CELL: THE UNIT OF LIFE
Previous Year Questions (2010 - 2018)
2010 March
1. Label the marked parts in the given diagram of a chloroplast. (1)
1. ........................
2. ........................
2. (a) Choose from the bracket, the name of the part of a bacterial cell that constitutes extra genomic DNA. (Mesosome/plasmid/basal body)
(b) Write any one of its functions.
(c) Comment on its practical application.
1. ........................2. ........................
2. (a) Choose from the bracket, the name of the part of a bacterial cell that constitutes extra genomic DNA. (Mesosome/plasmid/basal body)
(b) Write any one of its functions.
(c) Comment on its practical application.
Answers:
1. 1. Grana / Thylakoid, 2. Stroma.
2. (a) Plasmid.
(b) It confers unique phenotypic characters like antibiotic resistance.
(c) Used as a vector in Genetic Engineering.
1. 1. Grana / Thylakoid, 2. Stroma.
2. (a) Plasmid.
(b) It confers unique phenotypic characters like antibiotic resistance.
(c) Used as a vector in Genetic Engineering.
2010 September
1. Cell membrane is comprised of lipids and proteins. Membrane proteins mediate transfer of molecules across it. (1)
a. Suggest a model of membrane constitution that is suitable for this function.
b. Give the name of scientist who proposed it.
2. State the reasons for the following: (2)
a. Mitochondria are called the powerhouses of the cell.
b. A metabolic product from cytoplasm is needed for energy production in mitochondria.
a. Suggest a model of membrane constitution that is suitable for this function.
b. Give the name of scientist who proposed it.
2. State the reasons for the following: (2)
a. Mitochondria are called the powerhouses of the cell.
b. A metabolic product from cytoplasm is needed for energy production in mitochondria.
Answers:
1. a) Fluid Mosaic Model.
b) Singer and Nicolson (1972).
2. a) Because they produce cellular energy in the form of ATP.
b) Pyruvate (produced by glycolysis in cytoplasm) enters mitochondria for the Krebs cycle.
1. a) Fluid Mosaic Model.
b) Singer and Nicolson (1972).
2. a) Because they produce cellular energy in the form of ATP.
b) Pyruvate (produced by glycolysis in cytoplasm) enters mitochondria for the Krebs cycle.
2011 March
1. A cell with a chromosome number 42 undergoes mitosis and another cell with 42 chromosomes undergoes meiosis. Give the chromosome number of daughter cells after mitosis and meiosis. Give reasons for your answer. (2)
2. Draw a diagram of the chloroplast and label the following parts:
a. Grana, b. Stroma, c. Thylakoid, d. Stroma lamella
2. Draw a diagram of the chloroplast and label the following parts:
a. Grana, b. Stroma, c. Thylakoid, d. Stroma lamella
Answers:
1. Mitosis: 42 (Equational division, chromosome number remains same).
Meiosis: 21 (Reduction division, chromosome number is halved).
2. (Refer to the diagram in 2010 March Q1 for labelling help).
1. Mitosis: 42 (Equational division, chromosome number remains same).
Meiosis: 21 (Reduction division, chromosome number is halved).
2. (Refer to the diagram in 2010 March Q1 for labelling help).
2011 October (Improvement)
1. Examine the diagram of a eukaryotic cell. Which one of the labeled cell organelles is present in bacteria? Membrane extensions into the bacterial cell are called mesosomes. What are their forms and function? (3)
Answer:
- Organelle present in bacteria: Ribosome.
- Mesosomes: Formed by plasma membrane extensions into the cell in the form of vesicles, tubules, and lamellae.
- Functions: Cell wall formation, DNA replication, Respiration, Secretion.
- Organelle present in bacteria: Ribosome.
- Mesosomes: Formed by plasma membrane extensions into the cell in the form of vesicles, tubules, and lamellae.
- Functions: Cell wall formation, DNA replication, Respiration, Secretion.
2012 March
1. a) Identify the cell organelle found both in eukaryotic and prokaryotic cells. (½)
b) Justify its presence in both types of cells. (½)
2. Match the following: (2)
b) Justify its presence in both types of cells. (½)
2. Match the following: (2)
| a) Synthesis and storage of energy | i. Golgi apparatus |
| b) Packaging and delivery of materials | ii. Mitochondria |
| c) Digestion of intercellular materials | iii. Centriole |
| d) Formation of basal body of cilia/flagella | iv. Lysosome |
| v. Chloroplast |
Answers:
1. a) Ribosome.
b) It is required for protein synthesis, which is essential for all cells.
2. Match:
a - ii (Mitochondria)
b - i (Golgi apparatus)
c - iv (Lysosome)
d - iii (Centriole)
1. a) Ribosome.
b) It is required for protein synthesis, which is essential for all cells.
2. Match:
a - ii (Mitochondria)
b - i (Golgi apparatus)
c - iv (Lysosome)
d - iii (Centriole)
2012 September (Improvement)
1. The following is a list of cell organelles (nucleus, endoplasmic reticulum, lysosomes, chloroplast, Golgi complex, mitochondria, ribosome). (3)
a. Identify the organelles with double membrane envelope.
b. Mention the functions of these organelles.
a. Identify the organelles with double membrane envelope.
b. Mention the functions of these organelles.
Answer:
a) Nucleus, Mitochondria, Chloroplast.
b) Nucleus: Controls cellular activities, stores genetic information.
Mitochondria: Aerobic respiration (ATP production).
Chloroplast: Photosynthesis.
a) Nucleus, Mitochondria, Chloroplast.
b) Nucleus: Controls cellular activities, stores genetic information.
Mitochondria: Aerobic respiration (ATP production).
Chloroplast: Photosynthesis.
2013 March
1. An accepted model of the structure of a cell membrane was proposed by Singer and Nicolson.
a. Name the model. (½)
b. List the 2 major biomolecules which this membrane is composed of. (1)
c. Mention two important points of this model from the point of view of function. (1)
a. Name the model. (½)
b. List the 2 major biomolecules which this membrane is composed of. (1)
c. Mention two important points of this model from the point of view of function. (1)
Answers:
a) Fluid Mosaic Model.
b) Lipids and Proteins.
c) The fluid nature allows cell growth, formation of intercellular junctions, secretion, and cell division.
a) Fluid Mosaic Model.
b) Lipids and Proteins.
c) The fluid nature allows cell growth, formation of intercellular junctions, secretion, and cell division.
2013 September-October
1. The diagrams a, b, c given below show three kinds of chromosomes. Of this, which is metacentric non-satellite chromosome? Justify your answer. (1)
Answer:
Figure (b).
Justification: The centromere is exactly at the middle, forming two equal arms (V-shape), and it lacks a secondary constriction (satellite).
Figure (b).
Justification: The centromere is exactly at the middle, forming two equal arms (V-shape), and it lacks a secondary constriction (satellite).
2014 March
1. Prokaryotic cells possess a special membranous structure which is formed by the extensions of the plasma membrane. Identify this structure and write any one of its functions. (1)
2. State whether the statements are ‘true’ or ‘false’. If false, correct them. (2)
a. Aleuroplasts store carbohydrates.
b. The centrioles form the basal body of cilia and flagella.
c. Ribosomes are not surrounded by membranes.
d. RER is the major site for synthesis of lipids.
2. State whether the statements are ‘true’ or ‘false’. If false, correct them. (2)
a. Aleuroplasts store carbohydrates.
b. The centrioles form the basal body of cilia and flagella.
c. Ribosomes are not surrounded by membranes.
d. RER is the major site for synthesis of lipids.
Answers:
1. Mesosome. Function: Respiration / DNA replication.
2. a) False (Proteins).
b) True.
c) True.
d) False (SER is the site for lipid synthesis).
1. Mesosome. Function: Respiration / DNA replication.
2. a) False (Proteins).
b) True.
c) True.
d) False (SER is the site for lipid synthesis).
2014 August (Improvement)
1. In which hydrolases, the membrane bound vesicles are present? (1)
2. Distinguish between the characters of chloroplast and ribosomes from the given list and write them in appropriate columns. (2)
(Double membrane, George Palade, sac-like thylakoid, 70 S and 80 S)
2. Distinguish between the characters of chloroplast and ribosomes from the given list and write them in appropriate columns. (2)
(Double membrane, George Palade, sac-like thylakoid, 70 S and 80 S)
Answers:
1. Lysosomes.
2.
1. Lysosomes.
2.
| Chloroplast | Ribosome |
|---|---|
| - Double membrane - Sac-like thylakoid | - George Palade - 70 S and 80 S |
2015 March
1. a) Due to the presence of a secondary construction, a knob-like small fragment appears in some chromosomes called:
i) Kinetochore, ii) Histone, iii) Satellite, iv) Chiasmata
b) Classify chromosomes based on the position of centromere. (2)
i) Kinetochore, ii) Histone, iii) Satellite, iv) Chiasmata
b) Classify chromosomes based on the position of centromere. (2)
Answers:
a) iii) Satellite
b) Metacentric (Middle), Sub-metacentric (Slightly away from middle), Acrocentric (Close to end), Telocentric (Terminal).
a) iii) Satellite
b) Metacentric (Middle), Sub-metacentric (Slightly away from middle), Acrocentric (Close to end), Telocentric (Terminal).
2015 September (Improvement)
1. Several ribosomes may attach to a single mRNA and form a chain called ............ (1)
2. Name the types of chromosome based on the position of centromere in the figure and label the parts A, B & C. (2)
2. Name the types of chromosome based on the position of centromere in the figure and label the parts A, B & C. (2)
Answers:
1. Polysome (or Polyribosome).
2. Type: Acrocentric.
Labels: A - Satellite, B - Secondary Constriction, C - Centromere.
1. Polysome (or Polyribosome).
2. Type: Acrocentric.
Labels: A - Satellite, B - Secondary Constriction, C - Centromere.
2016 March
1. Observe the given diagram. Analyze this diagram and explain the structure of plasma membrane. (3)
Answer:
This is the Fluid Mosaic Model. - It consists of a lipid bilayer (phospholipids) with polar heads outwards and hydrophobic tails inwards.
- Proteins are embedded in (Integral) or lie on the surface (Peripheral) of the bilayer.
- The quasi-fluid nature of lipid enables lateral movement of proteins.
This is the Fluid Mosaic Model. - It consists of a lipid bilayer (phospholipids) with polar heads outwards and hydrophobic tails inwards.
- Proteins are embedded in (Integral) or lie on the surface (Peripheral) of the bilayer.
- The quasi-fluid nature of lipid enables lateral movement of proteins.
2017 March
1. a) Identify a cell organelle which contains hydrolytic enzymes.
b) Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER) are morphologically and functionally different. Justify this statement. (3)
b) Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER) are morphologically and functionally different. Justify this statement. (3)
Answers:
a) Lysosome.
b)
a) Lysosome.
b)
| RER | SER |
|---|---|
| Ribosomes present on surface. | Ribosomes absent. |
| Involved in protein synthesis. | Involved in lipid synthesis. |
2017 July (Improvement)
1. Position of centromere determine the shape of the chromosomes.
a) Name the different types of chromosomes based on the position of centromere.
b) Draw any one chromosome among them. (3)
a) Name the different types of chromosomes based on the position of centromere.
b) Draw any one chromosome among them. (3)
Answers:
a) Metacentric, Sub-metacentric, Acrocentric, Telocentric.
b) (Student is expected to draw a diagram like the one in 2015 Sept Q2).
a) Metacentric, Sub-metacentric, Acrocentric, Telocentric.
b) (Student is expected to draw a diagram like the one in 2015 Sept Q2).
2018 March
1. Ribosomes are organelles without a membrane found in all cells. Name another organelle devoid of membrane, seen in animal cells. Write its function.
Answer:
Centriole (or Centrosome).
Function: It forms the basal body of cilia/flagella and spindle fibres during cell division in animal cells.
Centriole (or Centrosome).
Function: It forms the basal body of cilia/flagella and spindle fibres during cell division in animal cells.