Cell Cycle Checkpoints

What is the purpose the the cell cycle checkpoints?

• To repair damaged cells before they enter cell division.

• To remove damaged cells from an organism.

Tags

NGSS.HS-LS1-4

This is the cell cycle checkpoint that makes sure DNA has been replicated correctly during S phase.

• G1 Checkpoint

• G2 Checkpoint

• M Checkpoint

• I Checkpoint

This is the cell cycle checkpoint that makes sure the correct number of chromosomes are present and attached to microtubules.

• G1 Checkpoint

• G2 Checkpoint

• M Checkpoint

• I Checkpoint

Name the 3 checkpoints of the cell cycle

• Anaphase checkpoint, mitosis/metaphase checkpoint, and telophase checkpoint

• Interphase checkpoint, S phase checkpoint, and M phase checkpoint

• G1 checkpoint, G2 checkpoint, and S phase checkpoint

• G1 checkpoint, G2 checkpoint, and mitosis/metaphase checkpoint

Genetic mutations cause faulty checkpoint activity in normal cells thus causing them to transform. Which type of mutation below discussed in lecture best describes Epigenetic modification?

• chromosomal rearrangement

• DNA is overly amplified or not amplified enough (down regulated).

• a point mutation

• Changes to the DNA, which regulates gene expression, but have no affect on the nucleotide sequence. Includes methylation.

The p53 gene is a major factor insuring proper cell cycle functioning. This "Guardian of the Genome" is responsible for proteins that repair DNA as well as those for apoptosis. Which below is the 3rd function of p53?

• It activates the p21 gene which makes proteins for cell arrest, thus closing the checkpoints until cell damage can be repaired.

• it activates CDK1 and all of the cyclins to bind together.

• It makes the RAS gene increase protein production

• It activates p390 to force the cell back to a G0 phase.

Uncontrolled cell division is stopped by...

• tumor suppressor genes

• oncogenes

This is the cell cycle checkpoint that makes sure DNA has been replicated correctly during S phase.

• G1 Checkpoint

• G2 Checkpoint

• M Checkpoint

• I Checkpoint

Answer explanation

The G2 Checkpoint ensures DNA replication is accurate before entering mitosis, making it the cell cycle checkpoint that verifies correct DNA replication during S phase.

This is the cell cycle checkpoint that makes sure the correct number of chromosomes are present and attached to microtubules.

• G1 Checkpoint

• G2 Checkpoint

• M Checkpoint

• I Checkpoint

Answer explanation

The M Checkpoint ensures the correct number of chromosomes are present and attached to microtubules during the cell cycle.

What is the primary role of the G1 checkpoint in the cell cycle?

• To ensure DNA is undamaged before replication

• To verify DNA replication is complete

• To check for chromosome alignment

• To initiate cell division