Cell Cycle & Homeostasis Feedback

Cell Cycle

The life of a cell from its formation until it divides.

Chromatin

The non-condensed form of DNA when a cell is not actively dividing.

Chromosome

Condensed form of chromatin that occurs after DNA replication, consisting of two sister chromatids.

Sister Chromatids

The two identical copies of a chromosome joined together.

Centromere

The region on each sister chromatid where they are most closely attached.

Kinetochore

Protein structures that link each sister chromatid to the mitotic spindle.

Genome

All of a cell's genetic information (DNA).

Somatic Cells

Body cells that are diploid (2n) with two sets of chromosomes.

Gametes

Reproductive cells (eggs/sperm) that are haploid (n) with one set of chromosomes.

Interphase

The longest portion of the cell cycle where the cell grows and prepares for mitosis.

Mitosis

The process of nuclear division resulting in two identical diploid daughter cells.

Cytokinesis

The division of the cytoplasm, resulting in two separate cells.

G1 Checkpoint

The checkpoint that regulates cell size, growth factors, and DNA damage before DNA synthesis.

Apoptosis

Programmed cell death that occurs when DNA damage cannot be repaired.

Cyclins

Proteins whose concentration varies during the cell cycle and regulate progression.

CDKs (Cyclin-dependent kinases)

Enzymes that remain constant in concentration and are activated by specific cyclins.

Contact Inhibition

A mechanism that stops the cell cycle in G1 phase when cells come into contact with each other.

Anchorage Dependence

The requirement for cells to be attached to another cell or extracellular matrix to divide.

Tumor

A mass of tissue formed by abnormal cells, which can be benign or malignant.

Metastasis

The process of cancer cells spreading from the original tumor to other parts of the body.

Homeostasis

The state of relatively stable internal conditions in the body.

Feedback Loop

A mechanism that regulates homeostasis; can be negative or positive.

Negative Feedback

A feedback mechanism that reduces the effect of the stimulus.

Positive Feedback

A feedback mechanism that increases the effect of the stimulus.