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Cell Division
Mitosis vs. Meiosis
Honors Biology
Ch. 5 & Ch. 6-1, 6-2
1
2
Why do cells divide?
1) ______________:
• increase number of cells by cell division
• _________________________________; occurs via
_________
2) ______________:
• _________ reproduction = production of offspring from
one parent (in ________); ____________
• _________ reproduction = formation of a new individual
from union of 2 sex cells (fertilization of sperm and egg);
occurs via ___________
3
Cell Cycle
• the sequence of cell growth and division
that occurs in a cell
(Interphase)
___ -> ___ -> ___ -> Mitosis/meiosis
____ = rapid growth
____ = DNA synthesis/replication
____ = centrioles replicate
4
Chromtain, Chromatid, Chromsome
• _________ is DNA
wrapped around proteins
called _________.
• A _________ has two
sister _________ held
together by a
___________.
5
6
4 Phases of Mitosis
• _________
- Chromosomes appear; nuclear membrane disappears;
centrioles start migrating to opposite ends; spindle fibers
start forming
• _________
- Chromosomes line up on spindle fibers along the equator
of the cell.
• _________
- Centromeres split apart and sister chromatids separate.
• _________
- Chromatids reach the opposite ends; chromosomes
unwind; spindle breaks down; nuclear membrane
reappears; _________ (splitting of cytoplasm);
7
8
9
Phases of Mitosis Analogy
Interphase (G1, S, G2) __________________
• Prophase (_________)
•
Metaphase (___________________)
•
Anaphase (_______________________)
•
Telophase (__________________)
10
Difference between
animal and plant cell division
• Plant cell forms ______ (_____________
_____________________________) during
___________ whereas animal cell
cytoplasm pinches in along the equator.
• Plant cells DO NOT have _________.
11
How is meiosis different from
mitosis?
12
13
Mitosis vs. Meiosis
Mitosis
• ________ reproduction
• _______cells (body cells)
• ___ division
• __ daughter cells formed
• Daughter cells are
_________to parent cells
• Chromosome # is
___________(_______)
• No pairing of _________
chromosome
• No _______________.
Meiosis
• ________ reproduction
• __________ cells (eggs
& sperms = _________)
• ____ divisions
• __ daughter cells formed
• Daughter cells are
_____________ identical
to parent cells
• Chromosome # is _____
(________)
• Pairing of ___________
chromosome
• __________ btwn
_________ chromosome
may occur
14
Meiosis
15
# of Chromosomes
• Humans have ____
chromosomes in a
body cell. ________
• Humans have ____
chromosomes in
reproductive cells
such as sperm or
egg. ________
16
Fertilization
________
sperm (___) + egg (___)
_______ (a fertilized egg ) (___)
-> embryo
17
18
True or False
1. Mitosis occurs in sex cells and meiosis
occurs in body cells.
2. Centrioles are involved in cell division in
both plants and animals.
3. Each human body cell has 23
chromosomes.
4. Chromosomes are tightly coiled DNA.
5. Each chromosome has 2 sister
chromatids.
19
Homologous chromosomes
• Each pair of _____________
chromosomes has genes for
the ________ ( such as hair
color/eye color) arranged in
the _________. It may not
be exactly identical though
b/c of different __________
(forms of genes).
• ___________ chromosomes
may cross-over during the
__________ of ________.
20
Crossing Over
(during _____________)
21
How is Meiosis I different from
Meiosis II?
Meiosis I
• ___________
chromosomes pair up
and ___________ during
___________.
• ________________split.
• ___ lines
• Chromosomes # is
________.
Meiosis II
• ___________
chromosomes do not
line up.
• _______________ split.
• ___ line
• Similar to _______
• Chromosome # stays as
________.
22
23
24
True or False
1. Homolgous chromosomes line up during the
metaphase of mitosis.
2. Crossing over occurs between 2 sister
chromatids.
3. In meiosis II, sister chromatids split, not
homologous chromosomes.
4. Mitosis produces haploid cells and meiosis
produces diploid cells.
5. Cytokinesis occurs during the anaphase of
mitosis and meiosis.
25
What is Cancer?
•
____________ cell
division caused by
damage to ______
regulating the cell
division cycle.
• Types of Cancer
a) _______ - a sedentary
mass of cancerous cells
b) ________ - a moving
mass of cancerous cells
metastasis
26
Change in US Death Rates* from
1991 to 2006
Rate Per 100,000
1991
400
2006
313.0
300
215.1
200.2
200
180.7
100
63.3
43.6
34.8
17.8
0
Heart diseases
Cerebrovascular
diseases
Influenza &
pneumonia
Cancer
* Age-adjusted to 2000 US standard population.
Sources: US Mortality Data, National Center for Health Statistics, Centers for Disease Control and
Prevention, 2009.
Causes of Cancer
• Carcinogenic chemicals, _______, ______
• Mechanism – ___________.
- ________ agents cause mutations in
genes that encode for proteins that
regulate cell division and growth; cell
growth is no longer under control.
28
Non-disnjunction
• chromosomes fail to
separate during
_________ (an error
in ________)
• Leads to genetic
disorders such as
________, ________
and ________.
29
Disorders caused by
non-disjunction
Ex: _________ - one too few chromosomes
-Turner Syndrome (XO)
_________- one too many
chromosomes
-___________ (trisomy 21)
-________________ (XXY)
30
True or False
1. Cancer is caused by mutations in genes
that control cell cycle.
2. Non-disjunction that occurs during
mitosis affect the offspring.
3. Down syndrome is monosomy.
4. Turner syndrome is caused by nondisjunction.