covered by a loose fold of muco-cutaneous skin called the prepuce (foreskin).
The enlarged distal end of the penis is the glans penis, covered by a loose fold of muco-cutaneous skin called the prepuce (foreskin).
55. Gametogenesis produces haploid gametes. In human males and females, the ploidy of primary spermatocytes and secondary oocytes is respectively:
Correct Answer: B (Diploid 2n and Haploid n)
Primary spermatocytes are diploid ($2n=46$) before entering Meiosis I. Secondary oocytes are haploid ($n=23$), formed after completing the first reductional meiotic division.
Primary spermatocytes are diploid ($2n=46$) before entering Meiosis I. Secondary oocytes are haploid ($n=23$), formed after completing the first reductional meiotic division.
56. Menstruation in human females occurs due to the withdrawal of which ovarian hormone?
Correct Answer: C (Progesterone)
When fertilization does not occur, the corpus luteum degenerates, causing progesterone levels to plummet and triggering the breakdown and shedding of the functional endometrium.
When fertilization does not occur, the corpus luteum degenerates, causing progesterone levels to plummet and triggering the breakdown and shedding of the functional endometrium.
57. Implantation of the human blastocyst into the uterine endometrium typically occurs how many days after fertilization?
Correct Answer: B (Around 6 to 7 days post-fertilization)
The fertilized zygote cleaves into a blastocyst as it travels down the fallopian tube, hatching from the zona pellucida and implanting into the endometrium around days 6–7.
The fertilized zygote cleaves into a blastocyst as it travels down the fallopian tube, hatching from the zona pellucida and implanting into the endometrium around days 6–7.
58. The major hormone responsible for stimulating milk synthesis in mammary alveoli during lactation is:
Correct Answer: B (Prolactin)
Prolactin from the anterior pituitary stimulates milk synthesis by alveolar epithelial cells, while oxytocin from the posterior pituitary mediates milk ejection (let-down reflex).
Prolactin from the anterior pituitary stimulates milk synthesis by alveolar epithelial cells, while oxytocin from the posterior pituitary mediates milk ejection (let-down reflex).
59. Contraceptive oral pills contain progestogen or progestogen-estrogen combinations that work primarily by:
Correct Answer: A (Inhibiting ovulation and altering cervical mucus)
Combined pills exert negative feedback on pituitary LH/FSH secretion to suppress ovulation while thickening cervical mucus to impede sperm motility.
Combined pills exert negative feedback on pituitary LH/FSH secretion to suppress ovulation while thickening cervical mucus to impede sperm motility.
60. In an infertility treatment protocol, Intra-Uterine Insemination (IUI) involves:
Correct Answer: B (Introducing processed semen directly into the uterus)
In IUI, washed and concentrated sperm from the partner or donor is introduced directly into the uterine cavity via a catheter around the time of ovulation.
In IUI, washed and concentrated sperm from the partner or donor is introduced directly into the uterine cavity via a catheter around the time of ovulation.
61. Haemophilia is an X-linked recessive bleeding disorder. If a haemophilic man ($X^h Y$) marries a homozygous normal woman ($X^H X^H$):
Correct Answer: B (All daughters will be carriers and all sons will be normal)
The father transmits his mutant $X^h$ exclusively to his daughters (making 100% of daughters carriers) and his Y chromosome to his sons (all sons receive normal $X^H$ from the mother).
The father transmits his mutant $X^h$ exclusively to his daughters (making 100% of daughters carriers) and his Y chromosome to his sons (all sons receive normal $X^H$ from the mother).
62. The chromosomal basis of sex determination in honeybees is haplodiploidy, where:
Correct Answer: B (Females are diploid 32, and males are haploid 16)
In honeybees, fertilized eggs develop into diploid females (queens or workers), while unfertilized eggs develop parthenogenetically into haploid males (drones).
In honeybees, fertilized eggs develop into diploid females (queens or workers), while unfertilized eggs develop parthenogenetically into haploid males (drones).
63. In alpha-thalassemia, the loss or deletion of alpha-globin genes on chromosome 16 results in excess unbound:
Correct Answer: B (Beta-globin chains)
Reduced alpha-globin production in alpha-thalassemia causes excess gamma-chains in fetuses ($Hb\text{ Barts}$) and excess beta-chains in adults ($HbH$), causing microcytic anemia.
Reduced alpha-globin production in alpha-thalassemia causes excess gamma-chains in fetuses ($Hb\text{ Barts}$) and excess beta-chains in adults ($HbH$), causing microcytic anemia.
64. In eukaryotic DNA packaging, the linker DNA between two adjacent nucleosome cores is associated with histone protein:
Correct Answer: D (H1)
The nucleosome octamer core consists of two copies each of H2A, H2B, H3, and H4. Histone H1 binds to the entering and exiting linker DNA to seal the nucleosome.
The nucleosome octamer core consists of two copies each of H2A, H2B, H3, and H4. Histone H1 binds to the entering and exiting linker DNA to seal the nucleosome.
65. The enzyme that relieves supercoiling tension ahead of the replication fork by making transient cuts in DNA strands is:
Correct Answer: B (Topoisomerase)
DNA helicase unwinds the double helix, creating positive torsional supercoils ahead of the replication fork that are relaxed by DNA topoisomerase/gyrase.
DNA helicase unwinds the double helix, creating positive torsional supercoils ahead of the replication fork that are relaxed by DNA topoisomerase/gyrase.
66. The post-transcriptional addition of 200–300 adenylate residues to the 3′-end of eukaryotic pre-mRNA is called:
Correct Answer: B (Tailing / Polyadenylation)
Eukaryotic hnRNA undergoes 5′-capping (7-methylguanosine) and 3′-polyadenylation (poly-A tail of 200–300 adenylates) to protect the transcript and facilitate nuclear export.
Eukaryotic hnRNA undergoes 5′-capping (7-methylguanosine) and 3′-polyadenylation (poly-A tail of 200–300 adenylates) to protect the transcript and facilitate nuclear export.
67. In the lac operon of E. coli, allolactose functions as an inducer by:
Correct Answer: B (Binding to the repressor protein and preventing it from binding the operator)
Allolactose binds to the lac repressor, altering its allosteric shape so it detaches from the operator, allowing RNA polymerase to transcribe the operon.
Allolactose binds to the lac repressor, altering its allosteric shape so it detaches from the operator, allowing RNA polymerase to transcribe the operon.
68. The thorny protective structures of Bougainvillea and the climbing tendrils of Passiflora/Cucurbita are homologous because they both:
Correct Answer: B (Originate from modified axillary buds)
Homologous structures share a common structural origin but have diverged to perform different functions (e.g., thorns for defense vs. tendrils for climbing).
Homologous structures share a common structural origin but have diverged to perform different functions (e.g., thorns for defense vs. tendrils for climbing).
69. The drastic reduction in population size and genetic diversity caused by natural disasters (volcanoes, floods) is termed:
Correct Answer: B (Bottleneck effect)
A population bottleneck occurs when environmental disasters drastically reduce population numbers; surviving allele frequencies shift purely by chance (genetic drift).
A population bottleneck occurs when environmental disasters drastically reduce population numbers; surviving allele frequencies shift purely by chance (genetic drift).
70. Prehistoric cave art developed by early Homo sapiens dates back to approximately:
Correct Answer: A (18,000 years ago)
Prehistoric cave paintings produced by Homo sapiens date back ~18,000 years (e.g., Bhimbetka caves in Madhya Pradesh). Agriculture and settled civilizations arose ~10,000 years ago.
Prehistoric cave paintings produced by Homo sapiens date back ~18,000 years (e.g., Bhimbetka caves in Madhya Pradesh). Agriculture and settled civilizations arose ~10,000 years ago.
71. Ringworm skin infections in humans are caused by dermatophyte fungi that feed on:
Correct Answer: B (Keratin protein of skin, hair, and nails)
Dermatophytes (Microsporum, Trichophyton, Epidermophyton) secrete keratinases to break down keratin in superficial skin folds, causing scaly, itchy lesions.
Dermatophytes (Microsporum, Trichophyton, Epidermophyton) secrete keratinases to break down keratin in superficial skin folds, causing scaly, itchy lesions.
72. Which antibody class is the only maternal immunoglobulin capable of crossing the placenta to protect the developing fetus?
Correct Answer: C (IgG)
IgG is the smallest and most abundant circulating antibody (75–80%) and the only isotype that crosses the placental barrier to confer passive prenatal immunity.
IgG is the smallest and most abundant circulating antibody (75–80%) and the only isotype that crosses the placental barrier to confer passive prenatal immunity.
73. A patient with advanced AIDS develops severe opportunistic infections primarily because the CD4+ Helper T-cell count falls below:
Correct Answer: B (200 cells / mm3)
When HIV replication reduces helper T-cell counts below 200 cells/mm3, cellular immunity collapses, predisposing patients to opportunistic pathogens like Mycobacterium and Toxoplasma.
When HIV replication reduces helper T-cell counts below 200 cells/mm3, cellular immunity collapses, predisposing patients to opportunistic pathogens like Mycobacterium and Toxoplasma.
74. The Epstein-Barr virus (EBV) and Human Papillomavirus (HPV) are oncogenic viruses associated respectively with:
Correct Answer: A (Burkitt’s lymphoma and Cervical cancer)
Oncogenic viruses integrate viral oncogenes into host DNA: HPV causes cervical carcinoma, and EBV is linked to Burkitt’s lymphoma and nasopharyngeal carcinoma.
Oncogenic viruses integrate viral oncogenes into host DNA: HPV causes cervical carcinoma, and EBV is linked to Burkitt’s lymphoma and nasopharyngeal carcinoma.
75. The psychoactive drug Morphine is chemically classified as a/an:
Correct Answer: B (Opioid alkaloid)
Morphine binds to specific opioid receptors in the central nervous system and gastrointestinal tract, acting as a potent analgesic and sedative.
Morphine binds to specific opioid receptors in the central nervous system and gastrointestinal tract, acting as a potent analgesic and sedative.
76. Roquefort cheese is ripened to attain its characteristic sharp flavor by inoculating it with:
Correct Answer: B (Penicillium roqueforti)
Roquefort cheese is ripened by growing the mold Penicillium roqueforti, whose lipases and proteases produce its distinctive blue veins and flavor.
Roquefort cheese is ripened by growing the mold Penicillium roqueforti, whose lipases and proteases produce its distinctive blue veins and flavor.
77. The commercial enzyme preparation used in laundry detergents to remove oily and greasy stains from fabrics is:
Correct Answer: C (Lipase)
Lipases synthesized by microbes like Candida and Pseudomonas are formulated into laundry detergents to hydrolyze lipid and oil stains on clothing.
Lipases synthesized by microbes like Candida and Pseudomonas are formulated into laundry detergents to hydrolyze lipid and oil stains on clothing.
78. The Ministry of Environment and Forests initiated which national action plans to clean major polluted Indian rivers through sewage treatment plants?
Correct Answer: A (Ganga Action Plan and Yamuna Action Plan)
The Ganga Action Plan and Yamuna Action Plan were launched by the Ministry of Environment and Forests to build sewage treatment facilities and curb municipal pollution in major rivers.
The Ganga Action Plan and Yamuna Action Plan were launched by the Ministry of Environment and Forests to build sewage treatment facilities and curb municipal pollution in major rivers.
79. Integrated Pest Management (IPM) programs emphasize:
Correct Answer: B (Biological control agents and cultural practices to keep pests below economic injury levels)
IPM employs ecological biocontrols (e.g., parasitoids, Baculoviruses) to manage pest numbers sustainably while minimizing pesticide toxicity to ecosystems.
IPM employs ecological biocontrols (e.g., parasitoids, Baculoviruses) to manage pest numbers sustainably while minimizing pesticide toxicity to ecosystems.
80. Cyanobacteria like Anabaena and Nostoc serve as important biofertilizers especially in which agricultural crop fields?
Correct Answer: B (Paddy fields)
Free-living and symbiotic cyanobacteria thrive in water-logged paddy fields, fixing nitrogen and adding organic matter to improve soil fertility.
Free-living and symbiotic cyanobacteria thrive in water-logged paddy fields, fixing nitrogen and adding organic matter to improve soil fertility.
81. The first artificial recombinant DNA was constructed by Cohen and Boyer in 1972 by linking an antibiotic resistance gene into a plasmid of:
Correct Answer: B (Salmonella typhimurium)
Stanley Cohen and Herbert Boyer constructed the first recombinant DNA molecule by splicing an antibiotic-resistance gene into a native plasmid of Salmonella typhimurium.
Stanley Cohen and Herbert Boyer constructed the first recombinant DNA molecule by splicing an antibiotic-resistance gene into a native plasmid of Salmonella typhimurium.
82. In recombinant cloning vectors, selectable markers function to:
Correct Answer: B (Identify transformants while eliminating non-transformants)
Selectable markers (e.g., $amp^R$, $tet^R$, or lacZ) allow positive selection of successfully transformed host cells on antibiotic or chromogenic growth media.
Selectable markers (e.g., $amp^R$, $tet^R$, or lacZ) allow positive selection of successfully transformed host cells on antibiotic or chromogenic growth media.
83. In genetic engineering, treating bacterial cells with ice-cold divalent calcium ions ($Ca^{2+}$) followed by a heat shock at 42°C:
Correct Answer: B (Increases membrane permeability for DNA uptake)
Divalent $Ca^{2+}$ ions neutralize negative charges on DNA and membrane phosphates, facilitating plasmid entry through transient wall pores during thermal heat shock.
Divalent $Ca^{2+}$ ions neutralize negative charges on DNA and membrane phosphates, facilitating plasmid entry through transient wall pores during thermal heat shock.
84. The method of direct gene transfer where foreign DNA is microinjected directly into the nucleus of an animal zygote or cell using a fine micropipette is:
Correct Answer: A (Microinjection)
Microinjection directly introduces recombinant DNA into the male or female pronucleus of fertilized animal eggs using glass micropipettes under microscopic guidance.
Microinjection directly introduces recombinant DNA into the male or female pronucleus of fertilized animal eggs using glass micropipettes under microscopic guidance.
85. Bt toxin proteins produced by Bacillus thuringiensis are encoded by genes called:
Correct Answer: B (cry genes)
The insecticidal crystal proteins of Bt are encoded by cry genes (such as cryIAc and cryIIAb for bollworms, and cryIAb for corn borer).
The insecticidal crystal proteins of Bt are encoded by cry genes (such as cryIAc and cryIIAb for bollworms, and cryIAb for corn borer).
86. In agricultural biotechnology, the Flavr Savr tomato was engineered for delayed softening and extended shelf-life by using antisense technology to suppress:
Correct Answer: B (Polygalacturonase)
Antisense RNA inhibits polygalacturonase expression, preventing pectin degradation in fruit cell walls and slowing post-harvest rotting.
Antisense RNA inhibits polygalacturonase expression, preventing pectin degradation in fruit cell walls and slowing post-harvest rotting.
87. Commercial recombinant human insulin (Humulin) consists of:
Correct Answer: B (Chain A of 21 amino acids and Chain B of 30 amino acids connected by disulfide bridges)
Mature human insulin is a 51-amino-acid polypeptide composed of an A chain (21 residues) and a B chain (30 residues) linked covalently by two interchain disulfide bonds.
Mature human insulin is a 51-amino-acid polypeptide composed of an A chain (21 residues) and a B chain (30 residues) linked covalently by two interchain disulfide bonds.
88. In the treatment of SCID via gene therapy, functional ADA cDNA is transferred into cultured patient lymphocytes using a:
Correct Answer: B (Disarmed Retrovirus vector)
Retroviral vectors integrate therapeutic human ADA cDNA into host T-lymphocyte chromosomes, enabling expression of active adenosine deaminase.
Retroviral vectors integrate therapeutic human ADA cDNA into host T-lymphocyte chromosomes, enabling expression of active adenosine deaminase.
89. The first transgenic sheep, ‘Tracy’, was genetically engineered to produce human proteins in her milk for treating:
Correct Answer: B (Alpha-1-antitrypsin deficiency)
Transgenic sheep like Tracy were engineered to secrete human alpha-1-antitrypsin in their milk to treat emphysema and cystic fibrosis.
Transgenic sheep like Tracy were engineered to secrete human alpha-1-antitrypsin in their milk to treat emphysema and cystic fibrosis.
90. Patenting of indigenous neem products and turmeric wound-healing remedies by foreign corporations are classic examples of:
Correct Answer: B (Biopiracy)
Biopiracy refers to foreign commercial entities patenting traditional bioresources and indigenous knowledge (e.g., turmeric, neem, Basmati rice) without compensation or consent.
Biopiracy refers to foreign commercial entities patenting traditional bioresources and indigenous knowledge (e.g., turmeric, neem, Basmati rice) without compensation or consent.
91. An interaction between clownfish sheltered among the stinging tentacles of a sea anemone represents:
Correct Answer: A (Commensalism)
Clownfish gain protection from predators among the stinging tentacles of sea anemones without providing benefit or causing harm to the anemone (+, 0).
Clownfish gain protection from predators among the stinging tentacles of sea anemones without providing benefit or causing harm to the anemone (+, 0).
92. In a population undergoing exponential growth under unlimited resources, the geometric growth equation is expressed as:
Correct Answer: A (dN / dt = rN)
When resources are non-limiting, population growth is exponential (J-shaped curve), represented by the differential equation $dN/dt = rN$ (where r is the intrinsic rate of natural increase).
When resources are non-limiting, population growth is exponential (J-shaped curve), represented by the differential equation $dN/dt = rN$ (where r is the intrinsic rate of natural increase).
93. The stable, self-perpetuating terminal community that reaches equilibrium with the regional climate at the end of ecological succession is the:
Correct Answer: B (Climax community)
The climax community is the final, stable ecological equilibrium stage of succession that remains unchanged unless disrupted by major environmental disturbances.
The climax community is the final, stable ecological equilibrium stage of succession that remains unchanged unless disrupted by major environmental disturbances.
94. The rate of synthesis of new organic biomass by primary consumers (herbivores) per unit time is termed:
Correct Answer: C (Secondary Productivity)
Secondary productivity is the rate at which heterotrophs (consumers) assimilate food energy into new living tissue biomass.
Secondary productivity is the rate at which heterotrophs (consumers) assimilate food energy into new living tissue biomass.
95. In a parasitic food chain where an oak tree supports hundreds of birds and thousands of lice and ticks, the pyramid of biomass is:
Correct Answer: A (Upright)
Even though the pyramid of numbers is inverted, the biomass of the single large oak tree vastly outweighs the total dry weight of birds and parasites, keeping the biomass pyramid upright.
Even though the pyramid of numbers is inverted, the biomass of the single large oak tree vastly outweighs the total dry weight of birds and parasites, keeping the biomass pyramid upright.
96. The German naturalist Alexander von Humboldt observed that within a region, species richness increases with increasing explored area, but only up to a limit, generating a:
Correct Answer: B (Rectangular Hyperbola)
Species-area relationships plot as a rectangular hyperbola on linear coordinates ($S = C \cdot A^Z$) and as a straight line on logarithmic scales ($\log S = \log C + Z \log A$).
Species-area relationships plot as a rectangular hyperbola on linear coordinates ($S = C \cdot A^Z$) and as a straight line on logarithmic scales ($\log S = \log C + Z \log A$).
97. When a host fish species goes extinct, its unique obligate monogenean parasites also face immediate extinction, an example of:
Correct Answer: D (Co-extinction)
Co-extinction occurs when the extinction of a host species automatically causes the loss of all specialized obligate mutualists and parasites dependent upon it.
Co-extinction occurs when the extinction of a host species automatically causes the loss of all specialized obligate mutualists and parasites dependent upon it.
98. The aggressive African Catfish illegally introduced for aquaculture purposes that threatens indigenous catfish species in Indian rivers is:
Correct Answer: C (Clarias gariepinus)
Clarias gariepinus (African catfish) is an invasive predatory fish introduced for aquaculture that preys upon and outcompetes endemic riverine catfishes.
Clarias gariepinus (African catfish) is an invasive predatory fish introduced for aquaculture that preys upon and outcompetes endemic riverine catfishes.
99. Sacred Groves in Rajasthan that provide protection to threatened desert wildlife and relict flora are located in the:
Correct Answer: B (Aravalli Hills)
Sacred groves in Rajasthan’s Aravalli Hills are protected by Bishnoi and tribal communities through cultural and religious traditions, conserving rare arid flora and fauna.
Sacred groves in Rajasthan’s Aravalli Hills are protected by Bishnoi and tribal communities through cultural and religious traditions, conserving rare arid flora and fauna.
100. In an In-situ conservation strategy, a Biosphere Reserve is divided into three zones from center to periphery comprising:
Correct Answer: A (Core Zone -> Buffer Zone -> Transition Zone)
A Biosphere Reserve has an undisturbed legal Core zone, a surrounding educational/research Buffer zone, and an outer Transition (manipulation) zone where sustainable human activity occurs.
A Biosphere Reserve has an undisturbed legal Core zone, a surrounding educational/research Buffer zone, and an outer Transition (manipulation) zone where sustainable human activity occurs.