InSidk cuu 120.201 F Page 7 of 15 of Biology/Spring 2018 Practice questions for
ID: 132417 • Letter: I
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InSidk cuu 120.201 F Page 7 of 15 of Biology/Spring 2018 Practice questions for Exam 3 42. Cell membranes are fuid and thus proteins can diuse lateraly within the lipid bilayer most likely by specific lipids. This association of protein and lipids is called a) lipid graft b) phase diagram. c) lipid raft d) protein raft 43. Cystic fibrosis is a term that describes a syndrome produced by delective C channels in humans or their lack of intracolular transport from the ER to the plasma membrane. Why would a cystic fibrosis patient have mucus accumulation in the lungs? a) Mucus biosynthesis enzymes need Ch. Water molecules that keep the insarior of the lungs wot leave cells as solvation spheres for Cr Ch breaks the interactions between mucus and alveolar cells; its absence leads to mucus accumulation. d) It is not known 44. A hungry yeast celf lands in a vat of grape juice and begins to teast on the sugars there, producing carbon dioxide and ethanol in the process: Unfortunately, the grape julce is contaminated with proteases that attack some of the transport proteins in demise? a) Taxic buildup of carbon dioxide inside the cell alat the yoast cel membrane, and the yoast coll dies. Which of the following could account for the yoast celit's b) Toxic buildup of ethanol inside the cel UTS Diffusion of ATP out of the cell d) Inabality to import sugar into the cell 45. Pumps are transporters that are able to harness enorgy provised by other components in the cells to drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called a) active transport. b) free diffusion c) faciltated diéfusion. d) passive transport. 46. Facilitated diffusion can be described as the favorable movement of one solute down its concentration gradient boing coupled with the unfavorable movement of a second solute up its concentration gradient a)True False 47. You have gonerated antibodies that rocognize the extracellular domain ot the Ca?+ pump. Adding these antibodies to animal cells blocks the active transport of Ca2 trom the cytosol into the extracellular environment. What do you expect to observe with respoct to intracellular Ca? a) Ca pumps in newly formed vesicle membranes keep cytosolic calcium levels low b) Ca pumps in the endoplasmic reticulum membrane koep cytosolic calclum levels low c) Ca2 pumps in the Golgi apparatus keep cytosolic calcium levels low d) Ca2 concentrations in the cytosol increase at steady rate. 48. Transporters transition between different conformations, depending upon whether the substrate-binding pocket is empty or occupied a)True False 49. Cells make use of H electrochemical gradients (apH) in many ways. Which of the following proton transporters is used to regulate pH in animal cells? a) Light-driven pump b) H'-ATPase c) H symport d) NaH' exchangerExplanation / Answer
42.C)lipid rafts.
Plasma membrane contains glycospingolipids in combination with protein receptors organised in glycoprotein microdomain termed as a lipid raft.
43.b)water molecules leave interior of lungs and enter alveolar cells to dilute excessive chloride ions accumulated in cells due to cystic fibrosis. This makes mucous thick.
44)d)inability to import sugars into the cell.Since protease contamination attacked transport proteins, yeast cell wont be able to take up sugars from environment and may have died due to starvation.
45)a)Transport of solutes in the cell against concentration gradient is called active transport.Active transport requires supply of energy in form of ATP.