• One parent produces offspring
• Offspring is a clone of parent
• Occurs by mitosis

• Occurs by meiosis
• Genetic variation
• Union of 2 gametes

• Contain all of the heritable information
• Are particular stretches of chromosomes

• Different forms of genes
• Inherit one from mom and one from dad

• Nuclear division that cuts the chromosome number in half
• Germ cells divide into gametes
• Diploid becomes haploid

• Chromosomes coil up
• Nuclear envelop breaks down
• Centrioles form & move to opposite poles
• Spindle fibers form
• Chromosomes pair up - Tetrad
• Crossing Over

Pair of homologous chromosomes that form in prophase I

• Nonsister chromatids of a pair of homologous chromosomes becak and exchange segements of DNA
• Occurs in Prophase I
• Genetic variation
• 2-3 crossovers per chromosome

• Spindle fibers attach to kinetochore
• Chromosomes line up randomy in the middle as pairs
• Genetic variation

• Chromosomes pairs are pulled apart toward opposite poles

• Chromosomes uncoil
• Nuclear envelop forms
• Centrioles break down
• Spindle fibers break down

• 2 cells that are haploid, but the DNA is still duplicated

• Identical to mitosis
• Purpose of this division is to unduplicate the DNA
• End up with 4 haploid cells

• Chromosomes coil up
• Nuclear envelope breaks down
• Centrioles form & move to opposite poles
• Spindle fibers form

• Spindle fibers attach to kinetochore
• Chromosome line up in the middle in a single file line

• Sister chromatids are pulled to opposite poles
• Each chromatide is now called a chromosome

• Chromosomes uncoil
• Nuclear envelop forms
• Centrioles break down
• Spindle fibers break down

• Male gamete unites with female gamete

• Fusion of two haploid gametes

1. Crossing Over in prophase I
2. Pairs line up in metaphase I
3. Which egg and sperm meet to form a zygote

Mitosis produces _____ cells

Meiosis produces _____ cells

2

4

Mitosis takes place in _____ cells

Meiosis takes place in _____ cells

Somatic (body) Cells

Germ Cells

• Mitosis starts out diploid and ends with 2 cells that are _____
• Meiosis start out diploid and ends with 4 cells that are _____

• diploid
• haploid

Mitosis divides _____

Meiosis divides _____

once

twice

Mitosis produces cells that are _______

Meiosis produces cells that are _______

identical (clones)

different (genetic variation)

• In metaphase of mitosis the chromosomes line up ...
• In metaphse I of meiosis the chromosomes line up ...

• single file
• as pairs of homologous chromosomes