Mitosis vs. Meiosis

Stand and Say - Mitosis

1) Face your table partner

2) Each will take a turn talking for 30 seconds about what they remember regarding Mitosis (what happens, why does it happen, etc)

3) The listener MAY NOT TALK but should use non-verbal communication to support the “talker”

4) Class discussion

5) Write one question on the post-it you have about cell division and organisms reproduce and grow.

Meiosis

MeiosisMitosis

Based on the diagram,

The difference between mitosis and meiosis is The difference between mitosis and meiosis is thatthat mitosis produces mitosis produces two identical daughter two identical daughter cellscells and and meiosis produces meiosis produces four genetically four genetically

different daughter cellsdifferent daughter cells

Parent cellDiploid (2n)

Daughter cellDiploid (2n)

Daughter cellDiploid (2n)

Parent cellDiploid (2n)

1st divisionDiploid (2n)

1st divisionDiploid (2n)

2nd divisionDaughter cell

Haploid (n)

2nd divisionDaughter cellHaploid (n)

2nd divisionDaughter cell

Haploid (n)

2nd divisionDaughter cell

Haploid (n)

MitosisMitosis MeiosisMeiosis

The numbersThe numbers

• The cells created from The cells created from mitosismitosis are are diploid or 2n.diploid or 2n.

• The cells created from The cells created from meiosismeiosis are are haploid or nhaploid or n

Definitions:Definitions:• Diploid (2n)Diploid (2n) – two of each type of chromosome – two of each type of chromosome

(in homologous pair – carry the same trait)(in homologous pair – carry the same trait)• Haploid (n)Haploid (n) – one of each type of chromosome – one of each type of chromosome

The numbersThe numbers

• Human cells have Human cells have 46 chromosomes46 chromosomes. .

• Therefore, the Therefore, the diploid number (2n)diploid number (2n) of of chromosomes in humans ischromosomes in humans is 46 46..

• The The haploid number (n)haploid number (n) of chromosomes in of chromosomes in humans is humans is 2323..

The reason why: mitosis

• To To replacereplace other cells that have been other cells that have been damaged or worn outdamaged or worn out

• To allow multicellular organisms to To allow multicellular organisms to growgrow

• For For asexual reproductionasexual reproduction

The reason why: meiosis

• Meiosis results in FOUR CELLS with HALF Meiosis results in FOUR CELLS with HALF the number of chromosomes so that the number of chromosomes so that when when the sex cells (sperm and egg) combine, the the sex cells (sperm and egg) combine, the original or normal number of chromosomes original or normal number of chromosomes will be restoredwill be restored

One last thing… [the] where?

• Mitosis occurs in normal body cells (i.e. skin cells), and meiosis occurs in sex cells (i.e. sperm and egg) only.

Videos explanations

Meiosis: Crossing Over and Variability [3D Animation]•https://www.youtube.com/watch?v=rqPMp0U0HOA

Nova•http://www.pbs.org/wgbh/nova/miracle/divi_flash.html

Amoeba Sisters•https://www.youtube.com/watch?v=toWK0fIyFlY