1. 10-2 Cell division

2. 2 phases of cell division
Mitosis: division of the cell nucleus, including DNA replication.
Cytokinesis: division of the cytoplasm and organelles
cytokinesis
Pair share: how is cytokinesis different from
mitosis?

3. Chromosomes Genetic material (DNA) is usually in thin strands.
Before cell division, it thickens into chromosomes
Each chromosome makes a copy of itself , and attaches to a centromere.
Nucleolus disappears.
Nuclear envelope breaks down.
WB: how many copies of DNA are present before cell division?

4. Cell cycle
A series of events that cells go through as they grow and divide.
The cell grows, prepares to divide, then divides into 2 daughter cells.
The cycle resumes with each daughter cell.

5. Events of the cell cycle
G1: cells grow
S: DNA replicates
G2: preparation for mitosis
M: mitosis and cytokinesis
P/S: how long is interphase
compared to mitotic phase?

6. Prophase First and longest phase Chromosomes become visible
Centrioles separate to opposite sides of the nucleus, forming a spindle of microtubules

7. Metaphase Lasts only a few minutes
Chromosomes line up across the center of the cell, held by fibers of the spindle.
WB: where are the chromosomes in this phase?

8. Anaphase Sister chromatids split apart
Each moves to a different pole of the spindle as the spindle fibers contract.

9. Telophase 4th and last phase of mitosis Chromosomes uncoil
Frog cell telophase
4th and last phase of mitosis
Chromosomes uncoil
Nuclear envelope re-forms around each cluster of chromosomes
Spindle breaks apart
Nucleolus is visible in each daughter nucleus
P/S: how is telophase like the reverse of prophase?

10. Cytokinesis: division of the cytoplasm
In animal cells, the cell membrane pinches in.
In plants, a cell plate forms midway between the divided nuclei.
The cell plate becomes a membrane,
Later, a cell wall forms in the cell plate.
Animal cell
Plant
cell

11. Summary 4 5
Name the
stages of
the cell
cycle: 3 6 2 7 1