Meiosis

VOCAB THAT MUST BE KNOWN

Ploidy:1n, Haploid2n, DiploidChromatidHomologous chromsomesTetrad

Crossing Over

9. Meiosis10.Sexual

Reproduction11. Asexual

Reproduction12.Chromatid13.Chromosome14.Genetic

Recombination15.Fertilization16. Independent

Assortment

Write Down…

ALL THE Key Terms!

1. Prophase I2. Metaphase I3. Anaphase I4. Telophase I5. Prophase II6. Metaphase II7. Anaphase II8. Telophase II

17.Ploidy18.Haploid (n)19.Diploid (2n)20.Tetrad21.Homologous

Pair22.Crossing Over23.Somatic Cell24.Germ Cell25.Gamete26.Zygote

nb - You have to actually define them to get credit at the end of the unit

BellworkObj: Describe the process of meiosis

1. What are the 4 stages of mitosis?2. Is interphase a part of mitosis?

Explain.3. What is the purpose of mitosis?4. What is the difference between

sexual reproduction and asexual reproduction? Give an example of a species for each.

5. Which type of reproduction would be more advantageous in nature and why? Explain in 1-2 complete sentences.

On science fair boards:

Each of the nucleus of your cells contains all this:

Special cells in your body only have ½ this amount.

Where?Why?

Long red: mother/chromosome 1Short red:Mother/chromosome 2

Long blue: father/chromosome 1Short blue: father/chromosome 2

Each gamete has:1 MIXED copy of chromosome ONE1 MIXED copy of chromosome TWO

Each somatic cell has:2 copies of chromosome ONE -1 from mom, 1 from dad2 copies of chromosome TWO -1 from mom, 1 from dad

How to create a gamete: MeiosisOr ‘How to create an egg or a sperm’

Make a copy!

• the diploid somatic cells of an individual contain one copy of the chromosome set from the sperm and one copy of the chromosome set from the egg; that is, the cells of the offspring have genes expressing characteristics of both the father and the mother.

• A gamete (from Ancient Greek γαμετή gamete "wife"[1]) is a cell that fuses with another cell during fertilization (conception) in organisms that reproduce sexually.

• A gamete's chromosomes are not exact duplicates of either of the sets of chromosomes carried in the dfs chromosomes.

CROSSING OVER

GAMETES 23=NHAPLOID

SOMATIC 46=2NDIPLOID MITOSISMEIOSIS

Long red: mother/chromosome 1Short red:Mother/chromosome 2

Long blue: father/chromosome 1Short blue: father/chromosome 2

Each gamete has:1 MIXED copy of chromosome ONE1 MIXED copy of chromosome TWO

Each somatic cell has:2 copies of chromosome ONE -1 from mom, 1 from dad2 copies of chromosome TWO -1 from mom, 1 from dad

How to create a gamete: MeiosisOr ‘How to create an egg or a sperm’

Make a copy!

Mitosis vs Meiosis

Mitosis Body cell division (cloning)Mitosis makes “my toes-es”

MeiosisMaking sex cells (halving)Meiosis makes “my OH…baby!”

Meiosis

• _________________ is the process that ___________________ cells undergo when a single cell ____________ to make ___ unique ________________ daughter cells

Meiosis

Somatic (diploid)

divides 4haploid

Meiosis

Explain to your partner 1. How many original cells were there?2. How many cells did it divide into?3. Were all these new cells the same?4. What do we call the new cells?

How do Organisms Reproduce?

Organisms either reproduce sexually or asexually.

• Meiosis only occurs in ____________________speciesSexually reproducing

Asexual reproduction

Asexual reproduction involves formation of a new individual from cells of the parent, without meiosis, gamete formation, or fertilization.

Question????• So, why, if an animal is reproducing

asexually, does meiosis NOT occur?

Asexual reproduction involves formation of a new individual from cells of the parent, without meiosis, gamete formation, or fertilization.

Sexual Reproduction

In sexual reproduction the ______________________ of one parent are _______________ with that of the other parent to produce a __________________ _________________ offspring.

chromosomescombined

geneticallyunique

Meiosis Video

• http://www.youtube.com/watch?v=kVMb4Js99tA

Fill in the diagram as we goMeiosis I Meiosis II

Prophase I

__________ form and ___________ _______ occurs!

Tetrads

crossingover

Tetrads & Crossing Over

Tetrads- ______ association of sister chromatids of _________________________ (4)

close

homologous chromosomes

Crossing Over:Homologous chromosomes _________ small pieces, resulting in ____ chromosomes!

exchange

NEW

Tet Cr-O

1. What are ‘sister chromatids’– Why did we keep them together in mitosis?

2. What are ‘homologous’ chromosomes?-Genes for eye color and height are both on chromosome 11 for humans.

Metaphase I

Anaphase I

_____________ _____________ occurs creating _____combinations!

Independent Assortmentnew

Independent Assortment

Chromosomes from the _____ & _____ _________ move to one side or the other

momdad randomly

Telophase I

(Cytokinesis)

Long red: mother/chromosome 1Short red:Mother/chromosome 2

Long blue: father/chromosome 1Short blue: father/chromosome 2

Each gamete has:1 MIXED copy of chromosome ONE1 MIXED copy of chromosome TWO

Each somatic cell has:2 copies of chromosome ONE -1 from mom, 1 from dad2 copies of chromosome TWO -1 from mom, 1 from dad

How to create a gamete: MeiosisOr ‘How to create an egg or a sperm’

Make a copy!

Prophase II

Metaphase II

Anaphase II

Telophase II

(Cytokinesis)

Summary of ways Meiosis is different from Mitosis

• Involves _________________________________________2 consecutive cell divisions

Summary of ways Meiosis is different from Mitosis

• Ends with ___ cells that are all _______________ (sex cells: _______& ____)

4 haploidsperm egg

Summary of ways Meiosis is different from Mitosis

• Makes _____ _________________ combinations through ___________ ______ and _____________ __________

NEW geneticcrossing over

independent assortment

Meiosis Card Sort

Order the 11 cards to show the progress from a single cell in interphase and progressing to 4 haploid sex cells

Funny Meiosis Video

• http://www.youtube.com/watch?v=iCL6d0OwKt8

Slate Quiz!

• Look at the pictures on the following slides & name the stage of meiosis!

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