Biology MCQs

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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.

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Question #901
Gregor Mendel is known as the 'father of genetics' for his experiments on:
A. Pea plants (Pisum sativum)
B. Four o'clock plants (Mirabilis)
C. Snapdragons (Antirrhinum)
D. Fruit flies (Drosophila)
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Correct Answer: Option A

Explanation:
Gregor Mendel, an Austrian monk, is known as the 'father of genetics' for his pioneering experiments on inheritance in the garden pea plant (Pisum sativum) between 1856 and 1863. He studied seven pairs of contrasting traits and formulated the fundamental laws of inheritance: the Law of Segregation and the Law of Independent Assortment, which form the basis of classical genetics.
This question belongs to: Science Biology
Question #902
Charles Darwin proposed the theory of evolution by:
A. Use and disuse of organs
B. Mutation theory
C. Inheritance of acquired characters
D. Natural selection
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Correct Answer: Option D

Explanation:
Charles Darwin, an English naturalist, proposed the theory of evolution by natural selection in his seminal book 'On the Origin of Species' (1859). His theory, based on observations from his voyage on the HMS Beagle (especially the Galapagos finches), states that species evolve over time through the process of natural selection, where individuals with advantageous traits are more likely to survive and reproduce.
This question belongs to: Science Biology
Question #903
The double helix structure of DNA was elucidated by:
A. Avery, MacLeod, and McCarty
B. Watson and Crick
C. Meselson and Stahl
D. Hershey and Chase
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Correct Answer: Option B

Explanation:
The double helix structure of DNA was elucidated by James Watson (an American biologist) and Francis Crick (a British physicist) in 1953 at the University of Cambridge. Their model was based on X-ray diffraction data produced by Rosalind Franklin and Maurice Wilkins. They proposed that DNA consists of two antiparallel strands held together by hydrogen bonds between complementary base pairs (A-T, G-C).
This question belongs to: Science Biology
Question #904
The Cell Theory was proposed by:
A. Watson and Crick
B. Schleiden and Schwann
C. Virchow and Brown
D. Hooke and Leeuwenhoek
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Correct Answer: Option B

Explanation:
The Cell Theory, one of the fundamental principles of biology, was proposed by Matthias Schleiden (a German botanist) in 1838 and Theodor Schwann (a British zoologist) in 1839. Schleiden concluded that all plants are composed of cells, and Schwann extended this to animals. Rudolf Virchow later added the third tenet in 1855: 'Omnis cellula e cellula' (all cells arise from pre-existing cells).
This question belongs to: Science Biology
Question #905
Carolus Linnaeus is known as the father of:
A. Genetics
B. Evolution
C. Taxonomy and Binomial Nomenclature
D. Ecology
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Correct Answer: Option C

Explanation:
Carolus Linnaeus (Carl von Linné), a Swedish botanist, zoologist, and physician, is known as the 'father of modern taxonomy'. He formalized the modern system of naming organisms called binomial nomenclature, where each species is given a two-part scientific name (genus and specific epithet). His major works include 'Systema Naturae' and 'Species Plantarum', which laid the foundation for the classification of living organisms.
This question belongs to: Science Biology
Question #906
Which of the following is a characteristic of living organisms but NOT of non-living objects?
A. Possession of mass
B. Ability to respond to stimuli
C. Occurrence in nature
D. Increase in size
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Correct Answer: Option B

Explanation:
Living organisms exhibit irritability, i.e., they detect and respond to changes in their environment. Non-living objects can increase in size (e.g., crystal growth), possess mass, and occur in nature, but they lack consciousness and the ability to respond to stimuli. Thus, responsiveness is a defining property of life.
This question belongs to: Science Biology
Question #907
The scientific name of the Indian cobra is:
A. Ophiophagus hannah
B. Naja naja
C. Bungarus fasciatus
D. Vipera russellii
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Correct Answer: Option B

Explanation:
Naja naja is the binomial name of the spectacled cobra, common in India. Vipera russellii is Russell's viper, Bungarus fasciatus is the banded krait, Ophiophagus hannah is the king cobra. Binomial nomenclature was introduced by Carolus Linnaeus to provide a universal naming system.
This question belongs to: Science Biology
Question #908
Which branch of biology deals with the study of external form and structure of organisms?
A. Morphology
B. Physiology
C. Histology
D. Anatomy
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Correct Answer: Option A

Explanation:
Morphology is the study of the form and external structure of organisms. Anatomy deals with internal structures, physiology with functions, and histology with tissues. Morphology includes aspects like shape, size, color, and pattern.
This question belongs to: Science Biology
Question #909
Assertion (A): All organisms are composed of cells. Reason (R): The cell is the basic unit of life.
A. A is true, but R is false.
B. Both A and R are true, and R is the correct explanation of A.
C. A is false, but R is true.
D. Both A and R are true, but R is not the correct explanation of A.
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Correct Answer: Option B

Explanation:
The cell theory states that all organisms are composed of one or more cells, and the cell is the fundamental structural and functional unit of life. The reason directly supports the assertion. Thus, both are true and the reason correctly explains the assertion.
This question belongs to: Science Biology
Question #910
Which organelle is called the 'kitchen of the cell'?
A. Golgi apparatus
B. Ribosome
C. Mitochondria
D. Chloroplast
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Correct Answer: Option D

Explanation:
Chloroplasts are the sites of photosynthesis in plant cells, converting solar energy into chemical energy (food). Hence they are called the kitchen of the cell. Mitochondria are the powerhouse, generating ATP; ribosomes are protein factories; Golgi apparatus is the packaging center.
This question belongs to: Science Biology
Question #911
In which phase of mitosis do chromosomes become visible and the nucleolus disappears?
A. Prophase
B. Interphase
C. Metaphase
D. Telophase
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Correct Answer: Option A

Explanation:
Prophase is the first stage of mitosis where chromatin condenses into visible chromosomes, the nucleolus fades, and the mitotic spindle begins to form. In metaphase chromosomes align, in telophase they decondense and the nucleolus reappears. Interphase is not a mitotic phase.
This question belongs to: Science Biology
Question #912
Crossing over occurs between:
A. Non-homologous chromosomes
B. Two different cells
C. Non-sister chromatids of homologous chromosomes
D. Sister chromatids of the same chromosome
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Correct Answer: Option C

Explanation:
Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I of meiosis. This leads to genetic recombination. Sister chromatid exchange does occur but crossing over specifically refers to the exchange between homologues.
This question belongs to: Science Biology
Question #913
The cell wall of bacteria is composed of:
A. Cellulose
B. Chitin
C. Hemicellulose
D. Peptidoglycan
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Correct Answer: Option D

Explanation:
Bacterial cell walls (except Mycoplasma) contain peptidoglycan (murein), a polymer of N-acetylglucosamine and N-acetylmuramic acid cross-linked by short peptides. Chitin is in fungi and arthropods, cellulose in plants, hemicellulose in plant cell walls along with cellulose.
This question belongs to: Science Biology
Question #914
The organelle that processes and packages proteins for secretion is the:
A. Ribosome
B. Rough endoplasmic reticulum
C. Golgi apparatus
D. Lysosome
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Correct Answer: Option C

Explanation:
The Golgi apparatus modifies, sorts, and packages proteins and lipids into vesicles for transport to their destinations (secretion, plasma membrane, lysosomes). Ribosomes synthesize proteins, rough ER folds and transports them, lysosomes digest materials.
This question belongs to: Science Biology
Question #915
Which of the following is a feature of eukaryotic cells but NOT prokaryotic cells?
A. Presence of ribosomes
B. Presence of cell wall
C. Presence of plasma membrane
D. Presence of mitochondria
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Correct Answer: Option D

Explanation:
Mitochondria are membrane-bound organelles present in almost all eukaryotic cells but absent in prokaryotes, which carry out respiration on the plasma membrane or mesosomes. Ribosomes, cell wall (in most), and plasma membrane are present in both.
This question belongs to: Science Biology
Question #916
The kingdom that includes unicellular eukaryotic organisms is:
A. Monera
B. Fungi
C. Protista
D. Plantae
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Correct Answer: Option C

Explanation:
Protista consists of unicellular eukaryotes like protozoans, unicellular algae, and slime molds. Monera includes prokaryotes, Fungi are mostly multicellular eukaryotes (except yeast), Plantae are multicellular autotrophs.
This question belongs to: Science Biology
Question #917
The botanical name of the rice plant is:
A. Triticum aestivum
B. Hordeum vulgare
C. Zea mays
D. Oryza sativa
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Correct Answer: Option D

Explanation:
Oryza sativa is the scientific name of rice, the staple food for a large part of the world. Triticum aestivum is wheat, Zea mays is maize, Hordeum vulgare is barley. All are cereals of the Poaceae family.
This question belongs to: Science Biology
Question #918
The tissue responsible for the transport of water in plants is:
A. Collenchyma
B. Phloem
C. Xylem
D. Epidermis
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Correct Answer: Option C

Explanation:
Xylem is a complex permanent tissue that conducts water and dissolved minerals from roots to the aerial parts. It consists of tracheids, vessels, xylem parenchyma, and fibers. Phloem transports organic solutes, collenchyma provides flexible support, epidermis protects.
This question belongs to: Science Biology
Question #919
The pigment that absorbs light energy for photosynthesis is mainly located in the:
A. Cell wall
B. Cytoplasm
C. Thylakoid membrane
D. Stroma
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Correct Answer: Option C

Explanation:
Chlorophyll and other photosynthetic pigments are embedded in the thylakoid membranes of chloroplasts, where they participate in light-dependent reactions. The stroma contains enzymes for the Calvin cycle. The cell wall and cytoplasm are not sites of photosynthesis.
This question belongs to: Science Biology
Question #920
The movement of water through a semipermeable membrane from a region of lower solute concentration to higher solute concentration is:
A. Active transport
B. Osmosis
C. Diffusion
D. Plasmolysis
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Correct Answer: Option B

Explanation:
Osmosis is the net diffusion of water across a selectively permeable membrane from a region of high water potential (low solute) to low water potential (high solute). Diffusion refers to solute movement, active transport uses energy, plasmolysis is cell shrinkage.
This question belongs to: Science Biology

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