Ch 21 & 19 Gene Mutations Cancer

Objectives Describe how mutations may affect traits. Cite examples of mutagens. Present a position on mutations, genetic technology, and bioethics

Mutagens- cause mutation in the base sequence of DNA Radiation UV rays X rays Gamma rays Chemicals Tobacco n-nitrosonornicotine mixed with alcohol Vinyl chloride Benzoapyrene Benzene Asbestos Radon

Mutagens Viruses Hepapitis B and C (liver cancer) Epstein-Barr Human papillomavirus Retroviruses which are RNA that use the human body to change the DNA Kaposi’s sarcoma- suppresses the immune system HTLV-1 hairy cell leukemia

Ames test Determines if a substance is a mutagen

Loss of function Mutations Are changes in the nitrogen base of a DNA molecule that stop a function. Cyclin is a protein that sends the cell into mitosis. If it is mutated the cell will go repeatedly into mitosis. Proto-oncogenes make proteins that prevent apoptosis. They accelerate the cell cycle and turn on the production of Cyclin. Tumor suppressor genes make proteins that stop the cell cycle and cause apoptosis. P53 activates repair enzymes or stops cell cycle. One proto-oncogene shuts down p53. Many tumors lack p53.

Bax Protein that promotes apoptosis. Has 8 consecutive G bases.

Cancer types Carcinoma- epithelial tissues Adenocarcinoma- skin, breast, ovary, cervix, liver, pancreas, intestines, lung, prostate, thyroid. Sarcoma- muscle and connective tissue Leukemia- blood Lymphoma- lymph

Cancer is not yet cured 1st cancer gene discovered in 1990. Breast cancer 1 (BRCA1) BRCA2 are tumor suppressor genes. Mutation in both genes (one from each parent) produce cancer. RB gene is a tumor suppressor gene. Found from eye cancer retinoblastoma.

Skin cancer test

Telomerase gene Enzyme that keeps genes a constant length. When turned off, this gene produces cancer cells.

HeLa cells Henrietta Lacks, woman had 5 children, had vaginal bleeding in 1951. Doctors found a quarter size tumor on her cervix. Samples of the tumor were sent to Johns Hopkins University. She died after 8 months. Her cells were still living and multiplying in the lab of Johns Hopkins. Jonas Salk used these cells to make a vaccine for polio. 1974 her cells were still multiplying.

Mutations Deletions Additions Substitutions Inversions

Sickle cell anemia Deletion of one base in the hemoglobin gene

Videos https://www.youtube.com/watch?v=LOX_59RSF68 https://www.youtube.com/watch?v=MOtRqBs0jxE