MCQs on Cell: The Unit of Life – Class 11 Biology NCERT
MCQs on Cell: The Unit of Life – CBSE Class 11 Biology (Unit III | NCERT-Based)
CBSE Class 11 Biology – MCQs with Answers and Explanations
Unit III: Cell Structure and Function
Topic: Cell – The Unit of Life
Section A: Discovery of Cell & Cell Theory (Q1–Q10)
Q1. Who discovered the cell for the first time?
A. Robert Hooke
B. Anton van Leeuwenhoek
C. Schleiden
D. Schwann
Answer: A
Explanation: Robert Hooke discovered cells in 1665 while observing a thin slice of cork under a microscope.
Q2. Who observed living cells for the first time?
A. Robert Hooke
B. Rudolf Virchow
C. Anton van Leeuwenhoek
D. Schleiden
Answer: C
Explanation: Anton van Leeuwenhoek observed living cells like bacteria and protozoa using a simple microscope.
Q3. The cell theory was proposed by:
A. Hooke and Leeuwenhoek
B. Schleiden and Schwann
C. Virchow and Hooke
D. Schwann and Virchow
Answer: B
Explanation: Schleiden and Schwann proposed that all plants and animals are composed of cells.
Q4. The statement “Omnis cellula e cellula” was given by:
A. Schleiden
B. Schwann
C. Virchow
D. Hooke
Answer: C
Explanation: Rudolf Virchow stated that all cells arise from pre-existing cells.
Q5. Which is NOT a part of modern cell theory?
A. Cells arise from pre-existing cells
B. Cell is the basic unit of life
C. All organisms are multicellular
D. Cells contain hereditary information
Answer: C
Explanation: Many organisms are unicellular; hence this statement is incorrect.
Q6. Which organism lacks cellular organization?
A. Bacteria
B. Amoeba
C. Virus
D. Paramecium
Answer: C
Explanation: Viruses are acellular and show living properties only inside host cells.
Q7. Cell theory applies to:
A. Plants only
B. Animals only
C. Microorganisms only
D. All living organisms
Answer: D
Explanation: Cell theory is universal for all living organisms.
Q8. Which structure was observed by Hooke in cork cells?
A. Nucleus
B. Cytoplasm
C. Vacuole
D. Cell wall
Answer: D
Explanation: Hooke observed empty box-like structures representing cell walls.
Q9. Which of the following organisms is unicellular?
A. Hydra
B. Amoeba
C. Frog
D. Earthworm
Answer: B
Explanation: Amoeba consists of a single cell performing all life functions.
Q10. Which branch of biology deals with the study of cells?
A. Histology
B. Cytology
C. Physiology
D. Morphology
Answer: B
Explanation: Cytology is the study of cell structure and function.
Section B: Prokaryotic and Eukaryotic Cells (Q11–Q20)
Q11. Which of the following is a prokaryotic cell?
A. Amoeba
B. Yeast
C. Bacterium
D. Paramecium
Answer: C
Explanation: Bacteria lack membrane-bound organelles and true nucleus.
Q12. Prokaryotic cells lack:
A. Ribosomes
B. Plasma membrane
C. Nucleus
D. Cell wall
Answer: C
Explanation: Prokaryotes do not have a true nucleus.
Q13. Which structure contains genetic material in prokaryotes?
A. Nucleus
B. Nucleolus
C. Nucleoid
D. Chromosome
Answer: C
Explanation: Nucleoid region contains naked DNA in prokaryotes.
Q14. Ribosomes in prokaryotic cells are:
A. 80S
B. 70S
C. 60S
D. 90S
Answer: B
Explanation: Prokaryotic ribosomes are smaller (70S).
Q15. Which cell organelle is absent in prokaryotes but present in eukaryotes?
A. Ribosome
B. Cell wall
C. Mitochondria
D. Plasma membrane
Answer: C
Explanation: Mitochondria are membrane-bound organelles absent in prokaryotes.
Q16. Mesosomes in bacteria are involved in:
A. Protein synthesis
B. Respiration
C. Photosynthesis
D. Movement
Answer: B
Explanation: Mesosomes help in respiration and cell division.
Q17. Which cell has membrane-bound organelles?
A. Bacterial cell
B. Prokaryotic cell
C. Eukaryotic cell
D. Virus
Answer: C
Explanation: Eukaryotic cells possess membrane-bound organelles.
Q18. Plasmids are:
A. RNA molecules
B. Ribosomal units
C. Extra-chromosomal DNA
D. Cell organelles
Answer: C
Explanation: Plasmids are small circular DNA molecules in bacteria.
Q19. Which organism has both prokaryotic and eukaryotic features?
A. Virus
B. Bacteria
C. Cyanobacteria
D. Euglena
Answer: D
Explanation: Euglena shows plant-like and animal-like features.
Q20. The cell wall of bacteria is mainly composed of:
A. Cellulose
B. Chitin
C. Peptidoglycan
D. Pectin
Answer: C
Explanation: Bacterial cell walls contain peptidoglycan.
Section C: Cell Envelope & Cytoplasm (Q21–Q30)
Q21. Plasma membrane is composed of:
A. Protein only
B. Lipid only
C. Lipid and protein
D. Cellulose
Answer: C
Explanation: Plasma membrane follows the fluid mosaic model.
Q22. The fluid mosaic model was proposed by:
A. Watson and Crick
B. Singer and Nicolson
C. Schleiden and Schwann
D. Hooke and Leeuwenhoek
Answer: B
Explanation: Singer and Nicolson proposed this model in 1972.
Q23. Which movement occurs without energy expenditure?
A. Active transport
B. Endocytosis
C. Diffusion
D. Phagocytosis
Answer: C
Explanation: Diffusion is a passive transport process.
Q24. Osmosis is the movement of:
A. Solute molecules
B. Water across membrane
C. Ions against gradient
D. Proteins
Answer: B
Explanation: Osmosis involves movement of water through a semi-permeable membrane.
Q25. Cytoplasm is absent in:
A. Bacteria
B. Amoeba
C. Virus
D. Plant cell
Answer: C
Explanation: Viruses lack cytoplasm.
Q26. Which structure maintains cell shape in plants?
A. Plasma membrane
B. Cell wall
C. Vacuole
D. Cytoplasm
Answer: B
Explanation: Cell wall provides rigidity and protection.
Q27. Glycocalyx is found in:
A. Plant cells
B. Animal cells
C. Prokaryotic cells
D. Virus
Answer: C
Explanation: Glycocalyx is the outer covering of many bacteria.
Q28. Which process involves intake of solid particles?
A. Pinocytosis
B. Diffusion
C. Phagocytosis
D. Osmosis
Answer: C
Explanation: Phagocytosis is “cell eating”.
Q29. Which membrane is selectively permeable?
A. Cell wall
B. Nuclear membrane
C. Plasma membrane
D. Tonoplast
Answer: C
Explanation: Plasma membrane regulates entry and exit of substances.
Q30. Cytoskeleton is made of:
A. Microtubules only
B. Microfilaments only
C. Intermediate filaments only
D. All of these
Answer: D
Explanation: Cytoskeleton includes microtubules, microfilaments and intermediate filaments.
Section D: Cell Organelles (Q31–Q50)
Q31. Mitochondria are known as:
A. Protein factories
B. Powerhouses of cell
C. Digestive bodies
D. Storage bodies
Answer: B
Explanation: Mitochondria generate ATP during respiration.
Q32. Cristae increase the surface area for:
A. Photosynthesis
B. Protein synthesis
C. Respiration
D. Lipid synthesis
Answer: C
Explanation: Cristae enhance surface area for oxidative phosphorylation.
Q33. Which organelle lacks its own DNA?
A. Mitochondria
B. Chloroplast
C. Ribosome
D. Nucleus
Answer: C
Explanation: Ribosomes do not contain DNA.
Q34. Ribosomes are the sites of:
A. Lipid synthesis
B. Protein synthesis
C. ATP formation
D. Respiration
Answer: B
Explanation: Ribosomes translate mRNA into proteins.
Q35. Endoplasmic reticulum without ribosomes is:
A. Rough ER
B. Smooth ER
C. Golgi body
D. Lysosome
Answer: B
Explanation: Smooth ER synthesizes lipids and steroids.
Q36. Golgi apparatus is involved in:
A. Respiration
B. Protein modification
C. DNA replication
D. Photosynthesis
Answer: B
Explanation: Golgi modifies, packages, and transports proteins.
Q37. Lysosomes are known as:
A. Protein factories
B. Powerhouses
C. Suicide bags
D. Storage bodies
Answer: C
Explanation: Lysosomes contain hydrolytic enzymes that digest cellular waste.
Q38. Vacuole in plant cell helps in:
A. Photosynthesis
B. Storage and turgidity
C. Protein synthesis
D. Respiration
Answer: B
Explanation: Vacuole maintains turgor pressure and stores substances.
Q39. Which organelle is absent in animal cells?
A. Ribosome
B. Lysosome
C. Chloroplast
D. Mitochondria
Answer: C
Explanation: Chloroplasts are present only in plant cells.
Q40. Chlorophyll is present in:
A. Thylakoid membrane
B. Stroma
C. Outer membrane
D. Inner membrane
Answer: A
Explanation: Chlorophyll pigments are embedded in thylakoid membranes.
Q41. The nucleus controls cell activities by regulating:
A. Enzymes
B. Hormones
C. Protein synthesis
D. ATP production
Answer: C
Explanation: Nucleus controls gene expression and protein synthesis.
Q42. Nuclear envelope is composed of:
A. Single membrane
B. Double membrane
C. Triple membrane
D. No membrane
Answer: B
Explanation: Nuclear envelope has two membranes with pores.
Q43. Nucleolus is the site of:
A. DNA synthesis
B. rRNA synthesis
C. Protein synthesis
D. Lipid synthesis
Answer: B
Explanation: Nucleolus synthesizes ribosomal RNA.
Q44. Which organelle helps in spindle formation during cell division?
A. Lysosome
B. Centriole
C. Ribosome
D. Golgi body
Answer: B
Explanation: Centrioles organize spindle fibres.
Q45. Plastids are found in:
A. Animal cells
B. Fungal cells
C. Plant cells
D. Bacterial cells
Answer: C
Explanation: Plastids are unique to plant cells.
Q46. Amyloplast stores:
A. Proteins
B. Lipids
C. Starch
D. Pigments
Answer: C
Explanation: Amyloplast stores starch.
Q47. Elaioplast stores:
A. Starch
B. Protein
C. Oil
D. Pigment
Answer: C
Explanation: Elaioplasts store oils and fats.
Q48. Chromatin is composed of:
A. DNA only
B. RNA only
C. DNA and protein
D. Protein only
Answer: C
Explanation: Chromatin consists of DNA and histone proteins.
Q49. Which cell organelle is involved in detoxification?
A. Golgi body
B. Lysosome
C. Smooth ER
D. Ribosome
Answer: C
Explanation: Smooth ER detoxifies drugs and poisons.
Q50. Which organelle is called the “suicidal bag” of the cell?
A. Mitochondria
B. Lysosome
C. Golgi body
D. Vacuole
Answer: B
Explanation: Lysosomes can digest their own cell during autolysis.