Cell Cycle, Mitosis, and Cancer

Vocabulary flashcards covering the cell cycle phases, DNA replication mechanisms, checkpoints, mitosis, and tumor suppression regulation.

Mitosis

The process of separating duplicated DNA into two equal and identical groups, dividing already copied genetic material to produce $2$ cells that are genetically identical to the original cell.

$G_1$ Phase

The first phase of interphase where proteins are produced and organelles undergo duplication.

$S$ Phase

The second phase of interphase where DNA is copied through the process of DNA replication.

$G_2$ Phase

The third phase of interphase where the cell double-checks DNA replication and synthesizes proteins that assist with mitosis.

Chromatin

The uncondensed, string-like state of DNA found in the nucleus of a cell during the $G_1$ phase.

Chromosomes

The condensed form of DNA visible in the nucleus just before the cell enters the $S$ phase of interphase.

DNA Helicase

The enzyme that helps separate hydrogen bonds between DNA strands during DNA replication.

DNA Polymerase

The enzyme that adds bases to the newly exposed single strands during DNA replication.

Semiconservative

The term describing DNA replication where each newly formed DNA molecule consists of half new and half old DNA.

Centromere

The structure that connects two sister chromatids together after an entire chromosome has been copied.

Cytokinesis

The step in the cell cycle where the parent cell is cleaved in half.

Sister Chromatids

A duplicated chromosome and its connected duplicate that are separated during mitosis so that each new cell receives a complete set of chromosomes.

Somatic Cells

Body cells, such as hair and skin cells, in which mitosis takes place ($2n = 4$).

Cell Cycle Controls

Regulatory mechanisms and checkpoints that determine when a cell receives the signal to begin cell division and proceed through mitosis.

$G_1$ Checkpoint

A control checkpoint that verifies whether cell division is necessary, whether growth factors are present, whether sufficient nutrients and energy are available, and whether the cell is large and mature enough before allowing transition into the $S$ phase.

Proto-oncogenes

Genes that code for growth factors or their receptors to stimulate cell division so that cells only divide when properly signaled and necessary.

$G_2$ Checkpoint

A control checkpoint involving genes that verify whether DNA was replicated correctly and the cell is large enough, inhibiting cell division if the DNA is too mutated.

Tumor Suppressor Proteins

Proteins that check DNA for errors, fix DNA (such as changing 'G' to 'A' to connect with 'T'), or halt division via apoptosis when major DNA errors exist.

Apoptosis

Programmed cell death that involves the cell self-destructing from the inside out so that it pops when major DNA errors cannot be easily fixed.

Tumor Suppressor Genes

Genes that produce proteins to regulate and inhibit flawed cell division; if they fail to function, multiple other mutations can occur.