This lesson will increase your knowledge of concepts covered in the following TEKS for biology:

This lesson will increase your knowledge of concepts covered in the following TEKS for biology: 3.c – Evaluate impact of research on scientific thought, society, and the environment 3.e – Evaluate models according to their adequacy in representing biological objects or events 3.f – Research and describe the history of biology and contribution of scientists 5.a – Compare cells from different parts of the plant and animal 5.b – Identify cell differentiation in the development of organisms 10.a – Interpret the functions of systems in organisms 10.b – Compare the interrelationships of organ systems to each other and to the body as a whole

Previous LessonProstate Cancer

QUESTION: A vasectomy involves cutting pieces out of both vas deferens. Why does a vasectomy result in sterility? Based on: Farish, D. Human Biology, Jones and Bartlett

A vasectomy prevents movement of sperm through the vas deferens to urethra

QUESTION: LH-RH blockers are used to treat prostate cancer. How would this treatment control prostate cancer?

Blocking LH and RH prevents the testes from receiving the messages to make testosterone Male Hormones Based on: Mader, S. Inquiry Into Life, McGraw-Hill

QUESTION: What are the advantages and disadvantages of PSA tests for older men?

Advantage of PSA test Stages of Prostate Cancer PSA + needle biopsy detects cancer when only a few cells are present so treatments are more successful Based on: Mayo Clinic Health Letter, April 1985

May detect tiny slow growing prostate cancers that would not affect the health of men over 80 causing needless worry and treatment Disadvantage of PSA test

Today’s LessonHuman Development and Stem Cells

Overview of Lesson • Life cycle and development of humans • Miracle of Life video • Infertility and in vitro fertilization • Stem cells

Life Cycle of Humans Fig. 5.15 Based on: Mader, S. Inquiry Into Life, McGraw-Hill

Human Development Involves • Addition of more cells through mitosis • Creation of adult cells with special functions through cell differentiation, creating about 210 different tissues in the body

Mitosis of Body Cells • Prior to mitosis, replication of all 46 chromosomes forming 46 replicated chromosomes • Chromosome before replication • Replicated chromosome with two sister chromatids • Splitting of replicated chromosomes • Formation of two daughter cells with 46 chromosomes like the original cell

Mitosis of Body Cells Based on: Mader, S. Inquiry Into Life, McGraw-Hill

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

Human Development To Implantation Based on: Mader, S. Inquiry Into Life, McGraw-Hill

Cell Differentiation • DNA directs changes in cells from a general cell type (embryonic stem cells) to specialized cell types in the adult • Until recently, scientists thought that once cells became specialized in the adult, the DNA could not be reprogrammed back to its undifferentiated state Based on: Scientific American, June 2004

Example of Adult Cell with Specialized Function Nerve Cells Based on: Mader, S. Inquiry Into Life, McGraw-Hill

Example of Adult Cell with Specialized Function Muscle Cell Based on: Mader, S. Inquiry Into Life, McGraw-Hill

Excerpt from The Miracle of Life Nova

Infertility In Women • Hormone imbalance • Blocked fallopian tube • Ovarian cysts • Endometriosis • Uterine cysts

Infertility In Men • Low sperm count • Weak sperm • Impotence • Hormone imbalance • Medication side effects

In Vitro Fertilization (Test Tube Baby) • Hormones given to woman to stimulate eggs • Eggs harvested from ovary • Eggs fertilized with man’s sperm in glass container • Embryos allowed to develop for a few days • Embryos implanted in uterus and allowed to develop for 9 months • Extra embryos are frozen for later attempts if first attempt fails

Louise Brown, the first “test-tube baby” From Time, December 1, 1997

Dr. James Thomson University 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 Click on URL below to upload cover of TIME TIME Magazine Cover: Scientist James Thomson - Aug. 20, 2001

Source of Stem Cells Based on: Scientific American, June 2004

Potential of Stem Cell Research Based on: Time, July 23, 2001

Against Funding Research From: Time, July 23, 2001 For Funding Research From: Time, July 23, 2001

Fate of Stem Cell Research Funding? From: Time, July 23, 2001 • 2000 President Clinton stated only embryos from fertility clinics and in excess could be used for research • 2001 President Bush banned federal funds for stem cell research except on stem cell lines already cultured in labs- 78 lines • 2003 European Parliament voted in Brussels to support funding of stem cell research

Fate of Original 78 Stem Cell Lines • 1 still under development • 1 donor consent withdrawn • 7 duplicates of other cultures • 16 died after being thawed • 31 are at overseas labs unavailable to U.S. • 21 viable stem cell lines remain in U.S.- aging, limited in genetic diversity, hinderance Time 2006 http://www.time.com/time/magazine/article/0,9171,1220538-2,00.html

Why a fight over federal funding? • Federal funding drives the speed of research progress • Without federal funding, the U.S. could slip behind in the biotechnology race

What are the sources? Based on: Mader, S. Inquiry Into Life, McGraw-Hill • Embryonic stem cells • Adult stem cells • Nuclear-transfer embryos • Umbilical-cord blood and placental cells

Next Lesson DNA and the Human Genome Project

This lesson will increase your knowledge of concepts covered in the following TEKS for biology: