Exam 19: Cancer and Regulation of the Cell Cycle

The retinoblastoma protein (pRB),like p53,serves as a(n)________ in regulating the cell cycle.

What is the name of a normal gene that serves to promote cellular division?

List three general categories of genetic changes that lead to the formation of oncogenes.

There are two types of retinoblastoma,familial and sporadic.In the familial form,one generally inherits a defective gene from one parent.

Describe three genetic mechanisms whereby proto-oncogenes can become overexpressed.

A tumor-suppressor gene normally functions to suppress cell division.

The familial form of retinoblastoma is characterized by cancer appearing in both eyes relatively early in life.In contrast,the sporadic form is usually unilateral and appears later.Why the difference?

Provide a definition of cancer at the genetic level.

Why do cancer researchers study molecular events associated with mitosis?

Chronic myelogenous leukemia appears to be associated with a chromosomal rearrangement.How is a chromosomal rearrangement responsible for this disease?

Any agent that causes damage to DNA is a potential carcinogen.

Mutant versions of genes that are normally involved in promoting the cell cycle are known as ________.

The genetic difference between familial retinoblastoma and sporadic retinoblastoma appears to be based on those with the familial form starting out being ________,whereas those with the sporadic form start out being ________.

When the normal retinoblastoma protein is dephosphorylated,it acts to suppress cell division by binding to and inactivating the E2F transcription factor.

Provide a simple definition of a carcinogen.

Name three human cancers with a genetic predisposition.What appears to be the genetic cause of each?

Name two of the classes of proteins that combine to directly control progression through the cell cycle.

The gene p53 is called the "guardian of the genome" because it corrects mutations in the spindle apparatus before nondisjunction can occur.

What is a tumor-suppressor gene? What are oncogenes? What is the normal (nonmutant)cellular version of an oncogene called?

In what way might a virus contribute to cancer formation?