Download Prentice Hall Biology

In eukaryotes, cell division occurs in 2 major stages.
1. Mitosis: cell nucleus divides (exact copy made)
2. Cytokinesis: division of the cell cytoplasm.
Cyto = cell
kinesis = movement
cytoplasm
cytoskeleton
pyrokinesis
telekinesis
Chromosomes: How genetic information is
passed from one generation to the next.
Before cell division, each chromosome is
duplicated (copied).
Chromosomes
Each chromosome
consists of two identical
“sister” chromatids.
Sister chromatids
Each pair of chromatids
is attached at an area
called the centromere.
Centromere
Copyright Pearson Prentice Hall
Chromosomes
When the cell divides, the
chromatids separate.
Each new cell gets one
chromatid – which becomes
a new chromosome for the
new cell
Draw and label a chromosome:
Draw and label a chromosome:
The “other”
Sister
Chromatid
Sister
Chromatid
centromere
the whole thing
is a chromosome
chromatin
DNA
• When can you see chromosomes?
Normally the DNA is unraveled as
Chromatin …. BUT
During Mitosis you can see the DNA
as chromosomes!!!
Mitosis
Is divided into four phases:

Prophase

Metaphase

Anaphase

Telophase
(PMAT)
Bellwork: Fri. Oct. 23, 2015
1. Draw the dividing plant and animal cells
and label the dividing features J
Plant: forms a “cell plate”
Animal: forms a “cleavage furrow”
What is this?
Copyright Pearson Prentice Hall
cleavage
1
Interphase
2
Prophase
Nuclear
DNA = chromatin membrane
Sister chromatids
3
Metaphase
centrioles
centromere
Spindle fiber
5
Telophase
4
Anaphase
Slide
17 of 38
End Show
1
Interphase
2
Prophase
Nuclear
DNA = chromatin membrane
Sister chromatids
3
Metaphase
centrioles
centromere
Spindle fiber
5
Telophase
4
Anaphase
Slide
18 of 38
End Show
Cytokinesis in an animal cell
Cytokinesis in Plants
In plants, a structure known as the cell plate forms
midway between the divided nuclei.
Cell plate
Cell wall
Copyright Pearson Prentice Hall
http://www.biologycorner.com/bio1/cellcycle.html
Animals - cell pinches inward
Plants - a new cell wall forms between the two new cells
Bellwork: Mon. Oct. 26, 2015
Do you know the 4 phases of mitosis?
Prophase
Metaphase
_________
__________
_________
Telophase
Anaphase _______
What is the long phase between mitosis?
Interphase
___________
Series of events cells go through as they grow
and divide.
Interphase: period of growth that occurs
between cell divisions.
During cell cycle:



cell prepares for division
grows
divides to form 2 daughter cells - each of
which begins the cycle again
Cell Cycle = 4 phases –
1st 3 occur during Interphase:




G1 (First Gap Phase)
S Phase
G2 (Second Gap Phase)
M Phase (mitosis)
use your
ruler to
divide one
quarter into
fifths
Now label the
G1 Phase
Phases of the
S Phase
Cell Cycle
G1, S, G2 are
Interphase!!!
Mitosis
G2 Phase
PMAT !!!
Cell Cycle
Cell increases in size &
synthesizes new proteins and
organelles
chromosomes
are replicated
DNA synthesis
takes place
Organelles &
molecules
required for cell
division made
Cell Cycle
Cell increases in size &
synthesizes new proteins and
organelles
chromosomes
are replicated
DNA synthesis
takes place
Organelles &
molecules
required for cell
division made
Why Do Cells Divide?
•Reproduction
•Growth
•Repair
Mitosis: nuclear division, number of chromosomes
remains the same
Skin cells are always “falling off” of us so skin is
constantly going through mitosis to replace the
lost skin cells
Mitosis – Cell Cycle
• http://www.youtube.com/watch?v=C6hn3sA0ip0
What's the difference between identical and
fraternal twins?
• http://www.youtube.com/watch?v=LSJKXl
K3Lx8
Cell getting ready to come
out of Interphase and move
into early prophase
During telophase
the cell looks like
a “telophone”
You can see the
“cleavage furrow”
right before
cytokinesis in later
telophase
Chromosomes
condensing in later
prophase
Chromosomes “met”
up in the middle
during metaphase
Sister chromatids
being “ripped
apart” during
anaphase
But when you look at a cell it may not be so clearly defined
Mitosis
Section 10-2
Spindle
forming
Prophase
Prophase
Chromosomes
(paired
chromatids)
Centromere
Click to Continue
Copyright Pearson Prentice Hall
Mitosis
Spindle
forming
Prophase
Prophase is the first and
longest phase of mitosis.
The centrioles separate
and take up positions on
opposite sides of the
nucleus.
Centromere
Chromosomes
(paired
chromatids)
Copyright Pearson Prentice Hall
Mitosis
The centrioles lie in a
region called the
centrosome.
The centrosome helps
to organize the spindle,
a fanlike microtubule
structure that helps
separate the
chromosomes.
Spindle
forming
Centromere
Chromosomes
(paired
chromatids)
Copyright Pearson Prentice Hall
Mitosis
Spindle
forming
Chromatin condenses
into chromosomes.
The centrioles separate
and a spindle begins to
form.
The nuclear envelope
breaks down.
Centromere
Chromosomes
(paired
chromatids)
10-2 Cell Division
Slide
43 of 38
End Show
Mitosis
Metaphase
Centriole
Spindle
Centriole
Metaphase
Click to Continue
Copyright Pearson Prentice Hall
Mitosis
Centriole
Metaphase
The second phase of
mitosis is metaphase.
The chromosomes line
up across the center of
the cell.
Microtubules connect
the centromere of each
chromosome to the
poles of the spindle.
Spindle
Copyright Pearson Prentice Hall
10-2 Cell Division
Slide
46 of 38
End Show
Mitosis
Anaphase
Individual
chromosomes
Anaphase
Copyright Pearson Prentice Hall
Mitosis
Anaphase
Individual
chromosomes
Anaphase is the third
phase of mitosis.
The sister chromatids
separate into individual
chromosomes.
The chromosomes
continue to move until
they have separated into
two groups.
Copyright Pearson Prentice Hall
10-2 Cell Division
Slide
49 of 38
End Show
Mitosis
Telophase
Nuclear
envelope
reforming
Telophase
Copyright Pearson Prentice Hall
Mitosis
Telophase
Telophase is the
fourth and final phase
of mitosis.
Chromosomes gather
at opposite ends of the
cell and lose their
distinct shape.
Copyright Pearson Prentice Hall
Mitosis
A new nuclear envelope
forms around each cluster
of chromosomes.
Copyright Pearson Prentice Hall
10-2 Cell Division
Slide
53 of 38
End Show
Cytokinesis
Cytokinesis
Cytokinesis
Copyright Pearson Prentice Hall
Cytokinesis
During cytokinesis, the
cytoplasm pinches in
half.
Each daughter cell has
an identical set of
duplicate chromosomes
Bellwork: Thurs. Nov. 4, 2010
Series of events cells go through as they grow &
divide is called
a. cell cycle.
b. mitosis.
c. interphase.
d. cytokinesis.
Copyright Pearson Prentice Hall
10-2
Longest phase in mitosis is
a. prophase.
b. metaphase.
c. anaphase.
d. telophase.
10-2
Longest phase in cell cycle is
a. interphase.
b. cytokinesis
c. prophase
d. metaphase
Copyright Pearson Prentice Hall
DNA replication takes place during the
a. S phase of the cell cycle.
b. G1 phase of the cell cycle.
c. G2 phase of the cell cycle.
d. M phase of the cell cycle.
Copyright Pearson Prentice Hall
Bellwork: Thurs. Nov. 4, 2010
During mitosis, “sister” chromatids separate from
one another during
a. telophase.
b. interphase.
c. anaphase.
d. metaphase.
Copyright Pearson Prentice Hall