Interphase and Mitosis

What happens to chromatin at the beginning of cell division?

Chromatin starts changing into chromosomes

What happens to chromosomes before cell division?

They replicate to form identical chromosomes (in humans, 46 to 92)

What surrounds the nucleus during this stage?

A nuclear membrane.

What are centrioles and where are they located?

A pair of structures called a centrosome, located near the nucleus.

What happens to the centrosomes before cell division?

They make a copy of themselves

What extends outward from the centrosomes?

Microtubules

What happens during Prophase?

Identical chromosomes called sister chromatids pair up (2 chromatids = 1 chromosome) and are joined at the centromere. The centrosomes move to opposite poles and spindle fibers form.

What happens during Prometaphase?

The nuclear membrane fragments. The spindle connects the two centrosomes (now at the poles), and some spindle fibers attach to the kinetochore region of the sister chromatids.

What happens during Metaphase?

Chromosomes line up at the center (equator) of the cell and attach to the spindle fibers.

What happens during Anaphase?

Paired sister chromatids separate and move toward opposite poles of the cell.

What happens during Telophase?

A nuclear envelope forms around each set of chromosomes at the poles, two nuclei appear, and cytokinesis (division of the cytoplasm) begins.