100 GK Biology Questions with Answer Key

August 12, 2026

100 GK Biology Questions with Answer Key

A curated bank of 100 General Knowledge questions covering fundamental topics in Biology—including Cell Biology, Human Anatomy & Physiology, Genetics, Botany, Zoology, Microbiology, and Ecology.

Biology GK Question Bank

Cell Biology & Biochemistry (Q1–Q20)

What basic structural and functional unit forms all living organisms?
Which organelle is commonly referred to as the “powerhouse of the cell”?
What molecule carries genetic instructions in almost all living organisms?
Which cell organelle is responsible for synthesizing proteins?
What green pigment in plant cells absorbs light energy for photosynthesis?
Which cell organelle contains digestive enzymes to break down waste materials?
What type of cell lacks a distinct, membrane-bound nucleus?
Which organelle modifies, sorts, and packages proteins for secretion?
What lipid bilayer structure regulates the movement of substances into and out of the cell?
What rigid outer layer provides structural support and protection to plant cells, fungi, and bacteria?
Which nitrogenous base is present in RNA but absent in DNA?
What process do somatic cells use to divide into two genetically identical daughter cells?
What specialized cell division process reduces the chromosome number by half to produce gametes?
What sugar forms the structural backbone of a DNA molecule?
Which organelle in plant cells serves as the primary site of photosynthesis?
What molecule acts as the primary energy currency of cells?
What biological catalysts speed up chemical reactions inside living organisms?
What structural process causes proteins to lose their native shape and biological activity due to heat or extreme pH?
What network of protein filaments helps maintain cell shape, internal organization, and motility?
Which cell organelle plays a central role in lipid synthesis and toxin detoxification?

Human Anatomy & Physiology (Q21–Q50)

What is the largest organ of the human body?
Which iron-rich protein in red blood cells carries oxygen from the lungs to the tissues?
What is the hardest substance in the human body?
How many bones make up the adult human skeleton?
Which chamber of the human heart pumps oxygenated blood into the aorta?
What type of blood cells primarily fight infections and pathogens?
Which endocrine gland is often called the “master gland” because it controls other glands?
What filtering units in the human kidney process waste from the blood to produce urine?
Which hormone regulates blood glucose levels by enabling cells to absorb glucose?
What fluid produced by the liver aids in the digestion and emulsification of fats?
What bone protects the human brain?
What is the longest and strongest bone in the human body?
Which part of the human brain controls balance, posture, and motor coordination?
What valve prevents the backflow of blood from the left ventricle into the left atrium?
What muscular organ connects the pharynx to the stomach?
Which human blood type is designated as the universal donor for red blood cells?
Which human blood type is designated as the universal recipient for red blood cells?
What structural air sacs in the lungs facilitate gas exchange between air and blood?
What band of fibrous connective tissue connects bone to bone?
What band of fibrous connective tissue connects muscle to bone?
Which hormone is released by the adrenal glands during the “fight-or-flight” response?
What is the average lifespan of a human red blood cell in days?
Which organ in the human body stores bile produced by the liver?
What involuntary muscular contractions move food through the digestive tract?
Which part of the brain regulates basic autonomic functions such as heart rate and respiration?
What system of ductless glands secretes hormones directly into the bloodstream?
What transparent front layer of the human eye bends light rays entering the eye?
What light-sensitive tissue lining the back of the eye contains photoreceptor cells?
What small bone in the middle ear is the smallest bone in the human body?
What major blood vessel carries deoxygenated blood from the heart to the lungs?

Genetics, Evolution & Biotechnology (Q51–Q65)

Who is widely regarded as the “Father of Modern Genetics”?
How many pairs of chromosomes do human somatic cells normally contain?
What term describes alternative forms or variants of a specific gene?
What scientist proposed the theory of evolution by natural selection in On the Origin of Species?
What pair of sex chromosomes produces a biological male in humans?
What pair of sex chromosomes produces a biological female in humans?
What term describes a permanent change in the nucleotide sequence of an organism’s genome?
What genetic condition results from having three copies of chromosome 21?
What structure at the tip of a chromosome protects it from deterioration and degradation?
What laboratory technique is used to amplify specific segments of DNA exponentially?
What grid diagram is used to predict the genetic combinations resulting from a cross?
What term describes an organism that possesses two identical alleles for a specific trait?
What term describes an organism that possesses two different alleles for a specific trait?
What fundamental evolutionary concept explains how traits that enhance survival and reproduction become more common over generations?
Who, alongside James Watson, derived the double-helix structural model of DNA using experimental evidence from Rosalind Franklin?

Plant Biology & Botany (Q66–Q80)

What plant tissue transports water and dissolved minerals from roots to the rest of the plant?
What plant tissue transports organic nutrients (primarily sucrose) manufactured during photosynthesis?
What tiny pores on leaf surfaces facilitate gas exchange and water transpiration?
What process involves the loss of water vapor through the stomata of plants?
What plant hormone promotes cell elongation and plays a key role in phototropism?
What plant hormone in gaseous form triggers fruit ripening?
What specialized plant organ absorbs water and minerals while anchoring the plant in soil?
What type of flowering plant produces seeds containing two embryonic seed leaves (cotyledons)?
What male reproductive structure of a flower produces pollen grains?
What female reproductive organ of a flower contains the ovary, style, and stigma?
What process describes the transfer of pollen grains from an anther to a stigma?
What primary polysaccharide component forms the rigid framework of plant cell walls?
What root-like structures anchor non-vascular plants, such as mosses, to substrates?
What term describes a plant’s directional growth response toward a light source?
What specialized tissue in plants consists of actively dividing cells responsible for growth?

Zoology, Microbiology & Ecology (Q81–Q100)

What single-celled, eukaryotic organisms belong to Kingdom Protista and include Amoeba and Paramecium?
What infectious, non-living agent consists of genetic material enclosed within a protein coat (capsid)?
What field of biology focuses on the scientific study and classification of organisms?
What Kingdom of organisms includes mushrooms, yeasts, and molds?
What symbiotic association consists of a fungus living alongside an alga or cyanobacterium?
What term describes cold-blooded animals whose body temperature depends on external environmental sources?
What term describes warm-blooded animals capable of maintaining a stable internal body temperature?
What biological process involves a complete physical transformation from a larval stage to an adult form (e.g., caterpillar to butterfly)?
What primary structural material makes up the exoskeletons of arthropods and the cell walls of fungi?
What organisms break down dead or decaying organic material, recycling nutrients back into the ecosystem?
What position or feeding step does an organism occupy within a food chain or ecological pyramid?
What term describes a close, long-term biological interaction between two different species?
What type of symbiotic relationship benefits one species while leaving the other unaffected?
What type of symbiotic relationship benefits both participating species?
What measure quantifies the variety of living species within a given habitat or ecosystem?
What gas, released as a byproduct of plant photosynthesis, is essential for aerobic respiration in animals?
What marine ecosystems, formed by calcium carbonate structures secreted by tiny polyps, harbour immense biodiversity?
What microscopic organisms form the foundation of aquatic food webs by producing organic matter via photosynthesis?
What scientific term describes the maximum population size an environment can sustainably support?
What biological domain contains ancient single-celled microorganisms that thrive in extreme environments?