High-Scoring MCQs for CBSE Class 11 Biology Board & School Exams

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

Section A: Diversity in Living World (10 MCQs)

Q1. The term “systematics” refers to the study of:
A. Only classification
B. Only nomenclature
C. Diversity and relationships among organisms
D. Morphology of organisms

Answer: C. Diversity and relationships among organisms
Explanation: Systematics includes identification, nomenclature, classification, and evolutionary relationships.

Q2. According to binomial nomenclature, the scientific name of an organism consists of:
A. Family and genus
B. Genus and species
C. Order and family
D. Species and variety

Answer: B. Genus and species
Explanation: The first word is the genus (capitalized) and the second is the species (lowercase).

Q3. Which taxonomic category includes organisms with maximum similarities?
A. Kingdom
B. Class
C. Genus
D. Species

Answer: D. Species
Explanation: Species is the basic unit of classification with maximum resemblance.

Q4. The cell wall of fungi is made up of:
A. Cellulose
B. Chitin
C. Peptidoglycan
D. Lignin

Answer: B. Chitin
Explanation: Chitin provides rigidity to fungal cell walls.

Q5. Which group shows both autotrophic and heterotrophic nutrition?
A. Fungi
B. Protista
C. Monera
D. Plantae

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

Q6. Which of the following is a prokaryote?
A. Amoeba
B. Yeast
C. Mycoplasma
D. Paramecium

Answer: C. Mycoplasma
Explanation: Mycoplasma lacks a true nucleus and is the smallest living cell.

Q7. Viruses are placed at the border of living and non-living because they:
A. Lack nucleic acids
B. Reproduce only inside host cells
C. Are multicellular
D. Have cell walls

Answer: B. Reproduce only inside host cells
Explanation: Viruses are inert outside hosts but show life-like properties inside them.

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

Answer: B. Fungi and algae
Explanation: Algae provide food, fungi provide shelter.

Q9. Which plant division lacks vascular tissues?
A. Pteridophyta
B. Gymnosperms
C. Angiosperms
D. Bryophyta

Answer: D. Bryophyta
Explanation: Bryophytes are non-vascular plants.

Q10. The correct hierarchy of taxonomic categories is:
A. Species → Genus → Family → Order
B. Genus → Species → Family → Order
C. Order → Family → Genus → Species
D. Family → Order → Species → Genus

Answer: A. Species → Genus → Family → Order
Explanation: This represents increasing inclusiveness.

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

Q11. The basic unit of plant tissue system is:
A. Cell
B. Tissue
C. Organ
D. Organ system

Answer: A. Cell
Explanation: Cells combine to form tissues.

Q12. Simple permanent tissues include:
A. Xylem and phloem
B. Parenchyma, collenchyma, sclerenchyma
C. Epidermis and cortex
D. Tracheids and vessels

Answer: B. Parenchyma, collenchyma, sclerenchyma
Explanation: These tissues are composed of one type of cells.

Q13. The function of collenchyma is to provide:
A. Storage
B. Mechanical support and flexibility
C. Conduction
D. Protection

Answer: B. Mechanical support and flexibility
Explanation: Collenchyma cells have unevenly thickened walls.

Q14. Which tissue is responsible for upward movement of water?
A. Phloem
B. Cortex
C. Xylem
D. Cambium

Answer: C. Xylem
Explanation: Xylem conducts water and minerals.

Q15. The outermost protective layer of plant organs is:
A. Endodermis
B. Pericycle
C. Epidermis
D. Cortex

Answer: C. Epidermis
Explanation: Epidermis protects plant parts from injury and water loss.

Q16. Which blood cells lack nucleus in humans?
A. RBCs
B. WBCs
C. Platelets
D. Lymphocytes

Answer: A. RBCs
Explanation: Mammalian RBCs lose nucleus to carry more hemoglobin.

Q17. Which connective tissue stores fat?
A. Areolar tissue
B. Adipose tissue
C. Cartilage
D. Bone

Answer: B. Adipose tissue
Explanation: Adipose tissue stores fat and provides insulation.

Q18. The striations in muscles are due to:
A. Actin only
B. Myosin only
C. Alternating actin and myosin filaments
D. Sarcolemma

Answer: C. Alternating actin and myosin filaments
Explanation: This arrangement gives a striped appearance.

Q19. The functional unit of kidney is:
A. Neuron
B. Nephron
C. Alveolus
D. Sarcomere

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

Q20. Which tissue connects muscles to bones?
A. Ligament
B. Tendon
C. Cartilage
D. Areolar tissue

Answer: B. Tendon
Explanation: Tendons are strong fibrous connective tissues.

Section C: Cell Structure & Function (10 MCQs)

Q21. The fluid mosaic model of plasma membrane was proposed by:
A. Watson and Crick
B. Singer and Nicolson
C. Schleiden and Schwann
D. Robert Hooke

Answer: B. Singer and Nicolson
Explanation: It describes membrane as a dynamic structure.

Q22. Which organelle is known as the powerhouse of the cell?
A. Ribosome
B. Golgi apparatus
C. Mitochondria
D. Lysosome

Answer: C. Mitochondria
Explanation: It produces ATP via cellular respiration.

Q23. Ribosomes are involved in:
A. Lipid synthesis
B. Protein synthesis
C. DNA replication
D. Photosynthesis

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

Q24. Which plastid is responsible for photosynthesis?
A. Leucoplast
B. Chromoplast
C. Chloroplast
D. Amyloplast

Answer: C. Chloroplast
Explanation: Chloroplast contains chlorophyll.

Q25. Lysosomes are called “suicidal bags” because they:
A. Store food
B. Synthesize enzymes
C. Digest cell components
D. Produce energy

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

Q26. Prokaryotic ribosomes are:
A. 80S
B. 70S
C. 60S
D. 90S

Answer: B. 70S
Explanation: Prokaryotes have smaller ribosomes.

Q27. The main function of Golgi apparatus is:
A. Protein synthesis
B. Protein modification and packaging
C. Respiration
D. Lipid digestion

Answer: B. Protein modification and packaging
Explanation: Golgi modifies proteins from ER.

Q28. Which organelle is absent in prokaryotic cells?
A. Ribosome
B. Cell membrane
C. Mitochondria
D. Cytoplasm

Answer: C. Mitochondria
Explanation: Prokaryotes lack membrane-bound organelles.

Q29. The largest cell in human body is:
A. Neuron
B. RBC
C. Ovum
D. Muscle cell

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

Q30. Cristae are associated with:
A. Chloroplast
B. Mitochondria
C. Golgi body
D. Nucleus

Answer: B. Mitochondria
Explanation: Cristae increase surface area for ATP synthesis.

Section D: Plant Physiology (10 MCQs)

Q31. Water movement through root cells occurs mainly by:
A. Diffusion
B. Osmosis
C. Translocation
D. Mass flow

Answer: B. Osmosis
Explanation: Water moves from higher to lower water potential.

Q32. The upward movement of water in tall trees is explained by:
A. Root pressure theory
B. Diffusion theory
C. Transpiration pull theory
D. Active transport

Answer: C. Transpiration pull theory
Explanation: It is the most accepted theory.

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

Answer: C. Stomata
Explanation: Most water loss occurs through stomata.

Q34. Which element is a component of chlorophyll?
A. Nitrogen
B. Magnesium
C. Iron
D. Sulphur

Answer: B. Magnesium
Explanation: Magnesium lies at the center of chlorophyll molecule.

Q35. The opening and closing of stomata is controlled by:
A. Epidermal cells
B. Guard cells
C. Companion cells
D. Root hairs

Answer: B. Guard cells
Explanation: Changes in turgidity regulate stomatal movement.

Q36. Light reactions of photosynthesis occur in:
A. Stroma
B. Thylakoid membranes
C. Cytoplasm
D. Outer membrane

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

Q37. The Calvin cycle occurs in:
A. Grana
B. Thylakoids
C. Stroma
D. Cytoplasm

Answer: C. Stroma
Explanation: CO₂ fixation occurs in stroma.

Q38. Which plant hormone promotes cell elongation?
A. Cytokinin
B. Auxin
C. Ethylene
D. ABA

Answer: B. Auxin
Explanation: Auxins promote elongation of stem cells.

Q39. Respiration that occurs without oxygen is called:
A. Aerobic respiration
B. Oxidative phosphorylation
C. Anaerobic respiration
D. Photorespiration

Answer: C. Anaerobic respiration
Explanation: It produces less energy compared to aerobic respiration.

Q40. The end product of glycolysis is:
A. Acetyl CoA
B. Lactic acid
C. Pyruvic acid
D. Ethanol

Answer: C. Pyruvic acid
Explanation: Glycolysis breaks glucose into pyruvate.

Section E: Human Physiology (10 MCQs)

Q41. The functional unit of lung is:
A. Bronchiole
B. Alveolus
C. Trachea
D. Pleura

Answer: B. Alveolus
Explanation: Gas exchange occurs in alveoli.

Q42. Which blood group is universal donor?
A. A
B. B
C. AB
D. O

Answer: D. O
Explanation: O group lacks A and B antigens.

Q43. The enzyme present in saliva is:
A. Pepsin
B. Trypsin
C. Amylase
D. Lipase

Answer: C. Amylase
Explanation: Salivary amylase digests starch.

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

Answer: C. SA node
Explanation: SA node initiates heartbeat.

Q45. Which vitamin helps in blood clotting?
A. Vitamin A
B. Vitamin B₁₂
C. Vitamin K
D. Vitamin C

Answer: C. Vitamin K
Explanation: It is essential for synthesis of clotting factors.

Q46. The hormone insulin is secreted by:
A. Liver
B. Adrenal gland
C. Pancreas
D. Thyroid

Answer: C. Pancreas
Explanation: Insulin is secreted by β-cells of pancreas.

Q47. The main nitrogenous waste in humans is:
A. Ammonia
B. Urea
C. Uric acid
D. Creatinine

Answer: B. Urea
Explanation: Humans are ureotelic animals.

Q48. The functional unit of muscle contraction is:
A. Sarcolemma
B. Sarcoplasm
C. Sarcomere
D. Myofibril

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

Q49. Which part of brain controls balance?
A. Cerebrum
B. Medulla oblongata
C. Cerebellum
D. Hypothalamus

Answer: C. Cerebellum
Explanation: Cerebellum coordinates movement and balance.

Q50. The hormone responsible for fight-or-flight response is:
A. Insulin
B. Thyroxine
C. Adrenaline
D. Estrogen

Answer: C. Adrenaline
Explanation: Adrenaline prepares the body for emergencies.

✅ These high-scoring, NCERT-aligned MCQs provide complete revision support for CBSE Class 11 Biology school and annual exams.