AP Biology 2

Notes Chapter 14

Mendel and the Gene Idea

Gregor Mendel

Who was Mendel? Pure breeds 3 Generations 4 Hypotheses

Mendel’s 4 Hypothesis

Law of Segregation

Useful Vocabulary

Homozygous / Heterozygous

Genotype / Phenotype

Punnett Squares

Monohybrid crosses

Dihybrid crosses Test Cross Pedigrees

Rules of Probability

Genes are like coins– 2 choices & not

related to any other gene/coin

– Chance is always ½

Rules of Multiplication– p both coins being

heads?

Bio– chances of getting

white flower from Pp self fertilization?

Rules of Probability

Exceptions to the 2 Allele Rule

Incomplete Dominance

Codominance Pleiotropy Epistasis Polygenic

Inhertiance

Genetic Disorders

Dominant genetic disorders– Many not lethal as would not be able to passed on– Huntington’s – late in life deteriorates nervous system

(should you find out?) Recessive genetic disorders

– Cystic Fibrosis – must have aa to have it (no code for protein) (27 years)

– Tay Sachs – failure to break down brain lipid (3-5 years)– Sickle Cell – Aa have fairly normal function

Multifactorial Diseases– Determined by more than 1 gene and environment

Heart disease, cancer, diabetes, alcoholism

Genetic Tools and Counseling

Genetic counseling Fetal testing

– Amniocentesis (Mid pregnancy)(14-16wks)

– Chorionic Villi Sampling (Earliest)(8-10wks)

– Ultrasound (Anytime)– Fetoscopy– Newborn screening

(PKU)