Question 1

Which of the following best describes the primary function of the SERCA pump in muscle cells?

Accepted Answer

To pump $$\mathrm{Ca$$^{2+}$$}$$ from the cytoplasm into the sarcoplasmic/endoplasmic reticulum

Question 2

What type of transport mechanism does the SERCA pump utilize?

Accepted Answer

Primary active transport

Question 3

Which ion is directly transported by the SERCA pump, and in which direction?

Accepted Answer

$$\mathrm{Ca$$^{2+}$$}$$ into the sarcoplasmic/endoplasmic reticulum

Question 4

Which of the following statements about the SERCA pump is FALSE?

Accepted Answer

It allows $$\mathrm{Ca$$^{2+}$$} to $$move passively down its concentration gradient

Question 5

During muscle contraction, what is the role of the SERCA pump in the relaxation phase?

Accepted Answer

It pumps $$\mathrm{Ca$$^{2+}$$}$$ back into the sarcoplasmic reticulum, lowering cytoplasmic $$\mathrm{Ca$$^{2+}$$}$$

Question 6

Which of the following best explains why the SERCA pump is classified as a primary active transporter?

Accepted Answer

It directly hydrolyzes ATP to move ions against their gradient

Question 7

A mutation in the SERCA pump that prevents ATP binding would most likely result in which of the following?

Accepted Answer

Increased cytoplasmic $$\mathrm{Ca$$^{2+}$$}$$ concentration

Question 8

Which of the following equations best represents the reaction catalyzed by the SERCA pump?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H_2O} + \mathrm{Ca$$^{2+}$$}_{cyto} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \mathrm{Ca$$^{2+}$$}_{ER}$$

Question 9

If the SERCA pump is inhibited by a toxin, what would be the expected effect on muscle cell function?

Accepted Answer

Prolonged muscle contraction due to elevated cytoplasmic $$\mathrm{Ca$$^{2+}$$}$$

Question 10

Which of the following is a distinguishing feature of P-type ATPases such as SERCA?

Accepted Answer

They form a phosphorylated intermediate during the transport cycle

Question 11

A researcher adds a non-hydrolyzable ATP analog to a preparation of muscle cells. What is the most likely effect on SERCA pump activity?

Accepted Answer

SERCA activity will decrease because ATP hydrolysis is required for function

Question 12

Which of the following best describes the energy coupling in the SERCA pump?

Accepted Answer

The energy from ATP hydrolysis is used to move $$\mathrm{Ca$$^{2+}$$}$$ against its concentration gradient

Question 13

Which of the following would most likely occur if the SERCA pump was overactive in a muscle cell?

Accepted Answer

Cytoplasmic $$\mathrm{Ca$$^{2+}$$}$$ would decrease rapidly, leading to impaired muscle contraction

Question 14

Which of the following is NOT a characteristic of the SERCA pump?

Accepted Answer

It transports $$\mathrm{Ca$$^{2+}$$}$$ into the cytoplasm

SERCA Calcium Ion Pump: Mechanism and Function

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