Genetics Vicky “Bio-lover” Atzl Farah “Bird-hater” Momen

Meiosis a. Meiosis 1 separates homologous pairs (known as reduction division) crossing over occurs in Prophase 1 resulting in genetic variation (not in mitosis) b. Meiosis 2 separates homologous pairs into sister chromatids: produces 4 haploid gametes (meiosis 2 resembles mitosis)

Alleles a. dominant vs. recessive Dominant allele is expressed over recessive b. homozygous vs. heterozygous Homozygous has two of the same allele (AA or aa); heterozygous has two different alleles (Aa) and therefore has dominant phenotype c. phenotype vs. genotype Phenotype is the physical appearance of an expressed allele; genotype is the genetic makeup of an organism

Non-Mendelian inheritance a. incomplete dominance (pink flower color) When a heterozygote’s two alleles blend b. co-dominance (blood type) When a heterozygote’s two alleles are expressed equally. c. sex linked (mainly X-linked: color blindness, hemophilia) epistasis (coat color) presence of certain alleles on one locus mask the expression of alleles on another locus and express their own phenotype instead. pleiotropy (dwarfism, giantism) one allele affects various phenotypes in an organism. polygenic (skin color) multiple alleles are required for the expression of a characteristic

Chi-square analysis a. used to determine if observed results are significantly different from expected results b. know how to use formula when given & how to interpret results degrees freedom (1 less than number of classes of results) if x^2 less than p=.05, then difference can be due to random chance and hypothesis accepted

DNA & RNA a. DNA: ACTG nitrogen based nucleotides in double helix formation A pairs with T, C pairs with G b. RNA: ACUG nitrogen based nucleotides in single helix formation

Central Dogma DNA is transcribed into RNA; that is further translated into proteins that code for traits. Transcription: RNA polymerase copies template strand and makes mRNA Translation: ribosomes in cytoplasm match tRNA codons to mRNA codons; amino acids carried to P site of ribosome and forms polypeptide chain. Chain ends at one of stop codons.

Gene regulation Operons Inducible: lac operon I DIDN’T FINISH!

Mendelian inheritance a. monohybrid crosses Aa x Aa = 3:1 ratio Law of Segregation