This set of Cell Biology Multiple Choice Questions & Answers (MCQs) focuses on “Cellular Reproduction – Cell Cycle”.
1. Which term is used to refer to a period between the cell divisions?
a) M phase
b) G0 phase
d) Resting phase
Explanation: The period between cell divisions is termed as interphase. It is the time in which a cell prepares for cell division, grows and performs metabolic activities. Interphase is a long period and may last for days, weeks or longer.
2. There are ______ major phases in a cell cycle.
Explanation: Cells in vivo and in vitro pass through a series of defined stages, constituting the cell cycle. The two major phases of the cell cycle are M phase (constituting mitosis and cytokinesis) and interphase.
3. Meiosis produces cells that have half the genetic content as their parent cells.
Explanation: There are two types of cell divisions in eukaryotes – meiosis and mitosis. Mitosis produces cells identical to the parent cells while meiosis produces cells that contain half the genetic content as present in their parents.
4. Asynchronous cultures are the ones whose cells are _______________________
a) of different origin
b) randomly distributed through the cell cycle
c) have different genomic content
d) have different nutrient requirements
Explanation: Asynchronous culture is the term used for cultures that have cells that are randomly distributed throughout the cell cycle i.e. all the cells might be at different stages of their life.
5. DNA replication can be monitored by incorporation of ______________________
Explanation: DNA replication can be monitored by incorporating [3H]thymidine in the strands of double helix. In this way, microscopy can be used to illustrate how the cells pass through each stage of the cell cycle.
6. DNA replication occurs during _________________ of the cell cycle.
a) S phase
c) G2 phase
d) G0 phase
Explanation: DNA replication occurs during the synthesis (S) phase of the cycle. During this phase additional histones are also synthesized that will be needed as the cell doubles the number of nucleosomes in its chromosomes.
7. Which of the following cells do not lack the ability to divide?
a) skin cells
b) nerve cells
c) muscle cells
d) red blood cells
Explanation: Only highly specialized cells of the body such as nerve cells, muscle cells and red blood cells lack the ability to divide, once they have differentiated they remain in that state till the end of their life cycles.
8. Which of the following cells do not usually divide but can be induced to divide?
a) red blood cells
b) liver cells
c) hair cells
d) hair follicles
Explanation: Liver cells do not usually grow and divide but can be made to do so under specific conditions such as liver surgery. Lymphocytes can also be induced to regrow and divide by interaction with a proper antigen.
9. Which of the following cells are capable of asymmetric cell division?
b) epithelial cells
Explanation: Stem cells have this peculiar property of being able to divide asymmetrically. Asymmetric cell division is the one in which the arising daughter cells have different properties. One daughter cell remains undifferentiated and the other commits to differentiation.
10. Cells that have stopped dividing and are arrested in a state preceding that of DNA synthesis, are said to be in the__________
a) S phase
b) G1 phase
c) G0 phase
d) G2 phase
Explanation: Cells that have stopped dividing either temporarily or permanently are referred to as being in the G0 state, to distinguish them from cells in the G1 phase that are about to enter the synthesis phase.
11. When were the experiments in an effort to understand cell cycle regulation first conducted?
Explanation: In 1970s, an attempt was made by Potu Rao and Robert Johnson of the University of Colorado in a series of experiments to understand how the cell cycle is regulated.
12. What will happen if a G2 phase cell is fused with an M phase cell?
a) premature chromosome compaction
b) chromosome aggregation
c) gene transcription
d) inhibition of transcription
Explanation: If a G1 cell and M phase cell are fused together, premature chromosome compaction takes place. If G2 and M phase cell are fused together G2 chromosomes will appear visibly doubled and undergone premature gene compaction.
13. The entry of a cell into M phase is initiated by _________________
a) interleukin factor
b) maturation promoting factor
c) transcription factor
d) necrosis factor
Explanation: The entry of a cell into mitotic (division or M phase) phase is initiated by the maturation promoting factor (MPF). It consists of two subunits – one with kinase activity and the other with regulatory activity.
14. The regulatory subunit of maturation-promoting factor (MPF) is called _______________
Explanation: The regulatory subunit of maturation-promoting factor (MPF) is called cyclin. The concentration of this regulatory protein changes in a predictable pattern. When the cyclin concentration is low, the enzyme is inactive.
15. Cyclin binding leads to a change in the _________________ of kinase.
Explanation: Cyclin binding leads to a change in the conformation of catalytic subunit of kinase enzyme by binding to its catalytic site. This binding allows the cyclin dependent kinase (CDK) to phosphorylate its substrates.
Sanfoundry Global Education & Learning Series – Cell Biology.
To practice all areas of Cell Biology, here is complete set of 1000+ Multiple Choice Questions and Answers.