Unit 4: The Cell Cycle and Division Mechanisms

Cell Cycle

The ordered sequence of events a cell undergoes from formation to division.

Interphase

The phase where a cell prepares for division, spending about 90% of its life.

G1 Phase

The first gap phase where the cell grows and synthesizes proteins.

S Phase

The synthesis phase where DNA replication occurs.

G2 Phase

The second gap phase where the cell prepares for division by synthesizing enzymes and proteins.

G0 Phase

A nondividing state where some cells remain permanently or temporarily.

M-Phase

The phase of the cell cycle that includes Mitosis and Cytokinesis.

Mitosis

The process of nuclear division that produces two identical daughter nuclei.

Cytokinesis

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

Chromatin

Loose, uncoiled DNA during Interphase.

Chromosomes

Tight, condensed DNA during M-Phase.

Sister Chromatids

Identical halves of a duplicated chromosome.

Prophase

The stage where chromatin condenses and the nuclear envelope breaks down.

Metaphase

The stage where chromosomes align at the metaphase plate.

Anaphase

The stage where sister chromatids separate and become independent chromosomes.

Telophase

The stage where two daughter nuclei form and chromosomes decondense.

Cleavage Furrow

The structure formed in animal cells during cytokinesis to divide the cell.

Cell Plate

The structure formed in plant cells to create a new cell wall during cytokinesis.

G1 Checkpoint

The critical checkpoint that checks cell size, nutrients, and DNA integrity.

G2 Checkpoint

The checkpoint that ensures DNA replication is complete and DNA is undamaged.

M Checkpoint

The checkpoint during Metaphase that checks for proper chromosome alignment.

Cyclins

Proteins that regulate the cell cycle by fluctuating in concentration.

Cyclin-Dependent Kinases (CDKs)

Enzymes that activate the cell cycle when bound to cyclins.

Proto-oncogenes

Genes that promote normal cell growth and division.

Oncogenes

Mutated proto-oncogenes that lead to excessive cell division.

Tumor Suppressor Genes

Genes that inhibit cell division and can repair DNA damage.

p53 Gene

A tumor suppressor gene known as the 'Guardian of the Genome'.

Apoptosis

The programmed cell death mechanism triggered by the p53 gene.