Understanding the Cell Cycle and Mitosis Process

The Cell Cycle and Mitosis
 
The cell cycle is a sequence of 
growth
 and
division 
in a cell.
It has 2 distinct periods:  
Interphase
 and
Mitosis.
1.
Period of growth is called 
Interphase.
A cell 
increases
 in size.
Chromosomes
 are copied to get ready for
division.
New 
organelles
 are synthesized for the new cell.
 
2.  Period of Division is called 
Mitosis
(Division of Nucleus)
 
2 daughter cells are formed with 
identical
copies of chromosomes.
 
3.
Period of Cellular Division called
Cytokinesis.
 
Cell Division (Mitosis)
 
Definitions
 
1.
Chromatin – Uncoiled DNA
2.
Chromosomes – Coiled DNA
3.
Chromatid – ½ of a chromosome
4.
Centromere – Connects two chromatids
together to make a chromosome
5.
Centrioles – Organelles used in cell division
to move chromosomes to opposite side of
the cell.
6.
Mitosis - is normal cell division (
makes body
cells)
7.
Meiosis - is the special cell division that
creates the sperm and eggs
8.
Daughter Cell(s) – the new cells produced
by Mitosis.
 
Cell Growth and Death
 
Growth
Mitosis: growth and development
Meiosis: reproductive cells
Death
Apoptosis: programmed cell death
Mitosis
 
Cells divide to make more
cells.
Chromosomes must be
precisely divided so that each
daughter cell gets 
exactly the
same DNA.
Mitosis
 is normal cell division,
which goes on throughout life
in all parts of the body.
Meiosis
 is the special cell
division that creates the sperm
and eggs, the gametes.  We
will discuss meiosis separately.
Mitosis: development
(
a
)
(
b
)
(
c
)
m
i
t
o
t
i
c
c
e
l
l
d
i
v
i
s
i
o
n
m
i
t
o
t
i
c
c
e
l
l
d
i
v
i
s
i
o
n
Chromosomes
 
The DNA is supported and neatly
packaged. DNA in the nucleus is
uncoiled (
chromatin
), or tightly
condensed into the X-shaped
chromosomes
 we can see in the
microscope.
Each chromosome has a central
constricted region called a
centromere
 that serves as an
attachment point for the
machinery of mitosis.
 
Centromere
 
Mitosis Overview
Machinery of Mitosis
 
The chromosomes are
pulled apart by the
spindle fibers
, which is
made of microtubules.
The spindle fibers are
attached to each
centromere 
, and
anchored on the other
end to a 
centriole
(which is the organizing
center for the spindle).
Prophase
 
1.  The chromatin condense
making chromosomes, which
makes them easier to pull
apart.
2.  The nuclear envelope and
nucleolus 
disappears
.
3.  The centrioles move to
opposite poles
.
4. The microtubules form
spindle fibers, growing out of
the centrioles towards the
chromosomes.
Metaphase
 
Metaphase
 is a short
resting period where the
chromosomes are 
lined up
on the equator
 of the cell,
with the centrioles at
opposite ends and the
spindle fibers 
attached to
the centromeres.
Everything is aligned for the
rest of the division process
to occur.
Anaphase
 
In 
anaphase
, the
centromeres divide.
Spindle fibers are
attached to the
centromeres
Then the 
spindle
fibers contract
, and
the chromosomes are
pulled to opposite
poles
, towards the
centrioles.
Telophase
 
In 
telophase
 
the cell
begins to divide.
The chromosomes are at
the poles.
The 
spindle fibers
disintegrates
,
The 
nuclear
envelope and nucleolus
re-forms
The cytoplasm is divided
into 2 separate cells, the
process of 
cytokinesis
.
Cytokinesis
 
The organelles (other
than the chromosomes)
get divided up into the 2
daughter cells passively:
they go with whichever
cell they find themselves
in.
In animal cells, a ring of
actin fibers
(microfilaments are
composed of actin) forms
around the cell equator
and contacts, pinching
the cell in half.
Summary of Mitosis
 
Prophase:
Chromatin condenses into chromosomes
Nuclear envelope and nucleolus disappears
centrioles move to opposite sides of the cell
Spindle fibers form and attaches to centromeres on the
chromosomes
 
Metaphase
Chromosomes lined up on equator of cell
centrioles at opposite ends of cell
Anaphase
Centromeres divide: each  chromosome becomes two
chromatids
Chromosomes pulled to opposite poles by the spindle fibers
Telophase
Chromosomes de-condense
Nuclear envelope and nucleolus reappears
Spindle fibers disappear
Cytokinesis: the cytoplasm is divided into 2 cells
Late Interphase
Prophase
Meta- Ana- and Telo-phase
(
d
)
 
A
n
a
p
h
a
s
e
(
a
)
 
I
n
t
e
r
p
h
a
s
e
(
b
)
 
L
a
t
e
p
r
o
p
h
a
s
e
(
e
)
 
T
e
l
o
p
h
a
s
e
(
c
)
 
M
e
t
a
p
h
a
s
e
(
f
)
 
i
n
t
e
r
p
h
a
s
e
 
Control of the Cell
Cycle -
 
Normal Control of the Cell Cycle
Controlled by 
enzymes
 and 
proteins
 which
are controlled by the 
environment
.
Uncontrolled division  can result in 
cancer
.
Cancer: A mistake in the Cell Cycle
 
Results of 
mistakes
 in one or more genes
that produce substances involved in
controlling 
the enzymes of the cell cycle
(cyclins).
This can lead to the formation of masses
of 
cells (tumors)
Can enter the 
circulatory system
 and spread
throughout  the body (metastasis).
2
nd
 leading cause of 
death
 in U.S. after heart
disease.
Causes of Cancer
 
Genetic – passed on from 
parent
 to
offspring.
Environmental – different cancers are
more 
prevalent
 in different areas.
Cigarette smoke, air/water pollution, UV
radiation, and 
chemicals are called
carcinogens or mutagens
.
Cancer Prevention
 
Diets low in 
fats
 and high in 
fiber
 can
reduce the risks of many kinds of cancer.
Why?
Vaccines
 and 
sunscreen
 may also help
prevent cancer.
Daily 
exercise
 and not using 
alcohol
,
drugs
, or 
cigarettes
 also reduce the risk of
cancer.
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The cell cycle consists of two main periods: Interphase and Mitosis. During Interphase, the cell prepares for division by growing in size and copying chromosomes. Mitosis, the division of the nucleus, results in the formation of two daughter cells with identical chromosome copies. Centrioles and centromeres play crucial roles in chromosome movement and organization. Mitosis is essential for cell growth and development, while meiosis is specialized for reproductive cell formation. Chromosomes, consisting of coiled DNA, are key structures in cell division, tightly regulated during the process. Mitosis is a common cellular division process occurring throughout an organism's life.


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  1. The Cell Cycle and Mitosis The cell cycle is a sequence of growth and division in a cell. It has 2 distinct periods: Interphase and Mitosis. 1. Period of growth is called Interphase. A cell increases in size. Chromosomes are copied to get ready for division. New organelles are synthesized for the new cell.

  2. 2. Period of Division is called Mitosis (Division of Nucleus) 2 daughter cells are formed with identical copies of chromosomes. 3.Period of Cellular Division called Cytokinesis.

  3. Cell Division (Mitosis)

  4. Definitions 1. Chromatin Uncoiled DNA 2. Chromosomes Coiled DNA 3. Chromatid of a chromosome 4. Centromere Connects two chromatids together to make a chromosome 5. Centrioles Organelles used in cell division to move chromosomes to opposite side of the cell. 6. Mitosis - is normal cell division (makes body cells) 7. Meiosis - is the special cell division that creates the sperm and eggs 8. Daughter Cell(s) the new cells produced by Mitosis.

  5. Cell Growth and Death Growth Mitosis: growth and development Meiosis: reproductive cells Death Apoptosis: programmed cell death

  6. Mitosis Cells divide to make more cells. Chromosomes must be precisely divided so that each daughter cell gets exactly the same DNA. Mitosis is normal cell division, which goes on throughout life in all parts of the body. Meiosis is the special cell division that creates the sperm and eggs, the gametes. We will discuss meiosis separately.

  7. Mitosis: development mitotic cell division mitotic cell division (a) (b) (c)

  8. Chromosomes The DNA is supported and neatly packaged. DNA in the nucleus is uncoiled (chromatin), or tightly condensed into the X-shaped chromosomes we can see in the microscope. Each chromosome has a central constricted region called a centromere that serves as an attachment point for the machinery of mitosis. Centromere

  9. Mitosis Overview

  10. Machinery of Mitosis The chromosomes are pulled apart by the spindle fibers, which is made of microtubules. The spindle fibers are attached to each centromere , and anchored on the other end to a centriole (which is the organizing center for the spindle).

  11. Prophase 1. The chromatin condense making chromosomes, which makes them easier to pull apart. 2. The nuclear envelope and nucleolus disappears. 3. The centrioles move to opposite poles. 4. The microtubules form spindle fibers, growing out of the centrioles towards the chromosomes.

  12. Metaphase Metaphase is a short resting period where the chromosomes are lined up on the equator of the cell, with the centrioles at opposite ends and the spindle fibers attached to the centromeres. Everything is aligned for the rest of the division process to occur.

  13. Anaphase In anaphase, the centromeres divide. Spindle fibers are attached to the centromeres Then the spindle fibers contract, and the chromosomes are pulled to opposite poles, towards the centrioles.

  14. Telophase In telophase the cell begins to divide. The chromosomes are at the poles. The spindle fibers disintegrates,The nuclear envelope and nucleolus re-forms The cytoplasm is divided into 2 separate cells, the process of cytokinesis.

  15. Cytokinesis The organelles (other than the chromosomes) get divided up into the 2 daughter cells passively: they go with whichever cell they find themselves in. In animal cells, a ring of actin fibers (microfilaments are composed of actin) forms around the cell equator and contacts, pinching the cell in half.

  16. Summary of Mitosis Prophase: Chromatin condenses into chromosomes Nuclear envelope and nucleolus disappears centrioles move to opposite sides of the cell Spindle fibers form and attaches to centromeres on the chromosomes Metaphase Chromosomes lined up on equator of cell centrioles at opposite ends of cell Anaphase Centromeres divide: each chromosome becomes two chromatids Chromosomes pulled to opposite poles by the spindle fibers Telophase Chromosomes de-condense Nuclear envelope and nucleolus reappears Spindle fibers disappear Cytokinesis: the cytoplasm is divided into 2 cells

  17. Late Interphase

  18. Prophase

  19. Meta- Ana- and Telo-phase

  20. (a) Interphase (b) Late prophase (c) Metaphase (f) interphase (e) Telophase (d) Anaphase

  21. The Cell Cycle and Cancer Learn the importance of the cell cycle and a real life example when it is not controlled: cancer. Music used with permission from Adrian Holovaty (http://www.youtube.com/c/adrianholovaty). Support us on Patreon! http://www.patreon.com/amoebasisters Our FREE resources: GIFs: http://www.amoebasisters.com/gifs.html Handouts: http://www.amoebasisters.com/handouts.html Comics: http://www.amoebasisters.com/parameciumparlorcomics Connect with us! Website: http://www.AmoebaSisters.com Twitter: http://www.twitter.com/AmoebaSisters Facebook: http://www.facebook.com/AmoebaSisters Tumblr: http://www.amoebasisters.tumblr.com Pinterest: http://www.pinterest.com/AmoebaSister-s Instagram: https://www.instagram.com/amoebasistersofficial/ Visit our Redbubble store at http://www.amoebasisters.com/store.html The Amoeba Sisters videos demystify science with humor and relevance. The videos center on Pinky's certification and experience in teaching science at the high school level. Pinky's teacher certification is in grades 4-8 science and 8-12 composite science (encompassing biology, chemistry, and physics). Amoeba Sisters videos only cover concepts that Pinky is certified to teach, and they focus on her specialty: secondary life science. For more information about The Amoeba Sisters, visit: http://www.amoebasisters.com/about-us.html We cover the basics in biology concepts at the secondary level. If you are looking to discover more about biology and go into depth beyond these basics, our recommended reference is the FREE, peer reviewed, open source OpenStax biology textbook: https://openstax.org/details/books/biology We take pride in our AWESOME community, and we welcome feedback and discussion. However, please remember that this is an education channel. See YouTube's community guidelines https://www.youtube.com/yt/policyandsafety/communityguidelines.html and YouTube's policy center https://support.google.com/youtube/topic/2676378?hl=enref_topic=6151248. We also reserve the right to remove comments with vulgar language. We have YouTube's community contributed subtitles feature on to allow translations for different languages. YouTube automatically credits the different language contributors below (unless the contributor had opted out of being credited). We are thankful for those that contribute different languages. If you have a concern about community contributed contributions, please contact us. Control of the Cell Cycle - Normal Control of the Cell Cycle Controlled by enzymes and proteins which are controlled by the environment. Uncontrolled division can result in cancer.

  22. Cancer: A mistake in the Cell Cycle Results of mistakes in one or more genes that produce substances involved in controlling the enzymes of the cell cycle (cyclins). This can lead to the formation of masses of cells (tumors) Can enter the circulatory system and spread throughout the body (metastasis). 2ndleading cause of death in U.S. after heart disease.

  23. Causes of Cancer Genetic passed on from parent to offspring. Environmental different cancers are more prevalent in different areas. Cigarette smoke, air/water pollution, UV radiation, and chemicals are called carcinogens or mutagens.

  24. Cancer Prevention Diets low in fats and high in fiber can reduce the risks of many kinds of cancer. Why? Vaccines and sunscreen may also help prevent cancer. Daily exercise and not using alcohol, drugs, or cigarettes also reduce the risk of cancer.

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