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Q:
People with high blood pressure have high blood levels of an endogenous Na+, K+-ATPase ____ that results in ____ of sodium and calcium in cells lining the blood vessel wall.
a. inhibitor; decrease
b. stimulator, decrease
c. inhibitor; accumulation
d. stimulator; accumulation
e. none of the above
Q:
Ouabain, an effective inhibitor of Na+, K+-ATPase, exhibits all of the following characteristics EXCEPT:
a. It has a basic steroid structure.
b. It contains an unsaturated lactone ring at C-17.
c. It binds on the extracellular surface of Na+, K+-ATPase.
d. It binds tightly to the enzyme/ATP complex in producing the inhibition.
e. It is a cardiac glycoside.
Q:
In the Na+, K+-ATPase mechanism, ATP is involved in all EXCEPT:
a. binding E2 to change conformation to E1 and release of K+.
b. binding E1 to facilitate binding of Na+.
c. transferring a phosphate group to make sodium phosphate.
d. hydrolysis to ADP and E1-P.
e. none of the above.
Q:
Secondary active transport is:
a. establishment of a cation or anion gradient with an ATPase that subsequently drives transport of an amino acid or sugar against a concentration gradient.
b. the use of an ATPase to establish an anion or cation gradient.
c. the antiport process of transporting species in opposite directions.
d. establishment of an ATP gradient across a membrane that drives uptake of sugars.
e. symport of malate and glutamate so that metabolism can synthesize ATP.
Q:
Active transport is uniquelycharacterized by:
a. transport of hydrophobic molecules.
b. transport of hydrophilic molecules.
c. transport of a molecule or ion across a membrane, with the species going from a greater concentration to a lesser concentration.
d. the tight coupling of an input of energy to drive a thermodynamically unfavorable reaction.
e. absolute requirement for ATP hydrolysis, and light energy or ion gradient energy will not work.
Q:
The anion transporter of erythrocytes exchanges HCO3- for ____ and operates by ____.a. Cl-; facilitated diffusionb. Cl-; active transportc. HPO42-; facilitated diffusiond. CO2; active transporte. HPO42-; passive diffusion
Q:
Hydropathy plots for transport proteins are utilized to reveal:
a. amino acid residues which may be highly modified.
b. amino acid residues which may be directly involved in facilitated transport.
c. stretches of amino acid residues that make up hydrophobic regions, which may be directly associated with the lipid bilayer.
d. amino acid residues which are hyper-reactive due to their location.
e. whether there is interaction between N-terminal and C-terminal amino acids.
Q:
Glucose transport across cell membranes varies depending upon blood glucose levels. When glucose levels are high, glucose transport exhibits saturation kinetics. When glucose concentrations are low, the transport of glucose across the membrane is dependent upon the sodium ion concentration. What types of transport is observed for glucose?
a. facilitated diffusion at high [glucose], secondary active transport at low [glucose]
b. simple diffusion at high [glucose], secondary active transport at low [glucose]
c. facilitated diffusion at high [glucose], primary active transport at low [glucose]
d. simple diffusion at high [glucose], primary active transport at low [glucose]
e. none of the above are correct
Q:
Facilitated diffusion of neutral metabolites is characterized by:
a. Lineweaver-Burk plots which pass through the origin.
b. its large dependence on membrane potential.
c. an upper limit in the transport velocity as the metabolite concentration increases.
d. a linear plot when velocity is plotted versus the concentration of the metabolite.
e. the ability to facilitate net movement against the thermodynamically favored direction.
Q:
In passive diffusion, the transported species moves across the membrane in the ____ favored direction ____.
a. kinetically; using a transport protein
b. kinetically; without a specific transport system/molecule
c. thermodynamically; using a transport protein
d. thermodynamically; without a specific transport system/molecule
e. none of the above.
Q:
Which of the following is true regarding membrane function?
a. a caveola contains a very high concentration of cholesterol and unsaturated phospholipids
b. scaffolding proteins, particularly those containing BAR domains, result in curvature of the cell membrane
c. lateral membrane diffusion within a biological membrane is a completely unrestricted process
d. membrane fusion with vesicles is often accomplished with the aid of a SNARE protein
e. both b and d are correct
Q:
The Ras proteins are associated to the membrane via what mechanism?
a. thioester-linked fatty acyl anchor
b. thioether-linked prenyl anchor
c. carboxy terminal ester-linked prenyl anchor
d. insertion of a portion of an amphipathic helix into the membrane
e. both b and c
Q:
G protein--subunits are anchored into membranes by:a. amine-linked myristoyl anchors.b. thioester-linked fatty acyl anchors.c. amide-linked prenyl anchors.d. thioester-linked prenyl anchors.e. amide-linked glycosyl phosphatidylinositol anchors.
Q:
Which of the following is a commonly used mechanism for anchoring a protein to a membrane?
a. attaching a fatty acid to a serine residue to form an ester
b. attaching a fatty acid to a methionine residue to form a thioester
c. attaching a farnesyl group to a cysteine residue to form a thioether
d. attaching a fatty acid to a glutamine residue to form an amide
e. none of the above
Q:
The porin proteins (e.g., maltoporin) utilize the ____ structural motif.a. single transmembrane -helixb. multiple transmembrane -helixesc. single -sheetd. multiple -sheete. none of the above
Q:
Generally, over 90% of all membrane phosphatidyl serine (PS) is found on the inner monolayer of the cell membrane. Which of the following explains this phenomenon?
a. when PS is found in the outer monolayer, a floppase enzyme is used to move it to the inner monolayer
b. the movement of phospholipids from one monolayer to another is a very slow reaction despite the fact that it works with the concentration gradient
c. under normal conditions within the cell, the activity of scramblase enzymes is relatively low and thus does not allow for movement between monolayers
d. All of the above are correct
e. B and C above are correct
Q:
Glycophorin is a membrane protein with:a. multiple transmembrane segments.b. most of the mass oriented outside the surface of the cell.c. about 10% carbohydrate and 90% protein.d. transmembrane -barrel segments.e. All are true
Q:
All are true for phase transitions of lipid bilayers EXCEPT:
a. the transitions are exothermic.
b. particular phospholipids display characteristic transition temperatures.
c. pure phospholipid bilayers have narrow transition ranges.
d. volume changes usually are associated with phase transitions.
e. solutes interacting with membrane lipids affect transition temperatures.
Q:
Flippases are enzymes that flip:a. fatty acids from one position on glycerol to another position.b. glucose from - to -glucose.c. amino acids from one position to another in a protein.d. cholesterol from one organelle to another.e. phospholipids across to the other side of a membrane.
Q:
In eukaryotic cells phospholipids, glycolipids and cholesterol are synthesized by enzymes located in the ____ and ____, and flow of these components to other membranes in the cell is mediated by ____.
a. plasma membrane; mitochondria; osmosis
b. endoplasmic reticulum; Golgi; osmosis
c. plasma membrane, Golgi; lipid transfer proteins
d. endoplasmic reticulum; Golgi; lipid transfer proteins
e. endoplasmic reticulum; plasma membrane; flippases
Q:
The two major phospholipids on the outer leaflet of erythrocytes are:
a. phosphatidylcholine and phosphatidylethanolamine.
b. phosphatidylcholine and sphingomyelin.
c. phosphatidylethanolamine and sphingomyelin.
d. phosphatidylserine and sphingomyelin.
e. phosphatidylcholine and phosphatidylserine.
Q:
When we say that biological membranes are asymmetric structures we mean that:
a. The lipids are not evenly distributed transversely in the membrane.
b. The proteins are not evenly distributed over the surface of the membrane.
c. Patches of cholesterol and other lipids occur on the surface of the membrane.
d. Certain membrane proteins seem to prefer association with specific lipids.
e. All are true
Q:
Which of the following would be the most likely interaction between a peripheral membrane protein that contained a high lysine content and a membrane?
a. ionic interaction
b. hydrophobic interaction
c. hydrogen bonding
d. covalent bonding
e. both a and c
Q:
Which of the following IS NOT a property of integral membrane proteins (intrinsic proteins)?
a. they contain both hydrophobic surfaces and hydrophilic surfaces
b. they dissociate from the membrane by treatment with salt solutions
c. they are exposed to at least one aqueous surface surrounding the membrane
d. they are inserted into the membrane and sequestered largely by hydrophobic interactions
e. they have significant lateral mobility
Q:
Liposomes are all EXCEPT:
a. used to introduce contrast agents into the body for diagnostic imaging procedures.
b. able to fuse with cells.
c. highly stable structures.
d. possible to prepare with different inside and outside solutions.
e. all are true.
Q:
Which of the following is an example of a unilamellar vesicle?
a. monolayer
b. bilayer
c. liposome
d. micelle
e. an inside out micelle
Q:
Lipid bilayers differ from micelles in that micelles are:
a. self limiting structures.
b. formed spontaneously.
c. stable in aqueous solution.
d. often transformed into vesicles.
e. all are true.
Q:
Lipids that spontaneously form micelles, monolayers and bilayers have what property?
a. waxy
b. polar
c. amphipathic
d. bipolar
e. polyisoprenoid
Q:
The plasma membrane is responsible for all EXCEPT:
a. energy transduction.
b. exclusion of certain toxic ions and molecules.
c. signal transduction.
d. accumulation of cell nutrients.
e. all are true.
Q:
Which of the following would be considered an ·-3 fatty acid?a. linoleic acid: 9,12-octadecadieneoic acid (18:2„9,12)b. eicosapentaenoic acid: 5,8,11,14,17-eicosapentaenoic acid (20:5„5,8,11,14,17)c. -linolenic acid: 6,9,12-octadecatrieneoic acid (18:3„6,9,12)d. arachidonic acid: 5,8,11,14-eicosatetraenoic acid (20:4„5,8,11,14)e. none of the above
Q:
Which of the following best describes the following molecule? a. a monoterpene with a tail-to-tail linkage
b. a monoterpene with a head-to-tail linkage
c. a diterpene with a tail-to-tail linkage
d. a diterpene with a head-to-tail linkage
e. none of the above
Q:
Which of the following bonds would be cleaved by phospholipase C? a. 1
b. 2
c. 3
d. 4
e. none of the above
Q:
Which of the following enzymes is responsible for the release of arachidonic acid from membrane phospholipids?
a. phospholipase A1
b. phospholipase A2
c. phospholipase B
d. phospholipase C
e. phospholipase D
Q:
Which of the following steroid hormones is NOT correctly defined?
a. testosterone: an androgen involved in male sexual development
b. progesterone: a progestin that controls the menstrual cycle.
c. cortisol: a glucocorticoid that controls nutrient metabolism
d. estradiol: a progestin involved in female sexual development
e. all are correctly defined
Q:
Plant sterols are:
a. so similar to cholesterol that they undergo the same physiology and metabolism.
b. different isomers of cholesterol at the double bond location only.
c. to be avoided in your diet because they elevate blood cholesterol levels.
d. highly effective in blocking the absorption of cholesterol by intestinal cells.
e. none are true.
Q:
The reaction below is catalyzed by:a. desmolase.b. 17-hydroxylase.c. 17,20-lyase.d. 17-hydroxysteroid dehydrogenase.e. none of the above are true.
Q:
All are plant steroids EXCEPT:a. campesterol.b. stigmasterol.c. -sitosterol.d. cortisol.e. all are true.
Q:
The steroid hormones that participate in the control of carbohydrate, protein and lipid metabolism are the:
a. progestins.
b. mineralocorticoids.
c. estrogens.
d. glucocorticoids.
e. androgens.
Q:
Cholesterol is a component of all EXCEPT:
a. lipoproteins.
b. plant cell plasma membranes.
c. membranes of intracellular organelles.
d. animal cell membranes.
e. all are true.
Q:
Of the following fatty acids, which would have physical and physiological properties most similar to elaidic acid, pictured below?a. oleic acid (18:1„9)b. lauric acid (12:0)c. linoleic acid (18:2„9,12)d. stearic acid (18:0)e. arachidonic acid (20:4„5,8,11,14)
Q:
All of the following are terpenes EXCEPT:a. squalene.b. -tocopherol (vitamin E).c. coenzyme Q (UQ).d. limonene.e. cetyl palmitate (spermaceti).
Q:
The terpenes are all EXCEPT:
a. made up of isoprene monomers.
b. formed from two or more 2-methyl-1,3-butadiene molecules.
c. components of wool wax.
d. monomers units linked head to tail.
e. all are true.
Q:
Which of the following lipids is correctly defined?
a. triacylglycerol: formed from glycerol and 3 fatty acids, primary lipid of membranes
b. phospholipid: contains glycerol with 2 fatty acids and a phosphate, very often forms bilayers
c. wax: contains a fatty acid and alcohol, used primarily for energy storage
d. cholesterol: the primary component of "saturated" fats
e. palmitic acid: the most commonly produced unsaturated fatty acid in animals
Q:
The structure is an example of a(n): a. diacylglycerol.
b. triacylglycerol.
c. wax ester.
d. eicosanoid.
e. monoacylglycerol.
Q:
Although present in small amounts in most membranes, glycosphingolipids have a number of cellular functions EXCEPT:
a. involvement in nerve impulse transmission.
b. water-repellant properties of animal skin.
c. tissue and organ specificity.
d. cell-cell recognition.
e. tissue immunity.
Q:
Glycosphingolipids consist of a ____ with one or more ____ residues in a(n) ____ linkage at the 1-hydroxyl moiety.a. sugar; fatty acids; esterb. ceramide; sugar; -glycosidicc. ceramide; fatty acid; amided. glycerol; fatty acids; estere. none are true
Q:
Which of the following alcohols is correctly paired with the functional group that it contains?
a. ethanolamine: secondary amine group
b. choline: quaternary ammonium group
c. inositol: aldehyde and alcohol groups
d. glycerol: ether
e. none of the above are correct
Q:
Platelet activating factor (PAF) has all of the characteristics EXCEPT:
a. PAF is a potential mediator in inflammation, allergic responses and shock.
b. PAF is a sphingolipid.
c. PAF has a beneficial effect on toxic-shock syndrome.
d. PAF is involved in implantation of the egg in the uterine wall.
e. PAF stimulates production of fetal lung surfactant.
Q:
Certain phospholipids, including ____ and ____, participate in complex cellular signaling events.
a. phosphatidylcholine; phosphatidylserine
b. phosphatidylserine; phosphatidylalanine
c. phosphatidylcholine; phosphatidylglycerol
d. phosphatidylinositol; phosphatidylcholine
e. phosphatidylethanolamine; phosphatidylserine
Q:
In most cases, glycerol phosphatides have ____ fatty acid at position 1 and ____ fatty acid at position 2 of the glycerol.
a. a saturated; a saturated
b. a saturated; an unsaturated
c. an unsaturated; a saturated
d. an unsaturated; an unsaturated
e. none are true.
Q:
Glycerolphospholipids are all EXCEPT:
a. also called sphingolipids.
b. essential components of cell membranes.
c. made up of 1,2-diacylglycerol and a phosphate group.
d. members of the phospholipids.
e. all are true.
Q:
Membranes with unsaturated fatty acids in their components are more flexible and fluid because:
a. Unsaturated fatty acids pack closely together to form ordered arrays.
b. Unsaturated fatty acids bend at the double bond preventing close packing.
c. Saturated fatty acids have a "kink" that produces more fluid aggregates.
d. Unsaturated fatty acids have cis double bonds that prevent formation of the "kink."
e. All of the above are correct.
Q:
Body fat is a major storage form of energy because it:
a. aggregates in a highly anhydrous form (without additional water weight).
b. yields about 17 kJ/g (4 cal/g) of energy.
c. has low insulation properties.
d. is highly hydrated and easy to metabolize.
e. yields about 25 kJ/g (6 cal/g) of energy.
Q:
Of the following, which would contain the largest amount of fatty acids with trans double bonds?
a. the fatty acid on carbon #1 of the glycerol of phosphatidylcholine
b. butter
c. canola oil
d. the 2 lb, 99 cent package of cookies containing partially hydrogenated cottonseed and/or soybean oil that you consumed with 3 (or more) cups of coffee while studying last night (or early this morning)
e. none of the above would have very much trans-double bond containing fatty acids
Q:
Diets aimed at reducing coronary heart disease should be:
a. low in trans-fatty acids and high in saturated fatty acids.
b. high in trans-fatty acids and high in saturated fatty acids.
c. high in trans-fatty acids and low in saturated fatty acids.
d. low in trans-fatty acids and low in saturated fatty acids.
e. low in trans-fatty acids and low in unsaturated fatty acids.
Q:
Lipids are the biomolecules of choice for storage of metabolic energy because they:
a. are soluble in water.
b. yield a large amount of energy upon oxidation.
c. are highly oxidized.
d. are easily hydrolyzed.
e. are amphipathic.
Q:
Alkali hydrolysis of triacylglycerols is called ____ and yields ____ and ____.
a. triacylation; fatty acids; glycerol
b. saponification; fatty alcohols; fatty acids
c. triesteration; salts of fatty acids, fatty alcohols
d. saponification; salts of fatty acids; glycerol
e. none are true
Q:
Dietary essential fatty acids for humans includea. -linolenic and oleic acids.b. oleic and linoleic acids.c. palmitic and oleic acids.d. linoleic and -linolenic acids.e. all are true.
Q:
Fatty acids are all EXCEPT:
a. either saturated or unsaturated.
b. found seldom in free form.
c. mostly found with an even number of carbons.
d. found in linear, branched and cyclic forms.
e. all are true.
Q:
A fatty acid with eighteen carbons and one double bond could be designated all EXCEPT:
a. linoleic acid.
b. 18:1.
c. cis-9-octadecenoic acid.
d. oleic acid.
e. elaidic acid
Q:
Which of the following would be the correct Haworth projection for ï¢-D-talose (linear form is shown on the left)? a. a
b. b
c. c
d. d
e. none of the above
Q:
Amylose and glycogen are both glucose polymers, yet they have somewhat different properties. What is one important difference between them?
a. One is made with D-glucose and the other with L-glucose
b. One is used as a structural polymer in insects; the other for energy in plants
c. One contains ï¡ glycosidic bonds while the other contains ï¢ glycosidic bonds
d. One is a linear polymer while the other is highly branched
e. none of the above explain the difference between amylose and glycogen
Q:
Which of the following statements is true regarding glycogen?a. the branches are formed by (2->6) glycosidic bondsb. glycogen is the primary energy storage molecule for animalsc. most of the glycosidic bonds are (1->4)d. glycogen is considered a heteropolysaccharidee. none of the above are true
Q:
Which of the following best describes the glycosidic bond below?a. (2->4)b. (1->3)c. (1->4)d. (1->3)e. (2->4)
Q:
Which of the following monosaccharides is an aldose? a. a
b. b
c. c
d. d
e. none of the above
Q:
Cartilage-matrix proteoglycan has all of the following properties EXCEPT:
a. responsible for the flexibility and resiliency of cartilage.
b. has a hyaluronic acid binding domain.
c. has reversible hydration-dehydration properties.
d. contains both N-linked and O-linked oligosaccharides.
e. is an integral transmembrane protein.
Q:
The core protein of a proteoglycan is noncovalently attached to:
a. oligosaccharides.
b. glycosaminoglycans.
c. keratin sulfate.
d. an outer protein.
e. hyaluronic acid backbone.
Q:
Which of the following represents an example of a proteoglycan?a. attachment of several molecules of heparin to the peptide antithrombin IIIb. attachment of a Gal-(1,3)-GalNAc disaccharide to the fish antifreeze proteinc. attachment of a small oligosaccharide to an immunoglobulind. attachment of a small antigenic determinant to a membrane bound protein of a celle. none of the above
Q:
Proteoglycans are a group of macromolecules formed from:
a. proteases and monosaccharides.
b. proteins and glycosaminoglycans.
c. proteins and polysaccharides.
d. proteases and glycosaminoglycans.
e. proteins and glycogen.
Q:
____ and ____ are found in tendons, cartilage and other connective tissue.
a. Heparin; chondroitins
b. Chondroitins; keratin sulfate
c. Keratin sulfate, dermatan sulfate
d. Hyaluronate, keratin sulfate
e. All are true.
Q:
Glycosaminoglycans are unbranched polysaccharides consisting of alternating residues of uronic acid and hexosamine. Which of the following is NOTa glycosaminoglycan?
a. agaropectin
b. heparin
c. dermatan sulfate
d. hyaluronate
e. chondroitin-4-sulfate
Q:
All are true for agarose EXCEPT:
a. Forms a double helix with a central core large enough to accommodate large quantities of water.
b. Consists of only a linear component.
c. Is a chain of alternating D-galactose and 3,6-anhydro-L-galactose, with side-chains of 6-methyl-D-galactose.
d. Readily forms gels that are up to 99.9% water.
e. All are true.
Q:
Cellulose and chitin are similar in all of the following ways EXCEPT:
a. Both are polymers of glucose.
b. Both are structural polysaccharides.
c. Both have extended ribbon conformations.
d. Both have extensive hydrogen bonding.
e. All are true.
Q:
Cellulase is considered a(n) ____.a. -(1->4) glucosidaseb. -(1->4) glucosidasec. -(1->6) glucosidased. (1->4) glucosidasee. -(1->1) glucosidase
Q:
Cellulose is extremely resistant to hydrolysis, but cellulase catalyzes the hydrolysis and comes from:
a. the pancreas.
b. bacteria that live in the rumen.
c. the liver.
d. H+ secreted into the rumen.
e. the intestinal wall.
Q:
All are true for cellulose and -amylose EXCEPT:a. Both are linear homopolymers of glucose.b. Both have (1->4) linkages.c. Both form extended ribbon most stable conformations.d. Both have extensive intramolecular hydrogen bonding.e. All are true.
Q:
Which of the following statements about cellulose fiber is true?a. It is a linear polymer of (1->4) glycosidic linked glucose and galactose residues.b. It is extremely susceptible to hydrolysis.c. It is water-soluble.d. It is made up of very weak microfibrils.e. Intermolecular hydrogen bonds play a major role in stabilization of the microfibrils.
Q:
All are true statements about dextrans EXCEPT:
a. They are used in research laboratories as a support for column chromatography (Sephadex or BioGel).
b. They are repeating units of isomaltose.
c. The branches may be 1ï‚®2, 1ï‚®3 or 1ï‚®4 in various species.
d. They are an important component of dental plaque.
e. All are true.
Q:
All of the following statements about the nature of glycogen are true EXCEPT:
a. It is a polysaccharide used for storage.
b. It is a branched polymer of linked glucose residues.
c. It has all non-reducing ends.
d. The highly branched structure allows the rapid mobilization of glucose during metabolic need.
e. It is found primarily in the liver and skeletal muscles.
Q:
____ is an enzyme found in liver and muscle tissue used to catalyze the phosphorolysis of glycogen to ____.a. (1->6)-Glucosidase; glucose-1-phosphateb. -Amylase; glucose-1-phosphatec. -Amylase; glucosed. Glycogen maltase; maltosee. Glycogen phosphorylase; glucose-1-phosphate