Question 1

Which of the following best describes the primary function of ABC transporters in cellular membranes?

Accepted Answer

They use the energy from ATP hydrolysis to actively transport substrates across the membrane.

Question 2

What is the role of the nucleotide-binding domains (NBDs) in ABC transporters?

Accepted Answer

They bind and hydrolyze ATP to provide energy for substrate transport.

Question 3

A mutation in the ATP-binding site of an ABC transporter would most likely result in which of the following?

Accepted Answer

Loss of ATP hydrolysis and impaired substrate transport.

Question 4

Which of the following nucleotides is hydrolyzed by ABC transporters to drive substrate movement?

Accepted Answer

ATP

Question 5

In the context of multidrug resistance in cancer, what is the significance of ABC transporters such as P-glycoprotein?

Accepted Answer

They pump chemotherapeutic drugs out of tumor cells, reducing drug efficacy.

Question 6

Which of the following statements is TRUE regarding the structure of ABC transporters?

Accepted Answer

They contain two transmembrane domains and two nucleotide-binding domains.

Question 7

A cell with a higher concentration of ATP is likely to exhibit which of the following regarding ABC transporter activity?

Accepted Answer

Increased substrate transport due to more available energy for the transporter.

Question 8

Which of the following best explains why ABC transporters are important in pharmacology?

Accepted Answer

They can mediate drug resistance by exporting drugs out of cells.

Question 9

Which of the following is a key difference between ABC transporters and P-type ATPases?

Accepted Answer

ABC transporters hydrolyze ATP to transport substrates, while P-type ATPases form a phosphorylated intermediate during transport.

Question 10

Which of the following statements about the mechanism of ABC transporters is CORRECT?

Accepted Answer

ATP binding induces a conformational change that allows substrate translocation.

Question 11

A patient is found to have a genetic defect in an ABC transporter responsible for cholesterol transport. Which of the following is a likely consequence?

Accepted Answer

Accumulation of cholesterol in cells leading to disease.

Question 12

Which of the following best describes the energy coupling in ABC transporter-mediated substrate movement?

Accepted Answer

The energy from ATP hydrolysis is directly used to change the conformation of the transporter.

Question 13

Which of the following is a common misconception about ABC transporters?

Accepted Answer

They always import substrates into the cell.

Question 14

Which of the following steps occurs FIRST in the transport cycle of an ABC transporter?

Accepted Answer

Binding of substrate to the transmembrane domain.

Question 15

Which of the following is a direct result of ATP binding to the nucleotide-binding domains of an ABC transporter?

Accepted Answer

Opening of the transporter to the opposite side of the membrane.

ABC Transporters: Structure, Function, and Role in Multidrug Resistance

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