Question 1

Medical entomology: Other than malaria, anopheles mosquitoes also transmit which disease as vectors?  Full question: Besides spreading malaria, Anopheles mosquitoes are vectors of which additional disease?  Choose the correct option.

Accepted Answer

Concept Anopheles spp. transmit malaria and, in several regions, are competent vectors for lymphatic filariasis (e.g., Wuchereria bancrofti). Dengue and yellow fever are primarily transmitted by Aedes mosquitoes; plague by fleas; typhus by lice. Final Answer Filariasis (lymphatic filariasis).

Question 2

Plant water uptake: Identify the structures through which plants absorb most of the water they need.  Full question: Plants absorb the major part of their water requirement primarily through which root structures?  Choose the correct option.

Accepted Answer

Concept Root hairs dramatically increase absorptive surface area and are the principal sites for water and mineral uptake from the soil solution. Why others are incorrect Stomata regulate gas exchange and transpiration; stems/leaves are not the main water-absorbing organs. Final Answer Root hairs.

Question 3

Nitrogen cycle check: Identify the false statement about nitrogen fixation and related processes in ecosystems. Full question: Nitrogen is fixed in ecosystems in the following ways. Which statement below is false? Choose the correct optio…

Accepted Answer

Concept The nitrogen cycle includes fixation (N₂ → NH₃/NH₄⁺), nitrification (NH₃/NH₄⁺ → NO₂⁻ → NO₃⁻), assimilation (into amino acids), and denitrification (NO₃⁻/NO₂⁻ → N₂). Why option D is false Nitrification does not convert nitrate to ammonia; instead, it converts ammonia to nitrite (by Nitrosomonas) and then to nitrate (by Nitrobacter). The reverse (NO₃⁻ → NH₄⁺) would be assimilatory/dissimilatory nitrate reduction, not nitrification. Verification Other options accurately describe nitrogen fixation, abiotic fixation by lightning, and denitrification. Final Answer Nitrification converts nitrate (NO₃⁻) to ammonia (NH₃/NH₄⁺) by Nitrosomonas and Nitrobacter. (This statement is false.)

Question 4

Monocot vs. dicot roots: Identify the feature that distinguishes monocot roots from dicot roots.  Full question: Monocot root differs from dicot root in having which of the following anatomical features?  Choose the correct option.

Accepted Answer

Concept Monocot roots are typically polyarch with a large, well-developed pith and lack secondary growth (no functional vascular cambium). Dicot roots often have fewer xylem arms, little to no central pith, and can show secondary growth. Option analysis (A) Correct: prominent pith in monocot roots.(B) Incorrect: secondary growth is characteristic of many dicot roots, not monocots.(C) Incorrect description of dicots, not monocots (monocots → many xylem strands).(D) Incorrect: roots have a defined stele.(E) Incorrect: roots show exarch, not endarch, xylem maturation. Final Answer A large, well-developed central pith.

Question 5

Plant ecology terminology: Name the plants adapted to grow in saline (high-salt) water or soils.  Full question: Plants that grow naturally in saline water or salt-affected habitats are called by which ecological term?  Choose the correct option.

Accepted Answer

Given data Ecology term sought for plants thriving in saline water/soils. Concept / Approach Halophytes are salt-tolerant plants that complete their life cycle in saline environments by employing adaptations such as salt excretion glands, succulence (dilution of internal salt), and ion compartmentalization. Option analysis Halophytes: Correct — salt-loving/salt-tolerant plants (e.g., Salicornia, mangroves).Xerophytes: Adapted to drought/arid conditions, not necessarily salinity.Hydrophytes: Aquatic plants in fresh water; not specifically salt-tolerant.Mesophytes: Moderate-moisture habitats.Glycophytes: Salt-sensitive plants (opposite of halophytes). Common pitfalls Confusing any water-associated plant (hydrophyte) with saline-tolerant plants (halophytes). Final Answer Halophytes.

Question 6

Plant water relations: Identify the process whose excess leads to wilting in plants.  Full question: Plants wilt due to an excessive rate of which physiological process?  Choose the correct option.

Accepted Answer

Given data Outcome: Wilting (loss of turgor, drooping). Cause asked: Excess of a particular plant process. Concept / Approach Wilting occurs when water loss exceeds uptake, reducing cell turgor. The process that drives most water loss is transpiration (evaporation of water from leaf surfaces via stomata). Why not the others? Imbibition is water absorption by colloids (seeds/wood). Photosynthesis and respiration do not directly cause rapid turgor loss. Root absorption mitigates, not causes, wilting. Mechanistic note High temperature, low humidity, and wind increase transpiration → water potential drops → plasmolysis risk → wilting. Final Answer Transpiration.

Question 7

Photosynthesis source of oxygen: Identify the molecule that provides the O₂ released.  Full question: During photosynthesis, the oxygen gas (O₂) evolved comes from which reactant molecule?  Choose the correct option.

Accepted Answer

Given data Target: Identify the source of released O₂ in photosynthesis. Concept / Approach In the light reactions, water undergoes photolysis at photosystem II, producing electrons, protons, and O₂. Isotopic tracing (using H18₂O) shows that the oxygen comes from water, not CO₂. Key reaction fragment 2 H₂O → O₂ + 4H⁺ + 4e⁻ (driven by light energy) Final Answer Water (H₂O).

Question 8

Definition check (plant physiology): Choose the best description of photo-oxidation.  Full question: Photo-oxidation is best described as which of the following processes?  Choose the correct option.

Accepted Answer

Given data Term: Photo-oxidation. Concept / Approach Photo-oxidation refers to oxidation reactions triggered by light, often mediated by reactive oxygen species. In plants, excessive light can cause chlorophyll photo-oxidation (bleaching) unless protected by carotenoids and non-photochemical quenching. Eliminating distractors CO₂ reduction by light is photosynthesis, not photo-oxidation. Oxidation in darkness is the opposite of photo-oxidation. Mitochondrial respiration is light-independent. Final Answer Oxidation (degradation) of molecules induced by light, e.g., bleaching of chlorophyll at high light.

Question 9

Skeletal system: Identify which is NOT a function performed by bones.  Full question: One of the following is not a recognized function of bones in vertebrates. Which one?  Choose the correct option.

Accepted Answer

Concept / Approach Bones provide support, protection, serve as levers for muscles, store minerals (Ca²⁺/PO₄³⁻), and house marrow for blood cell formation. Excretion of nitrogenous wastes is a function of the kidneys/urinary system, not bones. Final Answer Excretion of nitrogenous wastes (e.g., urea).

Question 10

Endocrine physiology: Identify the primary cardiovascular effect increased by norepinephrine (noradrenaline).  Full question: Norepinephrine increases which parameter most prominently via α₁-mediated vasoconstriction?  Choose the correct option.

Accepted Answer

Given data Hormone/neurotransmitter: Norepinephrine. Concept / Approach Norepinephrine predominantly stimulates α₁-adrenergic receptors in vascular smooth muscle → vasoconstriction → ↑ total peripheral resistance → ↑ blood pressure. It can also increase heart rate via β₁, but baroreflex may blunt HR; the hallmark effect is raised BP. Eliminating distractors Parasympathetic tone increases GI motility, not NE. NE does not directly increase GFR/urine output; intense vasoconstriction can reduce renal flow. Thermoregulation and pure HR-only effects are not the primary signature. Final Answer Blood pressure (via increased peripheral vascular resistance).

Question 11

Biogeochemical cycles: Identify why atmospheric N₂ remains approximately constant in the biosphere.  Full question: N₂ content is kept nearly constant in the biosphere due to which natural process?  Choose the correct option.

Accepted Answer

Concept / Approach Atmospheric N₂ is stabilized because nitrogen fixation (by diazotrophs/lightning) converts N₂ to bioavailable forms while denitrification (by anaerobic bacteria) returns nitrate/nitrite back to N₂. This dynamic nitrogen cycle keeps atmospheric N₂ levels relatively constant. Final Answer The nitrogen cycle (balance between nitrogen fixation and denitrification).

Question 12

Plant groups and human use: Classify our major food, fibre, spice, fruit, and beverage crops.  Full question: Our principal foods, fibres, spices, fruits, and beverage crops mostly belong to which plant group?  Choose the correct option.

Accepted Answer

Concept Humans rely predominantly on angiosperms (flowering plants) for cereals (rice, wheat, maize), legumes, fruits, oils, fibres (cotton, flax), spices (pepper, cardamom), and beverages (tea, coffee, cocoa). Other plant groups contribute less to these categories. Final Answer Angiosperms (flowering plants).

Question 13

Plant biochemistry: Identify the immediate biomolecules from which plants synthesize proteins.  Full question: Plants synthesize protein from which class of building-block molecules?  Choose the correct option.

Accepted Answer

Concept Proteins are polymers of amino acids. In plants, inorganic nitrogen (e.g., nitrate or ammonium) is assimilated via GS–GOGAT and other pathways to form amino acids (glutamine, glutamate), which are then assembled into proteins by ribosomes. Final Answer Amino acids.

Question 14

Virology basics: Name the proteinaceous outer covering of a virus particle.  Full question: The outer covering of a virus made up primarily of protein is called what?  Choose the correct option.

Accepted Answer

Concept A capsid is the protein shell of a virus composed of capsomeres that encloses the nucleic acid genome. Some viruses also possess a lipid envelope derived from host membranes, but the envelope is not present in all viruses, whereas the capsid is the defining protein coat. Common pitfalls Do not confuse bacterial capsule (polysaccharide) or cell wall with viral structures. The envelope is lipid-protein and optional; the protein coat is the capsid. Final Answer Capsid.

Question 15

Plant anatomy — radial vascular bundles: Identify the arrangement that defines a radial vascular bundle. In this bundle type (typical of roots), xylem and phloem occur on separate, alternating radii rather than together in the same strand. Choose th…

Accepted Answer

Given data Asked: definition of radial vascular bundle. Context: classification of vascular bundle arrangements. Concept / Approach In radial bundles, xylem and phloem are in separate strands arranged on alternate radii of the organ. This is characteristic of roots. By contrast, in conjoint bundles (typical of stems/leaves), xylem and phloem lie together on the same radius. Elimination Options describing conjoint, amphicribral, or bicollateral arrangements do not match the root-type alternating pattern. Final Answer Xylem and phloem occur on different, alternating radii (radial).

Question 16

Sites of photosynthesis in plants: Identify the plant parts where photosynthesis generally occurs. Consider chloroplast-rich tissues such as leaf mesophyll; some green stems and other green organs can also photosynthesize. Choose the best answer.

Accepted Answer

Given data Asked: where photosynthesis generally occurs. Concept / Approach Photosynthesis occurs in chloroplasts, abundant in leaf palisade and spongy mesophyll. Some green stems and other green organs can contribute, but the primary site is the leaf. Final Answer Green leaves (mesophyll chloroplasts), and other green parts.

Question 17

Model fungus in genetics — Neurospora: Why is Neurospora widely used as genetic material? Focus on ploidy, life cycle, and ease of detecting mutations. Choose the most fundamental reason.

Accepted Answer

Given data Question: Why use Neurospora in genetic studies? Concept / Approach Neurospora (e.g., N. crassa) is a classic model. Being haploid for most of its life cycle means any mutation (even recessive) is directly expressed, simplifying mapping and analysis. It is also easy to culture and has short generation time with ordered tetrads (asci) aiding genetic mapping. Final Answer Haploidy exposes recessive mutations.

Question 18

Human skin pigmentation response: Why does skin become darker after excess sun exposure? Identify the specific pigment that increases following UV exposure. Choose the correct pigment.

Accepted Answer

Concept / Approach UV exposure stimulates melanocytes to produce more melanin, which darkens the skin and helps protect underlying tissues from UV damage. Why others are incorrect Carotene is a dietary pigment; hemoglobin colors blood; bilirubin is associated with jaundice. Final Answer Melanin.

Question 19

Discovery of the nucleus (1831): Who first described the rounded, genetic-material–containing body in plant cells? Name the scientist who discovered the nucleus in 1831. Choose the correct name.

Accepted Answer

Given data Year: 1831; structure: the nucleus in plant cells. Answer Robert Brown first described the nucleus while studying orchid tissues. Final Answer Robert Brown.

Question 20

Effect of rainwater on soil: Rain water helps to increase the ______ to some extent. Consider natural nitrogen fixation in the atmosphere and deposition to soils. Fill the blank with the most appropriate soil property.

Accepted Answer

Given data Blank asks what rainwater increases to some extent. Concept / Approach Lightning and atmospheric processes convert N2 to oxides of nitrogen that form nitrates/nitrites, which are deposited by rain, slightly increasing soil nitrogen and thus fertility. Elimination Rain does not generally raise heavy metals or salinity; pH effects vary with local conditions and are not universally increased. Final Answer Soil fertility (nitrogen content).

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