S347 Cell Cycle and Regulation

What is the role of protein kinases?

• remove phosphate groups to deactivate enzymes

• trigger apoptosis

• add phosphate groups and energy to activate enzymes

• stop the cell cycle

Which of these may be assessed by various proteins during a "checkpoint"? CHECK ALL THAT APPLY

• Ensure that all chromosomes have lined up in the center of the cell before sister chromatids separate

• Ensure that spindle fibers have attached to all centromeres before cell division

• Ensure that DNA has been replicated properly

Which of the following correctly describes cells that are in the G₀ phase?

• Mature nerve and muscle cells are unable to divide and are permanently in G₀.

• Many cells enter G₀ when they reach the checkpoint during the M phase.

• Cells in G₀ are growing and preparing for cell division.

• DNA replication occurs during G₀.

The graph represents the amount of DNA in the nucleus of each cell during the cell cycle.
Which region represents the G2 phase?

• I
• II
• III
• IV

How does the concentration of cyclin dependent kinases (Cdk) change as the cell proceeds through the cell cycle?

• Cdk concentration remains constant.
• Cdk concentration increases during interphase and decreases during mitosis.
• Cdk concentration decreases during interphase and increases during mitosis.
• Cdk concentration correlates directly with MPF concentration.

How does the concentration of cyclin change as a cell goes through the cell cycle?

• Cyclin concentration remains constant.
• Cyclin concentration increases during interphase and decreases during mitosis.
• Cyclin concentration decreases during interphase and increases during mitosis.
• Cyclin concentration is inversely related to MPF concentrations.

The normal function of a tumor suppressor gene is 

• to produce growth signals
• to code for proteins that inhibit, or slow, cell division
• to cause the cell to move faster through the cell cycle
• to attack cancer cells in the body

When it occurs at the proper time, programmed cell death (apoptosis)

• will disrupt homeostasis
• may cause defective genetic info to be passed to the next generation of cells
• is an important regulatory process that maintains the health of a multicellular organism
• can contribute to the development of cancer

Which of these is a tumor that is noncancerous and does not spread?

• Malignant

• Benign

What is Apoptosis?

• A tumor

• A protein

• Programmed cell death

• Cell cycle checkpoints