Meiosis

Meiosis: formation of gametes, division of the sex cell (egg and sperm)

Based on: Mader, S., Inquiry Into Life, McGraw-Hill

Cell Division – Gametes

Meiosis 2 divisions Create genetically unique cells Crossing over

http://www.sumanasinc.com/webcontent/animations/content/meiosis.html

The two brothers The two brothers represent 2 out of represent 2 out of more than 10more than 101414 (100 000 000 000 000) (100 000 000 000 000) possible children that possible children that a couple could a couple could conceiveconceive

They are genetically They are genetically programmed to be programmed to be differentdifferent

Dr. James ThomsonUniversity of Wisconsin

•in 1998, collected stem cells from surplus embryos created at fertility clinics

•stopped stem cells from differentiating

•kept them alive and reproducing indefinitely

Female Organs

Egg stimulated by hormones in the ovary

Egg leaves ovary and travels down the oviduct (fallopian tubes)

Into the uterus Out of the body

The Egg’s Journey

Tubes in the testes make sperm Stored until needed Vas deferens – takes sperm to urethra Urethra – takes sperm out of body

All cell parts disappear except mitochondria

Out of the body

A Sperm’s Journey

Fertilization Fertilization actually occurs in the

oviduct Fertilized egg then travels the uterus

and attaches to the uterine wall

Based on: Mader, S. Based on: Mader, S. Inquiry Into LifeInquiry Into Life, Wm. C. Brown, Publishers, Wm. C. Brown, Publishers

In Vitro Fertilization