EOC Review

1. EOC Review Genetics

2. Finding an Amino Acid Practice • What amino acid is coded for by ACG? • Thr • What amino acid is coded for by UUC? • Phe • What amino acid is coded for by CAC? • His

3. Meiosis

4. Mendel’s Law of Segregation • The principles that govern heredity were discovered by a monk named Gregor Mendel in the 1860's. One of these principles, now called Mendel's law of segregation, states that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization.

5. Mendel’s Law of Independent Assortment • The principles that govern heredity were discovered by a monk named Gregor Mendel in the 1860's. One of these principles, now called Mendel's law of independent assortment, states that allele pairs separate independently during the formation of gametes. This means that traits are transmitted to offspring independently of one another.

6. Vocabulary • Genotype: AA, Aa, aa • Phenotype: tall, short, red, white • Dominant allele: hides the recessive. A • Recessive allele: must have 2 to show. aa • Codominant allele: both alleles are dominant, so both appear. RR, RR’, R’R’ (red, roan, white) OR RR, RW, WW • Incompletely dominant allele: dominant doesn’t completely hide recessive, so you get a mix. Rr = pink, not red • Homozygous: 2 of the same alleles. AA or aa • Heterozygous: both alleles are different. Aa • Carrier: Person doesn’t have the recessive trait but can pass it on. In autosomal inheritance, both parents can be carriers (Aa). In sex-linked inheritance, only the female can be a carrier (XAXa). If the trait is dominant, then carriers can’t exist, because the trait will be expressed.

7. Sex-Linked Genes • Connected to the X chromosome • Males: XY, so 50% chance of inheriting a dominant allele (XAY) and 50% chance of inheriting a recessive allele (XaY) • Females: XX, so 25% chance of being normal (XAXA), 50% chance of being a carrier (XAXa), and 25% chance of inheriting a recessive trait (XaXa)

8. Pedigree Rules • Box = male; circle = female • Line connecting male and female = marriage • Line coming down from a marriage line and branching = children • Colored in box/circle = person has the trait • Half colored in box/circle = carrier

10. Mode of Inheritance • Sickle cell anemia – autosomal recessive (aa) disorder. Both parents must either have sickle cell anemia or be carriers for the child to get the disorder. • Down syndrome – aka Trisomy 21. Abnormal cell division causes it, so the child ends up with three copies of chromosome #21 (two from one parent and one from the other), resulting in a total of 47 chromosomes rather than the normal 46. • Turner’s syndrome – XO syndrome. Caused by nondisjunction – a pair of sex chromosomes fails to separate during meiosis. When egg and sperm unite, the embryo may end up missing one of its sex chromosomes (X not XX). This results in a total of 45 chromosomes instead of the normal 46. • PKU – Autosomal recessive (aa) disorder. A birth defect that causes an amino acid called phenylalanine to build up in your body. Phenylketonuria is caused by a mutation in a gene that helps create the enzyme needed to break down phenylalanine.

11. Research • Recombinant DNA – DNA from 2 different species are combined in a lab, which would never happen in nature. Widely used in biotechnology, medicine, and research. Found in most food and medicines. Ex. Herbicide-resistant crops, golden rice, and treatments for HIV and diabetes • Cloning – making an exact copy of an organism. Used in research to test exact copies of mice, for example, in various medical studies. Scientists have the ability and technology to clone pretty much anything. • Stem cells – cells that have the ability to become anything in the body (liver, brain, ear drum, etc.). Used to make new organs when they stop working or become damaged. The body accepts the new cells, making transplants effective.