can you help me identify these?

Question

Identify the role of the following in the cell cycle clock

a. Kinase
b. Cyclin
c. CDKs

Answer 1

Okay. Not in exactly the same order.

A kinase in general is a protein that adds a phosphate group to something. Because many, many proteins and other things can be affected profoundly by such a comparatively minor and chemically easy change, they are heavily used by cells to control the rates and timing of other processes, including the cell cycle.

A cyclin-dependant kinase is a kinase that is inactive until it binds to a cyclin protein. These are almost exclusively involved in cell cycle regulation where they affect transcription and processing of mRNA. A cyclin and a cyclin-dependant kinase bound together is usually referred to as a cyclin-dependant kinase complex (to distinguish it from an unbound one).

Cyclin binds to a cyclin-dependant kinase and comes in a variety of forms. This is really the 'brains' of regulation in the sense that these different cyclins are produced at different points in the cycle and cause the cyclin-dependant kinase to do slightly different things. Thus, like dominoes, one cyclin can cause the next to start being produced, which can shut off the first one and start and third one, and so on... this allows a very specific sequencing of events in the cell cycle!

Hope that helps!