Life Sciences Questions and Answers for Campus interviews focuses on “Cytoskeleton”.
1. Cell shape and cellular motility is determined by the ___________
A. Centrioles
B. Intermediate filament
C. Microtubule
D. Microfilaments
Answer: C
Clarification: Microtubules are a cylindrical, hollow structure which plays a crucial role in determining the shape of the cell. Microtubule is resulted by the combination of 13 protofilaments into a tube-like structure.
2. Singlet microtubule can form a long shaft of cilia and flagella.
A. True
B. False
Answer: B
Clarification: Motile cell appendages like cilia and flagella are formed by the doublet microtubule. Another 10 or 11 protofilaments combined to form second microtubule, this second microtubule fused with 13 protofilaments of first microtubule and forms doublet microtubules.
3. What is treadmilling?
A. Depolymerization of microtubule
B. The breaking of heterodimer chain
C. Arrangement of microtubules
D. Addition of tubulin heterodimer
Answer: D
Clarification: Treadmilling is the process of adding tubulin heterodimer at one end and dissociating another heterodimer from other ends. This will keep the polymer length same or unchanged.
4. Which of the following feature is the same in cilia and flagella?
A. Help in locomotion
B. Wave-like motion
C. Occurring all over the surface of the cell
D. Very small in size
Answer: A
Clarification: Cilia and flagella differ from each other as cilia are smaller in size and many in numbers while flagella are larger in size and very less in numbers. Only the function of them is same as they both help in locomotion.
5. Name the drug which depolymerizes microtubule to tubulin subunit.
A. Cytochalasin D
B. Nocodazole
C. Latrunculin
D. Phalloidin
Answer: B
Clarification: Nocodazole causes depolymerization of microtubule into tubulin subunits while all the other drugs affect actin filaments.
6. What is the role of vinblastine and vincristine?
A. Causes depolymerization
B. Prevent depolymerization
C. Prevent polymerization
D. Prevent nucleation
Answer: C
Clarification: Vinblastine and vincristine are also known for their role in cancer, these drugs act by interfering with the polymerization and stop the growth of microtubule.
7. What is the name of the cell membrane of muscle cells?
A. Sarcoplasm
B. Perimysium
C. Endomysium
D. Sarcolemma
Answer: D
Clarification: Sarcolemma is the cell membrane of muscle cells while sarcoplasm is the cytoplasm of muscle fiber. Sarcoplasm also contains a modified endoplasmic reticulum which is known as sarcoplasmic reticulum.
8. What is the basic functional unit of myofibril?
A. Sarcomere
B. Tropomyosin
C. Troponin
D. Nebulin
Answer: A
Clarification: Myofibril consists of thick and thin filaments i.e. myosin and actin which are arranged into a linear chain of an ordered structure known as a sarcomere.
9. Which of the following take part in relaxation of muscles?
A. Nebulin
B. Titin
C. Tropomodulin
D. Myomesin
Answer: B
Clarification: Titin is the considered as largest protein in the body, and plays a role in the relaxation of muscles. It is present opposite to the Z disc and thick filament.
10. Which of the following is occluding junction?
A. Adherence junction
B. Desmosomes
C. Tight junction
D. Gap junction
Answer: C
Clarification: Occluding junction seal cells together so, tight junction is the type of occluding junction where there is the closest contact between adjacent cells which prevent the free passage of molecules across cells.
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