Introduction to Cell Cycle Regulation

This set of flashcards covers the introduction to the cell cycle, focusing on cyclin-CDK complexes, the regulation of phosphorylation, inhibitory proteins like p21 and p27, and the Ras/MAP kinase signaling pathway.

What controls whether or not an active CDK complex is formed?

The presence of the cyclin.

Why is cyclin named "cyclin"?

Because its expression is gonna cycle.

When does the s CDK exist in the cell cycle?

It exists through s, the s phase.

What is the role of the kinase called wee1 in cell cycle regulation?

It adds an inhibitory phosphate to what would otherwise be an active complex to make it pause for a little bit.

Which two proteins can bind to an active CDK complex to inhibit its function and cause a pause?

p 27 and p 21.

In what state are terminally differentiated cells like those of the heart, brain, and spinal cord?

They are in a place called G 0 and have lost their ability to go through the cell cycle.

What is Mitogen?

A particular type of signaling molecule that, when it binds and starts a signaling pathway, activates the cell cycle.

Why is the RAS protein initially inactive?

Because it has GDP.

How is the RAS protein activated?

The guanine exchange factor takes the GDP off and puts on the GTP.

RAF is an example of what type of enzyme in the signaling pathway?

An activated map kinase kinase kinase.

What specific cyclin transcription is stimulated by the RasPan kinase pathway?

cyclin d.

What must happen to the Retinoblastoma protein to allow for transcription important for the S phase?

Phosphorylation.

What is the significance of the phosphorylation of the helicase?

It gets the replication started.

What is the function of CBC 6 phosphorylation?

It ensures that the cell only replicates once.

How is the m-CDK inhibited to prevent entry into the M phase during a checkpoint check?

By using the V1 height (kinase).