Topic 5 Cell Division: Cell Cycle Regulation

Question 1

1. Cyclin-dependent Kinases
2. Growth Factors
3. Density-dependent Inhibition
4. Anchorage dependence

Answer 1

Signals that trigger cell division

Question 2

• CDK enzyme activates proteins that regulate cell cycle via phosphorylation
• Activated by protein cyclins, which vary in type and concentration throughout each phase

Answer 2

Cyclin-dependent Kinases

Question 3

• Plasma membrane contains receptors for growth factors that stimulate cell division, such as tumor cell

Answer 3

Growth Factors

Question 4

• Cells stop dividing when surrounding cell density reaches maximum

Answer 4

Density-dependent Inhibition

Question 5

• Most cells only divide when they are attached to an external surface such as neighboring cells or placed on a culture dish

Answer 5

Anchorage dependence

Question 6

• Defy all 4 of the above conditions and therefore are referred to as transformed cells
• Cancer drugs inhibit mitosis by disrupting the ability of microtubules to separate chromosomes during anaphase, thus stopping replication

Answer 6

Cancer Cells