Question 1

Which of the following is a plant extract of steroids used to treat heart failure?

Accepted Answer

A)  digitalis 
B)  nitroglycerin 
C)  St. John's wort 
D)  salicylic acid 
E)  warfarin 
A)  digitalis 
B)  nitroglycerin 
C)  St. John's wort 
D)  salicylic acid 
E)  warfarin

Question 2

The acetylcholine receptor is an example of a ____________-gated channel.

Accepted Answer

The answer of The acetylcholine receptor is an example of...

Question 3

Which of the following are true about gap junctions?

Accepted Answer

A)  They are important for intercellular communication. 
B)  Polar molecules smaller than 1 kDa can pass through them. 
C)  The channels stay open seconds to minutes. 
D)  All of the answers are correct. 
E)  None of the answers is correct. 
A)  They are important for intercellular communication. 
B)  Polar molecules smaller than 1 kDa can pass through them. 
C)  The channels stay open seconds to minutes. 
D)  All of the answers are correct. 
E)  None of the answers is correct.

Question 4

Explain how a voltage-gated channel opens.

Accepted Answer

The voltage-gated channel is composed of

Question 5

What are the similarities between sodium,potassium,and calcium ion channels?

Accepted Answer

A)  All allow passage of multiple different ions. 
B)  They contain homologous domains in the membrane spanning regions. 
C)  They all contain voltage-sensing segments that close the channel in response to a particular membrane potential. 
D)  They are capable of moving ions in both directions across a membrane. 
E)  None of the answers is correct. 
A)  All allow passage of multiple different ions. 
B)  They contain homologous domains in the membrane spanning regions. 
C)  They all contain voltage-sensing segments that close the channel in response to a particular membrane potential. 
D)  They are capable of moving ions in both directions across a membrane. 
E)  None of the answers is correct.

Question 6

Ion channels

Accepted Answer

A)  can be selective. 
B)  exist in open and closed states. 
C)  in the open state often spontaneously convert into an inactivated state. 
D)  can be selective and exist in open and closed states. 
E)  All of the answers are correct. 
A)  can be selective. 
B)  exist in open and closed states. 
C)  in the open state often spontaneously convert into an inactivated state. 
D)  can be selective and exist in open and closed states. 
E)  All of the answers are correct.

Question 7

Why are gap junctions sealed when high concentrations of calcium ions and protons are present?

Accepted Answer

These conditions are common wh

Question 8

How does active transport differ from passive?

Accepted Answer

In active transport,molecules

Question 9

If the selectivity filter binds the potassium ion tightly,how are ions released to pass through the membrane?

Accepted Answer

The selectivity filter has four binding

Question 10

What type of membrane transporter moves two species in opposite directions across a membrane?

Accepted Answer

A)  symporter 
B)  antiporter 
C)  uniporter 
D)  cotransporter 
E)  None of the answers is correct. 
A)  symporter 
B)  antiporter 
C)  uniporter 
D)  cotransporter 
E)  None of the answers is correct.

Question 11

Membrane transporters that couple the downhill flow of one species to the uphill flow of another species in the opposite direction are called

Accepted Answer

A)  antiporters. 
B)  symporters. 
C)  exchangers. 
D)  P-type transporters. 
E)  None of the answers is correct. 
A)  antiporters. 
B)  symporters. 
C)  exchangers. 
D)  P-type transporters. 
E)  None of the answers is correct.

Question 12

In the potassium ion channel,which of the following is critical in the function of the selectivity filter?

Accepted Answer

A)  The K+ binds to a critical Glu residue. 
B)  The K+ binds to the amide groups of three residues in the selectivity filter. 
C)  The K+ binds to the carbonyl groups of the backbone of a conserved pentapeptide sequence. 
D)  An ATP molecule must be bound for the selectivity filter to operate. 
E)  None of the answers is correct. 
A)  The K+ binds to a critical Glu residue. 
B)  The K+ binds to the amide groups of three residues in the selectivity filter. 
C)  The K+ binds to the carbonyl groups of the backbone of a conserved pentapeptide sequence. 
D)  An ATP molecule must be bound for the selectivity filter to operate. 
E)  None of the answers is correct.

Exam 13: Membrane Channels and Pumps

Which of the following is a plant extract of steroids used to treat heart failure?

The acetylcholine receptor is an example of a ____________-gated channel.

Which of the following are true about gap junctions?

Explain how a voltage-gated channel opens.

What are the similarities between sodium,potassium,and calcium ion channels?

Ion channels

Why are gap junctions sealed when high concentrations of calcium ions and protons are present?

How does active transport differ from passive?

If the selectivity filter binds the potassium ion tightly,how are ions released to pass through the membrane?

What type of membrane transporter moves two species in opposite directions across a membrane?

Membrane transporters that couple the downhill flow of one species to the uphill flow of another species in the opposite direction are called

In the potassium ion channel,which of the following is critical in the function of the selectivity filter?

Biochemistry: An Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

Oxidative Phosphorylation

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Nucleotide Biosynthesis

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

DNA Replication, repair, and Recombination

RNA Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

Drug Development

Filters