Download Lab09TheCellCycle

Principles of Biology
By
Frank H. Osborne, Ph. D.
Lab 9 - The Cell Cycle
The G1, S and G2
phases are all part
of Interphase.
Interphase
A. The G1 Phase
1. The cell grows and doubles the number of
cytoplasmic components.
2. The cell prepares for DNA synthesis.
B. The S Phase
1. The cell synthesizes DNA.
2. Each chromosome develops a second
chromatid.
C. The G2 Phase
1. The cell completes
activities required for
cell division.
2. The cell prepares
to divide.
Phases of Mitosis
Interphase
Anaphase
Telophase
Metaphase
Prophase
Cell Division
A. Mitosis
1. Mitosis is the division of the nucleus.
2. Phases of mitosis.
a. Prophase
i. This occurs first.
(pro = pre)
ii. The nuclear membrane disappears.
iii. The nucleoli disappear.
iv. The chromosomes shorten and thicken.
v. The spindle forms.
Prophase
Spindle
spinning wheel
Spindle
b. Metaphase
i. The chromosomes line
up in the center (equator) of
the spindle.
ii. The centromere of
each chromosome divides.
iii. Each centromere is
attached to a microtubule of
the spindle.
c. Anaphase
i. The chromosomes
are pulled toward the
poles of the spindle.
ii. Each chromosome
has one chromatid.
d. Telophase
i. The chromosomes have
arrived at the poles of the
spindle.
ii. The nuclear membrane
is rebuilt
iii. The nucleoli reappear.
Mitosis in a
plant cell
B. Cytokinesis
1. Cytokinesis is a division of the cytoplasm.
2. Cytokinesis begins as telophase ends.
Cells pinch here
Cell plate
Cell Division
C. Differences in cell division
1. Animal cells
a. Animal cells need centrioles to help form
the spindle.
b. Animal cells pinch apart because they do
not have cell walls.
Cell Division
2. Plant cells
a. Plant cells can form a spindle without
centrioles.
b. Plant cells form a middle lamella during
cytokinesis.
Cell Division
D. Properties of cell division
1. There are two of each chromosome in each
body cell.
2. Mitosis assures that each daughter cell has
the same number of chromosomes as the mother
cell.
3. Formation of reproductive cells is different.
The End
Lab 9
The Cell Cycle