EXAM II Study GuideWhat are extrinsic proteins? Peripheral membrane proteins DON’T interact with the hydrophobic interiorNON-COVALENTLY bound to regions of integral membrane proteins thatproject out from the membrane or to the polar heads of phospholipids via hydrogen or ionic boundsIntrinsic proteins? Lipid anchored proteins which have segments located on both sides of the membrane (TRANSmembrane proteins)What is another name for each?PERIPHERAL(extrinsic)INTEGRAL(intrinsic)What is important about the protein-to-lipid ratio of a membrane, and what does it tell us about that membrane?What property of membranes is changed when we change the types of lipids in that membrane?Membrane fluidityCan proteins move in a biological membrane? YES (rotate and laterally move)Define diffusion-Movement of “material” from an area of  concentration to an area of concentrationWhat two criteria must be met for diffusion to occur across a biological membrane?Permeability/Concentration gradienDefine osmosis (remember that “diffusion of water” is NOT an appropriate definition for this class).-Movement of water from an area of hypotonic or low concentration of particles to an area of hypertonic or high concentration of particlesWhat is a hypertonic solution? High concentration of dissolved particles/ will cause cell to shrink What is a hypotonic solution? Low concentration of dissolved particles/ will cause cell to swell What about an isotonic solution? Concentrations of solute are equal on both sides/no change in cellWe covered two specific kinds of carrier-mediated transport. What are they?Active Transport/ Facilitated DiffusionWhat is facilitated diffusion and how does it work? Does it require metabolic energy (ATP energy)? If not, from where does the energy come? Transport proteins provide passage for subst. across membrane/ NO INPUT ENERGY (energy from concentrationgradient)What is active transport and how does it work? Moves substance from low to high concentration w/ aid of transport proteinDoes it require metabolic energy? YesIf not, from where does the energy come? ATPCarrier mediated transport systems exhibit specificity, saturation kinetics and competition. Know what each of these mean and how they influence the transport activityWe covered two kinds of bulk transport. What are they and how do they work?Exocyctosis-exported out of the cell via secretory vesicles/Golgi packages macromolecules into transport vesicles that travel and fuse w/ plasma membrane causing vesicle to spill its contents out of the cellEndocytosis-materials move into the cell/ phagocytosis or “cellular eating,” the cell’s plasma membrane surrounds a macromolecule or even an entire cell from the extracellular environment and buds off to form a food vacuole orphagosome then fuses with a lysosome whose hydrolytic enzymes digest the “food” insidePinocytosis “cellular drinking,” the cell engulfs drops of fluid by pinching in and forming vesicles that are smaller than the phagosomes formed in phagocytosis. Like phagocytosis, pinocytosis is a non-specific process in which the cell takes in whatever solutes that are dissolved in the liquid it envelops.receptor-mediated endocytosis is an extremely selective process of importingmaterials into the cell. This specificity is mediated by receptor proteins located on depressed areas of the cell membrane called coated pits. The cytosolic surface of coated pits is covered by coat proteins. In receptor-mediated endocytosis, the cell will only take in an extracellular molecule if it binds to its specific receptor protein on the cell’s surface. Once bound, the coated pit on which the bound receptor protein is located then invaginates, orpinches in, to form a coated vesicle. Similar to the digestive process in non-specific phagocytosis, this coated vesicle then fuses with a lysosome to digest the engulfed material and release it into the cytosol.Why do we need bulk transport for release of chemicals—why can’t we just use carrier mediated transport?-It is more efficient to remove large molecules of waste through bulk transportWhat is an enzyme? Protein that acts as a catalyst to lower activation for a reaction and speed up the reaction What kind of organic molecule are enzymes? ProteinsWhat is an active site? Region of an enzyme that binds to a protein or other substance during a reaction (where reaction takes place)What is a substrate?-Molecule that binds to an enzymes active site forming enzyme-substrate complex and aids in the reactionDiscuss the concept of enzyme specificity. On what molecular property is it based?-the active sites of enzymes may only allow specifically shaped substrates to bind to this site making the enzymes specific/enzymes can not bind with substrates that are not compatible to its active siteKnow enzyme saturation kinetics backwards and forwards.-What does a saturation curve look like (be sure to know the proper labels for the axes). -Why do enzymes saturate?- to reach maximal reaction rate/all active sites are occupied by substrate/ higher substrate concentrations would be negligible andthe reaction would plateau-What does the saturation curve look like when a competitive inhibitor is present, and why does it look like that?-Inhibit the ability of a substrate to bind to an enzyme increasing howlong it will take the reaction to reach its Vmax-What does the saturation curve look like when a non-competitive inhibitor is present and why does it look like that?-inhibits the enzymes function by attaching to an allosteric site of an enzyme and lowers the Vmax of the reactionKnow how temperature and pH impact the function of enzymes (we showed it with graphs)-Temp at optimum (enzyme functions well)-Temp to high (enzymes begin to denature)-Temp to low (Inhibit function of enzyme)(pH is almost same way)What is a cofactor?-inorganic ions (Fe, Zn) temporarily bind to surface of an enzyme and promote chemical reactionBe able to explain how allosteric modulation works.-regulation of an enzyme or other protein by binding an effector molecule at the protein's allosteric site (that is, a site other than the protein's active site)-Allosteric activators enhance proteins(enzymes) activity -Allosteric inhibitors decrease the proteins(enzymes) activityIn addition to ATP, what other high-energy molecules are used/produced in our metabolic reaction sequences?-NADH, FADHWhat is a redox reaction? Oxidation reduction reaction/transfer ofe-