Question

Sakar Cell bio Cells control their own cycle of growth & division very tightly. Please explain why cell cycle regulators are often involved in the development of neoplasms (cancers). Include examples of processes that must be affected in order to have uncontrolled cell growth. Please do not hand write responses. Please do not copy and paste from google. Please do not upload a handwritten cursive response. Type the text only!

Answer 1

Specific steps in the cell cycle are controlled by cyclines, which act through cyclin-dependent kinases (CDKs). Cyclins are the regulatory proteins to which the cyclin dependent kinases (CDKs) bind and activate the CDKs. The kinase activity of CDK is less in the absence of cyclins.

Cyclin D act through extracellular signals, but the other cyclins operate according to the predetermined schedule. Once the decision has been made to pass through the G1 phase, all the other cyclins accumulate rapidly followed by their immediate destruction, thus allowing the cycle to move only in one direction.

CDK inhibitors antagonize the functions of cyclin-CDK complexes. For example, Cyclin B plays a key role in the completion of the mitotic phase of a cell cycle. So, if it detects any defect during the mitosis phase, it does not allow the cell to exit the mitosis phase, similarly, if the mutations are not corrected prior to entering into the mitosis phase, these checkpoint genes do not allow the cell to enter into mitotic phase.

Defects in the cell cycle regulators fail to control the passage of cells with mutated genes to pass through the cell cycle. So, these mutated cells multiply and cause the accumulation of mutations, which can cause cancer. It results in "uncontrolled cell division," which is a characteristic of cancer cells.