CMMB 461 FINAL with 100% correct answers

CMMB 461 FINALBasic components of mass spec - correct answer 1. Ion source 2. mass analyzer 3. detector Two main types of ionization - correct answer 1. Electrospray ionization 2. MALDI Electrospray Ionization (ES) - correct answer Peptide solution is passed through a narrow metal needle with a high electrical potential resulting in highly charged droplets of protonated peptide ions. Matrix-assisted laser desorption ionization (MALDI) - correct answer Sample is co-crystallized with a solid matrix and irradiated with a laser results in protonated analyte ions Three main types of mass analyzers - correct answer 1. TOF 2. Quadrupole 3. Ion trap Time of flight (TOF) - correct answer Ions are accelerated at a fixed potential through a TOF drift tube, smaller molecules will travel faster than larger ones The m/z determined by the time it reaches the detector Quadrupole MA - correct answer An electrostatic field of specific strength and frequency is created from the four parallel stainless steel rods to allow ions of a single m/z to maintain a stable trajectory and reach the detector Ion trap MA - correct answer Ions are trapped in the device by applying a radio frequency voltage to the ring electrode Mass analysis is achieved by making ion trajectories unstable in a mass-selective manner Tissue microarrays - correct answer - complements microarray data (mRNA vs protein expression) - assist in classifying tumours and provide diagnostic and prognostic info - expression and localization profiles provide possible function of proteins Topology of interactome - correct answer power law relationship: number of protein interactions related to essentiality ie: most proteins have <6 links, while small number of proteins >15 links (essential) Party hub - correct answer if all protein interactions within a protein hub co-expressed at the mRNA level, then likely occurring at the same time Date hub - correct answer uncorrelated mRNA expression suggests that interactions with hub occurring at different times tend to function in multiple biological processes and be essential genes Synthetic lethality - correct answer Death of double mutant where the single mutants are viable; indicates functionally redundant pathway identifies functional and buffering relationships Synthetic genetic array (SGA) analysis - correct answer high-throughout analysis that involves mass matings, selecting for double mutants and scoring relative fitness Network typology: gene interactions - correct answer power law relationship: many genes with few interactions and few genes with many interactions