Question Bank — Cell: The Unit of Life

NCERT Class 11 Biology · Chapter 8 · CBSE Board Pattern

Class 11 Biology Chapter 8 Question Bank CBSE Board Pattern

Section A — MCQs (10 questions, 1 mark each)

  1. Who first saw and described a live cell?
    (a) Robert Brown (b) Antonie Von Leeuwenhoek (c) Matthias Schleiden (d) Rudolf Virchow

  2. Which of the following is not a part of the cell theory as understood today?
    (a) All living organisms are composed of cells and products of cells
    (b) All cells arise from pre-existing cells
    (c) Cells are formed de novo from abiotic materials
    (d) Cell is the fundamental structural and functional unit of life

  3. Assertion (A): Prokaryotic cells lack membrane-bound organelles.
    Reason (R): Prokaryotes have a poorly defined nuclear region and ribosomes as the only non-membrane-bound organelles.
    (a) Both A and R are true and R is the correct explanation of A.
    (b) Both A and R are true but R is not the correct explanation of A.
    (c) A is true but R is false.
    (d) A is false but R is true.

  4. The fluid mosaic model of plasma membrane was proposed by:
    (a) Schleiden and Schwann (b) Singer and Nicolson (c) Robert Brown (d) Camillo Golgi

  5. Assertion (A): Ribosomes are found in both prokaryotic and eukaryotic cells.
    Reason (R): Ribosomes are non-membrane bound organelles involved in protein synthesis.
    (a) Both A and R are true and R is the correct explanation of A.
    (b) Both A and R are true but R is not the correct explanation of A.
    (c) A is true but R is false.
    (d) A is false but R is true.

  6. The site of aerobic respiration and ATP production in the cell is:
    (a) Chloroplast (b) Mitochondrion (c) Golgi apparatus (d) Lysosome

  7. Which structure connects the cytoplasm of neighbouring plant cells?
    (a) Plasmodesmata (b) Middle lamella (c) Tonoplast (d) Mesosome

  8. In prokaryotes, the specialised differentiated form of cell membrane formed by infoldings is called:
    (a) Chromatophore (b) Mesosome (c) Glycocalyx (d) Plasmid

  9. The 70S ribosome consists of:
    (a) 50S and 30S subunits (b) 60S and 40S subunits (c) 80S and 20S subunits (d) Two 40S subunits

  10. Which plastid stores starch?
    (a) Chromoplast (b) Amyloplast (c) Elaioplast (d) Aleuroplast

Section B — Very Short Answer (6 questions, 2 marks each)

  1. State the two key points of the modern cell theory.
  2. Differentiate between rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER) on the basis of ribosomes and function.
  3. What is the role of mesosomes in prokaryotic cells?
  4. Why are mitochondria called the ‘power houses’ of the cell?
  5. Name the two types of chromatin and state when chromosomes become visible.
  6. What are inclusion bodies? Give two examples found in prokaryotes.

Section C — Short Answer (5 questions, 3 marks each)

  1. Describe the structure of a typical bacterial flagellum. How do pili differ from flagella?
  2. Explain the fluid mosaic model of the plasma membrane. Why is its fluidity important?
  3. Differentiate between Gram-positive and Gram-negative bacteria on the basis of cell envelope.
  4. What are microbodies? Mention their occurrence and general function.
  5. Describe the organisation of the endomembrane system and list its components.

Section D — Long Answer (3 questions, 5 marks each)

  1. Describe the structure of the nucleus with the help of a labelled diagram. Explain the functions of nuclear pores and nucleolus.
  2. Compare and contrast the structure of a typical plant cell and an animal cell. Highlight at least four major differences with reasons.
  3. Describe the structure of mitochondria with a labelled diagram. Explain why they possess their own DNA and ribosomes.

Section E — Case/Source-Based (2 questions, 4 marks each)

Case 1: A student observed onion peel cells under a microscope and noted a distinct outer boundary, dense nucleus and cytoplasm. When the same cells were placed in a hypertonic solution, they lost water and shrank.
(a) Identify the outer boundary observed and its chemical nature.
(b) Name the membrane that allowed water movement and state the process involved.
(c) Why did the cells shrink?
(d) How does this experiment demonstrate selective permeability?

Case 2: Electron micrographs of a cell showed extensive tubular network continuous with the nuclear envelope, some portions studded with granules, and a stack of flattened sacs near the nucleus with distinct cis and trans faces.
(a) Identify the tubular network and the two types based on the presence/absence of granules.
(b) What is the function of the granules-studded portion?
(c) Name the stack of sacs and its primary role in the cell.
(d) How are these two structures functionally connected?

▶ Answer Key Attempt all questions first,
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Section A

  1. (b) 2. (c) 3. (a) 4. (b) 5. (a) 6. (b) 7. (a) 8. (b) 9. (a) 10. (b)

Section B

  1. All living organisms composed of cells/products of cells; all cells arise from pre-existing cells (1+1).
  2. RER has ribosomes, involved in protein synthesis; SER lacks ribosomes, site of lipid synthesis (1+1).
  3. Help in cell wall formation, DNA replication, respiration, secretion, increase surface area (any two — 1+1).
  4. Sites of aerobic respiration producing ATP (2).
  5. Euchromatin (loosely packed) and heterochromatin (densely packed); become visible during cell division (1+1).
  6. Reserve material stored freely in cytoplasm; e.g., phosphate granules, glycogen granules (1+1).

Section C

  1. Filament, hook, basal body; pili are tubular protein structures for attachment, not motility (2+1).
  2. Phospholipid bilayer with proteins; fluidity allows growth, secretion, endocytosis, cell division (2+1).
  3. Gram-positive retain stain due to thick peptidoglycan; Gram-negative do not due to outer membrane (1½+1½).
  4. Membrane-bound vesicles with enzymes; present in plant and animal cells for various metabolic reactions (2+1).
  5. Coordinated membranous organelles: ER, Golgi, lysosomes, vacuoles; functions linked in secretion and digestion (2+1).

Section D

  1. Nuclear envelope with pores, nucleoplasm, chromatin, nucleolus; pores allow RNA/protein transport; nucleolus site of rRNA synthesis — diagram points (3+1+1).
  2. Plant: cell wall, plastids, large vacuole; animal: centrioles, no cell wall/plastids — four differences with reasons (4+1).
  3. Double membrane, cristae, matrix with own circular DNA and 70S ribosomes; self-replicating by fission — diagram points (3+1+1).

Section E

Case 1

(a) Cell wall — cellulose (1)
(b) Plasma membrane — osmosis (1)
(c) Hypertonic solution causes exosmosis (1)
(d) Membrane allows water but not all solutes freely (1)

Case 2

(a) Endoplasmic reticulum; RER (with ribosomes) and SER (1)
(b) Protein synthesis and secretion (1)
(c) Golgi apparatus; packaging and modification of materials (1)
(d) Vesicles from ER fuse with cis face of Golgi (1)

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All questions are answerable from the NCERT chapter text. Reviewed by GFIS faculty.