Biology MCQs With Answers

Ans: a

Explanation: Carbohydrates provide energy (glucose). After fats are broken down into fatty acids, they are used for energy. Protein can be utilized for energy as well, but its primary function is to aid in the production of hormones, muscle, and other proteins. Glucose is broken down and used to provide energy to cells.

Ans:b

Explanation: Parasitic feeding is a type of heterotrophic nutrition in which an organism (known as a parasite) lives on the surface of another creature's body or inside it (known as a host). The parasite gets its nutrients directly from the host's body. Parasitic feeding is when an organism obtains its sustenance from the bodies of other living species without harming them.

Ans:d

Explanation: Saprotrophic nutrition refers to the intake of nutrients in the form of the solution by organisms from dead and decaying substances. Saprotrophs are creatures that feed through a saprotrophic method of nutrition. Fungi, for example. Saprophytes are fungi that get their nutrition from decaying organic materials. Fungi create digestive enzymes that help to break down complex foods into simpler forms. Fungi feed on such a simple source of nourishment. The saprophytic mode of nourishment is what it's called.

Ans:c

Explanation: The spontaneous flow or diffusion of water or other solvents across a semipermeable barrier (one that blocks the passage of dissolved substances, i.e., solutes) is referred to as osmosis. Osmosis is a technique that allows water to be absorbed into the body. Osmosis is a process in which water (or a solvent) passes through a semipermeable membrane from a high water concentration to a low water concentration.

Ans: a

Explanation: A chloroplast is a type of organelle found in the cells of plants and algae that are responsible for photosynthesis, or the conversion of solar energy into chemical energy for growth. Photosynthesis occurs in chloroplasts, which contain chlorophyll in plants. Chloroplasts have a double membrane around them and a third inner membrane called the thylakoid membrane that folds into lengthy folds within the organelle.

Ans: a

Explanation: Amoeba is a protozoan, and all protozoa are thought to be the ancestors of all animals. In Amoeba, digestion takes place mostly in the food vacuole. When food is ingested via phagocytosis, a food vacuole is created. These vacuoles are driven deeper into the cytoplasm, where they create secondary lysosomes by joining with the lysosome. All of the enzymes required to break down the food particles are found in the secondary lysosome. Holozoic nutrition refers to the process of food digestion in amoebae, which includes ingestion, digestion, absorption, assimilation, and egestion.

Ans: b

Explanation: The small intestine, also known as the small bowel, is a 20-foot-long hollow tube that connects the stomach to the beginning of the large intestine. The small intestine breaks down food in the stomach and absorbs a large portion of the nutrients. The initial segment of the small intestine is the duodenum. Most digested food molecules, as well as water and minerals, are absorbed by the small intestine and passed on to other areas of the body for storage or chemical transformation. Absorbable elements are helped to penetrate the intestinal lining and into the bloodstream by specialized cells.

Ans:c

Explanation: Peristalsis is a succession of muscle contractions that propel food through the digestive tract in a wave-like pattern. The process begins in the oesophagus, where strong wave-like motions of the smooth muscle transport eaten food balls to the stomach. It will be easier to see the wave-like motion if you stretch out a segment of the intestine. Peristalsis is a wave-like movement that occurs in the alimentary canal and involves muscular contraction and relaxation.

Ans: c

Explanation: All green plants produce starch, which is a white, granular organic molecule. Starch is a tasteless, soft white powder that is insoluble in cold water, alcohol, and other solvents. Starch is a polysaccharide made up of α 1,4 connections between glucose monomers. Amylose in starch is the key factor in color development because iodine reacts with the beta coils structure of amylose and produces a blue-black color when it comes into touch with it. As a result of the iodine reaction with rice water, rice water contains starch.

Ans:d

Explanation: Stress hormone is another name for abscisic acid.

- It functions as a plant growth inhibitor as well as a metabolic inhibitor.

- It prevents seeds from germinating.

- It causes the stomata in the epidermis to close and raises the tolerance of plants to various stressors.

ABA functions as an antagonist to GAs in several circumstances (Gibberellins).

Ans: a

Explanation: Plant roots are positively geotropic because they gravitationally follow the direction of the stimulus. Roots are positively geotropic, which means they bend and grow downwards, towards the Earth's center. Shoots, on the other hand, are negatively geotropic, meaning they bend and grow upwards or away from the surface. The root will then bend and develop downwards, while the shoot will grow upwards.

Ans: c

Explanation: A common example is a plant root growing in humid air bending towards a greater relative humidity level. Hydrotropism is a plant growth response in which the direction of growth is dictated by a stimulus gradient in water concentration. The ability of terrestrial plants' roots to receive water and nutrients from the soil is critical to their survival. Hydrotropism is the controlled growth of roots in response to a moisture gradient. It starts in the root cap with the detection of the moisture gradient.

Ans: c

Explanation: The growth of an organism in response to light stimulation is known as phototropism. Positive phototropism refers to development toward a light source, whereas negative phototropism refers to growth away from light. The movement of a plant component in response to stimulation is known as phototropism (light). As a result, phototropism is responsible for the sunflower's movement in accordance with the sun's path.

Ans: c

Explanation: Cytokinins are plant-specific chemical messengers (hormones) that play a key role in the plant cell cycle and a variety of developmental processes. Cytokinins can be found in every plant tissue. The root tip, shoot apex, and immature seeds are all rich in them. It promotes mitosis, which promotes meristem differentiation into roots and shoots. Cytokinin is a plant hormone that encourages cell division.

Ans: b

Explanation: Abscisic acid is a sesquiterpene that plays an important role in seed development and maturation, protein synthesis, and the synthesis of compatible osmolytes, which allow plants to withstand stresses caused by environmental or biotic factors, as well as acting as general growth and metabolic inhibitor.

Ans: d

Explanation: Auxins and gibberellins (GA) are growth-promoting phytohormones, whereas abscisic acid (ABA) and ethylene are growth-inhibiting phytohormones. Abscisic acid (ABA) causes mature leaves and fruits to fall from plants. Because of the creation of the abscission layer, which is responsible for the fall of mature leaves and fruits from plants, it is named abscisic acid. Abscisic acid is the substance that causes the abscission layer to develop. This layer separates the leaf's live tissue from the rest of the structure.

Ans: a

Explanation: Light, gravity, weather, and touch are only some of the environmental cues that the plant responds to. A plant's response is either positive (growth toward the stimulus) or negative (growth away from the stimulus) (grow away from the stimulus). Phototropism, for example, is a plant's response to a stimulus, such as sunshine. The term "stimulus" refers to any change in the environment that an organism reacts to. The stimuli cause an appropriate electrical impulse to be generated in the sensory neurons, which then transmit the information to the brain or spinal cord as electrical impulses.

Ans: b

Explanation: Ethylene receptors are found in plants and are structurally linked. They're a pair of dimeric transmembrane proteins that act as histidine kinases. Ethylene receptors have an extracellular domain with a copper atom for ethylene binding and an intracellular histidine-kinase-like domain. The term "effector" refers to a portion of the body that responds to commands from the neurological system.

Ans: c

Explanation: In vertebrates, an axon, also known as a nerve fiber, is a long, slender projection of a nerve cell, or neuron, that transports electrical impulses known as action potentials away from the nerve cell body. The axon's job is to communicate information between neurons, muscles, and glands. Axon refers to the longest fiber on a neuron's cell body.

Ans: b

Explanation: Bryophyllum is a genus of plant species belonging to the Crassulaceae family that is native to Madagascar. It is a subdivision or subgenus of the Kalanchoe genus that was formerly put at the genus level. This part is famous for the vegetative growth of little plantlets on the leaf fringes, which eventually drop off and root. Mitosis of meristematic-type tissue in notches in the leaves produces these plantlets. Bryophyllum can be propagated vegetatively by cutting off a section of its stem or leaves. A Bryophyllum plant's leaves feature unique buds in their margins that can detach from the leaves, fall to the ground, and grow into a new plant

Ans: d

Explanation: When an axillary bud develops into a lateral shoot with its own roots, this is known as natural vegetative propagation (also known as adventitious roots). Bulbs, rhizomes, stolons, and tubers are plant structures that allow for natural vegetative proliferation. Vegetative propagation is an asexual reproduction method in which a new plant is created from the root, stem, leaves, and buds of an existing plant. Vegetative propagation is the process of producing new plants from the vegetative parts of an existing plant.

Ans: (c)

Explanation: The development of a new plant from vegetative parts of the plant, such as roots, stems, or leaves, is known as vegetative propagation. Adventitious buds occur in the roots of some plants, such as sweet potatoes, and break away from the root to generate new plants. The production of a new plant from the plant's vegetative parts, such as roots, stems, or leaves, is known as vegetative propagation. Adventitious buds occur in the roots of some plants, such as potatoes, which break away from the root and sprout new plants.

Ans: c

Explanation: Plants produced through vegetative propagation are genetically similar to the parent plant. Plants and lesser animals, on the other hand, can reproduce asexually, that is, without the generation of gametes. Recombination of genes is not possible in asexual means of reproduction. When crop plants don't produce seeds, or the seeds they do produce aren't viable or have a long dormancy, vegetative propagation is frequently used. Cuttings are the parts of the plant that are cut and utilized for crop propagation; when planted, they form roots and sprout new plants.

Ans: b

Explanation: At maturity, an organism's fragmentation is a sort of asexual reproduction in which the organism simply separates into individual parts. Individually, these little bits grow to form a new organism. Both sexual and asexual reproduction is possible in the Spirogyra species. The filaments are simply fragmented during asexual, or vegetative, reproduction. Conjugation is a sexual reproduction process in which cells from two strands lying side by side are linked by outgrowths termed conjugation tubes.

Ans:b

Explanation: Rhizopus is a saprobic fungus that feeds on dead organic materials that have decayed. Rhizoids, stolons, and unbranched sporangiophores make up its body, which is made up of branching mycelia formed of three types of hyphae: rhizoids, stolons, and unbranched sporangiophores. Rhizoids are hyphae that grow downward into the soil and aid in water absorption. A stolen is a slender horizontal hypha that aids in an organism's proliferation. Sporangiophores are hyphae that are straight, unbranched tubular threads with spherical sporangia at their tips. For asexual reproduction, sporangia create non-motile multinucleate spores.

Ans: d

Explanation: Vestigial organs are organs, tissues, or cells in the body that are no longer functional in their ancestral version of the feature. It is proof of evolution and hence helps to explain adaptation. A structure like this can form as a result of a protein mutation caused by a gene mutation. Vestigial organs are organs that existed in a functional state in our forefathers. In humans, they serve as primitive structures. The ear muscle, tailbone, wisdom teeth, nictitating membrane, and other vestigial organs are widespread in humans. The gall bladder is not a vestigial organ in human beings.

Ans: a

Explanation: Humans use artificial selection to consciously select for or against specific traits in organisms. From a single common ancestor, artificial selection has enabled the growth of novel crops with desirable features. Furthermore, after a plant with the appropriate allele combination has been created, it can be propagated asexually by taking cuttings, grafting, nurturing runners, or layering. By selective breeding and artificial selection, man has generated various agricultural plants such as broccoli, cabbage, cauliflower, kohlrabi, and other vegetables from a common wild cabbage species.

Ans: a

Explanation: When a round, green seeded pea plant (RRyy) is crossed with a wrinkled, yellow seeded pea plant (rrYY), the F1 generation produces round, yellow seeds. When round green seeded pea plants (RRyy) are crossed with wrinkled yellow seeded pea plants (rrYY), F1 progeny with Round and Yellow seeds are produced.

Ans: b

Explanation: A child's gender is determined by the XX chromosomal pair. The XY combination indicates that the child is a boy. As a result, an X chromosome will always be present in a female egg. The X chromosome is found in 50% of sperm while the Y chromosome is found in 50% of sperm. When an egg is fertilized by sperm carrying the X chromosome, the XX combination is generated, resulting in the birth of a girl child. A daughter will develop from a zygote with an X-chromosome inherited from the father. The X-chromosome is inherited by all children, whether they are boys or girls, from their mother.

Ans: b

Explanation: One of man's earliest and most beneficial inventions is leather. It is a long-lasting material, and the skins used are environmentally friendly because they are a byproduct of the meat industry. Leather and leather goods have a high potential for biodegradability. It depends on a variety of factors, including the chemicals utilized.

Ans: c

Explanation: The sun is the ultimate source of energy in all ecosystems. Green plants capture solar energy and convert it into a form that other species at higher trophic levels can utilize. Photosynthesis is a process in which green plants use sunlight and carbon dioxide from the atmosphere to make carbohydrates (food). Plants are classified as producers because they make nourishment for themselves. As a result, they are the very first link in any food chain.