Mitosis

1
Mitosis
- Cell Division

• During mitosis, the cells nucleus divides into
  two new nuclei. One copy of the DNA is
  distributed into each of the two daughter cells.

2
The Cell Cycle
- Cell Division
3
Length of the Cell Cycle
- Cell Division

• How long does it take for a cell to go through
  one cell cycle? It all depends on the cell. A
  human liver cell, for example, completes one cell
  cycle in about 22 hours, as shown in the graph.
  Study the graph and then answer the following
  questions.

4
Length of the Cell Cycle
- Cell Division

• Reading Graphs
• What do the three curved arrows outside the
  circle represent?

• The longest curved arrow represents the cells
  interphase the shortest represents cytokinesis
  and the middle one represents mitosis.

5
Length of the Cell Cycle
- Cell Division

• Reading Graphs
• In what stage of the cell cycle is the wedge
  representing growth?

• Interphase

6
Length of the Cell Cycle
- Cell Division

• Interpreting Data
• In human liver cells, how long does it take DNA
  replication to occur?

• 10 hours

7
Length of the Cell Cycle
- Cell Division

• Drawing Conclusions
• In human liver cells, what stage in the cell
  cycle takes the longest time?

• Interphase

8
Structure of DNA
- Cell Division

• The DNA molecule is shaped like a twisted ladder.

9
Replication of DNA
- Cell Division

• Because of the way in which the nitrogen bases
  pair with one another, the order of the bases in
  each new DNA molecule exactly matches the order
  in the original DNA molecule.

10
Sequencing
- Cell Division

• As you read, make a cycle diagram that shows the
  events in the cell cycle, including the phases of
  mitosis. Write each even in a separate circle.

Cell grows, makes a copy of DNA.
Cell pinches in two each daughter cell has same
number of identical chromosomes.
Chromosomes and spindle fibers form nuclear
envelope breaks down.
Chromosomes line up across the center and attach
to a spindle fiber.
Chromosomes stretch out new nuclear envelope
forms around chromosomes.
Centromeres split chromatids separate and move
to opposite ends.
11
End of SectionCell Division