Transcript The Cell Cycle

Mitosis and
Asexual Reproduction
I.
A.
The Cell Cycle
Why Cells Divide...
1. cells obtain most resources through
diffusion
a. diffusion = FAST small distances
b. diffusion = SLOW over long
distances
I.
A.
The Cell Cycle
Why Cells Divide...
2. Surface Area to Volume ratio (SA : V)
a. small cells = efficient diffusion
1. membrane is big enough to
allow enough materials
through
I.
A.
The Cell Cycle
Why Cells Divide...
2. Surface Area to Volume ratio (SA : V)
b. as cell grows, V increases
FASTER than SA.
1. diffusion distance increases
2. diffusion efficiency decreases
Surface Area to
Volume Ratio
I.
A.
The Cell Cycle
Why Cells Divide...
2. Surface Area to Volume ratio
*growth is a requirement for most cells – so how
do they solve this problem?
c. cells divide in order to keep from
getting too large.
- also happen to make clones of
themselves in the process
I.
B.
The Cell Cycle
The Cell Cycle
1. Interphase (90% of time)
a. normal functions
(making proteins, homeostasis)
b. replicating DNA
(in preparation for dividing)
c. make enzymes for division, and
organelles for the new cell
I.
B.
The Cell Cycle
The Cell Cycle
2. Mitosis (Nuclear Division)
a. Prophase
1. chromatin coils into
chromosomes
I.
B.
The Cell Cycle
The Cell Cycle
2. Mitosis (Cell Division)
b. Metaphase
1. chromosomes line up
at equator
2. centrioles move to poles
3. spindle fibers appear
I.
B.
The Cell Cycle
The Cell Cycle
2. Mitosis (Cell Division)
c. Anaphase
1. centrioles pull sister
chromatids apart
I.
B.
The Cell Cycle
The Cell Cycle
2. Mitosis (Cell Division)
d. Telophase
1. spindle fibers break down
2. chromosomes uncoil
3. nucleus reappears
I.
The Cell Cycle
B.
The Cell Cycle
2. Mitosis (Cell Division)
e. Cytokinesis
1. final division of cytoplasm
2. cells separate
Asexual Reproduction and Cancer
II. Asexual Reproduction
A.
Types
1. Budding (bud)
a. bud that is released from cell and
grows into clone
b. common in yeast (fungi)
II. Asexual Reproduction
A.
Types
1. Budding
2. binary fission
a. “split in two”
b. bacterial mitosis (some protists)
II. Asexual Reproduction
A.
Types
1. Budding
2. binary fission
3. fragmentation
a. growth of new organism from
fragments of parent organism
III. Cancer and the Cell Cycle
A.
What is Cancer?
1. uncontrolled cell division
2. results in a tumor
a. benign
1. harmless growth
2. no death to surrounding
tissue
III. Cancer and the Cell Cycle
A.
What is Cancer?
2. results in a tumor
b. malignant
1. tumor causes damage/death
to surrounding tissue
2. spreads easily (metastasis)
III. Cancer and the Cell Cycle
A.
What is Cancer?
3. caused by mutation in cell cycle genes
a. “On” genes work
b. “Off” genes don’t work