BIOL 133 Study Guide - Final Guide: Aureus, Edwards Syndrome, Apoptosis
Document Summary
Mutation --- a change in a phenotype: change in nucleotide base sequence of a gene (change in genotype mutant is change in phenotype) Mutations don"t always cause a mutant phenotype: mutations: ultimate source of genetic variation, most are bad for individual. *somatic mutations affect body cells (not passed on)- often result in cancer. Sickle cell anemia: 1 bp substitution, val substituted for glu, causes hemoglobin to be sticky - - sickling of blood cells (reducancy protects us against mutation --- several base pairs result in the same protein) Causes of mutations: spontaneous mutations generated spontaneously (random mistake in dna replication, induced mutations chemicals or radiation causes the mutation. Mutational hot spots: sites of increased chance of mutation, usually found in regions where base pairs repeat (atatat) Radiation is naturally occurring but accidents release greater amounts of radiation to the environment. Types of mutations: point mutation - change in single dna base.
