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What Are Genes? . . . Units of inheritance that determine hereditary traits.Located on chromosomes.23 pairs of chromosomes.A, C, G, TA-T C-GHuman genome project93% of DNA codes for proteins.7% of human genes are different for every individual.. Genetic Defects. Error during transcription and
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2. Chapter 7 Genes and Disease: Defects, Quirks, and Compromises
3. What Are Genes?
4. Genetic Defects Error during transcription and translation
Chemical damage
Ionizing radiation
5. Genetic Diseases Caused by dominant or recessive traits
Genotype and phenotype
Huntingtons disease
Sickle-cell anemia
Cystic fibrosis
Tay-Sachs disease
Myopia
6. Huntingtons Disease Caused by one dominant gene
Memory loss, muscles stop working
Easily passed on to offspring
Gene found on chromosome 4
7. Sickle-cell Anemia Heterozygous (Aa).
Changes hemoglobin structure which prevents malaria because it quickly removes infected genes.
Homozygous (AA).
Have sickle-cell anemia which causes irregular red blood cells.
Do not have resistance to malaria.
Short lifespan.
Heterozygous advantage.
8. Tay-Sachs Disease Heterozygous protects against tuberculosis
Homozygous individual dies
Heterozygous advantage
9. Myopia Genetic quirk
Causes nearsightedness
Different parts of the eye grow at different times
Eye should stop growing when vision is no longer blurry
Genes cause eye to keep growing
Influenced by environment
10. T-locus Gene Found in mice
2 copies is lethal
1 copy is passed to 90% of offspring
Gene benefits, mouse does not
11. Summary Genes are the building blocks for the body.
Genetic defects cause different diseases.
Recessive advantage.
Sickle-cell anemia.
Tay-sacs disease.
Environmental influence myopia would not occur without genetic defect and environmental influence.
Gene benefits.
Huntingtons disease.
T-locus gene.