Biology MCQs

Science

Biology MCQs

Practice complete Biology MCQs covering Introduction to Biology, Cell Biology, Cell Structure, Cell Division, Biomolecules, Plant Physiology, Human Physiology, Genetics, Evolution, Biotechnology, Ecology, Classification of Living Organisms, Plant Kingdom, Animal Kingdom, Microbiology, Human Diseases, Nutrition, Reproduction, Environmental Biology, and all other important topics. Includes chapter-wise and exam-oriented multiple-choice questions with detailed answers and explanations for JKSSB, SSC, Banking, Railway, UPSC, CUET, NEET, State PSCs, and other competitive exams.

2054
Total Questions

Practice Questions

Page 52 of 103
Question #1021
The enzyme that catalyzes the synthesis of ATP in mitochondria is:
A. Succinate dehydrogenase
B. Cytochrome oxidase
C. ATP synthase
D. Citrate synthase
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
ATP synthase (Complex V) uses the proton gradient generated by the electron transport chain to phosphorylate ADP to ATP. Cytochrome oxidase is Complex IV, succinate dehydrogenase is part of the Krebs cycle and Complex II, citrate synthase is in the Krebs cycle.
This question belongs to: Science Biology
Question #1022
The term 'metastasis' refers to:
A. Benign tumor growth
B. Programmed cell death
C. Spread of cancer cells to distant sites
D. Inflammation
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
Metastasis is the process by which malignant cancer cells detach from the primary tumor, travel through the blood or lymph, and establish secondary tumors in other organs. Benign tumors do not metastasize. Apoptosis is programmed cell death.
This question belongs to: Science Biology
Question #1023
The plant that exhibits 'insectivorous' nutrition to obtain nitrogen is:
A. Nepenthes
B. Cuscuta
C. Monotropa
D. Loranthus
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
Nepenthes (pitcher plant) is an insectivorous plant that traps insects in its modified leaf pitchers to supplement nitrogen in nutrient-poor soils. Cuscuta is parasitic, Loranthus partial parasite, Monotropa saprophytic.
This question belongs to: Science Biology
Question #1024
The hormone that decreases blood glucose by promoting its uptake into cells is:
A. Cortisol
B. Growth hormone
C. Insulin
D. Glucagon
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
Insulin, from beta cells, lowers blood glucose by stimulating glucose uptake into muscle and adipose tissue (via GLUT4) and promoting glycogenesis. Glucagon, cortisol, and GH raise blood glucose. Insulin is the only hormone that significantly lowers blood glucose.
This question belongs to: Science Biology
Question #1025
The structure that connects the kidney to the urinary bladder is the:
A. Nephron
B. Ureter
C. Urethra
D. Renal pelvis
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
The ureter is a muscular tube that carries urine from the renal pelvis of each kidney to the urinary bladder by peristalsis. The urethra carries urine from the bladder to the exterior. Renal pelvis collects urine from calyces, nephron is the functional unit.
This question belongs to: Science Biology
Question #1026
The molecule that carries the genetic information from DNA to the ribosome is:
A. tRNA
B. rRNA
C. snRNA
D. mRNA
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Messenger RNA (mRNA) is transcribed from DNA and carries the codon sequence to ribosomes, where it is translated into a polypeptide. tRNA brings amino acids, rRNA forms ribosomal structure, snRNA involved in splicing.
This question belongs to: Science Biology
Question #1027
The technique of growing plants in nutrient-rich water without soil is known as:
A. Aeroponics
B. Geoponics
C. Tissue culture
D. Hydroponics
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Hydroponics is a method of growing plants in a water-based, nutrient-rich solution without soil. Aeroponics uses mist, geoponics is soil-based, tissue culture is in vitro on agar media. Hydroponics enables controlled nutrient delivery.
This question belongs to: Science Biology
Question #1028
The scientist who developed the first effective polio vaccine was:
A. Louis Pasteur
B. Albert Sabin
C. Edward Jenner
D. Jonas Salk
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Jonas Salk developed the inactivated polio vaccine (IPV) in 1955, which was the first effective vaccine. Albert Sabin later developed the oral polio vaccine (OPV). Pasteur rabies, Jenner smallpox.
This question belongs to: Science Biology
Question #1029
The term for the death of tissue due to lack of blood supply is:
A. Hypertrophy
B. Atrophy
C. Apoptosis
D. Necrosis
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Necrosis is the premature death of cells or tissue due to injury, ischemia, or infection, often causing inflammation. Atrophy is shrinkage, hypertrophy growth, apoptosis programmed cell death. Infarction leads to coagulative necrosis.
This question belongs to: Science Biology
Question #1030
The blood vessel that has valves to prevent backflow is:
A. Capillary
B. Artery
C. Arteriole
D. Vein
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Veins, especially in limbs, have one-way valves that prevent the backflow of blood as it returns to the heart against gravity. Arteries have thick walls to withstand pressure and lack valves. Capillaries have no valves.
This question belongs to: Science Biology
Question #1031
The process of formation of gametes in the testes is called:
A. Fertilization
B. Spermatogenesis
C. Oogenesis
D. Gametogenesis
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
Spermatogenesis is the production of haploid spermatozoa from diploid spermatogonia in the seminiferous tubules of the testes. Oogenesis is egg production, gametogenesis is the general term for both, fertilization is fusion.
This question belongs to: Science Biology
Question #1032
The enzyme that catalyzes the breakdown of hydrogen peroxide into water and oxygen is:
A. Lipase
B. Amylase
C. Pepsin
D. Catalase
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Catalase is an antioxidant enzyme found in peroxisomes that efficiently decomposes hydrogen peroxide (a toxic byproduct) into water and oxygen. Lipase digests fats, amylase starch, pepsin proteins.
This question belongs to: Science Biology
Question #1033
The plant hormone that promotes the formation of abscission layers and fruit ripening is:
A. Cytokinin
B. Gibberellin
C. Auxin
D. Ethylene
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Ethylene is a gaseous hormone that accelerates ripening, promotes leaf and fruit abscission, and senescence. Auxin and cytokinin promote growth, gibberellin elongation. Ethylene is used commercially for fruit ripening.
This question belongs to: Science Biology
Question #1034
The process by which a cell engulfs liquid droplets is:
A. Endocytosis
B. Exocytosis
C. Pinocytosis
D. Phagocytosis
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
Pinocytosis (cell drinking) is a type of endocytosis where the cell membrane forms small vesicles to engulf extracellular fluid and dissolved substances. Phagocytosis is for large particles, exocytosis is export, endocytosis is general term.
This question belongs to: Science Biology
Question #1035
The scientist who introduced the term 'biology' was:
A. Lamarck and Treviranus
B. Darwin
C. Linnaeus
D. Aristotle
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
The term 'biology' was independently coined by Jean-Baptiste Lamarck (France) and Gottfried Reinhold Treviranus (Germany) around 1802. Aristotle is father of biology, Linnaeus taxonomy, Darwin evolution.
This question belongs to: Science Biology
Question #1036
The organ that is a part of both the digestive and endocrine systems is the:
A. Gall bladder
B. Spleen
C. Pancreas
D. Liver
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
The pancreas acts as an exocrine gland (secreting digestive enzymes into the duodenum) and an endocrine gland (secreting insulin and glucagon into blood). The liver has metabolic but not major endocrine function, spleen is lymphoid, gall bladder stores bile.
This question belongs to: Science Biology
Question #1037
The pigment that gives carrots their orange color and is a precursor of vitamin A is:
A. Lycopene
B. Xanthophyll
C. Beta-carotene
D. Chlorophyll
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
Beta-carotene is a provitamin A carotenoid, giving orange color; the body can convert it to retinol. Lycopene is red (tomato), xanthophyll yellow, chlorophyll green. Carotenoids are accessory pigments in photosynthesis.
This question belongs to: Science Biology
Question #1038
The technique used to introduce foreign DNA into animal cells by fine needle injection is:
A. Biolistics
B. Microinjection
C. Electroporation
D. Lipofection
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
Microinjection uses a very fine glass micropipette to inject DNA directly into the nucleus of a target cell. Electroporation uses electrical pulses, biolistics is gene gun for plant cells, lipofection uses lipid vesicles.
This question belongs to: Science Biology
Question #1039
The part of the seed that contains stored food for the embryo is the:
A. Radicle
B. Seed coat
C. Cotyledon
D. Plumule
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
Cotyledons are seed leaves that store food (starch, proteins, lipids) for the developing embryo and may become photosynthetic after germination. Monocots have one, dicots two. Radicle is root, plumule shoot, seed coat protects.
This question belongs to: Science Biology
Question #1040
The disease caused by the fungus Candida albicans is:
A. Candidiasis
B. Ringworm
C. Athlete's foot
D. Aspergillosis
Discuss
Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
Candidiasis (thrush) is an opportunistic fungal infection caused by Candida albicans, affecting moist areas like mouth, vagina, and skin folds. Ringworm is caused by dermatophytes, athlete's foot by Trichophyton, aspergillosis by Aspergillus.
This question belongs to: Science Biology

More Science Topics

chemistry MCQs
Physics MCQs
Today's Top Topics
Physics 1287 chemistry 1089 Biology 2054
Explore Subjects
Computer 5279 History GK 3374 English 15164 Static General Knowledge 6362 Reasoning 1120
Practice Mix
The term 'Deuce' is used when the score is tied in tennis. What specific score does it denote?
The 'Vittala Temple' is known for its:
Two stations A and B are 450 km apart. A train leaves station A at 4:00 PM at 60 km/h. Another train leaves station B at 5:00 PM at 70 km/h traveling towards A. At what time will they meet?
Which of the following is a characteristic of a distributed operating system?
Select the correct passive voice of: 'She gave me a book.'