We’re Comparing Mitosis from Chapter 8 to Meiosis from Chapter 10

FROM MOM

FROM DAD

** Mitosis is asexual reproduction & occurs ONLY in regular old body cells called SOMATIC CELLS (skin, nails, your pancreas, etc..) NOT sperm and eggs

** These cells contain autosomal chromosomes that are non-sex chromosomes

** 22 from Mom autosomal chromosomes from mom and 22 from dad

Diploid (2n) number of chromosomes you have 44 or 22 pair of autosomal chromosomes (2n=44)

**Haploid means 1 (n). You receive a haploid number of chromosomes from mom and a haploid number from Dad that makes YOU diploid!! (

**46 in all; 22 autosomal, an X from mom and an X or Y from dad

**SO there are half as many chromosomes in gametes (sperm and eggs)

Replicates

Same types if genes on each chromosome, just different variations from each parent

Required for Sexual Reproduction

**Diploid to haploid cells

**Genetic Recombination Occurs

**Results in 4 NON-IDENTICAL haploid (n) cells

Either sperm or egg

**Produces gametes in the ovaries (females) and testes (male)

Similar to Mitosis but there are two sets of phases and the end result are haploid cells (gametes)

From Dad From Mom

They Replicate Prior to Meiosis to form a tedtrad………

A Tetrad of Homologous Chromosomes

Four Haploid gametes are produced!!

Look On Page 264 #1-4

**Meiosis II Prophase II, Metaphase II, Anaphase II, Telophase II and cytokinesis

**4 cells, the gametes!!

**Meiosis I Prophase I, Metaphase I, Anaphase I, telophase I and cytokenisis.

**2 cells

**After interphase (DNA replication phase)

**independent segregation of homologous chromosomes

** A reassortment of chromosomes and genetic information they carry

**crossing over between non-sister chromatids during Prophase 1

**Non-sister chromatids exchange

genetic information

**Pink is from your mom, blue

from your dad

**Nondisjunction BOTH chromosomes of a homologous pair (tetrad) fail to separate and move to the same pole of the cell.

**Occur in all living organisms, but they are especially common in plants.

**Few harmful gene mutations are passed on to the next generation because the zygote usually dies. If it lives, the offspring may have birth defects.

Deletion

A B C D E F G H A B C E F G H

**When part of a chromatid breaks off and attaches to its sister chromatid

Insertion

A B C D E F G H A B C B C D E F G H

**When part of a chromosome breaks off and reattaches backwards onto the same chromosome

Inversion

A B C D E F G H A D C B E F G H

**When part of one chromosome breaks off and is added to a different chromosome, a translocation occurs.

A B E FDCBX AWC HGGE HD F

W X Y Z Y Z

Translocation

**Cut them out and paste them in the correct order !!!

Mitosis•Occurs in 1 stage

• It is Asexual Reproduction

• Produces “clones” with no genetic variability

• Occurs in body cells (autosomal) and creates two diploid cells

• 2n=46 22 pair of autosomal chromosomes and 1 pair sex chromosomes

Meiosis •Occurs in 2 stages

• For Sexual Reproduction

• Produces genetically variability due to recombination

• Occurs in sex cells called gametes or germ cells and four haploid cells (sperm and egg)

• n=23 22 autosomal chromosomes and 1 sex chromosome

•Forms a tetrad

MitosisMeiosis