BICH 410 - Exam 3 Carr

44. In passive diffusion, __________ solutes pass through the membrane from ______ to ________ concentration. A) Hydrophobic, high, low B) polar, low, high C) hydrophobic, low, high D) polar, high, low E) charged, low, high

A) Hydrophobic, high, low

26. Which of the following statements is true? A) Lipid bilayer membranes have a very low permeability for ions and polar molecules B) The favored structure for most glycerophospholipids and sphingolipids in aqueous media is a micelle. C) Hydrophilic interactions are the major driving force for the formation of lipid bilayers. D) There are electrostatic and hydrogen-bonding attractions between the hydrocarbon tails and water molecules. E) Micelles have aqueous compartments and are composed of glycolipids.

A) Lipid bilayer membranes have a very low permeability for ions and polar molecules

47. The potassium channel is which type of transporter? A) facilitated diffusion B) passive diffusion C) active transport D) passive transport E) secondary active transport

A) facilitated diffusion

20. What property is used to determine the probability that a segment of a protein will be found embedded in a membrane? A) hydropathy B) polarity C) acidity D) entropy E) solvation

A) hydropathy

37. All of the following describe trans-membrane domains of integral membrane proteins, EXCEPT A) hydropathy plots predict alpha-helices & beta barrels B) require detergent to release them from the membrane C) all backbone amides neutralized by hydrogen bonds D) lipid-facing side chains are nonpolar E) aqueous pore-facing side chains are polar

A) hydropathy plots predict alpha-helices & beta barrel

39. peripheral membrane proteins are in the __________ after lysis and in the _________after a _________ wash. A) pellet; supernatant fraction ; high salt B) pellet; pellet; high-salt. c) supernatant fraction ; supernatant fraction; detergent D) pellet; supernatant fraction; detergent E) supernatant fraction pellet high-salt

A) pellet; supernatant fraction ; high salt

49. Which of the following transportejs is an example of antiport? A) the sodium-potassium ATPase B) the potassium channel C) clathrin mediated endocytosis D) exocytosis of secretory proteins E) pinocytosis of dissolved nutrients

A) the sodium-potassium ATPase

3.Why is sucrose NOT a reducing sugar? A)Both anomeric carbons are involved in the glycosidic bond. B)Only the anomeric carbon of glucose can be oxidized,and it is involved in the glycosidic bond. C)Only the anomeric carbon of fructose can be oxidized,and it is involved in the glycosidic bond. D)Neither anomeric carbon is involved in the glycosidic bond. E)None of the answers is correct because sucrose is a reducing sugar.

A)Both anomeric carbons are involved in the glycosidic bond.

35. All of the following describe motions in a membrane, EXCEPT A) Rotation of lipids and proteins is fast. B) ATP-driven floppases move lipids from the outer to the inner leaflet. c) Integral membrane proteins anchored to the cytoskeleton slow lateral diffusion. D) Slower movement of lipids and proteins In the Lo phase. E) Decreased bilayer thickness in the La phase,

B) ATP-driven floppases move lipids from the outer to the inner leaflet.

46. Which of the following describes the Na+/K + pump? A) It is an example of secondary active transport. B) It is inhibited by the binding of ouabain to the extracellular domain. c) In one cycle of ATp hydrolysis two Na + are pumped into the cell. D) In one cycle of ATp hydrolysis three K + are pumped out of the cell. E) it is a symporter.

B) It is inhibited by the binding of ouabain to the extracellular domain.

9. Sugars are commonly linked to which amino acid residues in glycoproteins? A) tyrosine and asparagine B) serine, threonine, and asparagine C) serine, tyrosine, and asparagine D) serine and glutamine E) threonine and glutamine

B) serine, threonine, and asparagine

45. Which of the following statements explains saturation kinetics? A) transport rate independent of [solute] B) transport rate dependent on [solute], with a constant rate at very high [solute] C) linear dependence of transport rate on [solute] D). sigmoidal dependence of transport rate on [solute] E) no transport at very high [solute]

B) transport rate dependent on [solute], with a constant rate at very high [solute]

22. How many molecules thick are membranes? A) one B) two C) infinite D) varying thickness E) three

B) two

28. Which structure is composed of an aqueous compartment (lumen) enclosed by a lipid bilayer and can be used to deliver chemicals to cells? A) micelle B) vesicle C) Lysosome D) chloroplast E) ribosome

B) vesicle

5.In the figure of monosaccharides,which one is ribose? A)A B)B C)C D)D E)None of the above.

B)B

14.MOST glycogen monomers are connected by what type of linkage? A)a-1,6 B)a-1,4 C)a-1,4 and B-1,6 D)a-1,6 and B-1,4 E)B-1,4

B)a-1,4

4.Two monosaccharides that differ in stereochemistry at only a single asymmetric carbon are called: A)aldoses. B)epimers. C)anomers. D)pentoses. E)enantiomers.

B)epimers.

30. Transverse diffusion in biological membranes occurs by A) fast rotation of lipids within one face (leaflet) of a membrane. B) spontaneous, rapid flip-flop of membrane proteins across the bilayer. C) ATP- driven flip or flop of membrane proteins across the bilayer D)fast diffusion of proteins and lipids within one leaflet of the membrane. E) slow diffusion of proteins and lipids within one leallet of the membrane.

C) ATP- driven flip or flop of membrane proteins across the bilayer

10. Maltose is a disaccharide composed of: A) a-d-glucopyranose and B-d-fructofuranose. B) a-d-galactopyranose and a-d-glucopyranose. C) a-d-glucopyranose and a-d-glucopyranose, D) B-d-fructofuranose and a-d-galactopyranose. E) B-d-glucopyranose and B-d-fructofuranose.

C) a-d-glucopyranose and a-d-glucopyranose,

36. Which of the following accurately describes biological membranes? A) · peripheral membrane proteins act as scramblases. B)Lipid rafts are composed of GPI anchored proteins attached to the cytoplasmic leaflet C) asymmetric distribution of proteins and lipids D) triacylglycerols are a component of rafts E) high salt wash removes integral membrane proteins

C) asymmetric distribution of proteins and lipids

48. Which statement about transporters is correct? A)The potassium channel transports two potassium ions in and three sodium ions out, per ATP hydrolyzed. B) Ouabain blocks transport by the potassium channel C) glucose transport into the cell is an example of facilitated diffusion. D) the potassium pump is an excellent example of passive diffusion E) ATP hydrolysis is required for the function of the potassium channel

C) glucose transport into the cell is an example of facilitated diffusion.

21. What complex is observed between cholesterol and certain membrane lipids? A) salt bridge B) clathrate C) lipid raft D) phospholipid domain E) precipitate

C) lipid raft

27. Which of the following is an 18- carbon fatty acid? A) laurate B) palmitate C) stearate D) arachidonate E) myristate

C) stearate

1.Select the monosaccharide that is correctly paired with its description. A)d-glucose-ketohexose B)d-galactose-aldopentose C)d-fructose-ketohexose D)d-ribulose-ketotetrose E)d-ribose-ketopentose

C)d-fructose-ketohexose

25. what membrane lipid is composed of sphingosine, fatty acid, and a single sugar residue, either glucose or galactose? A) cholesterol B) sphingomyelin C) phosphatide D) cerebroside E) cardiolipin

D) Cerebroside

32. Which amino acid is most likely found in a trans-membrane domain of are integral membrane protein? A) D B) E C) S D) G E) K

D) G

38. which of the following lipids sweeps out a cone shape when it rotates on its vertical axis? A) sphingomyelin B) phosphatidylinositol C) cholesterol D) Ganglioside E) Phosphatidylserine

D) Ganglioside

12. Why is it more advantageous to store glucose in the form of glycogen rather than in its free form?. A) Glycogen more water soluble than glucose. B) Glycogen strengthens the cell wall. C) Glycogen is more reactive than glucose. D) Glucose is osmotically stressful to the cell. E) Glucose is less calorie-dense than glycogen.

D) Glucose is osmotically stressful to the cell.

23. Which statement is consistent with the structure of biological membranes? A) AIl membrane proteins are integral and associate with the hydrophobic region of the membrane B) Both proteins and lipids readily undergo transverse ("flip-flop") diffusion, C) Membranes are symmetric. D) The membrane lipids self-assemble to form the lipid bilayer E) A biological membrane consists of proteins sandwiched between two layers of lipids.

D) The membrane lipids self-assemble to form the lipid bilayer

19. What term describes molecules that have both hydrophilic and hydrophobic moieties? A) amphoteric B) amphiprotic C) amphibian D) amphipathic E) amphiapomictic

D) amphipathic

18. Cartilage-matrix proteoglycan has all of the following properties EXCEPT: A) helps maintain the flexibility and resiliency of cartilage. B) as reversible hydration-dehydration properties. C) Contains both N-linked and O-linked oligosaccharides. D) is a component of the cell membrane. E) contains O-linked keratan sulfate.

D) is a component of the cell membrane.

17. what protein facilitates cell-to-cell recognition by binding to specific carbohydrate structures A) mucoproteins B) glycosaminoglycans C) glycoproteins D) lectins E) proteoglycans

D) lectins

40. All of the following describe transporters, EXCEPT A) uniporters transport one type of solute in one direction B) They have aqueous pores to accommodate specific solutes C) They have transport rates that saturate with excess solute D) they can be lipid-anchored proteins in the inner leaflet of the bilayer E) they either facilitate diffusion, or actively transport solutes

D) they can be lipid-anchored proteins in the inner leaflet of the bilayer

42. All of the following describe primary active transport, EXCEPT A) solutes are transported against their concentration gradient B) transport is coupled to an energy source C) light, or ATp hydrolysis "pays" for transport D) transport of an ion down its concentration gradient "pays" for transport E) transport is against the thermodynamic potential of the solute

D) transport of an ion down its concentration gradient"pays"for transport

8. In the a anomer of a cyclic hemiacetal, the __________ hydroxyl is on the__________ side of the ring as the____________hydroxyl. A) C-1, opposite, C-3 B) C-2, opposite, C-6 C) C-2, same, C-6 D)C-1, opposite, C-6 E) C-1, same, C-6

D)C-1, opposite, C-6

13. What carbohydrate is the most abundant organic compound in the biosphere? A) glucose B) starch C) maltose D)cellulose E) amylopectin

D)cellulose

41. In which kind of transport (s) do solutes transport down their concentration gradient? A) passive diffusion B) primary active transport C) facilitated diffusion D) secondary active transport E) A & C

E) A & C

43. How does energy affect the functioning of the Na+ K + ATPase? A) ATP provides energy for this pump to function. B) The pump maintains the proper cellular concentration of Na+ and K+ C) Without ATP, the pump would not be able to function. D) Without ATP, the pump transport only K+. E) A, B, & C

E) A, B, & C

15. What property causes cellulose molecules to form long, straight chains and a proper supportive structure? A) osmolarity B) heteropolymeric structure C) molecular weight D) glucose residues E) B linkages

E) B linkages

33. Which statement best describes why 20 amino acids are optimal to span a membrane as an alpha helix? A) The rise per amino acid is 1.5 A. · B) The hydrophobic core of a bilayer is 30A thick C) The pitch of an alpha helix is 5.4 A. D) There are 3.6 amino acids per turn, E) Both A & B

E) Both A & B

50. Vesicle trafficking of cargo from one compartment of the cell to another depends on A) transporters B) hemagglutinin C) SNAREs D) scaffold proteins E) C &D

E) C &D

29. All of the following statements about peripheral membrane proteins are true, EXCEPT: A) They are membrane proteins that interact with the polar head groups of the membrane lipids. B) They are membrane proteins that can bind to integral membrane proteins. C) They are membrane proteins that can interact with on layer of the membrane lipid bilayer, D) Interactions with the membrane lipids can be disrupted by adding a high concentration of salt. E) They are membrane proteins that span the lipid bilayer.

E) They are membrane proteins that span the lipid bilayer.

11. Glycoproteins are normally: A) only found on membranes. B) only secreted as extracellular proteins. C) only found inside organelles. D) only found in the cytoplasm. E) found on cell surfaces and secreted as extracellular proteins.

E) found on cell surfaces and secreted as extracellular proteins.

34. A lipid anchored protein can have a_______ Group attached to a(n)_______,Through a __________ linkage. A) prenyl ; Cys; thioester B) palmitoyl; N-terminus; amide C) GPI; Cys; thioester D) myristoyl; Cys; amide E) geranylgeranyl ; Cys ; thioether

E) geranylgeranyl ; Cys ; thioether

16. which term describes a class of compounds with the molecular formula (CH2O) n? A) proteoglycans B) glycogen C) mucoproteins D) polysaccharides E) monosaccharides

E) monosaccharides

31. All of the following are ways to bend a membrane, EXCEPT A) lipid shape B) integral membrane protein shape C) insertion into one leaflet by an amphipathic helix D) peripheral membrane protein scaffolding E) raft formation

E) raft formation

7.Which of the following accurately describes lactose? A)an aldohexose B)contains a ß-1,4 linkage C)digested by bacteria found in the rumen D)a reducing sugar E)both B&D

E)both B&D

2.What monosaccharide lacks an asymmetric carbon atom? A)fructose B)mannose C)altrose D)galactose E)dihydroxyacetone

E)dihydroxyacetone

6.What is the chemical basis for the cyclization of sugars in solution? A)H-bond interaction of hydroxyl groups with each other B)formation of peptide bonds between atoms in modified sugars C)reaction between the aldehyde groups of sugar molecules D)formation of hydrogen bonds between sugar and water molecules E)reaction of the carbonyl group with an alcohol group

E)reaction of the carbonyl group with an alcohol group

24. carbohydrate residues attached to the membrane lipids are almost always A) positioned on the intracellular side of the membrane. B) positioned on the inside center of the bilayer. c) positioned on the extracellular side of the membrane. D) positioned equally on both sides of the membrane. E) also covalently attached to membrane proteins.

c) positioned on the extracellular side of the membrane.