This set of Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “Cell Cycle”.
1. Resting phase of the cell, where it undergoes growth and DNA replication is called_________
a) Mitosis phase
b) G1 phase
d) M phase
Explanation: Interphase is also known as resting phase, time in the cell cycle where a cell is preparing for division by undergoing the cell growth. Interphase is further divided into three stages.
2. Replication of DNA takes place in S phase.
Explanation: S phase is synthesis phase, characterized as the period of DNA replication. DNA replication is the process of duplication of cell’s genome.
3. Which of the following is not the part of Interphase in the cell cycle?
a) S phase
b) G1 phase
c) G2 phase
d) M phase
Explanation: Interphase is the period before division while M phase is mitosis phase where actual division takes place. G1, S, and G2 phase are the part of Interphase.
4. Name the state where never dividing cells of neurons and skeletal muscle present?
Explanation: G0 is the state where cell division never occurs; cells can remain in this state for days, weeks, and even a year. It is terminally differentiated state and most of the cell in our body like neurons and skeletal muscle cells are in G0 state.
5. How many hours does the M phase take to complete a cycle?
b) 1 hr
c) 4 hr
d) 11 hr
Explanation: A cell cycle of the eukaryotic cell takes 24 hr to divide. In total 24 hrs, the G1 phase takes 11 hr, S phase completed in 8 hrs, G2 about 4 hrs, and M phase about 1 hr.
6. Name the process of nuclear division?
Explanation: Nuclear division is the formation of two daughter nuclei and this process known as karyokinesis. M phase starts with the nuclear division followed by a division of cytoplasm (cytokinesis).
7. Name the regulatory component of the cell cycle?
Explanation: Cyclin is the regulatory component of the cell cycle as it undergoes synthesis and degradation in each division of the cell cycle. CDK is cyclin-dependent kinases which are catalytic in nature.
8. Cyclin dependent kinases are activated by which of the following?
a) Binding to cyclin
b) Binding to cyclin and CDK activating protein kinases
c) Phosphorylation with CDK activating kinase
d) Phosphorylation with tyrosine kinase
Explanation: The activation of CDK is triggered by the association of cyclin and phosphorylation with associated kinases. Kinases are the enzymes which add a phosphate group to the target substrate.
9. Name the cyclin which takes part in M phase?
a) Cyclin E
b) Cyclin A
c) Cyclin D
d) Cyclin B
Explanation: Different events of the cell cycle are controlled by the association of CDK with different cyclins. Cyclin B is mitotic cyclin which works in M phase while cyclin E is S phase cyclin, and cyclin D is G1 cyclin.
10. Name the enzyme which causes ubiquitylation and destruction of cyclin.
a) Acid hydrolases
c) Ubiquitin ligase
Explanation: Destruction of cyline takes place by ubiquitin dependent proteolysis. It is catalyzed by ubiquitin ligase, an enzyme which acts upon either G1-S phase or M phase cyclin.
Sanfoundry Global Education & Learning Series – Life Sciences.
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