KEY CONCEPT Mutations are changes in DNA that may or may not affect phenotype.

1. KEY CONCEPT Mutations are changes in DNA that may or may not affect phenotype.

2. Mutations Caused by errors in • Replication, transcription, cell division, or by external factors Germ-cell mutation – occurs in a gamete • Does not affect the individual but may be passed on to offspring Somatic mutation – occurs in a body cell • Will affect the individual but are not passed on to offspring

3. Lethal Mutations • Cause death, often before birth

4. mutated base Gene Mutations • point mutation – substitutes, adds or deletes a single nucleotide

5. Gene Mutations 2. Frame Shift Mutation • Deletion & addition point mutation cause the remaining codons to be incorrectly grouped

7. Chromosome Mutations • Deletion – loss of a piece of a chromosome due to chromosomal breakage • Inversion – chromosomal segment breaks off and then reattaches in reverse order to the same chromosome • Translocation – chromosome piece breaks off and reattaches to another non-homologous chromosome

9. 4. Nondisjunction – failure of homologous chromosomes to separate properly during meiosisTwo possible outcomes: • One gamete - an extra chromosome • when fertilized - 3 copies of chromosome • trisomy 2. One gamete - one less chromosome • when fertilized - 1 copy of chromosome • monosomy

10. 7.4 Human Genetics and Pedigrees KEY CONCEPT A combination of methods is used to study human genetics.

11. 7.4 Human Genetics and Pedigrees Pedigree – family record that shows how a trait is inherited over several generations

12. 7.4 Human Genetics and Pedigrees Pedigrees Circles  Girls Squares  Boys Carrier – individual with one copy of a recessive allele • Usually do not express the trait but can pass it along to offspring • ½ colored in • Ex: Autosomal  Hh Sex-linked  XHXh

13. 7.4 Human Genetics and Pedigrees

14. 7.4 Human Genetics and Pedigrees • Karyotypes can show changes in chromosomes. • deletion of part of a chromosome or loss of a chromosome • Some translocation changes in chromosomes • extra chromosomes or duplication of part of a chromosome

15. 7.4 Human Genetics and Pedigrees Detecting Human Genetic Disorders • Genetic screening – examination of a person’s genetic makeup • Genetic counseling – medical guidance that informs about possible problems that could affect their offspring Prenatal testing • Amniocentesis – removes a small amount of amniotic fluid between the 14th and 16th week of pregnancy

16. 7.4 Human Genetics and Pedigrees Chorionic villi sampling • physician obtains a sample of the chorionic villi • tissue that grows between the mothers uterus and the placenta, between the 8th and 10th week of pregnancy

17. 5.3 Regulation of Cell Cycle Cancer Tumor – abnormal group of cells that result from uncontrolled, abnormal cell division

18. normal cell cancer cell bloodstream 5.3 Regulation of Cell Cycle • Benign - tumors remain clustered and can be removed. • Malignant - uncontrolled dividing cells invade and destroy healthy tissues elsewhere in the body • Metastasize - spread of cancer cells beyond their original site

19. 5.3 Regulation of Cell Cycle Kinds of Cancer – based on types of tissue that affect • Carcinomas – grow in the skin and tissues that line organs. Ex: lung cancer & breast cancer • Sarcomas – grow in bone and muscle tissue • Lymphomas – solid tumors that grow in the tissues that form blood cells • Leukemia – tumors that form in blood-forming tissue – over production of white blood cells

20. 5.3 Regulation of Cell Cycle Causes of Cancer • Carcinogen – substance that increases the risk of developing cancer Ex: tobacco, asbestos, X-rays, or UV rays from sun • Mutagen – cause mutations to occur within a cell that leads to cancer

21. 5.3 Regulation of Cell Cycle • Standard cancer treatments typically kill both cancerous and healthy cells.

22. 5.3 Regulation of Cell Cycle Oncogenes – gene that causes cancer • Proto-oncogene – normal gene that control cell’s growth. When mutated  oncogene • Tumor-suppressor gene – code for proteins to prevent uncontrolled cell division. When mutated  cancer

23. 5.3 Regulation of Cell Cycle Viruses & Cancer • Viruses can stimulate uncontrolled cell division • Cause mutations in proto-oncogenes & tumor suppressor genes

24. 5.3 Regulation of Cell Cycle Cancer Prevention • Diet high in fiber and low in fat • Fruits & vegetables are high in fiber • Vitamins & minerals: carotenoids, vitamins A, C, and E, and calcium • Daily exercise • And lowering exposure to carcinogens (tobacco, UV rays)

25. 5.3 Regulation of Cell Cycle Extra Credit: • Millions of dollars are spent each year on cancer research. • Contact an oncologist in a cancer treatment center. • Conduct an interview, prepare a paper, and create a visual to show the new treatments that have been developed in the past 10 years