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Animal Bio Exam 2
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What do we need to do to make new cell?
An old one
What are the requirements for cell divison?
1. Grow
: build new macromolecular structures
2. Duplicate genetic material (DNA replication)
3. Partition/segregate genetic material (mitosis)
4. Divide content of cytoplasm (cytokinesis)
Describe Bacterial Cell Division
Simple process produces two cell from one
Call process binary fission
Actually more complex than we usually talk about
Proteins involved are similar to eukaryotic proteins
Process is distinct and different from mitosis
What are the key feature of bacterial division
Replication and segregation
concerted process
-Chromosome is "pushed" to poles during replications
-Chromosome finish replication at opposite poles
What is the exact mechanism of segregation of bacterial division?
Not Known
Appears to be under controll by cell
Appears to use cellular proteins (not passive)
What's the difference between bacterial and eukaryotic cell division?
More complex genome, multiple chromosomes
Genome inside nucleous
More complex cytoplasmic contents
What are the key feature of Eukaryotic cell division?
Keep products of replication together (protein glue)
Temporal separation and replication/segregation
Describe the cell cycle
G
1
: Gap 1 prepares for DNA replication
S
: During synthesis DNA is replicated
G
2
: Gap 2 prepares for mitosis
M
: Mitosis segregate chromosomes
What is the
interphase
in cell division?
G
1
, S, G
2
What is the
M phase
in cell division?
Mitosis and Cytokinesis
What is G
0
?
Cells have left the cycle: noncycling
Eukaryotic Chromosomes
Linear structure that contain
single DNA molecule
DNA molecule is alwways packaged into chromosomes
-1st DNA wrapped around protein is
Nucleosomes
Amount of condesation changes during cell cycle
Chromosome has visible constriction call
centromere
Centromere
Site where replicated chromosomes held together
Site of
kinetochore:
functional element of centromere
What are the phases of mitosis?
Prophase
(Prometaphase)
Metaphase
Anaphase
Telophase
What is the function of mitosis?
Segregate chromosomes
-Each cell gets 1 copy each chromsome
How do cells gets entire genome?
Keep chromosome together after replication
Align them together in the center of cell
Pull apart copies at the same time
What do the cell use to separate chromosomes?
Spindle - microtubules
Describe
prophase
chromosome condense; nucleus breaks down, spindle forms (microtubles)
Describe
metaphase
Chromosomes move to center of cell, attached to spindle at equator (metaphase plate)
What happens in
Anaphase
?
Chromosomes are pulled to poles
What happens in
telophase
?
reverse of prophase; spindle breaks down, nucleuos reform
What happens in
cytokinesis
?
Cell is actually divided
-contrictile ring of microfilaments
Events in the cell cycle that are irreversible
DNA replication
Anaphase
How do cell insure accuracy?
monitors process with mechanisms of control
Positive regulators that
drive
cell cycle
Cyclin
proteins are produced in synchrony with cell cycle
Cycclin dependent kinases (cdk)
drive cell cycle
1
st
Checkpoint of cell cycle
G
1
/S
- also called START
-Decision to replicate DNA
-Check for chromosome integrity
2
nd
Checkpoint of cell cycle
G
2
/M
-Replication complete?
-Damaged?
3
rd
Checkpoint of cell cycle
Metaphase/Anaphase
: decision to separate chromosomes
-All chromosome align properly
-Connected to both poles
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Author
skyy22
ID
42440
Card Set
Animal Bio Exam 2
Description
Review for exam 2
Updated
2010-10-19T17:58:54Z
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