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

When: can mutations occur Caused by errors during: Replication, transcription, cell division, or by external factors Where: can mutations occur Germ-cell mutation – occurs in a gamete Somatic mutation – occurs in a body cell Who: can mutations affect Germ-cell  Does not affect the individual but may be passed on to offspring Somatic  Will affect the individual but are not passed on to offspring

What: is mutated Gene Chromosome Silent Mutations Have no effect on phenotype Lethal Mutations Cause death, often before birth

Point mutation – substitutes, adds or deletes a single nucleotide Gene Mutations Point mutation – substitutes, adds or deletes a single nucleotide Generally mutations that affect a single gene happen during replication mutated base

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

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 Orig: ATAGCTA Inv: ATCGATA Translocation – chromosome piece breaks off and reattaches to another non-homologous chromosome

4. Nondisjunction – failure of homologous chromosomes to separate properly during meiosis Two possible outcomes: Trisomy - Three copies of chromosome One gamete has two copies Zygote = 3 copies of chromosome 2. Monosomy - One copy of chromosome One gamete has no copies Zygote - 1 copy of chromosome

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

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

Ex: Autosomal  Hh Sex-linked  XHXh 7.4 Human Genetics and 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

7.4 Human Genetics and Pedigrees

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

Detecting Human Genetic Disorders 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

Chorionic villi sampling 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

5.3 Regulation of Cell Cycle Cancer Tumor – abnormal group of cells that result from uncontrolled cell division Growth factors – proteins that bind to cells and stimulate cell division

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 cancer cell bloodstream normal cell

Kinds of Cancer – based on types of tissue that affect 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

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

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

Oncogenes – gene that causes cancer 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

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

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)

How do Cancer cells behave differently from Healthy ones http://www.youtube.com/watch?v=BmFEoCFDi-w&list=PLJicmE8fK0Ehrg3meytY7DT8LJiwuU3Th&index=92