Download The Cell Cycle

Science 103 (Spring 2006) – Outlines 10 & 11
Reading:
Cell cycle, chromosomes, and mitosis
P 423-424, 570
Importance of Cell Division
1.
2.
3.
The Cell Cycle
1. Description
2. Prokaryotic Cell Cycle
3. Eukaryotic Cell Cycle

The Cell Cycle in Eukaryotes is more Complex than in Prokaryotes, Why?
(a)
(b)
(c)
Eukaryotic Cell Cycle
1. Stages of the Cell Cycle
(See http://www.cellsalive.com/cell_cycle.htm for an animated version).
Figure 19.20
(a) Interphase:
 ~________ of the cell cycle.

 Composed of 3 phases:
(i)
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(ii)
(iii)
(b) Mitosis:
Occurs in _______________ cells.
(c) Cytokinesis:
3. Control of the Cell Cycle
(a) Rate of Cell division:
Important that the cell controls its rate of cell division (loss of control = __________).
(b) Checkpoints:
Cells use checkpoints to ensure that proper conditions have been achieved
before allowing the cell to proceed to the next stage in the cell cycle. These checkpoints
are at:
(i)
(ii)
(iii)
Figures (Slide)
Chromosomes
1. Chromosome Number
(a) Varies according to species.
(b) Humans –
2. Incorrect Chromosome Number
(Each chromosome has thousands of genes, all of which are important).
(a) Monosomy:
(b) Trisomy:
3. Chromosome Structure
Figure 25.11
(a) DNA and proteins:
2
(b) Why have proteins?
4. Homologous Chromosomes
(a)
(b)
5. Chromosome Duplication
During S phase each homologue replicates so that it is composed of 2 sister
chromatids that are joined at the centromere.
Mitosis
1. Definition
____________ division in ____________cells.
2. Stages
*A continuous process – scientists divide it into stages to better understand it*
(See http://www.cellsalive.com/mitosis.htm for animated version.
Figure 19.21
The stages are:
(a)
(b)
(c)
(d)
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3. Prophase
(a)
(b) (i) Animal Cells:
____________ move to opposite poles, forming __________________
(_______________) between them.
(ii) Plant Cells:
(c) ______________________ breaks down.
(d) The ________________ attach to ________________ by their kinetochores.
(i) Kinetochore:
Forms at the _______________ of each _________________ and includes
__________________.
(ii) Kinetochore Microtubules:
4. Metaphase
(a)
(b)
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5. Anaphase
(a)
(b)
6. Telophase
(a)
(b)
(c) Cytoplasmic division begins with the assembly of the __________________ (in
animals).
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Cytokinesis
1. Description
2. Animal Cells
(a) The cell is pinched in 2 by the contractile belt (composed of _______________).
(b) A ___________________ becomes evident.
3. Plant Cells
(Have _______________, so cytokinesis has to occur by a different mechanism –
).
(a) A ___________________ forms across the midline of the cell:
(b)
(d) The _____________________ is laid down between the 2 membranes.
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Cell death
1. Programmed Cell Death
Some cells are programmed to die.
eg.
Why do ducks have webbed feet?
2. Human Cell Timeline
(a)
(b)
3. Cancer Cells
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