meiosis - o'mara's science...
Post on 04-Aug-2020
4 Views
Preview:
TRANSCRIPT
MEIOSIS
Making gametes…
http://waynesword.palomar.edu/lmexer2a.htm
Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htm
Family http://babyhearing.org/Parenet2Parent/index.asp
Remember from Chapter 1:CHARACTERISTICS OF LIVING THINGS
ALL LIVING THINGS __________REPRODUCE
ASEXUAL REPRODUCTIONBacteria reproduce using__________________________________
Budding & regeneration are used by plants and animals to reproduce asexually (mitosis)
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmito.html
http://fig.cox.miami.edu/~cmallery/150/mitosis/c7.13.2.hydra.jpg
Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htm
BINARY FISSION
BINARY FISSION & MITOSIS
Produces cells that are __________ copies of parent cell
identical
ADVANTAGES OF ASEXUAL REPRODUCTION
Can make offspring faster
Don’t need a partner
http://www.mrgrow.com/images/cutting.jpg
DISVANTAGES OF ASEXUAL REPRODUCTION
ALL ALIKE
Species CAN’T change and adapt
One disease can wipe out whole population
http://www.mrgrow.com/images/cutting.jpg
SEXUAL REPRODUCTION
Combines genetic material
from 2 parents (sperm & egg)
so offspring are
genetically __________
from parents
DIFFERENT
Family image from: http://babyhearing.org/Parenet2Parent/index.asp
ADVANTAGES OF SEXUAL REPRODUCTION
Allows for variation in population
Individuals can be different
Provides foundation for EVOLUTION
Allow species to adapt to changes intheir environment
http://naturalsciences.sdsu.edu/classes/lab8/spindex.html
EGG + SPERM
If egg and sperm had same number of chromosomes as other body cells . . .
baby would have too many chromosomes!
http://www.angelbabygifts.com/Image by Riedell Image by Riedell
http://www.acmecompany.com/stock_thumbnails/13217.forty-six_chromosomes.jpg
MEIOSIS is the way…
to make cells with ½ the number of chromosomesfor sexual reproduction
http://waynesword.palomar.edu/lmexer2a.htm
DIPLOID & HAPLOIDMost cells have 2 copies of each chromosome = ______________
(one from mom; one from dad)
All BODY (___________) cells are diploid
DIPLOID 2n
HOMOLOGOUSCHROMOSOMES
= SOMATIC
DIPLOID & HAPLOID
Some cells have only one copy of each chromosome = _____________
All sperm and egg cells
are haploid. Called gametes or sex cells.
HAPLOID 1n
MITOSIS• Makes ___ cells genetically _________ to parent cell & to each other
• Makes ___ cells
• Makes __________
• Used by organisms to: increase size of organism, repair injuries, replace worn out cells
http://waynesword.palomar.edu/lmexer2a.htm
2identical
2n
SOMATIC (body)
MEIOSIS• Makes ____ cells genetically different from parent cell & from each other
• Makes _____ cells
• Makes ______________
• Used for ____________
4
1n
Gametes (sperm & eggs)
sexual reproduction
http://waynesword.palomar.edu/lmexer2a.htm
WHAT MAKES MEIOSIS DIFFERENT ?
1. SYNAPSIS & CROSSING OVER(PROPHASE I)
2. SEGREGATION &INDEPENDENT ASSORTMENT
(ANAPHASE I)
3. Skip INTERPHASE II (NO S)CELL DIVIDES TWICE, BUT…
ONLY COPIES DNA ONCE
WHAT MAKES MEIOSIS DIFFERENT ?
1.Homologous chromosomes pair up during ________________
= ______________SYNAPSIS
Images modified from: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Crossover.gif
This group of FOUR (4)chromatids is called a_________________TETRAD
PROPHASE I
HOMOLOGOUS CHROMOSOMESImage modified by Riedell • SAME SIZE
• SAME SHAPE
• CARRY GENES for the SAME TRAITS
• BUT ______________!
(Don’t have to have the SAME CHOICES)
http://sps.k12.ar.us/massengale/genetics%20tutorial.htm
NOT IDENTICAL
WHAT MAKES MEIOSIS DIFFERENT?
2. Exchange of DNA betweenhomologous pairs = _____________during PROPHASE I
CROSSING OVER
Allows shuffling of genetic material
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Crossover.gif
CROSSING OVER
Image modified by Riedell
• Allows for_________________
in different combinations
• After crossing over, chromatid arms are________________ anymore
http://sps.k12.ar.us/massengale/genetics%20tutorial.htm
rearranging of DNA
NOT IDENTICAL
WHAT MAKES MEIOSIS DIFFERENT ?
Separation of chromosomes during ANAPHASE I
INDEPENDENT ASSORTMENT
Separates gene choices and allows shuffling of genetic material
SEGREGATION &
SEGREGATION(Anaphase I)
SEGREGATION & CROSSING OVERtogether make even more combinations
http://waynesword.palomar.edu/lmexer2a.htm
INDEPENDENT ASSORTMENT
http://fig.cox.miami.edu/~cmallery/150/mitosis/c13x9independent-assortment.jpg
INDEPENDENT ASSORTMENTat ANAPHASE I
Lots of different combinations are possible!
This is why you don’t look exactly like your brothers and sisters even though you share the same parents!
http://www.tokyo-med.ac.jp/genet/anm/mimov.gi
WHAT MAKES MEIOSIS DIFFERENT ?
3. Skip INTERPHASE II (No S)CELL DIVIDES TWICE, BUT …
ONLY COPIES ITS DNA ONCE
G1 G2S P M A T C
G1
MITOSIS:
MEIOSIS:
S G2 P M A T C
P M A T C
( I )
( II )
WHAT MAKES MEIOSIS DIFFERENT ?
1. Crossing over 2. Segregation 3. Independent assortment
are ALL ways MEIOSIS results in =______________________________
So daughter cells are ______________
from parents and from each otherdifferent
GENETIC RECOMBINATION
Go to Section:
Meiosis I
Section 11-4
Figure 11-15 Meiosis
Go to Section:
Meiosis I
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Go to Section:
Meiosis I
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Go to Section:
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Go to Section:
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Go to Section:
Meiosis II
Meiosis I results in two
haploid (N) daughter cells,
each with half the number of
chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a
similar way to the metaphase
stage of mitosis.
The sister chromatids
separate and move toward
opposite ends of the cell.
Meiosis II results in four
haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Go to Section:
Meiosis II
Meiosis I results in two
haploid (N) daughter cells,
each with half the number of
chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a
similar way to the metaphase
stage of mitosis.
The sister chromatids
separate and move toward
opposite ends of the cell.
Meiosis II results in four
haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Go to Section:
Meiosis II
Meiosis I results in two
haploid (N) daughter cells,
each with half the number of
chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a
similar way to the metaphase
stage of mitosis.
The sister chromatids
separate and move toward
opposite ends of the cell.
Meiosis II results in four
haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Go to Section:
Meiosis II
Meiosis I results in two
haploid (N) daughter cells,
each with half the number of
chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a
similar way to the metaphase
stage of mitosis.
The sister chromatids
separate and move toward
opposite ends of the cell.
Meiosis II results in four
haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Go to Section:
Meiosis II
Meiosis I results in two
haploid (N) daughter cells,
each with half the number of
chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a
similar way to the metaphase
stage of mitosis.
The sister chromatids
separate and move toward
opposite ends of the cell.
Meiosis II results in four
haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
MITOSIS vs MEIOSIS
INTERPHASE INTERPHASE I
• DNA is spread out as chromatin
• Nuclear membrane/nucleolus visible
• DNA is copied during S phase
SAME AS
MITOSIS
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MITOSIS vs MEIOSIS
PROPHASE PROPHASE I
DNA scrunches into replicated chromosomes
Nuclear membrane/
nucleolus disappear
Centrioles/spindle fibers appear
DNA scrunches into
replicated chromosomes
Nuclear membrane/
nucleolus disappear
Centrioles/spindle fibers
appear Homologous pairs match up
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MITOSIS vs MEIOSISMETAPHASE METAPHASE I
Replicated
chromosomes line up
in middle
Replicated chromosomes line up
in middle
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
with homologous partner
MITOSIS vs MEIOSIS
ANAPHASE ANAPHASE I
APART:
Chromatids split
APART:
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
Chromatids stay together
Homologous pairs split
MITOSIS vs MEIOSIS
TELOPHASE TELOPHASE I
See TWO nuclei
Nuclear membrane/
nucleolus return
DNA spreads out as chromatin
Spindle/centrioles disappear
SAME AS MITOSIS
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MITOSIS vs MEIOSIS
CYTOKINESIS CYTOKINESIS I
Cytoplasm splits
into 2 cells
SAME AS
MITOSIS
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MITOSIS vs MEIOSIS
PROPHASE PROPHASE II
• DNA scrunches into replicated chromosomes
• Nuclear membrane/nucleolus disappear
• Centrioles/ spindle fibers appear
Two cells in meiosis II; no
Homologous pairs
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MITOSIS vs MEIOSISMETAPHASE METAPHASE II
• Replicated chromosomes line up in middle
SAME AS MITOSIS
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MITOSIS vs MEIOSIS
ANAPHASE ANAPHASE II
Chromatids split and move apart SAME AS MITOSIS
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MITOSIS vs MEIOSIS
TELOPHASE TELOPHASE II
Two nuclei
Nuclear membrane/nucleolus returns
Centrioles/spindle fibersdisappear
DNA spreads out as
chromatin
SAME AS MITOSIS
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MITOSIS vs MEIOSIS
CYTOKINESIS CYTOKINESIS II
Cytoplasm splits
2 daughter cells
Cytoplasm splits
4 cells
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MAKING
SPERM & EGGS
___________________= MAKING MATURE SPERMMature & grow flagella
SPERMATOGENESIS
Sperm
donates
mostly DNA
http://bestweekever.blogs.com/photos/uncategorized/imagemain_sperm_egg1_1.gif
WHY MAKE ONLY ONE “GOOD” EGG?
Most of the cell parts and nutrients
needed for baby come from EGG!
Sperm provides DNA
All the starting nutrients, organelles, molecule building blocks, etc. have to come from the egg.
POLAR BODIES
Produces:
1 “good” egg
3
CYTOPLASM DIVIDES UNEVENLY
__________________ = MAKING a MATURE EGG
OOGENESIS
“Self digest”
Using________________
POLAR BODIES DEGENERATE (DIE)
LYSOSOMES
= __________________“cell suicide” for good of organism
APOPTOSIS
top related