Exam #2 - Cheat Sheet

Complementation testing: 1. Cross two mutant strains that have recessive mutations in the same biological pathway. 2. Observe the phenotype of the offspring: o If the offspring show the wild-type (normal) phenotype, the mutations are in different genes (complementation occurs). o If the offspring still show the mutant phenotype, the mutations are in the same gene (no complementation). E. coli B—it allows phage reproduction even if the genes are defective. Mutation recombination allele mutate (complementation->Yes->different gene) Phenylalanine: serves as a building block of proteins. Phenotype wild type->mutation not on the same gene Phenotype mutant->same gene (complementation group) Recombination rate is higher than reverse mutation rate. Amino acid sequence 3D structure. Pericentric: includes chromosome Paracentric: not include chromosome Nondisjunction: Down Syndrome: 90% in mothers and 10% in fathers. Trisomy. In females, such nondisjunction events occur more often during the first meiotic division (75%) than the second. Colchicine (ONLY for plants): It will bind to tubulin therefore preventing microtubules forming->Chromosomes won’t separate during cell division->Polyploid! FISH: put it on telomere. Each chromosome has two sister chromatids and each chromatid has 2 telomeres Tetraploids make it through meiosis successfully: [1(AA):4(Aa):1(aa)], (AAAA, AAAa, AAaa, Aaaa, aaaa) (A---:aaaa=35:1) Autopolyploids: polyploids that derive all their chromosome sets from the same species. Parthenogenesis: In some bugs (like bees), males are monoploid and females are diploid. Males from these species develop from unfertilized eggs. ALL bacteria are lacking nuclear membrane and membrane bounded organelles. Bacteria Bacteria chromosomes Bacterial Phenotypes Colony morphology Resistance to antibiotics Resistance to phage Auxotrophy Nutrient utilization Temperature sensitivity Bacterial chromosome: Single circular molecule of double-helical DNA. 80% of the E.coli genome is variable in different strains. Insertion Sequences (ISs): small bacterial transposons that do not contain selectable markers. They cut and paste themselves into new locations, interrupt genes when they insert and causing mutations; also genome rearrangements. Tn elements: two IS at their ends, move within the bacterial chromosome, spread antibiotic resistance genes, transfer genes, cause mutations. Plasmids are for bacteria to produce antibiotic stuffs and make them survive better. Transformation: DNA from donor is added to the bacterial growth medium and taken up by recipient. Conjugation: Donor carries a plasmid that allows it to contact the recipient and transfer DNA directly. Transduction: DNA is packaged within the protein coat of a bacteriophage and transferred to recipient while phage particle infects it. Needed genes are transferred to each other. Transfer F+ to FIntegration of F+ into bacterial chromosome to make an Hfr (Killing the donors and use selection method getting different genes to see what genes are transferred) (The time a gene first enters the recipient cells reflects the distance) Points about interrupted mating (or time of-entry mapping) Donor and recipient must have different genotypes Any one Hfr strain always initiates transfer from the same point in the same direction Relative order of genes should be the same for any Hfr Map distance is in minutes not cM Kinetoplast: network of circular DNAs inside mitochondrion including genome copies and DNA encoding guide RNAs for RNA editing (mini circles) RNA editing: the process converts pre-mRNA->mRNA Maxicircle DNA: contained gene sequences that were related but far from identical to cDNAs corresponding to the protein-coding mRNAs. Minicircle DNA: not encode any protein-coding genes Blue region contains mtDNA and Krebs cycle enzymes. Breaking down glucose->NADH and FADH2->electron transferred from them to oxygen->protons pumped out of matrix->electrical potential->protons flow back into matrix thru ATP synthase->ADP to ATP Organellular DNA is usually inherited uniparentally In vertebrates mitochondria are maternally inherited Human diseases caused by mutations in mtDNA Typically effect post-mitotic cells with high metabolism such muscle and neurons Photosynthetic e transport forms NADPH and also drives synthesis of ATP->enzyme of Calvin cycle use ATP and NADPH to convert carbon dioxide into carbohydrates Endosymbiont theory: (Maternal) (Mostly Homo) (Caused by hypomorphic mutations in any one of three mitochondrial genes-ND1, ND4 or ND6)( Sometimes appear as incompletely penetrant.)(e transport chain gene) Homoplasmic: genomes are identical (all of the mtDNA copies have mutation) Hetero: genomes are different->mutant phenotype may be less severe and offspring may show varied severities (Hetero, if HOMO, cell will die)(Mutations affects translation of all mitochondrial mRNAs->not enough ATP production)(always wild-type) Differ in fractions of mutant mitochondria cus female whose cells are hetero for MERRF produces eggs that vary in relative proportions of mtDNAs with wild-type and mutant tRNA genes. The combination depends on random portioning of mitochondria during mitotic. Muscles in Neuro cells have the highest Energy need so the rank is: Brain->Heart->Type I skeletal muscle->Type II sm->Skin earlier gene higher percentage. So Gene order marker decreases as distance from the origin increases