Cell Cycle Checkpoints

Which molecules act as gatekeepers for each checkpoint of the cell cycle?

• p53 gene

• cyclins and cycline-dependent kinases

• thyroid hormones

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.

How many cell cycle checkpoints are there?

• 1

• 2

• 3

• 4

What is the first checkpoint of the cell cycle?

• Mitosis checkpoint

• G₁ checkpoint

• G₂ checkpoint

When is apoptosis initiated?

• When DNA damage is repaired.

• When cells are removed from the cell cycle.

• When DNA damage cannot be repaired.

Uncontrolled cell division is stopped by...

• tumor suppressor genes
• oncogenes

Which is an example of a tumor suppressor gene?

• apoptosis
• proto-oncogenes
• p53
• oncogenes

Normal cell division is regulated by...

• Proto-oncogenes
• oncogenes

p53 activates which of the following?

• Tumor suppressor genes
• cell cycle
• DNA repair proteins
• uncontrolled cell division

Proto-oncogenes can mutate into...

• oncogenes
• tumor suppressor genes
• DNA repair proteins