AP Biology Cell Cycle Review

Which type of cells divide only when necessary?

• Nerve cells

• Muscle cells

• Liver cells

• Skin cells

Answer explanation

Liver cells divide only when necessary, such as during tissue repair or regeneration, unlike other cell types like skin cells which continuously divide for maintenance purposes.

What is the G0 phase?

• The phase where mitosis occurs

• A non-dividing state of the cell

• A phase where DNA is replicated

• A phase where cells divide frequently

Answer explanation

The G0 phase is a non-dividing state of the cell, where the cell is not actively preparing to divide or replicate its DNA.

Which checkpoint is considered the most important in mammalian cells?

• G2 checkpoint

• M checkpoint

• G1 checkpoint

• S checkpoint

Answer explanation

The G1 checkpoint is considered the most important in mammalian cells as it determines whether the cell will continue to divide, enter a quiescent state, or undergo apoptosis.

Tags

NGSS.HS-LS1-4

What triggers the cell to pass the G1 checkpoint and divide?

• DNA damage

• Presence of growth factors

• Lack of nutrients

• Density-dependent inhibition

Answer explanation

The correct trigger for a cell to pass the G1 checkpoint and divide is the presence of growth factors, which signal the cell that conditions are favorable for division.

What is the role of cyclins and cyclin-dependent kinases (CDKs) in the cell cycle?

• To decrease cell size

• To initiate apoptosis

• To control the cell cycle through checkpoints

• To repair DNA damage

Answer explanation

Cyclins and CDKs work together to control the cell cycle by regulating checkpoints, ensuring proper progression and coordination of cell division.

What happens if DNA damage is detected at the G2 checkpoint?

• The cell returns to the G1 phase

• The cell divides uncontrollably

• The cell immediately enters mitosis

• The cell cycle stops until the DNA can be repaired or undergoes apoptosis

Answer explanation

If DNA damage is detected at the G2 checkpoint, the cell cycle stops until the DNA can be repaired or undergoes apoptosis, ensuring the integrity of the genetic material before proceeding.

What is the fate of a cell that does not receive signals to stop dividing?

• It differentiates

• It may lead to tumor formation

• It undergoes apoptosis

• It enters the G0 phase

Answer explanation

A cell that does not receive signals to stop dividing may lead to tumor formation, as uncontrolled cell division can result in the formation of a tumor.

Tags

NGSS.HS-LS1-4

What is the function of tumor suppressor genes?

• To stimulate cell division

• To promote the cell cycle

• To inhibit the cell cycle and promote apoptosis

• To repair DNA

Answer explanation

Tumor suppressor genes function by inhibiting the cell cycle and promoting apoptosis, which helps prevent the development of cancer.

What is the consequence of mutations in proto-oncogenes?

• They enhance DNA repair mechanisms

• They lead to uncontrolled cell division

• They cause the cell to differentiate

• They slow down the cell cycle

Answer explanation

Mutations in proto-oncogenes lead to uncontrolled cell division, which is a hallmark of cancer development.

Tags

NGSS.HS-LS3-2

What role does p53 play in the cell cycle?

• It promotes cell division

• It repairs damaged DNA

• It inhibits the CDK-cyclin complex when there is DNA damage

• It increases the concentration of cyclins

Answer explanation

p53 plays a role in the cell cycle by inhibiting the CDK-cyclin complex when there is DNA damage, preventing damaged cells from progressing through the cell cycle.