EMC Exam 2 (click questions)100% Correct!

Membrane Transport What is the major difference between V-ATPase and F-ATPase? - ANSWERSV-ATPase uses ATP to pump hydrogen against the concentration gradient; F-ATPase uses hydrogen concentration gradient to make ATP Why can't H3O+ flow through an aquaporin channel? - ANSWERSH3O+ size and charge; positively charged Asn repel H3O+ How would F-ATPase be affected with H3O+ could flow through aquaporins? - ANSWERSChange H+ gradient, affecting function of F-ATPase and production of ATP How does secondary active transport differ from active transport? - ANSWERSsecondary = concentration gradient of one provides energy to drive the other (symporters and antiporters) ; active uses ATP (ATPases) What transport proteins use active transport & what transport protein use secondary active transport - ANSWERSsecondary active transport: symporter & antiporter; active transport: P-, V-, F-ATPase, ABC transporters Do channels and uniporters require energy input? Why? - ANSWERSNo; they flow down concentration gradient What is the transport rate v0 of the GLUT1 transporter if the blood glucose concentration is 5 mM and Km = 1.5 mM.? (given graph has vmax = 500) - ANSWERSv0 = 384 (77% of Vmax); 500/(1 +(1.5 mM/5mM)) If you are designing a drug to block the transport of a molecule through that molecule's transporter, would you want that drug to have a higher or lower Km than the molecule? Why? - ANSWERSKm needs to be lower for drug so that it has higher affinity than glucose How could you test how effective your drug works? - ANSWERStest biological effect - whatever glucose is doing in the cell (for example ATP), see if the drug blocks that biology Cell Signaling What are steps of an extracellular signaling cascade? - ANSWERS1. Ligand binds receptor 2. Signaling cascade is activated 3. Intracellular response ( e.g. protein degradation, vesicle formation, gene expression) 4. Cell biological response (e.g. survival, proliferation, death, motility) What are the 4 types of extracellular signaling? - ANSWERSEndocrine, Autocrine, Paracrine, Plasma Membrane mediated Describe each type of extracellular signaling. Endocrine - ANSWERSendocrine cells secrete ligands that travel through blood stream and bind receptors on target cells Describe each type of extracellular signaling. Paracrine - ANSWERSsecretory cells secrete ligands that bind receptors on neighboring cells Describe each type of extracellular signaling. Autocrine - ANSWERSsecretory cells secrete ligands that bind receptors on the same cells Describe each type of extracellular signaling. Plasma membrane mediates - ANSW