The document summarizes the cell cycle and process of mitosis. It discusses that cells must divide to maintain an efficient surface area to volume ratio. The cell cycle consists of interphase, where the cell grows and DNA replicates, and M phase where the cell undergoes mitosis and divides. Mitosis is described in stages including prophase, metaphase, anaphase and telophase where chromosomes condense and separate, forming two daughter cells each with identical sets of chromosomes. Differences in mitosis between plant and animal cells are also noted.

1. The Cell Cycle

2. Cell Size
Surface Area
(length x width x 6)
Volume
(length x width x height)
Ratio of Surface Area
to Volume
Why Divide?
A higher surface area/volume allows the cell
to move materials in and out more efficiently
Smaller cells have higher SA/Vol. ratios

3. 10-2 Cell Cycle
G1 Phase
S Phase
G2 Phase
M Phase
Interphase
– G1- cell grows, normal
functions of life
– S Phase – DNA
replicates
– G2- cell grows and
prepares for mitosis
M Phase – Mitosis
– Cell division

4. Chromosomes
In Interphase, chromosomes
appear as chromatin
When mitosis begins, chromatin
condenses to form visible chromosomes
Sister chromatids are identical halves
of a duplicated chromosome
• Chromatids are joined at the centromere

6. Mitosis - Prophase
Chromosomes condense
Nuclear membrane disappears
Spindle fibers form as centrioles move toward
poles

7. Mitosis - Metaphase
Chromosomes line
up along the cell’s
center
Chromosomes
attach to spindle
fibers at the
centromeres

8. Mitosis - Anaphase
Sister chromatids
separate and
move toward
poles

9. Mitosis – Telophase
and Cytokinesis
Telophase – last step of mitosis
– Individual chromosomes gather
at poles
– Nuclear membrane reforms
Cytokinesis – follows telophase
– Cell pinches in half
– Two cells form
• Animal Cells – cleavage furrow
• Plant Cells – cell plate

10. Mitosis in Plant
vs. Animal Cells
Plant Cells Animal Cells
Spindle
Fibers
Stages of
mitosis
(PMAT)
No
centrioles
Cell plate
forms
between
cells
Cell
pinches at
cleavage
furrow
Centrioles

11. Another Look at Mitosis
Onion Cells
Mitosis in a Lily Cell
Mitosis in Whitefish Cells

12. Mitosis Review
How many chromosomes did
this cell start with?
– FOUR
During which phase are
sister chromatids separated?
– ANAPHASE
How many chromosomes are
in EACH daughter cell?
– FOUR