MEIOSIS DAY 2

Bellwork

1. Why do kids look similar to, but not identical to their parents?

2. List 2 ways mitosis is different from meiosis.

3. What is the product of meiosis? What is produced

*Be thinking of a compliment for your partner!

Announcements & PurposeReview meiosisUse book to fill in worksheet

Quiz on Meiosis Thursday

Friday: science fair walk through.

ClosureReview/improve closure from yesterday! Period 3/5 read and added to it.

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!

Meiosis Video http://www.youtube.com/watch?v=kVMb4Js99t

A

Finger Meiosis = 2 (chromatid) chromsomes in each cellHold up 1 pointer finger= this is chromosome 1

from your dad. Hold up other pointer finger= this is

chromosome 1 from your mom =homologous chromosomes

Have them replicate (hold up middle fingers too)

Recombination (mingle them together) Meiosis 1: Pull hands apart Meiosis 2: pull fingers apart= 1 chromatid chromosome in each cell

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

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

Make a copy!

Asexual Reproduction…… involves only one parent. It takes

several forms, but does not involve meiosis.

-Budding -Binary fission-Parthenogenesis

Cnemidophorus neomexicanus

Cylindropuntia bigelovii

Saccharomyces cerevisiae

New Organisms are CLONES

Aka Mitosis

But… if you want something new…

Sexual Reproduction Two gamete cells, a sperm and an egg,

unite to form a zygote, the single cell from which the organism develops

MEIOSIS is how gametes (sperm and eggs) are made.

Gametes Are Haploid Gametes (sperm/egg) must have half the

DNA of a normal cell (1 copy) If the DNA in the gametes was not halved,

when they combined the zygote would have more genetic material than the parents

Meiosis is special cell division to make gametes with half the genetic material of the parents

Gametes have exactly one set of chromosomes, this state is called haploid (1n)

Regular cells (somatic cells) have two sets of chromosomes, this state is called diploid (2n)

Sperm(1n)

Fertilization Results In A Diploid Zygote

Egg(1n)

Haploidnucleus

Haploidnucleus

From Zygote to Embryo

Zygote2n

Zygote

2n

CleavageFrom Zygote to Embryo

Cleavage = mitosis, but daughter cells don’t split apartFrom Zygote to Embryo

CleavageFrom Zygote to Embryo

CleavageFrom Zygote to Embryo

Finger Meiosis = 2 (chromatid) chromsomes in each cellHold up 1 pointer finger= this is chromosome 1

from your dad. Hold up other pointer finger= this is

chromosome 1 from your mom =homologous chromosomes

Have them replicate (hold up middle fingers too)

Recombination (mingle them together) Meiosis 1: Pull hands apart Meiosis 2: pull fingers apart= 1 chromatid chromosome in each cell

Crash Course MEIOSIS http://www.youtube.com/watch?

v=qCLmR9-YY7o

P. 116-117 Use book to fill in front side of worksheet

ClosureReview/improve closure from yesterday! Period 3/5 read and added to it.