After which checkpoint is the cell first committed to continue the cell cycle through M?
A: G0
B: G1
C: G2
D: S
E: Previous M
Answer: B
Explanation: Mainly, there are four conditioned processes in the cell cycle such as cell growth, replication of DNA, distribution of replicated chromosomes to daughter cells, and cell division. In addition, there are several checkpoints in the cell cycle; however, each cell undergoes three major checkpoints and their function is to ensure that incomplete or damaged chromosomes are not duplicated and distributed to daughter cells.
The three cell cycle checkpoints and their action………
- G1 checkpoint located at the end of the G1 phase, which inhibits cells entering the S phase.
- The intra-S checkpoint is located in the S phase, which responds to genomic errors that occurred during DNA replication and stops cells from entering the G2 phase.
- G2/M checkpoint located at G2 to M phase transition that responds to DNA damage and inhibits entry into mitosis until the damage is repaired.
G0 is a quiescent state in which cells stop growing (resting phase) but there is no specific G0 checkpoint in the cell cycle. If the cell committed to starting the cell cycle from the G0 phase, then first it should cross the G1 checkpoint, which is the point at which the cell becomes committed to entering the S phase after proper cell growth and nutrition.
Important questions:
Q. Thermogenin in the inner membrane of brown fat cell mitochondria does all of the following except?
Q. What is ATP synthase and what does it do?
Q. Brown fat cells produce a protein called Thermogenin
Q. Which of the following eukaryotic cell structures plays a role in protein trafficking and sorting?
Q. Which of these does not contain a structural protein?
