Question 1

Which of the following is true regarding membrane function?

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 with the aid of a SNARE protein 
E)  both b and d are correct 
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 E

Question 2

The Ca2+-ATPase structure is like many of the other active transport proteins in that it has all of the components EXCEPT:

Accepted Answer

A)  transmembrane domain of ten α-helical segments. 
B)  a large cytoplasmic domain with nucleotide binding domain. 
C)  a phosphorylation domain. 
D)  an actuator domain. 
E)  all are true. 
A)  transmembrane domain of ten α-helical segments. 
B)  a large cytoplasmic domain with nucleotide binding domain. 
C)  a phosphorylation domain. 
D)  an actuator domain. 
E)  all are true. E

Question 3

Multiple Drug Resistant (MDR)-ATPase is a ____ repeat protein that uses ATP hydrolysis to actively transport a wide variety of drugs ____ the cell.

Accepted Answer

A)  multiple; into 
B)  multiple; out of 
C)  tandem; into 
D)  tandem; out of 
E)  triple; into 
A)  multiple; into 
B)  multiple; out of 
C)  tandem; into 
D)  tandem; out of 
E)  triple; into D

Question 4

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 by utilizing extensive:

Accepted Answer

A)  salt bridge formation. 
B)  disulfide bond formation. 
C)  β-turns. 
D)  α-helices and β-sheets. 
E)  none of the above. 
A)  salt bridge formation. 
B)  disulfide bond formation. 
C)  β-turns. 
D)  α-helices and β-sheets. 
E)  none of the above.

Question 5

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?

Accepted Answer

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 
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

Question 6

Which of the following IS NOT a property of integral membrane proteins (intrinsic proteins)?

Accepted Answer

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 
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

Question 7

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?

Accepted Answer

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 
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

Question 8

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 ____.

Accepted Answer

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 
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

Question 9

Explain how gradients of Na+ and H+ drive secondary active transport systems.​

Accepted Answer

The gradients of H⁺, Na⁺, and other cation

Question 10

Bacteriorhodopsin affects a light driven ____ proton transport that results in a proton gradient sufficient to drive ____.

Accepted Answer

A)  inward; Na+-import 
B)  outward; ATP synthesis 
C)  inward; K+-export 
D)  outward; light emission 
E)  none are true 
A)  inward; Na+-import 
B)  outward; ATP synthesis 
C)  inward; K+-export 
D)  outward; light emission 
E)  none are true

Question 11

The Ras proteins are associated to the membrane via what mechanism?

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 
E)  both b and c 
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

Question 12

The System A for alanine transport into liver is a(n) ____ system that can be activated by ____ and ____.

Accepted Answer

A)  Na+-symport; substrate (alanine); hormones 
B)  K+-symport; substrate (alanine); hormones 
C)  H+-antiport; pH change; alanine 
D)  ATP-antiport; alanine; pH change 
E)  None are true 
A)  Na+-symport; substrate (alanine); hormones 
B)  K+-symport; substrate (alanine); hormones 
C)  H+-antiport; pH change; alanine 
D)  ATP-antiport; alanine; pH change 
E)  None are true

Question 13

Liposomes are all EXCEPT:

Accepted Answer

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. 
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.

Question 14

Secondary active transport is:

Accepted Answer

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. 
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.

Question 15

In passive diffusion, the transported species moves across the membrane in the ____ favored direction ____.

Accepted Answer

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. 
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.

Question 16

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

Accepted Answer

A)  monolayer 
B)  bilayer 
C)  liposome 
D)  micelle 
E)  an inside out micelle 
A)  monolayer 
B)  bilayer 
C)  liposome 
D)  micelle 
E)  an inside out micelle

Question 17

In the Na+, K+-ATPase mechanism, ATP is involved in all EXCEPT:

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. 
E)  none of the above. 
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.

Question 18

The two major phospholipids on the outer leaflet of erythrocytes are:

Accepted Answer

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

Question 19

Glycophorin is a membrane protein with:

Accepted Answer

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 β-barrel segments. 
E)  All are true 
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 β-barrel segments. 
E)  All are true

Question 20

Lipids that spontaneously form micelles, monolayers and bilayers have what property?

Accepted Answer

A)  waxy 
B)  polar 
C)  amphipathic 
D)  bipolar 
E)  polyisoprenoid 
A)  waxy 
B)  polar 
C)  amphipathic 
D)  bipolar 
E)  polyisoprenoid

Exam 9: Membranes and Membrane Transport

Which of the following is true regarding membrane function?

The Ca2+-ATPase structure is like many of the other active transport proteins in that it has all of the components EXCEPT:

Multiple Drug Resistant (MDR)-ATPase is a ____ repeat protein that uses ATP hydrolysis to actively transport a wide variety of drugs ____ the cell.

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 by utilizing extensive:

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?

Which of the following IS NOT a property of integral membrane proteins (intrinsic proteins)?

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 ____.

Explain how gradients of Na+ and H+ drive secondary active transport systems.​

Bacteriorhodopsin affects a light driven ____ proton transport that results in a proton gradient sufficient to drive ____.

The Ras proteins are associated to the membrane via what mechanism?

The System A for alanine transport into liver is a(n) ____ system that can be activated by ____ and ____.

Liposomes are all EXCEPT:

Secondary active transport is:

In passive diffusion, the transported species moves across the membrane in the ____ favored direction ____.

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

In the Na+, K+-ATPase mechanism, ATP is involved in all EXCEPT:

The two major phospholipids on the outer leaflet of erythrocytes are:

Glycophorin is a membrane protein with:

Lipids that spontaneously form micelles, monolayers and bilayers have what property?

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

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids and the Peptide Bond

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, Tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Recombinant Dna, Cloning, Chimeric Genes, and Synthetic Biology

Enzymeskinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Metabolism: an Overview

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Lipid Biosynthesis

Nitrogen Acquisition and Amino Acid Metabolism

Synthesis and Degradation of Nucleotides

Metabolic Integration and Organ Specialization

Dna Metabolism: Replication, Recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

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

The Reception and Transmission of Extracellular Information

Filters

The Ca²⁺-ATPase structure is like many of the other active transport proteins in that it has all of the components EXCEPT:

Multiple Drug Resistant (MDR)-ATPase is a repeat protein that uses ATP hydrolysis to actively transport a wide variety of drugs the cell.

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 .

Explain how gradients of Na⁺ and H⁺ drive secondary active transport systems.

Bacteriorhodopsin affects a light driven proton transport that results in a proton gradient sufficient to drive .

The System A for alanine transport into liver is a(n) system that can be activated by and .

In passive diffusion, the transported species moves across the membrane in the favored direction .

In the Na⁺, K⁺-ATPase mechanism, ATP is involved in all EXCEPT: