1. KEY CONCEPT Cells divide during mitosis and cytokinesis.

2. DNA + Histones form chromatin Chromosomes condense tightly for mitosis
Chromosome Structure
1 long thread of DNA
DNA wraps around proteins (histones) that condense it.
DNA + Histones form chromatin
Chromosomes condense tightly for mitosis
DNA double helix
DNA and histones
Chromatin
Supercoiled DNA

3. One half of a duplicated chromosome is a chromatid.
DNA plus proteins is called chromatin.
chromatid
telomere
centromere
Condensed, duplicated chromosome
One half of a duplicated chromosome is a chromatid.
Sister chromatids are held together at the centromere.
Telomeres protect DNA and do not include genes.

4. 1. Interphase prepares the cell to divide.
Mitosis and cytokinesis produce two genetically identical daughter cells.
Parent cell
centrioles
spindle fibers
centrosome
nucleus with
DNA
1. Interphase prepares the cell to divide.
Copies DNA
Cell grows
Organelles are duplicated

5. Mitosis divides the cell’s nucleus in four phases.
2. Prophase:
chromosomes condense
nuclear envelope breaks down
Spindle fibers form.

6. During metaphase, spindle fibers help chromosomes line up in the middle of the cell

7. 4. Anaphase, sister chromatids separate to opposite sides of the cell.

8. 5. Telophase: Nuclear membrane forms around chromosomes
chromosomes begin to uncoil
Spindle fibers fall apart

9. In animal cells, the membrane pinches closed.
Cytokinesis differs in animal and plant cells.
In animal cells, the membrane pinches closed.
In plant cells, a cell plate forms.