Question 1

Which of the following is a common mechanism for the covalent attachment of a lipid to a peripheral membrane protein?

Accepted Answer

A) addition of a geranylgeranyl group to the hydroxyl of serine, forming an ether 
B) addition of a farnesyl group to the thiol of cysteine, forming a thioether 
C) addition of a myristoyl group to the amine of lysine, forming an amide 
D) reaction of the amine group of phosphatidylethanolamine with the carboxylate of glutamic acid, forming an amide 
E) all of the above 
A) addition of a geranylgeranyl group to the hydroxyl of serine, forming an ether 
B) addition of a farnesyl group to the thiol of cysteine, forming a thioether 
C) addition of a myristoyl group to the amine of lysine, forming an amide 
D) reaction of the amine group of phosphatidylethanolamine with the carboxylate of glutamic acid, forming an amide 
E) all of the above B

Question 2

Which of the following mechanisms of membrane transport is correctly defined?

Accepted Answer

A) simple diffusion: uses concentration gradient to move highly polar molecules and ions across membranes 
B) facilitated diffusion: uses proteins such as ion channels to move substances against their concentration gradient across a membrane 
C) primary active transport: uses ATP hydrolysis to move ions against their concentration gradient across a membrane 
D) secondary active transport: uses ATP hydrolysis along with an ion gradient to move polar molecules or ions against their concentration gradient across a membrane 
E) all of the above 
A) simple diffusion: uses concentration gradient to move highly polar molecules and ions across membranes 
B) facilitated diffusion: uses proteins such as ion channels to move substances against their concentration gradient across a membrane 
C) primary active transport: uses ATP hydrolysis to move ions against their concentration gradient across a membrane 
D) secondary active transport: uses ATP hydrolysis along with an ion gradient to move polar molecules or ions against their concentration gradient across a membrane 
E) all of the above C

Question 3

In animals, the bulk of energy is stored as __________.

Accepted Answer

A) fatty acids 
B) triacylglycerols 
C) glycogen 
D) waxes 
E) glycerophospholipids 
A) fatty acids 
B) triacylglycerols 
C) glycogen 
D) waxes 
E) glycerophospholipids B

Question 4

Which of the following would most likely move across a membrane by simple diffusion?

Accepted Answer

A) potassium ions 
B) glucose 
C) carbon dioxide 
D) sodium ions 
E) water 
A) potassium ions 
B) glucose 
C) carbon dioxide 
D) sodium ions 
E) water

Question 5

The fatty acid designated 18:2c$\Delta$9,12 is best described as a _______ fatty acid.

Accepted Answer

A) saturated 
B) unsaturated 
C) polyunsaturated 
D) hydrogenated 
E) partially hydrogenated 
A) saturated 
B) unsaturated 
C) polyunsaturated 
D) hydrogenated 
E) partially hydrogenated

Question 6

Which of the following is correctly defined?

Accepted Answer

A) sphingomyelin: ceramide + choline 
B) glycoglycerolipid: glycerol + fatty acid + monosaccharide + phosphate 
C) cerebroside: ceramide + monosaccharide 
D) ganglioside: sphingomyelin + oligosaccharide 
E) none of the above 
A) sphingomyelin: ceramide + choline 
B) glycoglycerolipid: glycerol + fatty acid + monosaccharide + phosphate 
C) cerebroside: ceramide + monosaccharide 
D) ganglioside: sphingomyelin + oligosaccharide 
E) none of the above

Question 7

A ceramide is derived from which combination of the following?

Accepted Answer

A) a molecule of sphingosine and a monosaccharide 
B) a molecule of sphingosine and a molecule of phosphocholine 
C) a molecule of sphingosine and a fatty acid 
D) a molecule of sphingosine and two fatty acids 
E) a molecule of sphingosine, a fatty acid and a monosaccharide 
A) a molecule of sphingosine and a monosaccharide 
B) a molecule of sphingosine and a molecule of phosphocholine 
C) a molecule of sphingosine and a fatty acid 
D) a molecule of sphingosine and two fatty acids 
E) a molecule of sphingosine, a fatty acid and a monosaccharide

Question 8

Movement of ions across a cell membrane by the Na/K ATPase is best described as ________.

Accepted Answer

A) sodium moved outside to inside, potassium inside to outside 
B) sodium moved inside to outside, potassium outside to inside 
C) sodium moved inside to outside, potassium inside to outside 
D) sodium moved outside to inside, potassium outside to inside 
E) none of the above 
A) sodium moved outside to inside, potassium inside to outside 
B) sodium moved inside to outside, potassium outside to inside 
C) sodium moved inside to outside, potassium inside to outside 
D) sodium moved outside to inside, potassium outside to inside 
E) none of the above

Question 9

A flippase is an enzyme that moves lipids from one side of a lipid bilayer to another in order to maintain the concentrations of specific lipids on each side of the bilayer. Which of the following can be said regarding the reaction of the flippase enzyme?

Accepted Answer

A) it works against a concentration gradient and requires ATP 
B) it works against a concentration gradient but does not require ATP 
C) it works with a concentration gradient and requires ATP 
D) it works with a concentration gradient but does not require ATP 
E) none of the above 
A) it works against a concentration gradient and requires ATP 
B) it works against a concentration gradient but does not require ATP 
C) it works with a concentration gradient and requires ATP 
D) it works with a concentration gradient but does not require ATP 
E) none of the above

Question 10

Draw a molecule of phosphatidylserine with palmitic acid (16:0)and oleic acid (18:1c$\Delta$9)present. Make sure to put the saturated and unsaturated fatty acids in their proper location.

Accepted Answer

The answer of Draw a molecule of phosphatidylserine with palmitic...

Question 11

Which of the following is used to drive glucose uptake by intestinal epithelial cells?

Accepted Answer

A) potassium gradient across the blood vessel/epithelial cell membrane 
B) potassium gradient across the intestinal lumen/epithelial cell membrane 
C) sodium gradient across the blood vessel/epithelial cell membrane 
D) sodium gradient across the intestinal lumen/epithelial cell membrane 
E) none of the above 
A) potassium gradient across the blood vessel/epithelial cell membrane 
B) potassium gradient across the intestinal lumen/epithelial cell membrane 
C) sodium gradient across the blood vessel/epithelial cell membrane 
D) sodium gradient across the intestinal lumen/epithelial cell membrane 
E) none of the above

Question 12

The movement of potassium ions across a membrane aided by valinomycin is an example of _______________.

Accepted Answer

A) facilitated diffusion by transport through a pore 
B) facilitated diffusion by transport using a carrier molecule 
C) facilitated diffusion by use of a permease 
D) primary active transport since valinomycin is a sodium-potassium ATPase 
E) secondary active transport since valinomycin only moves with the aid of the sodium ion gradient 
A) facilitated diffusion by transport through a pore 
B) facilitated diffusion by transport using a carrier molecule 
C) facilitated diffusion by use of a permease 
D) primary active transport since valinomycin is a sodium-potassium ATPase 
E) secondary active transport since valinomycin only moves with the aid of the sodium ion gradient

Question 13

Given the following concentrations (in mM)for sodium and potassium ions, a membrane potential of 60 mV (inside negative), a temperature of 37$\circ$C and a $\Delta$G for ATP hydrolysis of -51 kJ/mol, what is the % efficiency of the Na/K ATPase?
inside
outside
Na+
12
145
K+
140
4

Accepted Answer

For each ATP hydrolyzed, 3 Na⁺ and 2 K⁺ ar

Question 14

Partial hydrogenation accomplishes which of the following?

Accepted Answer

A) prevents oxidative cleavage of carbon-carbon double bonds, thus preventing spoilage of fats 
B) raises the melting point of fatty acids 
C) converts cis double bonds to trans double bonds 
D) converts oils into fats 
E) all of the above 
A) prevents oxidative cleavage of carbon-carbon double bonds, thus preventing spoilage of fats 
B) raises the melting point of fatty acids 
C) converts cis double bonds to trans double bonds 
D) converts oils into fats 
E) all of the above

Question 15

Addition of a functional group to the pro-R carbon of glycerol places that group on carbon _____ while addition of a second functional group to the pro-S carbon of glycerol places the second group on carbon _____ of sn-glycerol.

Accepted Answer

A) 1; 2 
B) 1; 3 
C) 3; 2 
D) 3; 1 
E) 2; 2 
A) 1; 2 
B) 1; 3 
C) 3; 2 
D) 3; 1 
E) 2; 2

Question 16

The sequence of glycophorin A displays which of the following?

Accepted Answer

A) the N-terminal domain contains large amounts of hydrophobic amino acids indicating only the N-terminus is embedded in the membrane 
B) the C-terminal domain contains a high concentration of Ser and Thr for attachment of O-linked oligosaccharides 
C) both the N-terminal and C-terminal domains contain high concentrations of Ser and Thr for attachment of O-linked oligosaccharides 
D) the middle portion contains large amounts of hydrophobic amino acids indicating a transmembrane protein 
E) none of the above 
A) the N-terminal domain contains large amounts of hydrophobic amino acids indicating only the N-terminus is embedded in the membrane 
B) the C-terminal domain contains a high concentration of Ser and Thr for attachment of O-linked oligosaccharides 
C) both the N-terminal and C-terminal domains contain high concentrations of Ser and Thr for attachment of O-linked oligosaccharides 
D) the middle portion contains large amounts of hydrophobic amino acids indicating a transmembrane protein 
E) none of the above

Question 17

The transient association of lipid rafts is thought to play a significant role in which of the following?

Accepted Answer

A) cell signaling 
B) bacterial entry into host cells 
C) protein trafficking 
D) membrane receptor dimerization 
E) all of the above 
A) cell signaling 
B) bacterial entry into host cells 
C) protein trafficking 
D) membrane receptor dimerization 
E) all of the above

Question 18

Which of the following does not specifically cause a membrane to be more rigid or fluid, but rather causes the Tm to occur over a greater range?

Accepted Answer

A) increasing the content of unsaturated fatty acids 
B) raising the temperature 
C) increasing the cholesterol content 
D) decreasing the phosphatidylcholine content while increasing the phosphatidylethanolamine content 
E) all of the above 
A) increasing the content of unsaturated fatty acids 
B) raising the temperature 
C) increasing the cholesterol content 
D) decreasing the phosphatidylcholine content while increasing the phosphatidylethanolamine content 
E) all of the above

Question 19

What alcohol containing a quaternary amine is commonly found esterified to glycerophospholipids?

Accepted Answer

A) ethanolamine 
B) choline 
C) serine 
D) inositol 
E) cholesterol 
A) ethanolamine 
B) choline 
C) serine 
D) inositol 
E) cholesterol

Question 20

Which of the following correctly relates the status of the sodium channel during an action potential cycle? (m-gate = activation gate, h-gate = inactivation gate)

Accepted Answer

A) while resting, both the m-gate and h-gate are closed 
B) during depolarization, both the m-gate and h-gate open allowing Na+ to exit the cell 
C) during repolarization, only the m-gate is closed 
D) during the refractory period, both the m-gate and h-gate are closed 
E) none of the above 
A) while resting, both the m-gate and h-gate are closed 
B) during depolarization, both the m-gate and h-gate open allowing Na+ to exit the cell 
C) during repolarization, only the m-gate is closed 
D) during the refractory period, both the m-gate and h-gate are closed 
E) none of the above

Exam 10: Lipids, Membranes and Cellular Transport

Which of the following is a common mechanism for the covalent attachment of a lipid to a peripheral membrane protein?

Which of the following mechanisms of membrane transport is correctly defined?

In animals, the bulk of energy is stored as __________.

Which of the following would most likely move across a membrane by simple diffusion?

The fatty acid designated 18:2c Δ\DeltaΔ 9,12 is best described as a _______ fatty acid.

Which of the following is correctly defined?

A ceramide is derived from which combination of the following?

Movement of ions across a cell membrane by the Na/K ATPase is best described as ________.

A flippase is an enzyme that moves lipids from one side of a lipid bilayer to another in order to maintain the concentrations of specific lipids on each side of the bilayer. Which of the following can be said regarding the reaction of the flippase enzyme?

Draw a molecule of phosphatidylserine with palmitic acid (16:0)and oleic acid (18:1c Δ\DeltaΔ 9)present. Make sure to put the saturated and unsaturated fatty acids in their proper location.

Which of the following is used to drive glucose uptake by intestinal epithelial cells?

The movement of potassium ions across a membrane aided by valinomycin is an example of _______________.

Given the following concentrations (in mM)for sodium and potassium ions, a membrane potential of 60 mV (inside negative), a temperature of 37 ∘\circ∘ C and a Δ\DeltaΔ G for ATP hydrolysis of -51 kJ/mol, what is the % efficiency of the Na/K ATPase? inside outside Na+ 12 145 K+ 140 4

Partial hydrogenation accomplishes which of the following?

Addition of a functional group to the pro-R carbon of glycerol places that group on carbon _____ while addition of a second functional group to the pro-S carbon of glycerol places the second group on carbon _____ of sn-glycerol.

The sequence of glycophorin A displays which of the following?

The transient association of lipid rafts is thought to play a significant role in which of the following?

Which of the following does not specifically cause a membrane to be more rigid or fluid, but rather causes the Tm to occur over a greater range?

What alcohol containing a quaternary amine is commonly found esterified to glycerophospholipids?

Which of the following correctly relates the status of the sodium channel during an action potential cycle? (m-gate = activation gate, h-gate = inactivation gate)

The Scope of Biochemistry

The Matrix of Life: Weak Interactions in an Aqueous Environment

The Energetics of Life

Nucleic Acids

Introduction to Proteins: the Primary Level of Protein Structure

The Three-Dimensional Structure of Proteins

Protein Function and Evolution

Contractile Proteins and Molecular Motors

Carbohydrates: Sugars, Saccharides, Glycans

Enzymes: Biological Catalysts

Chemical Logic of Metabolism

Carbohydrate Metabolism: Glycolysis, Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Citric Acid Cycle and Glyoxylate Cycle

Electron Transport, Oxidative Phosphorylation, and Oxygen Metabolism

Photosynthesis

Lipid Metabolism I: Fatty Acids, Triacylglycerols, and Lipoproteins

Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Lipid Metabolism Ii: Membrane Lipids, Steroids, Isoprenoids, and Eicosanoids

Metabolism of Nitrogenous Compounds I: Principles of Biosynthesis, Utilization, and Turnover

Metabolism of Nitogenous Compounds II: Amino Acids, Porphyrins, and Neurotransmitters

Nucleotide Metabolism

Mechanisms of Signal Transduction

Genes, Genomes and Chromosomes

DNA Replication

DNA Restructuring: Repair, Recombination, Rearrangement, Amplification

Information Readout: Transcription and Post-Transcriptional Processing

Information Decoding: Translation and Post-Translational Protein Processing

Regulation of Gene Expression

Filters

The fatty acid designated 18:2c $\Delta$ 9,12 is best described as a _______ fatty acid.

Draw a molecule of phosphatidylserine with palmitic acid (16:0)and oleic acid (18:1c $\Delta$ 9)present. Make sure to put the saturated and unsaturated fatty acids in their proper location.

Given the following concentrations (in mM)for sodium and potassium ions, a membrane potential of 60 mV (inside negative), a temperature of 37^$\circ$C and a $\Delta$ G for ATP hydrolysis of -51 kJ/mol, what is the % efficiency of the Na/K ATPase? inside outside Na⁺ 12 145 K⁺ 140 4

Addition of a functional group to the pro-R carbon of glycerol places that group on carbon _ while addition of a second functional group to the pro-S carbon of glycerol places the second group on carbon _ of sn-glycerol.

Which of the following does not specifically cause a membrane to be more rigid or fluid, but rather causes the T_m to occur over a greater range?