11/15 CELL CYCLE

Cell Cycle Regulation

The process by which a cell controls its progression through the different phases of the cell cycle.

Checkpoints

Control mechanisms in the cell cycle that ensure the proper division of the cell.

G1 to S Checkpoint

The checkpoint at the end of G1 where the cell checks for growth factors, nutrients, cell size, and DNA damage before entering S phase.

Mitosis

The process where a cell divides its chromosomes into two identical sets creating two daughter cells.

Cyclin

A protein whose concentration varies throughout the cell cycle and regulates the activity of cyclin-dependent kinases.

Cyclin-Dependent Kinase (CDK)

A protein kinase that is activated by binding to a cyclin and is responsible for phosphorylating target proteins involved in cell cycle regulation.

Phosphorylation

The addition of a phosphate group to a protein by a kinase, often resulting in the activation or inactivation of that protein.

Anaphase-Promoting Complex (APC)

A protein complex that triggers the transition from metaphase to anaphase by promoting the degradation of specific proteins.

S Phase

The phase of the cell cycle in which DNA is replicated.

G2 Phase

The phase that follows DNA synthesis in which the cell prepares for mitosis.

Interphase

The phase of the cell cycle when the cell is not dividing and is engaged in growth and DNA replication.

Cohesin

A protein complex that holds sister chromatids together until they are separated during anaphase.

Securin

A protein that inhibits separase and prevents exit from metaphase until all chromosomes are properly attached.

Separase

An enzyme that degrades cohesin, allowing sister chromatids to separate during anaphase.

Metaphase to Anaphase Checkpoint

A checkpoint that ensures proper alignment of chromosomes at the metaphase plate before allowing their separation.

DNA Damage Check

A process within a checkpoint where a cell checks for DNA integrity before proceeding to the next phase of the cell cycle.

Growth Factors

Molecules that stimulate cell division; cells check for their presence at the G1 checkpoint.

Proteasome

A cellular complex that degrades ubiquitin-tagged proteins, including cyclins after their function is no longer needed.

Kinase

An enzyme that catalyzes the addition of phosphate groups to proteins.

Phosphatase

An enzyme that removes phosphate groups from proteins, reversing the process of phosphorylation.

Apoptosis

The programmed cell death process that can be triggered when conditions in the cell cycle are not met.