MEIOSIS Chapter 13 Slide show modified from Tracy Jackson and Kim Foglia.

MEIOSISChapter 13

http://waynesword.palomar.edu/lmexer2a.htm

Slide show modified from Tracy Jackson and Kim Foglia

Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htmFamily http://babyhearing.org/Parenet2Parent/index.asp

Remember from Chapter 1:CHARACTERISTICS OF LIVING THINGS ALL LIVING THINGS __________

REPRODUCE

ASEXUAL

SEXUAL

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)

Offspring are genetically different from parents

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 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


DIPLOID & HAPLOIDMost cells have 2 copies of each

chromosome = ______________(one from mom; one from dad)

All BODY (___________) cells are diploid

DIPLOID 2n

HOMOLOGOUSCHROMOSOMES

= SOMATIC

Chromosomes that determine the sex of an organism = _________________

All other chromosomes = _________________

Sex chromosomes

autosomes

Humans have two sex chromosomes

and _____ autosomes

X y44

http://www.angelbabygifts.com/

A __________ is a picture of an organism’s chromosomes

KARYOTYPE

DIPLOID & HAPLOID

Some cells have only one copy of each chromosome = _____________

All sperm and egg cells are haploid

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


2identical

2n

SOMATIC (body)

MEIOSIS•Makes ____ cells

genetically different from parent cell & from each other

•Makes _____ cells•Makes ______________

•Used for ____________

4

1n

Germ cellsOR Gametes (sperm & eggs)

sexual reproduction


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

WHAT MAKES MEIOSIS DIFFERENT?

1. 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

Places where crossing over happens= ____________________CHIASMATA

HOMOLOGOUS CHROMOSOMES

Image 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

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

SEGREGATION(Anaphase I)

SEGREGATION & CROSSING OVERtogether make even more

combinations

See ananimation


http://www.biostudio.com/d_%20Meiotic%20Recombination%20Between%20Unlinked%20Genes.htm

http://www.biostudio.com/d_%20Meiotic%20Recombination%20Between%20Unlinked%20Genes.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

GENETIC RECOMBINATIONcomes from:

• Crossing over • Segregation • Independent assortment

• Random fertilization

Section 11-4

Figure 11-15 Meiosis

Meiosis I

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 MEIOSISINTERPHASE INTERPHASE I

• DNA is spread out as chromatin• Nuclear membrane/

nucleolus visible• DNA is copied during S phase• Makes stuff new cell needs in G2

SAME AS MITOSIS

http://www.pbs.org/wgbh/nova/baby/divi_flash.html

http://www.biostudio.com/d_%20Mitosis.htm

http://www.biostudio.com/d_%20Meiosis.htm

MITOSIS vs MEIOSIS PROPHASE PROPHASE I

DNA scrunches into chromosomes

Nuclear membrane/ nucleolus disappearCentrioles/

spindle fibers appear

DNA scrunches into chromosomesNuclear membrane/ nucleolus disappear Centrioles/ spindle fibers appear Homologous pairs match up


MITOSIS vs MEIOSIS METAPHASE METAPHASE I

• Chromosomes line up in middle

Chromosomes line up in middle


with homologous partner

MITOSIS vs MEIOSIS ANAPHASE ANAPHASE I

APART:Chromatids split

APART:


Chromatids stay togetherHomologous pairs split

MITOSIS vs MEIOSIS TELOPHASE TELOPHASE I

See TWO nucleiNuclear membrane/ nucleolus returnDNA spreads out as chromatinSpindle/centrioles disappear

SAME AS MITOSIS


MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS I

Cytoplasm splits

into 2 cells

SAME AS MITOSIS


MITOSIS vs MEIOSIS INTERPHASE II

• DNA is spread out as chromatin• Nuclear membrane/

nucleolus visible• DNA is copied during S phase

SKIP INTERPHASE IIDNA NOT COPIED


MITOSIS vs MEIOSIS PROPHASE PROPHASE II

• DNA scrunches into chromosomes

• Nuclear membrane/nucleolus disappear

• Centrioles/ spindle fibers appear

SAME AS MITOSIS


MITOSIS vs MEIOSIS METAPHASE METAPHASE II

• Chromosomes line up in middle SAME AS MITOSIS


MITOSIS vs MEIOSIS ANAPHASE ANAPHASE II

Chromatids split and move apart

SAME AS MITOSIS


MITOSIS vs MEIOSIS TELOPHASE TELOPHASE II

Two nucleiNuclear membrane/

nucleolus returnsCentrioles/spindle fibers

disappearDNA spreads out as chromatin

SAME AS MITOSIS


MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS II

Cytoplasm splits SAME AS MITOSIS




Ways Meiosis is different?• Homologous pairs match up & trade DNA

(SYNAPSIS & CROSSING OVER) in PROPHASE I

•SEGREGATION

& INDEPENDENT ASSORTMENT in Anaphase I

create genetic recombination• Skipping INTERPHASE II- (Dividing TWICE but copying DNA once)

produces 1n cells

MAKING SPERM & EGGS

Gametogenesis =

process of forming gametes (n) from diploid (2n) cells

Spermatogenesis = process of forming sperm cells by meiosis in animals, by mitosis in plants in specialized organs

After division all 4 cells undergo differentiation to become sperm cells

___________________= MAKING MATURE SPERM

Mature & grow flagella

SPERMATOGENESIS

Sperm provides DNA

All the starting nutrients, organelles, molecule building blocks, etc. have to come from the egg.

http://www.moondragon.org/obgyn/pregnancy/twins.html

POLAR BODIES

Produces: 1 “good” egg

3

CYTOPLASM DIVIDES UNEVENLY

__________________ = MAKING a MATURE EGG

OOGENESIS

http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/Animal%20Reproduction/animal.htm

“Self digest”

Using ________________

POLAR BODIES DEGENERATE (DIE)

LYSOSOMES

= __________________ “cell suicide” for good of organism

APOPTOSIS

http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/Animal%20Reproduction/animal.htm

Oogenesis = process of forming an ovum (egg) by meiosis in animals by mitosis in the gametophyte in plants in specialized gonads known as ovaries.

Unlike spermatogenesis, cytoplasm divides unevenly so that all cytoplasm/organelles go to 1 large egg.

3 other cells = polar bodies; do not develop. Thus, all the cytoplasm and organelles go into the egg.

Human males produce 200,000,000 sperm per day, while the female produces one egg (usually) each menstrual cycle.

Life Cycles

• A life cycle is the generation-to-generation sequence of stages in the reproductive history of an organism, from conception to production of its own offspring.

ALTERNATION OF GENERATIONS

IN PLANTS AND SOME ALGAE:____________ = multicellular diploid stage in which meiosismakes haploid cells called _________

Spores give rise to a multicellular HAPLOID organism = ________________without fusing with another cell

SPORES

GAMETOPHYTE

SPOROPHYTE

Image from Biology Campbell and Reece

IN FUNGI and SOME PROTISTS:Gametes fuse to make a diploid zygote

Meiosis occurs in zygote withoutgrowing into a diploid organism

Meiosis makeshaploid cells thatgrow into haploidorganisms which useMITOSIS to makeGAMETES!

Image from Biology Campbell and Reece

Meiosis AnimationsFrame-by-frame animation• http://www.csuchico.edu/~jbell/Biol207/animations

/meiosis.html

Continuous animation – no words• http://www.people.virginia.edu/~rjh9u/meioanim.ht

ml

Continuous frame-by-frame• http://www.trentu.ca/biology/101/14.html

http://www.csuchico.edu/~jbell/Biol207/animations/meiosis.html

http://www.csuchico.edu/~jbell/Biol207/animations/meiosis.html

http://www.people.virginia.edu/~rjh9u/meioanim.html

http://www.people.virginia.edu/~rjh9u/meioanim.html

http://www.trentu.ca/biology/101/14.html

MEIOSIS Chapter 13 Slide show modified from Tracy Jackson and Kim Foglia.

Documents