Question 1

Which of the following mechanisms associates the Ras proteins to the membrane?

Accepted Answer

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 
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 B

Question 2

People with high blood pressure have high blood levels of an endogenous Na⁺,K⁺-ATPase inhibitor.Which of the following 2 ions accumulate in cells lining the blood vessel wall as a result of this?

Accepted Answer

A) magnesium and sodium 
B) hydrogen and calcium 
C) sodium and calcium 
D) magnesium and calcium 
A) magnesium and sodium 
B) hydrogen and calcium 
C) sodium and calcium 
D) magnesium and calcium C

Question 3

Which of the following terms represent 12-TMS?

Accepted Answer

A) 12-trans-methyl synthase 
B) 12-tris-methyl sulfate 
C) 12-trans-model symmetry 
D) 12-transmembrane segments 
A) 12-trans-methyl synthase 
B) 12-tris-methyl sulfate 
C) 12-trans-model symmetry 
D) 12-transmembrane segments D

Question 4

In the Na⁺,K⁺-ATPase mechanism,which of the following processes does NOT involve ATP?

Accepted Answer

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 
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

Question 5

Which of the following does the tandem repeat protein multiple drug resistant (MDR)-ATPase use to actively transport a wide variety of drugs out of the cell?

Accepted Answer

A) GTP hydrolysis 
B) calcium gradient 
C) glucose gradient 
D) ATP hydrolysis 
A) GTP hydrolysis 
B) calcium gradient 
C) glucose gradient 
D) ATP hydrolysis

Question 6

Which of the following is correct regarding the phase transitions of lipid bilayers?

Accepted Answer

A) Solutes interacting with membrane lipids affect transition temperatures. 
B) The transitions are exothermic. 
C) Pure phospholipid bilayers have wide transition ranges. 
D) Functional group changes usually are associated with phase transitions. 
A) Solutes interacting with membrane lipids affect transition temperatures. 
B) The transitions are exothermic. 
C) Pure phospholipid bilayers have wide transition ranges. 
D) Functional group changes usually are associated with phase transitions.

Question 7

How are G protein-α-subunits anchored into membranes?

Accepted Answer

A) by amine-linked myristoyl anchors 
B) by thioester-linked fatty acyl anchors 
C) by amide-linked prenyl anchors 
D) by thioester-linked prenyl anchors 
A) by amine-linked myristoyl anchors 
B) by thioester-linked fatty acyl anchors 
C) by amide-linked prenyl anchors 
D) by thioester-linked prenyl anchors

Question 8

Which of the following is an example of a unilamellar vesicle?

Accepted Answer

A) a monolayer 
B) a bilayer 
C) a liposome 
D) a micelle 
A) a monolayer 
B) a bilayer 
C) a liposome 
D) a micelle

Question 9

Which of the following is a unique characteristic of active transport?

Accepted Answer

A) transport of hydrophobic molecules 
B) absolute requirement for ATP hydrolysis and light energy,or ion gradient energy will not work 
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 unfavourable reaction 
A) transport of hydrophobic molecules 
B) absolute requirement for ATP hydrolysis and light energy,or ion gradient energy will not work 
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 unfavourable reaction

Question 10

What do hydropathy plots for transport proteins reveal?

Accepted Answer

A) amino acid residues that may be highly modified 
B) amino acid residues that 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 that are hyperreactive due to their location 
A) amino acid residues that may be highly modified 
B) amino acid residues that 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 that are hyperreactive due to their location

Question 11

Which of the following is a characteristic for facilitated diffusion of neutral metabolites?

Accepted Answer

A) Lineweaver-Burk plots which pass through the origin 
B) a linear plot when velocity is plotted versus the concentration of the metabolite 
C) an upper limit in the transport velocity as the metabolite concentration increases 
D) the ability to facilitate net movement against the thermodynamically favoured direction 
A) Lineweaver-Burk plots which pass through the origin 
B) a linear plot when velocity is plotted versus the concentration of the metabolite 
C) an upper limit in the transport velocity as the metabolite concentration increases 
D) the ability to facilitate net movement against the thermodynamically favoured direction

Question 12

Ionophore antibiotics are small-molecule toxins produced by microorganisms to facilitate ion transport across membranes.Which of the following antibiotics is NOT an ionophore?

Accepted Answer

A) actinomycin 
B) valinomycin 
C) nonactin 
D) monensin 
A) actinomycin 
B) valinomycin 
C) nonactin 
D) monensin

Question 13

Which of the following describes the energy and transport systems,respectively,associated with passive diffusion?

Accepted Answer

A) kinetically favoured;using a transport protein 
B) kinetically favoured;without a specific transport system/molecule 
C) thermodynamically favoured;using a transport protein 
D) thermodynamically favoured;without a specific transport system/molecule 
A) kinetically favoured;using a transport protein 
B) kinetically favoured;without a specific transport system/molecule 
C) thermodynamically favoured;using a transport protein 
D) thermodynamically favoured;without a specific transport system/molecule

Question 14

Which of the following is a characteristic of the gastric proton pump?

Accepted Answer

A) It is a H⁺,K⁺-ATPase. 
B) It requires high levels of dietary K⁺ to create a K⁺ gradient. 
C) It maintains a pH gradient of about 4.6 across the mucosal cell membrane. 
D) It produces a net efflux of HCl into the stomach. 
A) It is a H⁺,K⁺-ATPase. 
B) It requires high levels of dietary K⁺ to create a K⁺ gradient. 
C) It maintains a pH gradient of about 4.6 across the mucosal cell membrane. 
D) It produces a net efflux of HCl into the stomach.

Question 15

Which of the following regarding membrane function is correct?

Accepted Answer

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 independently of a SNARE protein. 
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 independently of a SNARE protein.

Question 16

Which of the following are the 2 major phospholipids on the outer leaflet of erythrocytes?

Accepted Answer

A) phosphatidylcholine and phosphatidylethanolamine 
B) phosphatidylcholine and sphingomyelin 
C) phosphatidylethanolamine and sphingomyelin 
D) phosphatidylserine and sphingomyelin 
A) phosphatidylcholine and phosphatidylethanolamine 
B) phosphatidylcholine and sphingomyelin 
C) phosphatidylethanolamine and sphingomyelin 
D) phosphatidylserine and sphingomyelin

Question 17

Pore-forming toxins solve the problem of a need to provide hydrogen-bonding partners for the polypeptide background N-H and C=O groups in the bilayer that lacks hydrogen-bond donors and acceptors.Which of the following structure(s)do they use extensively to do this?

Accepted Answer

A) salt bridge formation 
B) disulfide bond formation 
C) β-turns 
D) α-helices and b-sheets 
A) salt bridge formation 
B) disulfide bond formation 
C) β-turns 
D) α-helices and b-sheets

Question 18

Yeast α-factor ATPase and MDR ATPase are 2 members of a superfamily of transport proteins.Which of the following do they both actively transport?

Accepted Answer

A) H⁺ to dissolve bone mineral 
B) Ca²⁺ into the sarcoplasm 
C) a broad group of diverse organic molecules across membranes 
D) Mg²⁺ against a concentration gradient 
A) H⁺ to dissolve bone mineral 
B) Ca²⁺ into the sarcoplasm 
C) a broad group of diverse organic molecules across membranes 
D) Mg²⁺ against a concentration gradient

Question 19

Bacteriorhodopsin affects a light-driven outward proton transport that results in a proton gradient.Which of the following processes can sufficiently be driven by this proton gradient?

Accepted Answer

A) Na+ import 
B) ATP synthesis 
C) K⁺ export 
D) light emission 
A) Na+ import 
B) ATP synthesis 
C) K⁺ export 
D) light emission

Question 20

H⁺-transporting ATPases are found in osteoclasts and break down bone during normal bone remodelling.Which of the following types of ATPases are they?

Accepted Answer

A) vacuolar (V-) 
B) H⁺,K⁺-ATPase 
C) H⁺,Na+-ATPase 
D) Na+,K⁺-ATPase 
A) vacuolar (V-) 
B) H⁺,K⁺-ATPase 
C) H⁺,Na+-ATPase 
D) Na+,K⁺-ATPase

Exam 10: Membranes and Membrane Transport

Which of the following mechanisms associates the Ras proteins to the membrane?

People with high blood pressure have high blood levels of an endogenous Na⁺,K⁺-ATPase inhibitor.Which of the following 2 ions accumulate in cells lining the blood vessel wall as a result of this?

Which of the following terms represent 12-TMS?

In the Na⁺,K⁺-ATPase mechanism,which of the following processes does NOT involve ATP?

Which of the following does the tandem repeat protein multiple drug resistant (MDR)-ATPase use to actively transport a wide variety of drugs out of the cell?

Which of the following is correct regarding the phase transitions of lipid bilayers?

How are G protein-α-subunits anchored into membranes?

Which of the following is an example of a unilamellar vesicle?

Which of the following is a unique characteristic of active transport?

What do hydropathy plots for transport proteins reveal?

Which of the following is a characteristic for facilitated diffusion of neutral metabolites?

Ionophore antibiotics are small-molecule toxins produced by microorganisms to facilitate ion transport across membranes.Which of the following antibiotics is NOT an ionophore?

Which of the following describes the energy and transport systems,respectively,associated with passive diffusion?

Which of the following is a characteristic of the gastric proton pump?

Which of the following regarding membrane function is correct?

Which of the following are the 2 major phospholipids on the outer leaflet of erythrocytes?

Pore-forming toxins solve the problem of a need to provide hydrogen-bonding partners for the polypeptide background N-H and C=O groups in the bilayer that lacks hydrogen-bond donors and acceptors.Which of the following structure(s)do they use extensively to do this?

Yeast α-factor ATPase and MDR ATPase are 2 members of a superfamily of transport proteins.Which of the following do they both actively transport?

Bacteriorhodopsin affects a light-driven outward proton transport that results in a proton gradient.Which of the following processes can sufficiently be driven by this proton gradient?

H⁺-transporting ATPases are found in osteoclasts and break down bone during normal bone remodelling.Which of the following types of ATPases are they?

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Lipid Biosynthesis

The Reception and Transmission of Extracellular Information

Enzymes Kinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Nutrition and the Organization of Metabolism

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Nitrogen Acquisition and Amino Acid Metabolism

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Synthesis and Degradation of Nucleotides

Recombinant Dna: Cloning and Creation of Chimeric Genes

DNA Metabolism: Replication, recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Post-Transcriptional Regulation of Gene Expression

Completing the Protein Life Cycle: Folding, processing, and Degradation

Metabolic Integration and Organ Specialization

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