The scientist who introduced binomial nomenclature in the classification of organisms was
Carolus Linnaeus, in his 1753 work 'Species Plantarum' and 1758 'Systema Naturae', developed the binomial nomenclature system, assigning each species a two-part Latin name (genus and species), standardizing biological classification.
Which enzyme is primarily responsible for the breakdown of hydrogen peroxide into water and oxygen in living cells?
Catalase is a ubiquitous enzyme found in nearly all living organisms exposed to oxygen, functioning as a powerful antioxidant by catalyzing the decomposition of hydrogen peroxide (H₂O₂), a toxic byproduct of metabolism, into harmless water (H₂O) and oxygen (O₂). This reaction prevents oxidative damage to cells and is one of the fastest enzymatic reactions known, with a turnover number exceeding 1 million molecules per second.
What level of organization is Spirogyra?
Spirogyra is a filamentous alga consisting of a chain of multinucleate cells forming a multicellular structure, which is at the tissue level of organization, as it has specialized cells for functions like reproduction, but not organs or systems.
The streaming movement of cytoplasm within the Paramecium is known as
Cyclosis, or cytoplasmic streaming, is the circulation of cytoplasm within the cell of Paramecium, aiding in distribution of nutrients, waste removal, and organelle movement.
Which of the following organelles is found only in plant cells?
Plastids (chloroplasts, chromoplasts, leucoplasts) are double-membrane organelles unique to plants for photosynthesis, pigment storage, and starch accumulation; animal cells lack them.
Active transport differs from diffusion in that active transport
Active transport requires energy (ATP) to move molecules from low to high concentration (against gradient), unlike passive diffusion which follows the gradient without energy.
The growth of auxins in plants is mainly responsible for
Auxins (IAA) promote cell elongation in stems by acidifying the cell wall, loosening it for expansion, a key mechanism in phototropism and gravitropism.
In plants, the hormone that promotes cell division is
Cytokinins stimulate cell division (cytokinesis) in shoot meristems and delay senescence; they work with auxins to regulate growth.
The odontoid process is found on the
The odontoid process (dens) is a peg-like projection on the axis (C2) vertebra, allowing rotation of the head by pivoting in the atlas (C1) ring.
A seedling was made to stand in a solution of red ink for three hours and a transverse section of the stem was examined under the microscope. The process being investigated was
Red ink stains the xylem vessels, demonstrating the upward movement (ascent) of water and minerals from roots to shoots via transpiration pull and cohesion.
Which of the following structures would carry out cellular respiration?
Germinating seeds are metabolically active, using stored food for respiration to produce energy for growth; dead or boiled tissues cannot respire.
Which of the following is NOT an excretory product of animals?
Oxygen is inhaled as a respiratory gas, not excreted; CO2, urea (nitrogenous waste), and sweat (water/salts) are excretory products.
An example of homeostasis in living organisms is
Evaporative cooling by sweat maintains body temperature (thermoregulation), a homeostatic mechanism; B is phototropism, C camouflage, D nutrient uptake.
Ultrafiltration in the kidney takes place in the
In Bowman's capsule, glomerular filtration (ultrafiltration) forces blood plasma through capillary walls into the nephron, starting urine formation.
The thyroid gland is found at the base of the
The thyroid is a butterfly-shaped endocrine gland located anterior to the trachea at the base of the neck, regulating metabolism via thyroxine.
Which of the following statements about the response of neurones to stimulus is correct?
Neurons follow the all-or-none law: action potential fires only if stimulus reaches threshold (~ -55mV); subthreshold stimuli elicit no response.
Which of the following practices may lead to infection of the eye? Use of
Contact lenses can harbor bacteria if not cleaned properly, leading to infections like keratitis; spectacle lenses (B-D) do not touch the eye.
The structures for gaseous exchange in breathing roots are
Lenticels are porous tissues in breathing (pneumatophore) roots of mangroves, allowing O2 diffusion from air to waterlogged roots.
The adult stage in the life cycle of a housefly is characterized by
Houseflies undergo holometabolous(complete) metamorphosis: egg → larva (maggot) → pupa → imago (adult), with distinct larval and adult forms.
The larval stage of a housefly is known as
Housefly larvae are apodous, worm-like maggots that feed on decaying matter before pupating.
The source of energy required by plants during food production is
Sunlight provides the energy for photosynthesis, exciting electrons in chlorophyll to drive ATP and NADPH production for glucose synthesis.
One major difference between plant and animals nutrition is the ability of plants to synthesize
Plants are autotrophs, synthesizing organic food (glucose) via photosynthesis for themselves and herbivores, while animals are heterotrophs relying on external sources.
By what process is starch converted into maltose?
Hydrolysis by amylase (salivary/pancreatic) breaks glycosidic bonds in starch (polymer) to yield maltose (disaccharide) in digestion.
The ascent of water in tall trees is mainly due to
Transpiration pull creates negative pressure in xylem, drawing water upward; cohesion and adhesion aid, but pull is primary for heights >10m.
The duodenum of a person was surgically removed. Which of the following substances would have their digestion affected?
Duodenum hosts pancreatic amylase (starch), trypsin (protein), and lipase (lipids), plus bile emulsification; its removal impairs these digestions.
Which of the following dental formulae represents the dentition in rabbits?
Rabbits (lagomorphs) have dental formula I 2/1, C 0/0, P 3/2, M 3/3 = 28 teeth, with diastema and ever-growing incisors for herbivory.
The property of soil that allows water to rise against gravity is known as
Capillarity is the rise of water in fine soil pores due to adhesive/cohesive forces, important for water movement in unsaturated soils to roots.
In a soil experiment involving different soil types, water rises highest in
Clay has smallest particles and pores, maximizing capillary rise (up to 30-50cm), vs. sand's large pores with minimal rise.
The most important factor(s) that influence(s) the ecological niche of an organism is/are the
Ecological niche encompasses role including abiotic (water, light) and biotic (predator-prey) factors determining habitat suitability and interactions.
In a closed ecosystem like an aquarium, the primary factor required for the survival of organisms is
Light energy drives photosynthesis by aquatic plants/algae, producing O2 and food, sustaining the closed system's heterotrophs and autotrophs.
Which of the following instruments is used to determine the turbidity of water?
Secchi disc measures water transparency by depth of disappearance, indicating turbidity from suspended particles affecting light penetration.
In an ecosystem, the least efficient energy transfer link is from the
Energy transfer efficiency is ~10%; highest loss (least efficient) at carnivore levels (primary to secondary consumers) due to metabolic heat and indigestible parts.
Xerophytes have the following characteristics aimed at conserving water except
Xerophytes minimize transpiration with thick/waxy cuticles, sunken stomata; broad leaves increase surface area, promoting water loss, unsuitable for dry habitats.
An association between living organisms in which one lives on and feeds at the expense of the other is known as
Parasitism: parasite benefits (nutrients) at host's expense (harm), e.g., tapeworm in intestine; differs from predation (kills host) and mutualism (both benefit).
When large numbers of organisms share limited space and resources, the immediate result is
Overpopulation leads to intraspecific/interspecific competition for resources, influencing natural selection and population regulation.
Which of the following disease is caused by a bacterium?
Syphilis is caused by Treponema pallidum bacterium; ringworm (fungus), poliomyelitis (polio virus), malaria (Plasmodium protozoan).
Conservation of wildlife is necessary mainly because
Biodiversity conservation prevents species extinction due to habitat loss, poaching, maintaining ecosystem balance and genetic diversity for future.
Patients X and Y were likely transfused with blood of genotype
Assuming context of agglutination symptoms, O blood (universal donor) transfused to A/B recipients causes no reaction; but if mismatched, wait, the question is incomplete in user input, but key has A for 38. Likely, symptoms indicate mismatch, but for safe transfusion without reaction, OO to any.
What should the hospital have done to prevent X from showing the symptom described above? Patient X should have
Determining blood group (ABO/Rh) before transfusion prevents hemolytic reactions from incompatible blood.
The greatest contribution to genetic studies was made by
Gregor Mendel founded genetics with pea plant experiments (1865), establishing laws of inheritance (segregation, independent assortment), basis for modern genetics.
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