Download The Cell Cycle

Warm up Sep. 5
 What
happens in G1
 What happens during S phase?
 What happens during the cell
cycle?
Warm Up Sep. 11
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Two differences between plant an animal
cells.
Why are plant cells Eukaryotic?
What are two phases of mitosis?
Bell Work Sep. 8
 What
is happening in Prophase?
 In Metaphase?
 What are the other 2 phases?
Cell Growth and Division
Chapter 10: page 240-259
Cell Division
Vocabulary

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Cell division
Chromosomes
Chromatid
Cell Cycle
Interphase
Cell division

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Results in 2 cells that are identical to the
parent cell
Occurs in two main stages:
–
–
Mitosis: division of the cell nucleus
Cytokinesis: division of the cytoplasm
Chromosomes


chroma = colored ; soma = body
Chromosomes
–
structures which contain DNA
Chromosomes (continued)

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Each chromosome consists of
two identical sister chromatids
The chromatids are attached
to each other by an area
known as the centromere.
Essential Questions

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
What is a chromosome?
What is produced during cell division?
What happens during cytokinesis?
Cell Cycle

Three things occur during the cell cycle:
–
–
–
Growth
Preparation to divide
Divides to form two daughter cells
Events of the Cell Cycle

Interphase
–
–
–

G1
S
G2
Mitosis (PMAT)
–
–
–
–

Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Interphase

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Majority of the cell’s life
Cell is growing and preparing
for mitosis
Absence of visible
chromosomes
–
chromatin
Phases of Interphase

G1
–


Cell growth (in size)
S
–
DNA is synthesized


Replicated
G2
–
–
Prepare for mitosis
“mother cell”
G0
–
Cells are not dividing
Mitosis
Pg. 246-248
Vocabulary

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Mitosis
Prophase
Metaphase
Anaphase
Telophase
Characteristics of Mitosis

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Process of growth
Asexual reproduction
Results in 2 identical cells
Phases of Mitosis

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Prophase
Metaphase
Anaphase
Telophase
PMAT
Prophase

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

First and longest phase of mitosis
Chromatin condense into chromosomes
Nuclear membrane and nucleolus
disappear
Spindles form
–
Fanlike structures that help separate the
chromosomes
Metaphase


Short, second phase
Chromosomes line up at the
metaphase plate
Warm up

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What happens in Metaphase?
What happens in Prophase?
What happens in G1 of interphase?
Anaphase

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Third phase
Sister chromatids are pulled
toward the poles
Telophase


Final phase of mitosis
Reversal of prophase
–
–

Nuclear membrane and nucleolus reappear
Chromosomes unwrap into (chromatin)
A new double membrane begins to
form between the 2 new nuclei
Warm up

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What happens during Anaphase?
Telophase?
Cytokinesis?
Cytokinesis
pp. 248-249
Cytokinesis in Animal Cells

The plasma
membrane pinches
in along the equator
–

Cleavage furrow
2 new cells are
separated
Cytokinesis in Plant Cell


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
Plasma membrane
does not pinch off
Cell plate is laid down
across the equator
Cell membrane is
formed around each
cell
A new cell wall forms
on each side of the cell
plate
10-3 Regulating the Cell Cycle
pp. 250-252
Warm UP Sep. 9
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What happens in anaphase?
What happens in telophase?
What happens in S of interphase?
Controls on Cell Division –
Cell Cycle Regulators

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Cells will divide as long as there is space
available.
Cyclins regulate the timing of the cell cycle in
eukaryotic cells.
Controls on Cell Division –
Cell Cycle Regulators (continued)

External Regulators
–
–
Proteins that respond to event outside the cell
i.e., speed up or slow down the cell cycle (growth
regulators)
Checkpoints control the cell cycle

G1 checkpoint
–

G2 checkpoint
–

Checks cell size and suitable
environment
Checks replicated DNA, if the cell
is large enough, suitable
environment
Metaphase checkpoint
–
Checks if chromosomes are
aligned on spindles
Cancer: Uncontrolled Cell Growth
Characteristics of Cancer

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
Occurs when cells do not respond to the
signals that regulate growth
Form masses of tissue called tumors that
deprive normal cells of nutrients
2nd leading cause of death in the USA
Causes of Cancer

Environmental factors
–
–
–
Geographic location, cigarette smoke, air and
water pollution, and exposure of UV light
Viral infections
Damaged genes

p53
Cancer prevention

Diets low in fat and high in fiber
–

Vitamins and minerals
–
–
–

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Diets high in fat are linked to colon, breast, and
prostate cancers
Carotenoids
Vitamin A, C, E
Calcium
Daily exercise
Not using tobacco products
Cell Cycle Web Links
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http://www.cellsalive.com/cell_cycle.htm
http://www.cellsalive.com/mitosis.htm