Cell%20Division

1
Cell Division

• The Cell Cycle

2
Reviewing the Chromosome

• Each chromosome (coiled DNA) consists of two
  identical sister chromatids.
• Each pair of chromatids are attached at an area
  called the centromere.

Sister chromatids
Centromere
3
Cell Cycle

• The cell cycle is the series of events that cells
  go through as they grow and divide.

4
Cell Cycle
Interphase is the period of rest and growth that
occurs between cell divisions.
5
Your Turn!

• Based on the image, what does a cell spend most
  of its time doing?

6
The characteristics of Interphase

• G1 Phase
• The cell grows
• S Phase
• The DNA of the cell is copied into 2 sets (DNA
  replication)
• G2 Phase
• The cell finishes growing and gets ready for
  mitosis!

7
Cell Cycle
Cell Division

1. Mitosis the division of the nucleus that
   results in two genetically identical cells
2. Cytokinesis the division of the cytoplasm

8
Your Turn!

• What is the purpose of mitosis?

9
Mitosis
10
PROPHASE
Spindle fibers

• Things to remember
• it is the start of mitosis
• the nucleus breaks down
• the chromosomes form

Centrioles
Nuclear membrane
Chromosomes (paired chromatids)
11
METAPHASE

• Things to remember
• the chromosomes line up across the middle of the
  cell
• the spindle fibers attach at the centromeres

12
ANAPHASE

• Things to remember
• the chromatids are pulled away from each other

13
TELOPHASE

• Things to remember
• two nuclei start to reform
• cytokinesis starts

14
Your Turn!

• What do you think each cell would look like if
  this did occur? Why?

15
CELL DIVISION

• AT THE CONCLUSION OF CELL DIVISION EACH OFFSPRING
  WILL RECEIVE IDENTICAL COPIES OF THE CELLS
  CHROMOSOMES.

16
Your Turn!

• How many chromosomes are in a human skin cell
  before mitosis? After?