exam 3 cancer biology

Heterokaryon

Two isolated cells with their own DNA treated with PEG, which mimics a membrane.

Tumorigenic cells

Normal cells that are dominant and can lead to tumor formation.

Nontumorigenic cells

Cancer cells that are recessive and require mutations in both copies of a gene to exhibit a cancerous phenotype.

Knudson’s ‘two hit’ hypothesis

Suggests that both copies of a gene must be mutated for cancer to arise; relates to familial and spontaneous mutations.

Loss of Heterozygosity (LOH)

Condition where one allele of a gene is functional while the other is inactivated, often leading to cancer.

Mitotic recombination

Process that can lead to loss of heterozygosity; involves crossing over during cell division.

Gene conversion

Mechanism that can inactivate the second copy of a gene, often occurring in response to double strand breaks.

Retinoblastoma (Rb)

A cancer associated with mutations in the Rb gene, inherited as dominant but recessive at the cellular level.

Tumor suppressor gene

A gene that prevents uncontrolled growth or tumor formation; Rb is an example.

Cyclin

Regulatory protein that binds to CDKs to control cell cycle progression.

CDK (Cyclin-Dependent Kinase)

Enzyme involved in regulating the cell cycle by phosphorylating specific substrates.

Ubiquitin

A small protein that tags other proteins for degradation via the proteasome.

E3 ligase

A complex that facilitates the transfer of ubiquitin to substrate proteins, conferring specificity.

CDK Inhibitory Proteins (CKIs)

Proteins that can halt cell cycle progression by binding to and inhibiting CDK activity.

G1 Phase

The phase of the cell cycle where cells decide whether to divide, influenced by growth factors and cellular cues.

S Phase

The phase of the cell cycle responsible for DNA replication.

M Phase

The phase of the cell cycle where mitosis occurs, leading to cell division.

APC/C (Anaphase Promoting Complex/Cyclosome)

A key component in the cell cycle that initiates anaphase by targeting proteins for degradation.

E2F

A family of transcription factors that are regulated by the Rb protein and are essential for progression through the cell cycle.

G0 Phase

A resting phase where cells are not actively dividing.