CBSE Class 11 Biology MCQs with Answers & Explanations: Cell – The Unit of Life (NCERT-Based)

Course and Examination Framework

Course: CBSE Class 11 Biology

Board: Central Board of Secondary Education

Unit III: Cell Structure and Function

Chapter 8: Cell – The Unit of Life

Question Type: Multiple Choice Questions (MCQs)

Total Questions: 50

Assessment Focus: Definitions, Comparisons, Diagrams

Syllabus Compliance: 100% NCERT

Exam Relevance: CBSE Class 11 Annual & School Examinations

Section A: Cell Discovery and Cell Theory (MCQs 1–10)

Q1. Who first observed and named cells while examining cork?
A. Leeuwenhoek
B. Schwann
C. Hooke
D. Virchow

Correct Answer: C
Explanation: Robert Hooke observed dead cork cells in 1665 and coined the term “cell” due to their box-like appearance.

Q2. Which scientist first observed living cells?
A. Robert Hooke
B. Antonie van Leeuwenhoek
C. Schleiden
D. Schwann

Correct Answer: B
Explanation: Leeuwenhoek observed living cells like bacteria and protozoa using improved microscopes.

Q3. Who proposed the cell theory?
A. Hooke and Virchow
B. Schleiden and Schwann
C. Leeuwenhoek and Hooke
D. Darwin and Wallace

Correct Answer: B
Explanation: Schleiden studied plant cells and Schwann studied animal cells, leading to the formulation of cell theory.

Q4. The statement “All cells arise from pre-existing cells” was given by:
A. Schleiden
B. Schwann
C. Hooke
D. Virchow

Correct Answer: D
Explanation: Rudolf Virchow added this postulate, correcting earlier assumptions of spontaneous cell formation.

Q5. Which of the following is NOT a postulate of cell theory?
A. All living organisms are composed of cells
B. Cell is the basic unit of life
C. Cells arise spontaneously
D. Cells arise from pre-existing cells

Correct Answer: C
Explanation: Cell theory rejects spontaneous generation of cells.

Q6. Cytology is the study of:
A. Tissues
B. Organs
C. Cells
D. Organ systems

Correct Answer: C
Explanation: Cytology specifically deals with the structure and function of cells.

Q7. Which organism best represents a unicellular condition?
A. Frog
B. Amoeba
C. Hydra
D. Earthworm

Correct Answer: B
Explanation: Amoeba is unicellular and performs all life functions within one cell.

Q8. Which statement best explains why cell is called the basic unit of life?
A. Cells are microscopic
B. Cells contain DNA
C. Cells perform all life processes
D. Cells are structurally similar

Correct Answer: C
Explanation: Cells independently carry out all vital biological functions.

Q9. Which of the following lacks cellular organization?
A. Bacteria
B. Amoeba
C. Virus
D. Algae

Correct Answer: C
Explanation: Viruses lack cellular structure and are inert outside host cells.

Q10. Cell theory explains the:
A. Origin of life
B. Evolution of species
C. Unity of life
D. Extinction of organisms

Correct Answer: C
Explanation: Cell theory shows that all organisms share a common cellular basis.

Section B: Prokaryotic vs Eukaryotic Cells (MCQs 11–20)

Q11. Prokaryotic cells lack:
A. Ribosomes
B. Cell membrane
C. Cell wall
D. True nucleus

Correct Answer: D
Explanation: Prokaryotic cells have a nucleoid instead of a membrane-bound nucleus.

Q12. Which organism is prokaryotic?
A. Amoeba
B. Paramecium
C. Bacteria
D. Yeast

Correct Answer: C
Explanation: Bacteria are typical prokaryotic organisms.

Q13. DNA in prokaryotic cells is:
A. Linear with histones
B. Circular with histones
C. Circular without histones
D. Linear without histones

Correct Answer: C
Explanation: Prokaryotic DNA is naked, circular, and not associated with histones.

Q14. Which ribosomes are present in prokaryotic cells?
A. 60S
B. 70S
C. 80S
D. 90S

Correct Answer: B
Explanation: Prokaryotic ribosomes are smaller and denser, classified as 70S.

Q15. Eukaryotic cells are characterized by:
A. Absence of organelles
B. Presence of nucleoid
C. Presence of membrane-bound organelles
D. Circular DNA

Correct Answer: C
Explanation: Compartmentalization is a key feature of eukaryotic cells.

Q16. Which cell organelle is absent in prokaryotes?
A. Ribosome
B. Plasma membrane
C. Mitochondria
D. Cell wall

Correct Answer: C
Explanation: Prokaryotes lack membrane-bound organelles like mitochondria.

Q17. Glycocalyx is found in:
A. Animal cells
B. Plant cells
C. Prokaryotic cells
D. Fungal cells

Correct Answer: C
Explanation: Glycocalyx is an outer protective covering in many prokaryotes.

Q18. Which cell type shows compartmentalization?
A. Bacterial cell
B. Prokaryotic cell
C. Eukaryotic cell
D. Cyanobacteria

Correct Answer: C
Explanation: Eukaryotic cells have membrane-bound organelles creating compartments.

Q19. Histone proteins are associated with DNA in:
A. Prokaryotes
B. Viruses
C. Eukaryotes
D. Mycoplasma

Correct Answer: C
Explanation: Histones help in DNA packaging in eukaryotic chromosomes.

Q20. Which feature increases efficiency of eukaryotic cells?
A. Smaller size
B. Lack of organelles
C. Compartmentalization
D. Circular DNA

Correct Answer: C
Explanation: Compartmentalization allows simultaneous specialized functions.

Section C: Cell Membrane and Cell Wall (MCQs 21–30)

Q21. Plasma membrane is best described as:
A. Impermeable
B. Freely permeable
C. Selectively permeable
D. Non-living

Correct Answer: C
Explanation: It selectively allows substances to pass in and out.

Q22. Fluid Mosaic Model was proposed by:
A. Watson and Crick
B. Singer and Nicolson
C. Hooke and Schwann
D. Leeuwenhoek

Correct Answer: B
Explanation: This model explains the flexible nature of membrane proteins and lipids.

Q23. Major component of plasma membrane is:
A. Cellulose
B. Phospholipid
C. Chitin
D. Peptidoglycan

Correct Answer: B
Explanation: Phospholipid bilayer forms the basic membrane structure.

Q24. Movement of molecules without energy is called:
A. Active transport
B. Endocytosis
C. Diffusion
D. Pinocytosis

Correct Answer: C
Explanation: Diffusion is a passive transport process.

Q25. Transport of ions against gradient requires:
A. Diffusion
B. Osmosis
C. ATP
D. Water

Correct Answer: C
Explanation: Active transport uses energy from ATP.

Q26. Cell wall is absent in:
A. Plants
B. Fungi
C. Bacteria
D. Animals

Correct Answer: D
Explanation: Animal cells lack a cell wall.

Q27. Main component of plant cell wall is:
A. Chitin
B. Cellulose
C. Glycogen
D. Protein

Correct Answer: B
Explanation: Cellulose provides rigidity and strength to plant cells.

Q28. Endocytosis occurs mainly in:
A. Plant cells
B. Animal cells
C. Bacterial cells
D. Fungal cells

Correct Answer: B
Explanation: Presence of cell wall in plants prevents endocytosis.

Q29. Plasmolysis occurs when plant cell is placed in:
A. Hypotonic solution
B. Isotonic solution
C. Hypertonic solution
D. Distilled water

Correct Answer: C
Explanation: Water moves out, causing shrinkage of protoplast.

Q30. Which structure prevents bursting of plant cells?
A. Plasma membrane
B. Vacuole
C. Cell wall
D. Nucleus

Correct Answer: C
Explanation: Cell wall provides mechanical resistance.

Section D: Cell Organelles (MCQs 31–50)

Q31. Control centre of the cell is:
A. Mitochondria
B. Nucleus
C. Ribosome
D. Golgi body

Correct Answer: B
Explanation: Nucleus regulates gene expression and cell activities.

Q32. Nucleolus is involved in formation of:
A. DNA
B. mRNA
C. Ribosomes
D. Lysosomes

Correct Answer: C
Explanation: Nucleolus synthesizes rRNA and ribosomal subunits.

Q33. RER is associated with:
A. Lipid synthesis
B. Protein synthesis
C. Detoxification
D. Photosynthesis

Correct Answer: B
Explanation: Ribosomes on RER synthesize proteins.

Q34. Smooth ER is involved in:
A. Protein transport
B. Lipid synthesis
C. Ribosome formation
D. ATP production

Correct Answer: B
Explanation: SER synthesizes lipids and steroids.

Q35. Golgi apparatus mainly functions in:
A. Respiration
B. Digestion
C. Packaging and secretion
D. DNA replication

Correct Answer: C
Explanation: Golgi modifies and packages proteins.

Q36. “Suicidal bags” of cell are:
A. Mitochondria
B. Lysosomes
C. Ribosomes
D. Vacuoles

Correct Answer: B
Explanation: Lysosomes can digest cell components.

Q37. Powerhouse of the cell is:
A. Ribosome
B. Nucleus
C. Mitochondria
D. Golgi body

Correct Answer: C
Explanation: Mitochondria produce ATP.

Q38. Cristae are found in:
A. Nucleus
B. Chloroplast
C. Mitochondria
D. Golgi body

Correct Answer: C
Explanation: Cristae increase surface area for respiration.

Q39. Organelle with its own DNA is:
A. Golgi apparatus
B. Lysosome
C. Mitochondria
D. Vacuole

Correct Answer: C
Explanation: Mitochondria are semi-autonomous organelles.

Q40. Photosynthesis occurs in:
A. Mitochondria
B. Chloroplast
C. Ribosome
D. Nucleus

Correct Answer: B
Explanation: Chloroplasts contain chlorophyll.

Q41. Grana are found in:
A. Mitochondria
B. Chloroplast
C. Nucleus
D. Golgi body

Correct Answer: B
Explanation: Grana are stacks of thylakoids.

Q42. Ribosomes are:
A. Membrane-bound
B. Non-membranous
C. Double-membraned
D. Single-membraned

Correct Answer: B
Explanation: Ribosomes lack membranes.

Q43. 80S ribosomes are found in:
A. Prokaryotes
B. Mitochondria
C. Chloroplast
D. Eukaryotic cytoplasm

Correct Answer: D
Explanation: Eukaryotic cytoplasmic ribosomes are 80S.

Q44. Cytoskeleton is made of:
A. Proteins
B. Lipids
C. Carbohydrates
D. Nucleic acids

Correct Answer: A
Explanation: It consists of protein filaments.

Q45. Centrosome is present in:
A. Plant cells
B. Animal cells
C. Fungal cells
D. Prokaryotes

Correct Answer: B
Explanation: Centrosome is absent in higher plants.

Q46. Cilia and flagella show:
A. 9+1 arrangement
B. 9+2 arrangement
C. 8+2 arrangement
D. Random arrangement

Correct Answer: B
Explanation: Typical eukaryotic motile structure.

Q47. Vacuole in plant cell maintains:
A. Respiration
B. Turgidity
C. Protein synthesis
D. Cell division

Correct Answer: B
Explanation: Vacuole maintains osmotic balance.

Q48. Cell sap is present in:
A. Mitochondria
B. Vacuole
C. Nucleus
D. Golgi body

Correct Answer: B
Explanation: Vacuole stores cell sap.

Q49. Leucoplasts are mainly involved in:
A. Photosynthesis
B. Pigmentation
C. Storage
D. Respiration

Correct Answer: C
Explanation: Leucoplasts store starch, fats, and proteins.

Q50. Which organelle is absent in animal cells?
A. Ribosome
B. Mitochondria
C. Chloroplast
D. Golgi apparatus

Correct Answer: C
Explanation: Chloroplasts are plant-specific organelles.

Targeting Exams 

This MCQ set is carefully designed to support preparation for:

• CBSE Class 11 Annual Examinations

• CBSE School Unit Tests & Term Exams

• NCERT-Based Objective Assessments

• NEET Foundation / Medical Entrance Concept Building

• Biology Olympiad (Foundation Level)

Questions focus on definitions, comparisons, and diagram-based concepts, as prescribed in the CBSE assessment framework.

Related Keyphrases 

• CBSE Class 11 Biology Chapter 8 MCQs

• Cell The Unit of Life MCQ Questions

• NCERT Class 11 Biology MCQs with Explanations

• Prokaryotic vs Eukaryotic Cells MCQs

• Cell Organelles MCQs Class 11

• CBSE Biology Objective Questions Unit III

• Chapter 8 Cell Structure and Function MCQs