Exam-Oriented Biology MCQs for CBSE Class 11 (NCERT Aligned)

(Strictly NCERT-Based | Exam-Focused | With Answers & Concept-Clearing Explanations)

Section A: Diversity in Living World (10 MCQs)

Q1. The term taxonomy was coined by:
A. Linnaeus
B. de Candolle
C. Aristotle
D. Darwin

Answer: B. de Candolle
Explanation: A.P. de Candolle introduced the term taxonomy for classification of organisms.

Q2. The correct sequence of taxonomic hierarchy is:
A. Species → Genus → Family → Order
B. Genus → Species → Order → Family
C. Family → Genus → Species → Order
D. Order → Family → Species → Genus

Answer: A. Species → Genus → Family → Order
Explanation: Taxonomic categories increase in inclusiveness from species upward.

Q3. Which kingdom includes photosynthetic as well as heterotrophic unicellular organisms?
A. Monera
B. Protista
C. Fungi
D. Plantae

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

Q4. Cell wall of bacteria is composed of:
A. Cellulose
B. Chitin
C. Peptidoglycan
D. Lignin

Answer: C. Peptidoglycan
Explanation: Peptidoglycan provides rigidity to bacterial cell walls.

Q5. Viruses are considered obligate parasites because they:
A. Lack ribosomes
B. Lack cell wall
C. Reproduce only inside host cells
D. Are unicellular

Answer: C. Reproduce only inside host cells
Explanation: Viruses depend entirely on host machinery for replication.

Q6. Bryophytes are called amphibians of plant kingdom because they:
A. Grow in water
B. Require water for fertilization
C. Have vascular tissues
D. Produce seeds

Answer: B. Require water for fertilization
Explanation: Male gametes need water to reach female gametes.

Q7. Which group bears naked seeds?
A. Angiosperms
B. Gymnosperms
C. Pteridophytes
D. Bryophytes

Answer: B. Gymnosperms
Explanation: Seeds are not enclosed in fruits in gymnosperms.

Q8. Lichens represent a symbiotic association between:
A. Algae and bacteria
B. Algae and fungi
C. Fungi and moss
D. Algae and protozoa

Answer: B. Algae and fungi
Explanation: Algae provide food; fungi provide protection.

Q9. The smallest living cell is:
A. Virus
B. Bacteriophage
C. Mycoplasma
D. Amoeba

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

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

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

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

Q11. Which tissue provides mechanical strength to plant parts?
A. Parenchyma
B. Collenchyma
C. Sclerenchyma
D. Cortex

Answer: C. Sclerenchyma
Explanation: Thick, lignified walls give rigidity and strength.

Q12. Xylem tissue is responsible for transport of:
A. Food
B. Water and minerals
C. Hormones
D. Gases

Answer: B. 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 body systems by transport.

Q14. Which muscle is involuntary and striated?
A. Skeletal muscle
B. Smooth muscle
C. Cardiac muscle
D. Voluntary muscle

Answer: C. Cardiac muscle
Explanation: Cardiac muscles are involuntary but 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. Tendons connect:
A. Bone to bone
B. Muscle to muscle
C. Muscle to bone
D. Cartilage to bone

Answer: C. Muscle to bone
Explanation: Tendons are strong fibrous tissues.

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

Answer: B. Increase oxygen-carrying capacity
Explanation: More space is available 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. Which tissue transports food in plants?
A. Xylem
B. Cambium
C. Phloem
D. Cortex

Answer: C. Phloem
Explanation: Phloem transports sugars.

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

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

Section C: Cell Structure & Function (10 MCQs)

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

Answer: C. Robert Hooke
Explanation: He observed cork cells in 1665.

Q22. The fluid mosaic model was proposed by:
A. Watson and Crick
B. Singer and Nicolson
C. Schleiden and Schwann
D. Darwin

Answer: B. Singer and Nicolson
Explanation: It describes plasma membrane structure.

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

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

Q24. Ribosomes are the site of:
A. Lipid synthesis
B. Protein synthesis
C. DNA replication
D. Photosynthesis

Answer: B. Protein synthesis
Explanation: Ribosomes translate mRNA into proteins.

Q25. Which organelle is absent in animal cells?
A. Mitochondria
B. Ribosome
C. Chloroplast
D. Golgi body

Answer: C. Chloroplast
Explanation: Chloroplasts are present only in plant cells.

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

Answer: B. Digest cell components
Explanation: They contain hydrolytic enzymes.

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

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

Q28. The membrane surrounding vacuole is called:
A. Plasmalemma
B. Tonoplast
C. Cell wall
D. Cristae

Answer: B. Tonoplast
Explanation: Regulates transport into vacuole.

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

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

Q30. The largest cell in human body 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 a semi-permeable membrane is:
A. Diffusion
B. Osmosis
C. Active transport
D. Mass flow

Answer: B. Osmosis
Explanation: Water moves down its water potential gradient.

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

Answer: C. Transpiration pull
Explanation: Cohesion–tension theory explains upward movement.

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

Answer: C. Stomata
Explanation: Majority of water loss is stomatal.

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

Answer: C. Chlorophyll a
Explanation: It directly participates in light reactions.

Q35. Light reactions occur in:
A. Stroma
B. Thylakoids
C. Cytoplasm
D. Matrix

Answer: B. Thylakoids
Explanation: Light energy is trapped in thylakoids.

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

Answer: B. Pyruvate
Explanation: Glucose is broken into pyruvate.

Q37. Which hormone promotes cell elongation?
A. Cytokinin
B. Ethylene
C. Auxin
D. ABA

Answer: C. Auxin
Explanation: Auxins promote stem elongation.

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

Answer: B. Anaerobic respiration
Explanation: Occurs in absence of oxygen.

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

Answer: B. Chlorophyll
Explanation: Magnesium is central atom in chlorophyll.

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

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 gas exchange.

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

Answer: C. Amylase
Explanation: Begins starch digestion.

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. Purkinje fibres
D. Bundle of His

Answer: B. SA node
Explanation: Initiates heartbeat.

Q45. Hormone that lowers blood glucose level 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 factor synthesis.

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. Medulla
C. Cerebellum
D. Hypothalamus

Answer: C. Cerebellum
Explanation: Coordinates muscular activity.

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

Answer: C. Sarcomere
Explanation: Shortening of sarcomere leads to contraction.

✅ These exam-oriented, NCERT-aligned MCQs are ideal for CBSE Class 11 term tests, annual exams, and concept strengthening.