Biology is a diverse and constantly evolving field of science that explores the living organisms ranging from microorganisms to the most complex multicellular organisms. It has enormous practical applications in various fields such as medicine, agriculture, biotechnology, and environmental conservation. For students aspiring to pursue a career in medicine or life sciences, it is essential to have a strong foundation in biology. In India, the National Eligibility cum Entrance Test (NEET) is a highly competitive national-level entrance examination that determines admission to undergraduate medical and dental courses. The NEET exam covers a wide range of biology topics, and students are expected to have a deep understanding of the subject to succeed. To assist NEET aspirants in their preparation, this list of top 50 biology questions for NEET aims to provide a comprehensive overview of the most important concepts and topics in biology that are crucial for success in the NEET exam.
1. What is the structure of DNA?
Ans: DNA (deoxyribonucleic acid) is a double-stranded helix composed of nucleotides that contain a sugar (deoxyribose), a phosphate group, and a nitrogenous base (adenine, thymine, guanine, or cytosine). The bases pair up in a specific way (A-T, C-G) and the sequence of these base pairs encodes genetic information.
2. What is the function of ribosomes?
Ans: Ribosomes are cellular structures responsible for protein synthesis. They read the genetic information encoded in RNA and use it to assemble amino acids into a protein chain.
3. What is the difference between mitosis and meiosis?
Ans: Mitosis is a process of cell division that results in two identical daughter cells, each with the same number of chromosomes as the parent cell. Meiosis, on the other hand, is a specialized type of cell division that results in four genetically unique daughter cells with half the number of chromosomes as the parent cell.
4. What is a gene?
Ans: A gene is a segment of DNA that contains the instructions for making a specific protein or RNA molecule, which in turn performs a specific function in the cell or organism.
5. What is genetic variation?
Ans: Genetic variation refers to the differences in genetic information between individuals within a population or species. This variation can arise through mutations, genetic recombination during meiosis, and other genetic mechanisms.
6. What is natural selection?
Ans: Natural selection is the process by which certain traits become more or less common in a population over time, based on their ability to increase an organism's chances of survival and reproduction in a particular environment.
7. What is the role of enzymes in metabolic pathways?
Ans: Enzymes are proteins that catalyze chemical reactions in the cell. They play a critical role in metabolic pathways by lowering the activation energy required for a reaction to occur, thus increasing the speed and efficiency of the reaction.
8. What is the difference between aerobic and anaerobic respiration?
Ans: Aerobic respiration is a process that uses oxygen to produce ATP (the energy currency of the cell) from glucose. Anaerobic respiration, on the other hand, does not require oxygen and produces ATP through a process that usually produces lactic acid or ethanol as a byproduct.
9. What is the function of the mitochondria?
Ans: Mitochondria are organelles responsible for producing ATP through aerobic respiration. They contain their own DNA and can replicate independently of the cell.
10. What is the difference between prokaryotic and eukaryotic cells?
Ans: Prokaryotic cells are simple cells that lack a nucleus and other membrane-bound organelles, while eukaryotic cells are more complex and have a nucleus and other specialized organelles.
11. What is the structure and function of the cell membrane?
Ans: The cell membrane is a thin, semi-permeable barrier that surrounds the cell and separates its interior from the outside environment. It is composed of a phospholipid bilayer with embedded proteins that regulate the flow of materials into and out of the cell.
12. What is osmosis and diffusion?
Ans: Osmosis is the movement of water across a selectively permeable membrane from an area of high concentration to an area of low concentration. Diffusion is the movement of particles (e.g., ions, molecules) from an area of high concentration to an area of low concentration.
13. What is the role of hormones in the human body?
Ans: Hormones are chemical messengers that are produced by glands and released into the bloodstream. They regulate a wide range of physiological processes, including growth and development, metabolism, reproduction, and behavior.
14. What is the difference between exocrine and endocrine glands?
Ans: Exocrine glands secrete their products (e.g., enzymes, sweat) into ducts that lead to the body's surface or to internal organs, while endocrine glands secrete hormones directly into the bloodstream to affect distant target organs.
15. What is the structure and function of the nephron?
Ans: The nephron is the functional unit of the kidney, responsible for filtering blood and producing urine. It is composed of a glomerulus (a network of capillaries), a renal tubule (which reabsorbs water and other substances), and a collecting duct (which carries urine to the bladder).
16.What is the difference between arteries, veins, and capillaries?
Ans: Arteries carry oxygenated blood away from the heart to the body's tissues, while veins carry deoxygenated blood back to the heart. Capillaries are small, thin-walled vessels that allow for exchange of gases and nutrients between the blood and tissues.
17. What is the role of the lymphatic system?
Ans: The lymphatic system is responsible for maintaining fluid balance in the body and defending against infections. It consists of lymphatic vessels, lymph nodes, and lymphoid organs (e.g., spleen, thymus) that produce and house immune cells.
18. What is the difference between innate and adaptive immunity?
Ans: Innate immunity is the body's first line of defense against infections and includes physical barriers (e.g., skin, mucous membranes) and immune cells that respond non-specifically to foreign invaders. Adaptive immunity, on the other hand, is a more specific response that develops over time and involves the production of antibodies and specialized immune cells to target specific pathogens.
19. What is the function of the spleen?
Ans: The spleen is a lymphoid organ that filters blood, removing old or damaged red blood cells and recycling their components. It also plays a role in immune function, producing and storing immune cells.
20. What is the structure and function of the heart?
Ans: The heart is a muscular organ that pumps blood throughout the body. It is composed of four chambers (two atria and two ventricles) and a system of valves that ensure blood flows in one direction.
21. What is the difference between systolic and diastolic blood pressure?
Ans: Systolic blood pressure is the pressure exerted on the arteries when the heart contracts (i.e., during a heartbeat), while diastolic blood pressure is the pressure when the heart is at rest (i.e., between heartbeats).
22. What is the role of the liver in the human body?
Ans: The liver has many functions in the body, including detoxifying harmful substances, producing bile for digestion, storing glycogen, and regulating blood sugar levels.
23. What is the difference between RNA and DNA?
Ans: RNA (ribonucleic acid) is a single-stranded molecule that carries genetic information from DNA to the ribosome for protein synthesis. DNA (deoxyribonucleic acid) is a double-stranded molecule that stores genetic information.
24. What is the structure and function of the nervous system?
Ans: The nervous system is responsible for coordinating and controlling the body's functions. It is composed of the brain, spinal cord, and nerves, which transmit signals throughout the body.
25. What is the difference between a neuron and a glial cell?
Ans: Neurons are specialized cells that transmit electrical and chemical signals in the nervous system, while glial cells provide support and protection for neurons.
26. What is the structure and function of the cerebellum?
Ans: The cerebellum is a region of the brain responsible for coordinating movement and maintaining balance and posture. It receives information from sensory
27. What is the difference between a sensory and a motor neuron?
Ans: Sensory neurons transmit information from sensory receptors (e.g. touch, temperature, pain) to the central nervous system, while motor neurons transmit signals from the central nervous system to the muscles and glands, allowing for movement and secretion.
28. What is the difference between a reflex and a voluntary action?
Ans: A reflex is an automatic response to a stimulus, which is mediated by the spinal cord or lower brain centers, without conscious control. Voluntary actions are those that are under conscious control, and require conscious decision making and initiation.
29. What is the difference between a hormone and a neurotransmitter?
Ans: Hormones are chemical messengers secreted by endocrine glands, and travel through the bloodstream to target organs or tissues, where they exert their effects. Neurotransmitters are chemicals that are released by neurons, and transmit signals across the synapse to target cells, usually other neurons or muscles.
30. What is the structure and function of the endocrine system?
Ans: The endocrine system consists of glands and tissues that secrete hormones into the bloodstream, which travel to target organs or tissues and regulate various physiological processes, such as growth and development, metabolism, reproduction, and response to stress.
31. What is the difference between the sympathetic and parasympathetic nervous systems?
Ans: The sympathetic nervous system is responsible for the "fight or flight" response, which prepares the body for action in response to a perceived threat, while the parasympathetic nervous system is responsible for the "rest and digest" response, which promotes relaxation and digestion.
32. What is the role of the hypothalamus in the human body?
Ans: The hypothalamus is a region of the brain that plays a key role in regulating homeostasis, by controlling various physiological processes such as body temperature, hunger, thirst, and the sleep-wake cycle. It also regulates the release of hormones from the pituitary gland.
33. What is the difference between an autosome and a sex chromosome?
Ans: Autosomes are non-sex chromosomes that exist in pairs in both males and females, and determine the majority of an individual's genetic traits. Sex chromosomes, on the other hand, determine an individual's sex (XX for females, XY for males) and carry genes that are important for sexual development and function.
34. What is the structure and function of the respiratory system?
Ans: The respiratory system is responsible for the exchange of oxygen and carbon dioxide between the body and the environment. It consists of the lungs, airways (including the trachea, bronchi, and bronchioles), and muscles of respiration (including the diaphragm and intercostal muscles).
35. What is the difference between inhalation and exhalation?
Ans: Inhalation (or inspiration) is the process of breathing in, which involves the contraction of the diaphragm and intercostal muscles, and the expansion of the chest cavity, creating negative pressure that draws air into the lungs. Exhalation (or expiration) is the process of breathing out, which involves the relaxation of the diaphragm and intercostal muscles, and the compression of the chest cavity, expelling air from the lungs.
36. What is the role of hemoglobin in the blood?
Ans: Hemoglobin is a protein found in red blood cells, which binds to oxygen in the lungs and carries it to the tissues, where it is released and used for cellular respiration. It also helps transport carbon dioxide, a waste product of metabolism, back to the lungs for exhalation.
37. What is the difference between a somatic cell and a gamete?
Ans: A somatic cell is a typical body cell that makes up the organs and tissues of the body, and it contains two sets of chromosomes (diploid). Gametes, on the other hand, are reproductive cells (sperm or egg cells) that contain only one set of chromosomes (haploid). Gametes are produced through a process called meiosis, which reduces the chromosome number by half and ensures that offspring receive the correct number of chromosomes from each parent during fertilization.
38. What is the structure and function of the digestive system?
Ans: The digestive system is a group of organs that work together to break down food into nutrients that can be absorbed and used by the body. It includes the mouth, esophagus, stomach, small intestine, large intestine, pancreas, liver, and gallbladder. The digestive process begins in the mouth with mechanical and chemical digestion of food, which then passes through the esophagus and into the stomach where it is further broken down by enzymes and stomach acid. The partially digested food then enters the small intestine where most of the nutrients are absorbed, and then into the large intestine where water is reabsorbed and waste products are formed.
39. What is the difference between mechanical and chemical digestion?
Ans: Mechanical digestion refers to the physical breakdown of food into smaller pieces, such as chewing and grinding in the mouth and churning in the stomach. Chemical digestion refers to the breakdown of food molecules into smaller components by enzymes and digestive juices.
40. What is the role of bile in digestion?
Ans: Bile is a fluid produced by the liver and stored in the gallbladder. It is released into the small intestine to aid in the digestion and absorption of fats. Bile emulsifies fat, breaking it down into smaller droplets, which makes it easier for lipase (an enzyme) to break down the fats further. Bile also helps to neutralize stomach acid and aid in the absorption of fat-soluble vitamins.
41. What is the difference between anabolic and catabolic reactions?
Ans: Anabolic reactions refer to the building up of larger molecules from smaller ones, requiring energy input. Examples of anabolic reactions include the synthesis of proteins from amino acids and the formation of glucose from simpler molecules. Catabolic reactions refer to the breakdown of larger molecules into smaller ones, releasing energy in the process. Examples of catabolic reactions include the breakdown of glucose during cellular respiration and the breakdown of fats for energy.
42. What is the structure and function of the urinary system?
Ans: The urinary system is responsible for the formation, storage, and elimination of urine. It includes the kidneys, ureters, bladder, and urethra. The kidneys filter waste products and excess water from the blood to produce urine, which then travels through the ureters and is stored in the bladder until it is eliminated through the urethra.
43. What is the difference between filtration and reabsorption in the kidneys?
Ans: Filtration is the process by which the kidneys filter waste products and excess water from the blood. This occurs in the glomerulus, a network of capillaries in the kidney. Reabsorption is the process by which the kidneys reabsorb important molecules and ions from the filtered blood, returning them to the body. This occurs in the renal tubules, where water, glucose, amino acids, and electrolytes are reabsorbed back into the bloodstream.
44. What is the role of the renin-angiotensin system in the human body?
Ans: The renin-angiotensin system (RAS) is a hormonal system that helps to regulate blood pressure and fluid balance in the body. When blood pressure drops, the kidneys release an enzyme called renin, which converts angiotensinogen (a protein produced by the liver) into angiotensin I. Angiotensin I is then converted to angiotensin
45. What is the structure and function of the male reproductive system?
Ans: The male reproductive system includes the testes, epididymis, vas deferens, seminal vesicles, prostate gland, urethra, and penis. The testes produce sperm and the male sex hormone testosterone. The sperm mature and are stored in the epididymis before being transported through the vas deferens and mixed with fluids from the seminal vesicles and prostate gland to form semen. The urethra carries semen out of the body through the penis during ejaculation.
46. What is the difference between spermatogenesis and oogenesis?
Ans: Spermatogenesis is the process of producing sperm in the testes. It involves the division and differentiation of diploid germ cells (spermatogonia) into haploid sperm cells. In contrast, oogenesis is the process of producing eggs in the ovaries. It involves the division of diploid germ cells (oogonia) into haploid egg cells.
47. What is the structure and function of the female reproductive system?
Ans: The female reproductive system includes the ovaries, fallopian tubes, uterus, cervix, and vagina. The ovaries produce eggs and the female sex hormones estrogen and progesterone. During ovulation, an egg is released from the ovary and travels through the fallopian tube to the uterus. If the egg is fertilized by sperm, it implants in the uterus and develops into a fetus. If the egg is not fertilized, it is shed along with the lining of the uterus during menstruation.
48. What is the menstrual cycle?
Ans: The menstrual cycle is the regular monthly process that occurs in the female reproductive system, which prepares the body for pregnancy. It involves changes in hormone levels, the growth and shedding of the uterine lining, and the release of an egg from the ovary.
49. What is the role of the placenta in pregnancy?
Ans: The placenta is an organ that develops in the uterus during pregnancy. It provides a connection between the mother and fetus, allowing the exchange of nutrients, gases, and waste products. The placenta also produces hormones that help regulate pregnancy.
50. What is the difference between mitosis and meiosis in terms of genetic variation?
Ans: In mitosis, a single cell divides into two identical daughter cells, each with the same number of chromosomes as the parent cell. This process results in cells that are genetically identical to the original cell. In meiosis, a cell divides twice to produce four daughter cells, each with half the number of chromosomes as the parent cell. This process results in cells that are genetically different from the original cell due to genetic recombination and independent assortment of chromosomes. Meiosis is the process by which gametes (sperm and egg cells) are produced.