Episode 20: Welcome to the MCAT Podcast series, where Doctor Dan will cover the actual science material required for the MCAT. Starting off with an overview of Biological Sciences topics, we’ll get increasingly more specific as time passes.
Aliases Solubility Working Form Functions Deficiency Toxicity Vit A Carotene, Retinol Fat cis-retinol, trans-retinol, retinoic acid, carotene Vision, transcription regulation, antioxidant Vision problems, oxidative damage Yes (retinol); No (carotene) Vit B1 Thiamine Water TPP Keto group metabolism Beri-Beri No Vit B2 Riboflavin Water FMN, FAD Electron transfer Rare No Vit B3 Niacin, Nicotinate [...]
Enzymes Subject to Phosphorylation Ca++ and cAMP are intracellular 2nd messengers that respond to hormones binding cell surface receptors When adenylate cyclase is stimulated, intracellular cAMP levels are elevated (made from ATP) All protein phosphorylation (by kinases) is ATP-dependent and dephosphorylation (by phosphatases) uses H2O and releases Pi ENZYME Substrate, [...]
HYDROLASES: CLEAVES MOLECULES USING HYDROLYSIS Esterases: a hydrolase that hydrolyzes an ester into its components: an alcohol & an acid. Acetycholine esterase [nerve gas blocks] Phosphodiesterase 93,104, Cholesterol esterase 30 Lipases: a hydrolase that catalyzes the breakup of ester linkages between a fatty acid & glycerol, w/I triglycerides & phospholipids Serum [...]
Transport Mechanisms Ca++ efflux from ventricular myocardial cells during diastole – secondary active (Na+ coupled) Ca++ uptake by sarcoplasmic reticulum – primary active Ca++ uptake by terminal varicosities of sympathetic nerve endings – restricted diffusion Ca++ entry into heart muscle during plateau phase of the action potential – restricted diffusion [...]
Sickle Cell Anemia (Hb S disease) – Results when a glutamate is replaced by valine at position 6 of the b globin chain. Symptoms include anoxia, poor circulation, and crises when variables that lower oxygen affinity (i.e. BPG, ¯pH, etc) are experienced. Thalassemia – Results when either the a- or b- chain is defective. One [...]
Essential Amino Acids Lys, ISO, LEU, THR, VAL, TRY, PHE, MET, HIS, ARG Required in diet; no exception “Little TV Tonight (PM) – HA” Nonessentials Serine → Gly or Cys (from Homocysteine + Ser) Glutamate → Gln, Pro, Arg -His req. for the syn of Glu One Carbon Metabolism All begins [...]
