Question 1

Which of the following variables influences transport by mobile carriers and pores (or channels)?

Accepted Answer

A) pH 
B) ionic strength 
C) proton gradient 
D) temperature 
A) pH 
B) ionic strength 
C) proton gradient 
D) temperature

Question 2

Flippases are enzymes that flip cellular components.Which of the following best describes their mechanism of action?

Accepted Answer

A) flipping fatty acids from one position on glycerol to another position 
B) flipping glucose from a- to b-glucose 
C) flipping amino acids from one position to another in a protein 
D) flipping phospholipids across to the other side of a membrane 
A) flipping fatty acids from one position on glycerol to another position 
B) flipping glucose from a- to b-glucose 
C) flipping amino acids from one position to another in a protein 
D) flipping phospholipids across to the other side of a membrane

Question 3

Which of the following is a property of integral membrane proteins?

Accepted Answer

A) They only have hydrophobic surfaces. 
B) They have significant lateral mobility. 
C) They remain in the membrane when treated with salt solutions. 
D) They get exposed to one aqueous surface of the membrane. 
A) They only have hydrophobic surfaces. 
B) They have significant lateral mobility. 
C) They remain in the membrane when treated with salt solutions. 
D) They get exposed to one aqueous surface of the membrane.

Question 4

Which of the following best describes asymmetrical biological membranes?

Accepted Answer

A) The proteins are not evenly distributed over the surface of the membrane. 
B) Patches of cholesterol and other lipids occur on the surface of the membrane. 
C) The lipids are evenly distributed transversely in the membrane. 
D) Certain membrane proteins seem to prefer association with specific lipids. 
A) The proteins are not evenly distributed over the surface of the membrane. 
B) Patches of cholesterol and other lipids occur on the surface of the membrane. 
C) The lipids are evenly distributed transversely in the membrane. 
D) Certain membrane proteins seem to prefer association with specific lipids.

Question 5

Which of the following ions does the anion transporter of erythrocytes exchange HCO₃- for?

Accepted Answer

A) Cl- 
B) HPO4- 
C) Ca²⁺ 
D) H⁺ 
A) Cl- 
B) HPO4- 
C) Ca²⁺ 
D) H⁺

Question 6

Which of the following properties of lipids allows them to spontaneously form micelles,monolayers,and bilayers?

Accepted Answer

A) polyisoprenoid nature 
B) polar nature 
C) amphipathic nature 
D) bipolar nature 
A) polyisoprenoid nature 
B) polar nature 
C) amphipathic nature 
D) bipolar nature

Question 7

Which of the following is a component of the Ca²⁺-ATPase?

Accepted Answer

A) transmembrane domain of 12 a-helical segments 
B) an actuator domain 
C) a large extracellular domain with nucleotide binding domain 
D) a hydrolytic domain 
A) transmembrane domain of 12 a-helical segments 
B) an actuator domain 
C) a large extracellular domain with nucleotide binding domain 
D) a hydrolytic domain

Question 8

Which of the following structure(s)sequester(s)nearly all the calcium ions in muscle?

Accepted Answer

A) mitochondria 
B) sarcoplasmic reticulum 
C) endoplasmic reticulum 
D) secretory vesicles 
A) mitochondria 
B) sarcoplasmic reticulum 
C) endoplasmic reticulum 
D) secretory vesicles

Question 9

Which of the following fungal metabolites is a competitive inhibitor of facilitated diffusion glucose transport in erythrocytes?

Accepted Answer

A) amygdalin 
B) cytochalasin B 
C) dodecyl octa(oxyethylene)ether 
D) glycophorin 
A) amygdalin 
B) cytochalasin B 
C) dodecyl octa(oxyethylene)ether 
D) glycophorin

Question 10

Which of the following describes secondary active transport?

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,which drives uptake of sugars 
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,which drives uptake of sugars

Question 11

In eukaryotic cells phospholipids,glycolipids,and cholesterol are synthesized by enzymes located in the endoplasmic reticulum a Golgi.Which of the following mediates the flow of these components to other membranes in the cell?

Accepted Answer

A) osmosis 
B) flippases 
C) plasma membrane content 
D) lipid transfer proteins 
A) osmosis 
B) flippases 
C) plasma membrane content 
D) lipid transfer proteins

Question 12

The system A,for alanine transport into liver,can be activated by alanine and hormones.Which of the following terms defines the transport mechanism of system A?

Accepted Answer

A) Na+ symport 
B) K⁺ symport 
C) H⁺ antiport 
D) ATP antiport 
A) Na+ symport 
B) K⁺ symport 
C) H⁺ antiport 
D) ATP antiport

Question 13

Ouabain is an effective inhibitor of Na⁺,K⁺-ATPase.Which of the following characteristics does it exhibit?

Accepted Answer

A) It binds tightly to the enzyme/ATP complex in producing the inhibition. 
B) It contains an saturated lactone ring at C-17. 
C) It binds on the intracellular surface of Na+,K⁺-ATPase. 
D) It has a basic steroid structure. 
A) It binds tightly to the enzyme/ATP complex in producing the inhibition. 
B) It contains an saturated lactone ring at C-17. 
C) It binds on the intracellular surface of Na+,K⁺-ATPase. 
D) It has a basic steroid structure.

Question 14

Which of the following does NOT directly affect the ability of gap junctions to allow cells to communicate metabolically?

Accepted Answer

A) pH changes 
B) membrane potentials 
C) intracellular calcium levels 
D) DNA replication 
A) pH changes 
B) membrane potentials 
C) intracellular calcium levels 
D) DNA replication

Question 15

Which of the following is a feature of the membrane protein glycophorin?

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 b-barrel segments 
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 b-barrel segments

Question 16

Which of the following is a feature of liposomes?

Accepted Answer

A) They can be prepared with only one type of phospholipid. 
B) They are able to fuse with the nucleus. 
C) They are used to introduce contrast agents into the body for diagnostic imaging procedures. 
D) They are highly unstable structures. 
A) They can be prepared with only one type of phospholipid. 
B) They are able to fuse with the nucleus. 
C) They are used to introduce contrast agents into the body for diagnostic imaging procedures. 
D) They are highly unstable structures.

Question 17

Which of the following is a feature of melittin,a 26-residue peptide in honeybee venom?

Accepted Answer

A) It is a phospholipase that attacks red blood cells causing hemolysis. 
B) It is toxic to Na+,K⁺-ATPase. 
C) It forms a-helical aggregates with amphipathic character in membranes. 
D) It discharges mitochondrial proton gradients and thus inhibits ATP synthesis. 
A) It is a phospholipase that attacks red blood cells causing hemolysis. 
B) It is toxic to Na+,K⁺-ATPase. 
C) It forms a-helical aggregates with amphipathic character in membranes. 
D) It discharges mitochondrial proton gradients and thus inhibits ATP synthesis.

Question 18

Which of the following is NOT a similarity between muscle Ca²⁺-ATPase and Na⁺,K⁺-ATPase?

Accepted Answer

A) Both have residence on the sarcoplasmic reticulum. 
B) Both form covalent E-P intermediates during ATP hydrolysis. 
C) Both have similar mechanisms of ATP hydrolysis. 
D) Both have similar ion transport mechanisms. 
A) Both have residence on the sarcoplasmic reticulum. 
B) Both form covalent E-P intermediates during ATP hydrolysis. 
C) Both have similar mechanisms of ATP hydrolysis. 
D) Both have similar ion transport mechanisms.

Question 19

Which of the following structural motifs are utilized by the porin proteins?

Accepted Answer

A) single transmembrane a-helix 
B) multiple transmembrane a-helices 
C) single ?-sheet 
D) multiple ?-sheet 
A) single transmembrane a-helix 
B) multiple transmembrane a-helices 
C) single ?-sheet 
D) multiple ?-sheet

Question 20

Which of the following would be the most likely interaction between a membrane and a peripheral membrane protein that contained high lysine content?

Accepted Answer

A) ionic interaction 
B) hydrophobic interaction 
C) hydrogen bonding 
D) covalent bonding 
A) ionic interaction 
B) hydrophobic interaction 
C) hydrogen bonding 
D) covalent bonding

Exam 10: Membranes and Membrane Transport

Which of the following variables influences transport by mobile carriers and pores (or channels)?

Flippases are enzymes that flip cellular components.Which of the following best describes their mechanism of action?

Which of the following is a property of integral membrane proteins?

Which of the following best describes asymmetrical biological membranes?

Which of the following ions does the anion transporter of erythrocytes exchange HCO₃- for?

Which of the following properties of lipids allows them to spontaneously form micelles,monolayers,and bilayers?

Which of the following is a component of the Ca²⁺-ATPase?

Which of the following structure(s)sequester(s)nearly all the calcium ions in muscle?

Which of the following fungal metabolites is a competitive inhibitor of facilitated diffusion glucose transport in erythrocytes?

Which of the following describes secondary active transport?

In eukaryotic cells phospholipids,glycolipids,and cholesterol are synthesized by enzymes located in the endoplasmic reticulum a Golgi.Which of the following mediates the flow of these components to other membranes in the cell?

The system A,for alanine transport into liver,can be activated by alanine and hormones.Which of the following terms defines the transport mechanism of system A?

Ouabain is an effective inhibitor of Na⁺,K⁺-ATPase.Which of the following characteristics does it exhibit?

Which of the following does NOT directly affect the ability of gap junctions to allow cells to communicate metabolically?

Which of the following is a feature of the membrane protein glycophorin?

Which of the following is a feature of liposomes?

Which of the following is a feature of melittin,a 26-residue peptide in honeybee venom?

Which of the following is NOT a similarity between muscle Ca²⁺-ATPase and Na⁺,K⁺-ATPase?

Which of the following structural motifs are utilized by the porin proteins?

Which of the following would be the most likely interaction between a membrane and a peripheral membrane protein that contained high lysine content?

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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