CBSE Class 11 Biology MCQs for Quick Revision & Exams

(NCERT-Aligned | Exam-Focused | Quick-Revision Friendly with Detailed Explanations)

Section A: Diversity in Living World (10 MCQs)

Q1. The correct scientific name of human is written as:
A. Homo Sapiens
B. homo sapiens
C. Homo sapiens
D. homo Sapiens

Answer: C. Homo sapiens
Explanation: Genus name starts with a capital letter and species name with lowercase; both are italicized.

Q2. Which taxonomic category represents organisms with maximum similarity?
A. Genus
B. Species
C. Family
D. Order

Answer: B. Species
Explanation: Species is the basic unit of classification where members resemble each other closely.

Q3. Cell wall made of chitin is a feature of:
A. Plantae
B. Monera
C. Protista
D. Fungi

Answer: D. Fungi
Explanation: Fungal cell walls are composed mainly of chitin.

Q4. Which group contains both autotrophic and heterotrophic members?
A. Monera
B. Protista
C. Fungi
D. Plantae

Answer: B. Protista
Explanation: Protists include algae (autotrophs) and protozoa (heterotrophs).

Q5. The smallest living cell is:
A. Virus
B. Mycoplasma
C. Bacteriophage
D. Amoeba

Answer: B. Mycoplasma
Explanation: Mycoplasma lacks a cell wall and is the smallest free-living organism.

Q6. Bryophytes are called amphibians of the plant kingdom because they:
A. Live in water
B. Need water for fertilization
C. Have roots
D. Produce seeds

Answer: B. Need water for fertilization
Explanation: Water is essential for male gametes to reach female gametes.

Q7. Naked seeds are found in:
A. Angiosperms
B. Bryophytes
C. Pteridophytes
D. Gymnosperms

Answer: D. Gymnosperms
Explanation: Seeds are not enclosed by fruits.

Q8. Lichens are indicators of:
A. Water pollution
B. Air pollution
C. Soil fertility
D. Radiation

Answer: B. Air pollution
Explanation: Lichens are highly sensitive to SO₂.

Q9. Which kingdom includes prokaryotic organisms?
A. Protista
B. Fungi
C. Plantae
D. Monera

Answer: D. Monera
Explanation: Monerans lack a true nucleus.

Q10. The most inclusive taxonomic category is:
A. Species
B. Genus
C. Family
D. Kingdom

Answer: D. Kingdom
Explanation: Kingdom contains the largest number of organisms.

Section B: Structural Organisation in Animals & Plants (10 MCQs)

Q11. Tissue that provides mechanical strength to plants is:
A. Parenchyma
B. Collenchyma
C. Sclerenchyma
D. Xylem

Answer: C. Sclerenchyma
Explanation: Thick lignified walls provide rigidity.

Q12. Xylem transports:
A. Food
B. Hormones
C. Water and minerals
D. Gases

Answer: C. Water and minerals
Explanation: Xylem conducts water upward from roots.

Q13. Blood is classified as:
A. Muscular tissue
B. Nervous tissue
C. Epithelial tissue
D. Connective tissue

Answer: D. Connective tissue
Explanation: Blood connects different organs through transport.

Q14. Muscle that works involuntarily and is striated is:
A. Skeletal muscle
B. Smooth muscle
C. Cardiac muscle
D. Voluntary muscle

Answer: C. Cardiac muscle
Explanation: Found in heart, involuntary yet striated.

Q15. The functional unit of kidney is:
A. Neuron
B. Nephron
C. Alveolus
D. Sarcomere

Answer: B. Nephron
Explanation: Nephrons filter blood and form urine.

Q16. Ligaments connect:
A. Muscle to bone
B. Bone to bone
C. Muscle to muscle
D. Cartilage to bone

Answer: B. Bone to bone
Explanation: Ligaments provide flexibility to joints.

Q17. RBCs lack nucleus to:
A. Reduce size
B. Store nutrients
C. Increase oxygen-carrying capacity
D. Increase lifespan

Answer: C. Increase oxygen-carrying capacity
Explanation: More space for haemoglobin.

Q18. The outermost layer of plant body is:
A. Cortex
B. Endodermis
C. Epidermis
D. Pericycle

Answer: C. Epidermis
Explanation: Epidermis provides protection.

Q19. Transport of food in plants occurs through:
A. Xylem
B. Phloem
C. Cambium
D. Cortex

Answer: B. Phloem
Explanation: Phloem translocates sugars.

Q20. The structural unit of muscle contraction is:
A. Actin
B. Myosin
C. Myofibril
D. Sarcomere

Answer: D. Sarcomere
Explanation: Shortening of sarcomeres causes contraction.

Section C: Cell Structure & Function (10 MCQs)

Q21. The cell was discovered by:
A. Schwann
B. Schleiden
C. Robert Hooke
D. Virchow

Answer: C. Robert Hooke
Explanation: Observed cork cells in 1665.

Q22. The fluid mosaic model explains structure of:
A. Cell wall
B. Plasma membrane
C. Nuclear membrane
D. Mitochondria

Answer: B. Plasma membrane
Explanation: Proposed by Singer and Nicolson.

Q23. Powerhouse of the cell is:
A. Golgi body
B. Lysosome
C. Mitochondria
D. Ribosome

Answer: C. Mitochondria
Explanation: Produces ATP during respiration.

Q24. Ribosomes are made of:
A. DNA and protein
B. RNA and protein
C. Lipid and protein
D. Only protein

Answer: B. RNA and protein
Explanation: Ribonucleoprotein particles.

Q25. Organelle absent in animal cells:
A. Ribosome
B. Lysosome
C. Chloroplast
D. Mitochondria

Answer: C. Chloroplast
Explanation: Found only in plant cells.

Q26. Lysosomes are called suicidal bags because they:
A. Store enzymes
B. Destroy pathogens
C. Digest cell components
D. Produce ATP

Answer: C. Digest cell components
Explanation: Contain hydrolytic enzymes.

Q27. Prokaryotic ribosomes are:
A. 80S
B. 70S
C. 60S
D. 90S

Answer: B. 70S
Explanation: Smaller than eukaryotic ribosomes.

Q28. Membrane around vacuole is called:
A. Plasmalemma
B. Tonoplast
C. Cell wall
D. Cristae

Answer: B. Tonoplast
Explanation: Regulates ion movement.

Q29. Cristae are present in:
A. Chloroplast
B. Golgi body
C. Mitochondria
D. Nucleus

Answer: C. Mitochondria
Explanation: Increase surface area for ATP synthesis.

Q30. Largest human cell is:
A. Neuron
B. Muscle cell
C. Ovum
D. RBC

Answer: C. Ovum
Explanation: Human ovum is the largest cell.

Section D: Plant Physiology (10 MCQs)

Q31. Movement of water across semi-permeable membrane is:
A. Diffusion
B. Osmosis
C. Active transport
D. Mass flow

Answer: B. Osmosis
Explanation: Water moves along water potential gradient.

Q32. Ascent of sap is explained by:
A. Root pressure theory
B. Capillarity theory
C. Transpiration pull theory
D. Diffusion theory

Answer: C. Transpiration pull theory
Explanation: Most accepted theory.

Q33. Transpiration mainly occurs through:
A. Cuticle
B. Lenticels
C. Stomata
D. Root hairs

Answer: C. Stomata
Explanation: Major site of water loss.

Q34. Primary photosynthetic pigment is:
A. Chlorophyll b
B. Carotene
C. Chlorophyll a
D. Xanthophyll

Answer: C. Chlorophyll a
Explanation: Directly participates in photosynthesis.

Q35. Light reaction occurs in:
A. Stroma
B. Thylakoid
C. Cytoplasm
D. Matrix

Answer: B. Thylakoid
Explanation: Light energy is trapped here.

Q36. End product of glycolysis is:
A. Acetyl CoA
B. Pyruvate
C. CO₂
D. ATP

Answer: B. Pyruvate
Explanation: Glycolysis breaks glucose into pyruvate.

Q37. Hormone promoting cell elongation is:
A. Cytokinin
B. Ethylene
C. Auxin
D. ABA

Answer: C. Auxin
Explanation: Auxins stimulate elongation growth.

Q38. Respiration without oxygen is:
A. Aerobic respiration
B. Anaerobic respiration
C. Photorespiration
D. Transpiration

Answer: B. Anaerobic respiration
Explanation: Produces less energy.

Q39. Magnesium is a component of:
A. Hemoglobin
B. Cytochrome
C. Chlorophyll
D. Enzymes

Answer: C. Chlorophyll
Explanation: Central atom of chlorophyll molecule.

Q40. Loss of water vapour from plants is called:
A. Respiration
B. Guttation
C. Transpiration
D. Translocation

Answer: C. Transpiration
Explanation: Occurs mainly through stomata.

Section E: Human Physiology (10 MCQs)

Q41. Functional unit of lung is:
A. Bronchus
B. Bronchiole
C. Alveolus
D. Trachea

Answer: C. Alveolus
Explanation: Site of gaseous exchange.

Q42. Enzyme present in saliva is:
A. Pepsin
B. Trypsin
C. Amylase
D. Lipase

Answer: C. Amylase
Explanation: Digests starch.

Q43. Universal donor blood group is:
A. A
B. B
C. AB
D. O

Answer: D. O
Explanation: Lacks A and B antigens.

Q44. Pacemaker of heart is:
A. AV node
B. SA node
C. Bundle of His
D. Purkinje fibres

Answer: B. SA node
Explanation: Initiates heartbeat.

Q45. Hormone that lowers blood glucose is:
A. Glucagon
B. Adrenaline
C. Insulin
D. Thyroxine

Answer: C. Insulin
Explanation: Secreted by pancreas.

Q46. Main nitrogenous waste in humans is:
A. Ammonia
B. Uric acid
C. Urea
D. Creatinine

Answer: C. Urea
Explanation: Humans are ureotelic.

Q47. Vitamin required for blood clotting is:
A. Vitamin A
B. Vitamin B
C. Vitamin C
D. Vitamin K

Answer: D. Vitamin K
Explanation: Essential for clotting factors.

Q48. Fight-or-flight hormone is:
A. Insulin
B. Cortisol
C. Adrenaline
D. Thyroxine

Answer: C. Adrenaline
Explanation: Prepares body for emergencies.

Q49. Balance and posture are controlled by:
A. Cerebrum
B. Cerebellum
C. Medulla
D. Hypothalamus

Answer: B. Cerebellum
Explanation: Coordinates muscle movements.

Q50. Functional unit of muscle contraction is:
A. Actin
B. Myosin
C. Sarcomere
D. Myofibril

Answer: C. Sarcomere
Explanation: Shortening causes contraction.

✅ These quick-revision, NCERT-aligned MCQs are perfect for last-minute preparation before CBSE Class 11 exams.