Mitosis vs. Meiosis

What’s the Difference?

Mitosis• Asexual reproduction.• Produces offspring without a

mate.• An example:

Meiosis• Sexual reproduction.• Produces offspring with a

mate.• An example:

What Do They Create? Mitosis

• Sex Cells• Sperm• Egg

Meiosis• Somatic Cells• Muscle Cells• Nerve Cells• Bone Cells• Ect..

How Does It Happen?Mitosis• Prophase

• Metaphase• Anaphase• Telophase

Prophase

• DNA condenses• Nucleoli disappear• Nuclear envelope breaks down

Metaphase• Chromosomes line up at

equator.• They must become organized.• Once lined up there are 46

chromosomes total.

Anaphase• Chromosomes split evenly.• Chromosomes move towards

poles.• Each half is identical.

Telophase• REVERSE of prophase!• DNA de-condenses• Nucleoli reappear• Nuclear envelope reforms

Essentially:

Daughter Cell

Daughter Cell

Daughter Cell

Daughter Cell

Parent Cell

What Is Mitosis Used For?

• Growth• Repair• (Occurs in ALL living organisms)

Click HERE to View Mitosis Video!

How Does It Happen?Meiosis

• Halving of chromosome material

• Occurs in sperm and egg

How Does It Start?• Egg cell & Sperm cell• 46 chromosomes each

Sperm Cell 46 Chromosomes

Egg Cell 46Chromosomes

Next …• Each cell divides equally• 48 chromosomes ->

–2 sets of 23 chromosomes

Sperm Cell 46 Chromosomes

Egg Cell 46Chromosomes

23

23

23

23

Completion …• Cells combine• One sperm cell (23

Chromosomes)• One egg cell (23 Chromosomes)• Happens upon fertilization

What Happens If The Process Goes

Wrong?• Trisomy• Monosomy• Both can result in miscarriage

or stillbirth

Trisomy:• Baby receives extra chromosome• 47 chromosomes

Monosomy:• Baby is missing a chromosome• 45 chromosomes

a a b b a a b b

a b a b a b ba

a a b

a a b b b

Sperm Cell

Egg Cell

Error

Trisomy

Monosomy

Recap:Mitosis• Asexual• Produces two daughter cells• 4 stages: prophase, metaphase, anaphase,

telophaseMeiosis• Sexual• Sex cells• Chromosomes

CitesSlide 2: Ktylerconk, “Pocketbook Plant”, April 6, 2009 via FlickrSlide 3: Magbag, “My Parents”, June 30, 2005 via FlickrSlide 10: Clipart from MicrosoftSlide 11: Hybrid Medical Animation. "The Cell Cycle-Mitosis."

YouTube. N.p., 4 Dec. 2008. Web. 5 Oct. 2009. <http:// www.youtube.com/watch?v=Cg4ASxSKH2o>.

Slide 13: Clipart from MicrosoftSlide 14: Clipart from MicrosoftSlide 18: Clipart from Microsoft