Cell Structure & Function : 12th Class Biology Question Answer Lesson 4 – NIOS

Cell Structure & Function : 12th Class Biology Question Answer Lesson 4 – NIOS

Cell Structure & Function : 12th Class Biology Question Answer Lesson 4 - NIOS


  1. From where do new cells arise ? – Pre-existing cells
  2. Name the scientists who proposed the ‘cell theory’. – Schleiden and Schwann
  3. Name an organelle which a plant cell has but an animal cell does not. – Chloroplast / plastid
  4. Give two points of difference between a prokaryotic cell and a eukaryotic cell
    Ans. Prokaryote – naked nucleus, no membrane bound cell organelles
    Eukaryote – distinct nucleus with a cell membrane, membrane bound cell
    organelles present


  1. Define diffusion and osmosis.
    Ans. Diffusion : Movement of molecules from region of their higher concentrationto region of their lower concentration.
    Osmosis : Movement of water molecules across a semipermeable membranefrom region of their higher concentration to the region of their lowerconcentration.
  2. What does active transport mean?
    Ans. Movement of molecules against concentration gradient that is region oflower to higher concentration by expending energy.
  3. Give one point of difference between phagocytosis and pinocytosis.
    Ans. Intake of solid particles (phagocytosis)
    Intake of fluid droplets (pinocytosis)
  4. Match the following :
    (i) hydrophilic end (a) cell wall
    (ii) microfibrils (b) inner ends of lipids
    (iii) fluid-mosaic model (c) fluid droplets
    (iv) hydrophobic end (d) outer ends of lipids
    (v) pinocytosis (e) Nicholson and Singer
    Ans. (i) – d (ii) – a (iii) – e (iv)– b (v) – c
  5. Give two functions of the plant cell wall.
    (i) Protection / shape
    (ii) Provide communication between cells through plasmodesmata


  1. What is a cell organelle?
    Ans. Membrane bound bodies in the cytoplasm
  2. Name the chemical which provides energy trapped in its bonds to the cell. – ATP
  3. Which part of the chloroplasts is the site of light reaction? – Grana
  4. Name the sac like–structure which form the grana? – Thylakoids
  5. Why is mitochondrion called the “power house” of the cell?
    Ans. Because energy as ATP is generated and stored in mitochondria
  6. Which organelle contains enzymes for cellular respiration? – Mitochondria
  7. State two similarities between mitochondria and chloroplasts.
    Ans. (i) both are semiautonomous of Life
    (ii) both contain DNA or both contain ribosomes
  8. Which plastid imparts colour to flower petals? – Chromoplasts
  9. Which plastid is green in colour? – Chloroplast
  10. Why are mitochondria and chloroplast called semi-autonomous?
    Ans.They have their own DNA for production of more copies of themselves by self duplication but cannot lead independent life, outside the cell / cytoplasm.


  1. Given below is a list of functions, relate them to their respective organelles :
    (a) synthesis of some enzymes – Golgi Body
    (b) synthesis of steroids – ER
    (c) storage of carbohydrates – amyloplasts
    (d) Intracellular transport – ER
    (e) Synthesis of proteins – Ribosomes
  2. Name the equivalent structure of Golgi body in plants. Mention two differences between their structures.
    Ans. refer text
  3. Mention any two advantages of the extensive network of endoplasmic reticulum.
    Ans. (i) internal framework, (ii) transport of cellular substances
  4. What are the three places where ribosomes occur in a cell?
    Ans. cytoplasm, ER, Nucleolus; chloroplasts, mitochondria
  5. Name the membrane system that connects the nuclear membrane with the cell membrane?
    Ans. ER


  1. Why are lysosomes called suicidal bags?
    Ans. Because the lysosome can devour organelles of the same cell
  2. List the usefulness of intracellular digestion by lysosomes
    Ans. They help in cleaning up the cell by digesting useless matter
  3. What is the function of peroxisomes in plant cells
    Ans. Fat metabolism


  1. Why cannot the cell survive without the nucleus?
    Ans. Nucleus controls all the functions of the cell as it has the hereditary information
  2. Explain the following terms:
    (a) chromatin network – Chromosomes are present as a network when not dividing, that is,at early interphase or Go-stage (Differentiation stage during
    (b) chromosomes – Bearers of hereditary information as genes on them
  3. What is the function of the nucleolus in the cell?
    Ans. Site of RNA synthesis


  1. What is the importance of water in a living cell.
    Ans. (i) It is a universal solvent and most chemical reactions of the cell occurin aqueous medium
    (ii) It is a constituent of protoplasm
  2. Which is the basic molecule in starch?
    Ans. Glucose
  3. What is a peptide bond and where will you find it?
    Ans. –NHCO–, between amino acids in a polypeptide, found in proteins
  4. Which is the most energy rich biomolecule in living organisms?
    Ans. ATP
  5. What are nucleotides?
    Ans. building blocks of nucleic acids, each containing a pentose sugar,
    nitrogenous base and phosphate


  1. Explain in one sentence
    (i) Interphase – stage between two successive cell divisions;
    (ii) Synthetic-phase – DNA is synthesised
    (iii) Dividing-phase – Mitosis in somatic cells or meiosis in the germ cells take place
  2. What is the full form of the following in the cell cycle?
    (i) Gl – First growth phase;
    (ii) S – Synthetic phase
    (iii) G2 – Second Growth phase
    (iv) M-Phase – Mitosis / meiotic phase.


  1. Name the stage of cell cycle during which chromatin material is duplicated.
    Ans. S-shape of Interphase
  2. Is the number of chromosomes reduced in the daughter cells during mitosis? yes/no? – No
  3. Name the stage in nuclear division described by each of the following sentences:
    (i) disappearance of the nuclear membrane – Late Prophase
    (ii) The nuclear membrane and nucleolus reappear – Late Telophase
    (iii) The centromere divides and the chromatids move to opposite poles due to the shortening of spindle fibres – Anaphase
    (iv) The chromosomes arrange themselves at the equatorial plane of the spindle with the spindle fibres attached to the centromeres. – Metaphase


  1. Name the sub-stage of meiosis-I in which the :
    (i) Homologous chromosomes pair – zygotene (prophase I)
    (ii) Tetrads are formed – Pachytene
    (iii) Homologous chromosomes begin to move away from each other – Diplotene
  2. Sites of meiosis in flowering plants, are : Microspore / pollen mother cell in anthers and megaspore mother cell in the ovule.
  3. Rearrange the following stages of meiosis I in their proper sequence :
    zygotene, pachytene, leptotene, metaphase-I diakinesis, anaphase-I, telophase-I.
    Ans. Leptotene, zygotene, pachytene, diplotene, diakinesis, metaphase I,
    telophase I.
  4. Mention two major points in which meiosis I differs from meiosis II
    Ans. Reduction in chromosome number to half in Meiosis-II; exchange ofgenetic material in meiosis I.

NIOS 12th class biology Q Ans

I hope you liked this post (cell structure and function). If you have any problem in understanding – Cell Structure & Function : 12th Class Biology Question Answer Lesson 4 – NIOS, then write in the comment box below.

Be sure to subscribe to receive all new posts from this blog straight to your email inbox. Like my Facebook page to get notifications of similar posts on Facebook.

Share your love
Himanshu Kumar
Himanshu Kumar

Hellow friends, welcome to my blog NewFeatureBlog. I am Himanshu Kumar, a part time blogger from Bihar, India. Here at NewFeatureBlog I write about Blogging, Social media, WordPress and Making Money Online etc.

Leave a Reply

Your email address will not be published. Required fields are marked *