Control of the Cell Cycle

Review Questions

At which of the cell-cycle checkpoints do external forces have the greatest influence?

  1. G1 checkpoint
  2. G2 checkpoint
  3. M checkpoint
  4. G0 checkpoint

Hint:

A

What is the main prerequisite for clearance at the G2 checkpoint?

  1. cell has reached a sufficient size
  2. an adequate stockpile of nucleotides
  3. accurate and complete DNA replication
  4. proper attachment of mitotic spindle fibers to kinetochores

Hint:

C

If the M checkpoint is not cleared, what stage of mitosis will be blocked?

  1. prophase
  2. prometaphase
  3. metaphase
  4. anaphase

Hint:

D

Which protein is a positive regulator that phosphorylates other proteins when activated?

  1. p53
  2. retinoblastoma protein (Rb)
  3. cyclin
  4. cyclin-dependent kinase (Cdk)

Hint:

D

Many of the negative regulator proteins of the cell cycle were discovered in what type of cells?

  1. gametes
  2. cells in G0
  3. cancer cells
  4. stem cells

Hint:

C

Which negative regulatory molecule can trigger cell suicide (apoptosis) if vital cell cycle events do not occur?

  1. p53
  2. p21
  3. retinoblastoma protein (Rb)
  4. cyclin-dependent kinase (Cdk)

Hint:

A