Cell cycle

cell

Cell division

The process where 1 cell becomes 2

Why should cells divide?

1. Growth

2. Reproduction

3. Repair

Chromatin

Noodly DNA

Chromosome

Tightly coiled DNA

Chromatid

Half of a chromosome; there are 2 in a chromosome

Interphase + mitosis

Cell cycle

Mitosis + cytokinesis

Cell division

Mitosis

The process in which a cell divides into 2 daughter cells

Interphase

The longest phase in the cell cycle. The cell prepares itself for mitosis by growing and DNA synthesis.

G1

The cell grows and doubles its organelles. The cell still performs normal cell functions.

S

DNA is replicated.

G2

Cell continues to grow and proteins for cell division are made. Also ensures that DNA was replicated properly.

Prophase

DNA condenses and thicken, forming chromosomes. The centrioles move to the opposite poles and spindle fibres form. The nuclear membrane also dissolves.

Metaphase

The chromosomes aligns themselves along the middle of the cell and the spindle fibres attach to the centromere of the chromosome.

Anaphase

The spindle fibres shorten, which pulls a sister chromatid of each chromosome to each pole. There should be the same number of chromosomes at each pole if done corrrectly.

Nondisjunction

The failure of chromosomes or sister chromatids to separate properly during cell division. In meiosis, this can cause genetic conditions like down syndrome, triple X syndrome, kilnefelter’s syndrome, and turner’s syndrome.

Telophase

The chromosomes reach the opposite poles and begin to unwind. The spindle fibres dissolve and new nuclear membranes form.

Cleavage furrow

In animal cells. A pinch forms at the middle, where the cell is spliting into two.

Cell plate

In plant cells. Vesicles gather near the center and fuse together.

Cytokinesis

Cell divides its cytoplasm into the two new identical daughter cells.

Cell division will not occur if

1. DNA is not replicated

2. DNA is damaged

3. Not enough nutrients to support growth