Exam1 Cell Cycle

Cell cycle

The sequence of cell growth, DNA copying and division: G1 → S → G2 → mitosis → cytokinesis.

Interphase

G1, S and G2 together. The cell works, grows, copies DNA and prepares to divide.

G1 phase

The cell grows, does its normal work and gathers materials for DNA replication.

S phase

DNA synthesis: the cell copies its nuclear DNA. Centrioles also duplicate around this part of the cycle.

G2 phase

The cell checks and repairs copied DNA and makes materials needed for division.

G0 phase

A nondividing state outside the active cell cycle. It can last a long time or be permanent.

Helicase

The enzyme that opens or unzips the DNA double helix for replication.

DNA polymerase

The enzyme that builds new DNA strands by adding matching nucleotides.

Sister chromatids

The two matching copies of a chromosome after its DNA has been copied.

Mitosis

Division of the nucleus. Its phases are prophase, metaphase, anaphase and telophase: PMAT.

Prophase

Chromosomes condense and the spindle forms. The nuclear envelope breaks down as mitosis proceeds.

Metaphase

Chromosomes line up in the MIDDLE of the cell.

Anaphase

Sister chromatids separate and move AWAY toward opposite sides.

Telophase

TWO nuclei form. Nuclear envelopes return and chromosomes loosen.

Cytokinesis

Division of the cytoplasm into two daughter cells. In animal cells, a contractile ring pinches the cell in two.