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CHAPTER 5-3

CHAPTER 5-3. HUMAN GENETICS. The Human Genetic Makeup. Humans have: 23 pairs of chromosomes (46 individual chromosomes) 22 pairs of autosomes - 1 pair of sex chromosomes (X and Y). Mutations From Ch. 4-3. Any permanent change in a gene or chromosome is a mutation

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CHAPTER 5-3

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  1. CHAPTER 5-3 HUMAN GENETICS

  2. The Human Genetic Makeup • Humans have: • 23 pairs of chromosomes (46 individual chromosomes) • 22 pairs of autosomes • - 1 pair of sex chromosomes (X and Y)

  3. MutationsFrom Ch. 4-3 • Any permanent change in a gene or chromosome is a mutation • If the gene is changed, the trait may be changed. • These mutations may occur during: • DNA Replication • mRNA Transcription • tRNA Translation • This may result in incorrect protein production. • Sometimes a cell (zygote) may receive an extra chromosome.

  4. Down’s Syndromeaka Triplody 21

  5. Mutations cont. C. Mutation may be caused by: 1. Radiation 2. Ultraviolet rays 3. Chemicals a) Herbicides b) Insecticides c) Drugs d) Smoking e) Alcohol

  6. Mutations cont. D. Mutations in body cells may or may not be dangerous. 1. Cancer is the big exception E. Mutations in sex cells may affect any potential offspring. F. Many organisms with mutations do not survive to birth. G. Some mutations are good and may add variety to a species.

  7. HUMAN GENETICS Recessive Genetic Disorders A. Sickle-Cell Anemia 1. A homozygous recessive disorder 2. Red blood cells are sickle-shaped rather than disc-shaped. a) Creates problems with oxygen delivery b) Other tissues may be damaged due to lack of oxygen. 3. Found in tropical areas and African American populations. 4.Can be treated with drugs and transfusions http://sports.espn.go.com/broadband/video/videopage?videoId=3669128

  8. B. Cystic Fibrosis 1. A homozygous recessive disorder 2. An error of 3 base pairs on chromosome 7 3.Thick mucus is produced in the lungs and digestive system. a) Causes damage to lungs leading to breathing problems b) Causes damage to the pancreas leading to a reduction in digestive enzyme production 4. Common in Caucasians ,1 in 20 are carriers, Four babies are born with CF every day. 5. Treated with antibiotics, diet, and physical therapy

  9. Icf I Icf Icf Icf I Icf I II I Icf I = Autosome I Icf = Carrier for Cystic Fibrosis (does not have CF) Icf Icf = Has Cystic Fibrosis II = Healthy, Is not a carrier

  10. Sex Determination X Y X XX XY X XX XY 50% XX (female) 50% XY (male)

  11. Sex (X) – Linked Disorders • Color Blindness and Hemophilia X Xc X XX XcX Y XY XcY XX Not color-blind XY Not color-blind XcX Not color-blind but is a carrier XcY is color-blind WHY???????

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