Which of the following organisms contains chlorophyll in its cells?
Euglena is a unicellular protist capable of photosynthesis and contains chlorophyll in its chloroplasts. The other organisms listed are heterotrophs that do not perform photosynthesis: caterpillars and grasshoppers are insects, and Paramecium is a ciliate protozoan.
Species are groups of organisms that
According to the biological species concept, a species is defined as a group of organisms that share similar morphological features and can interbreed to produce fertile offspring. Options A and D describe ecological associations rather than species definitions, while B contradicts the ability to interbreed.
A plant with short, vertical underground stem is a
A corm is a short, vertical, swollen underground stem that stores food, covered by a thin tunic of dry leaf bases (e.g., onion corm or gladiolus). A bulb is a layered structure with fleshy scales, a rhizome is horizontal, and a tuber is a swollen root or stem tip.
The type of asexual reproduction in Hydra is
Hydra reproduces asexually through budding, where a small outgrowth (bud) develops on the parent body, grows, and eventually detaches to form a new individual. Binary fission occurs in unicellular organisms like Amoeba, fragmentation in filamentous algae or planarians, and spore formation in fungi or ferns.
Which organism can reproduce by both sexual and asexual means?
Hydra can reproduce asexually via budding and sexually by producing gametes during unfavorable conditions. Amoeba primarily uses binary fission (asexual) with rare sexual conjugation, yeast uses budding (asexual) and ascospore formation (sexual), and Spirogyra mainly uses conjugation (sexual) with fragmentation (asexual).
Which of the following organisms consists of unicellular cells joined to form a filament?
Spirogyra is a filamentous green alga where individual unicellular cells are arranged end-to-end to form a multicellular-like filament, connected by cytoplasmic bridges. Amoeba, Euglena, and Chlamydomonas are free-living unicellular organisms without filaments.
The structure in the cell that controls the movement of substances in and out of the cell is the
The cytoplasmic membrane, also known as the plasma membrane, is a selectively permeable barrier that regulates the entry and exit of substances via diffusion, osmosis, active transport, etc. The nuclear membrane protects the nucleus, protoplasm is the cell's living content, and endoplasm is part of the cytoplasm in some protists.
The bursting of a red blood cell placed in a hypotonic solution is called
Haemolysis occurs when red blood cells swell and burst in a hypotonic solution due to water influx by osmosis, releasing hemoglobin. Crenation is shrinkage in hypertonic solutions, plasmolysis is shrinkage of plant protoplasm away from the cell wall, and cytolysis is general cell bursting.
The function of the root hair in plants is to
Root hairs are extensions of epidermal cells that increase surface area for osmosis, allowing water absorption from soil into the plant. Guttation or transpiration excretes water, but not via root hairs; soil purification is not a function; translocation occurs in phloem.
If a germinating seed is attached horizontally to a revolving clinostat, the effect on the seedling after three days is that the
A clinostat rotates the seed constantly, nullifying the effects of gravity (geotropism) and light (phototropism), so neither the radicle (positive geotropism) nor plumule (negative geotropism/positive phototropism) shows curvature, growing straight.
The lumbar vertebra differs from the thoracic vertebra because it possesses a
Lumbar vertebrae have a thicker, larger centrum (body) to support the weight of the upper body and facilitate stronger attachment of back muscles. Thoracic vertebrae have longer neural spines for rib attachment, and lumbar have shorter transverse processes but not notably wider canal.
Which of the following blood vessels carries oxygenated blood into the heart?
The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart. Pulmonary artery carries deoxygenated blood to lungs, and vena cavae (anterior and posterior) carry deoxygenated blood to the right atrium.
Filtrates in the Bowman's capsule contain vitamins because
Vitamins are small molecules with low molecular weight, allowing them to pass through the glomerular filtration barrier into the Bowman's capsule filtrate. Fat solubility affects absorption elsewhere, but not filtration; most are reabsorbed if needed, and requirement doesn't affect filtration.
The structures that contain grey matter and white matter are found in the
Grey matter (cell bodies, dendrites) and white matter (myelinated axons) are components of the central nervous system, found in the brain and spinal cord for processing and transmitting neural signals. Other systems lack this neural tissue organization.
The part of the eye that protects the eyeball is the
The eyelid acts as a movable protective cover, shielding the eyeball from dust, debris, and injury by blinking. The cornea refracts light, sclera provides structural support, and conjunctiva lubricates the surface.
The coloured part of the eye is the
The iris is the pigmented, colored muscular ring around the pupil that controls light entry by adjusting pupil size. The pupil is the opening, cornea is transparent, and retina is the light-sensitive layer at the back.
In self pollination, the pollen is transferred from
Self-pollination involves transfer of pollen from the anther to the stigma within the same flower, promoting inbreeding. Cross-pollination (C) occurs between different flowers, and B/D reverse the direction incorrectly.
The condition necessary for reproduction to occur between plants P and Q is
For successful sexual reproduction (formation of viable zygote and offspring), plants must have compatible chromosome numbers to allow meiosis and fertilization without genetic imbalance. Other options facilitate pollination but not the genetic compatibility for reproduction.
The ability of organisms to maintain a constant internal environment is known as
Homeostasis is the maintenance of stable internal conditions (e.g., temperature, pH) despite external changes, via feedback mechanisms. Diuresis is urine production, endosmosis is water entry into cells, plasmolysis is cell shrinkage.
The cell is a functional unit of living organisms because
In multicellular organisms, the overall function emerges from the coordinated activities of individual cells, each performing specialized roles (cell theory). A is structural, B is incorrect, D reverses the hierarchy.
The organelle which eliminates water from the body of protozoa is
The contractile vacuole in freshwater protozoa like Paramecium collects excess water from osmosis and expels it periodically to maintain osmotic balance. Plasma membrane regulates exchange, cell wall provides rigidity (absent in protozoa), protoplasm is the cell content.
Spirogyra is regarded as a multicellular plant because
Spirogyra forms multicellular filaments by cylindrical cells aligned end-to-end, sharing a common wall but functioning as a chain. It lacks true organs (B), cytoplasmic strands are present but not the defining feature, and D is false as it's not unicellular.
The mechanism of gaseous exchange in living organisms is essentially by
Gaseous exchange (O2 in, CO2 out) occurs via diffusion across respiratory surfaces due to concentration gradients. Osmosis is for water, inhalation/exhalation are breathing movements aiding diffusion.
Which of the following statements is correct about diffusion?
Diffusion is the passive movement of molecules from high to low concentration until equilibrium. A limits to water, C confuses with osmosis/active transport, D describes supersaturation.
The part of the mammalian brain responsible for coordinating muscle actions is the
The cerebellum integrates sensory input to coordinate voluntary muscle movements, balance, and posture. Cerebrum handles higher functions, hypothalamus regulates homeostasis, medulla controls vital reflexes.
Which of the following is not a characteristic of living organisms?
Photosynthesis is a specific nutritional process in autotrophs, not universal to all living organisms (e.g., animals are heterotrophs). Irritability (response to stimuli), nutrition, and reproduction are defining characteristics of life.
The process by which green plants manufacture food is called
Photosynthesis uses sunlight, CO2, and water to produce glucose and oxygen in chloroplasts. Respiration releases energy, transpiration is water loss, translocation moves sugars.
The main source of energy for Earth's climate system is
Solar radiation from the sun drives Earth's climate by heating the atmosphere, oceans, and land, powering winds, currents, and weather patterns. Wind, water, and soil are influenced by solar energy.
In a food chain, the arrow points from
Arrows in food chains indicate energy flow direction from producers (autotrophs) to consumers (heterotrophs), showing who eats whom. B reverses it, C is partial, D is incorrect as decomposers break down dead matter.
The organelle responsible for protein synthesis is the
Ribosomes translate mRNA into proteins via the genetic code. Mitochondria produce ATP, Golgi modifies/packaging proteins, lysosomes digest waste.
The process of cell division in somatic cells is called
Mitosis is equitable division producing two identical diploid somatic (body) cells for growth/repair. Meiosis for gametes, binary fission in prokaryotes, budding in some eukaryotes.
Which gas is produced during photosynthesis?
Photosynthesis splits water (photolysis), releasing oxygen as a byproduct: 6CO2 + 6H2O → C6H12O6 + 6O2. CO2 is a reactant, nitrogen/hydrogen not directly involved.
The human heart has how many chambers?
The human heart has four chambers: two atria (receive blood) and two ventricles (pump blood), enabling double circulation (pulmonary/systemic).
The hormone that regulates blood sugar level is
Insulin, secreted by pancreatic beta cells, lowers blood glucose by promoting uptake/storage. Adrenaline raises it, thyroxine metabolism, estrogen reproductive.
The largest phylum in the animal kingdom is
Arthropoda (insects, crustaceans, arachnids) is the largest phylum with over 1 million species, due to adaptations like exoskeleton and segmentation. Chordata includes vertebrates (~65,000 species).
Water lily is adapted to aquatic life by having
Broad, waxy leaves of water lily float on water surface, maximizing light capture for photosynthesis and gas exchange via stomata on upper surface. Stems/roots are submerged, flowers are large for pollination.
The mode of nutrition in fungi is
Fungi are heterotrophs, absorbing digested organic matter externally. Parasitic and saprophytic are subtypes of heterotrophic nutrition; autotrophic is for plants.
The excretory organ in earthworm is
Nephridia are coiled tubules in each segment of earthworms that filter coelomic fluid, reabsorb nutrients, and excrete nitrogenous waste (ammonia) as urine. Kidneys in vertebrates, flame cells in flatworms, Malpighian in insects.
The vector for malaria is
Female Anopheles mosquito transmits Plasmodium parasite causing malaria via bite. Tsetse fly for sleeping sickness, housefly mechanical disease spread, black fly for river blindness.
The process of fusion of male and female gametes is called
Fertilization is the syngamy where sperm (male gamete) fuses with egg (female gamete) to form a zygote. Pollination transfers pollen, germination is seed sprouting, implantation is embryo attachment in uterus.
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