PCB 3023 Final Exam 08/27/2026
PCB 3023 Final Exam 1: (Latest Update 2026 /
2027) Molecular Cell Biology | Questions &
Answers | Grade A | 100% Correct - UCF
Pumps are transporters that are able to harness energy provided by other components in the cells to
drive the movement of solutes across membranes, against their concentration gradient. This type of
transport is called _____________.
(a) active transport.
(b) free diffusion.
(c) facilitated diffusion.
(d) passive transport. –
Correct Answer :(a) active transport.
Active transport requires the input of energy into a system so as to move solutes against their
electrochemical and concentration gradients. Which of the following is not one of the common ways
to perform active transport?
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, PCB 3023 Final Exam 08/27/2026
(a) Na+-coupled
(b) K+-coupled
(c) ATP-driven
(d) light-driven –
Correct Answer :(b) K+-coupled
The Na+-K+ ATPase is also known as the Na+-K+ pump. It is responsible for maintaining the high
extracellular sodium ion concentration and the high intracellular potassium ion concentration. What
happens immediately after the pump hydrolyzes ATP?
(a) Na+ is bound
(b) ADP is bound
(c) the pump is phosphorylated
(d) the pump changes conformation –
Correct Answer :(c) the pump is phosphorylated
The Aeroschmidt weed contains an ATP-driven ion pump in its vacuolar membrane that pumps
potentially toxic heavy metal ions such as Zn2+ and Pb2+ into the vacuole. The pump protein exists in
a phosphorylated and an unphosphorylated form and works in a similar way to the Na+-K+ pump of
animal cells. To study its action, you incorporate the unphosphorylated form of the protein into
phospholipid vesicles containing K+ in their interiors. (You ensure that all of the protein molecules are
in the same orientation in the lipid bilayer.) When you add Zn2+ and ATP to the solution outside such
vesicles, you find that Zn2+ is pumped into the vesicle lumen. You then expose vesicles containing the
pump protein to the solutes shown in Table Q12-25A.
Table Q12-25A
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, PCB 3023 Final Exam 08/27/2026
You then determine the amount of phosphorylated and unphosphorylated ATP-driven ion pump
protein in each sample. Your results are summarized in Table Q12-25B, where a - Correct Answer :(d) A
small amount of Zn2+ will move into the vesicle; no K+ will move out of the vesicle; the protein will
become unphosphorylated.
You have generated antibodies that recognize the extracellular domain of the Ca2+-pump. Adding
these antibodies to animal cells blocks the active transport of Ca2+ from the cytosol into the
extracellular environment. What do you expect to observe with respect to intracellular Ca2+?
(a) Ca2+-pumps in vesicle membranes keep cytosolic calcium levels low.
(b) Ca2+-pumps in the endoplasmic reticulum membrane keep cytosolic calcium levels low.
(c) Ca2+-pumps in the Golgi apparatus keep cytosolic calcium levels low.
(d) Ca2+ concentrations in the cytosol increase at a steady rate. –
Correct Answer :(b) Ca2+-pumps in the endoplasmic reticulum membrane keep cytosolic calcium
levels low.
Cells make use of H+ electrochemical gradients in many ways. Which of the following proton
transporters is used to regulate pH in animal cells?
(a) light-driven pump
(b) H+ ATPase
(c) H+ symporter
(d) Na+-H+ exchanger –
Correct Answer :(d) Na+-H+ exchanger
Which of the following statements is true?
(a) Amoebae have transporter proteins that actively pump water molecules from the cytoplasm to the
cell exterior.
(b) Bacteria and animal cells rely on the Na+-K+ pump in the plasma membrane to prevent lysis
resulting from osmotic imbalances.
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, PCB 3023 Final Exam 08/27/2026
(c) The Na+-K+ pump allows animal cells to thrive under conditions of very low ionic strength.
(d) The Na+-K+ pump helps to keep both Na+ and Cl- ions out of the cell.
- Correct Answer :(d) The Na+-K+ pump helps to keep both Na+ and Cl- ions out of the cell.
Ca2+-pumps in the plasma membrane and endoplasmic reticulum are important for _____________.
(a) maintaining osmotic balance.
(b) preventing Ca2+ from altering the activity of molecules in the cytosol.
(c) providing enzymes in the endoplasmic reticulum with Ca2+ ions that are necessary for their
catalytic activity.
(d) maintaining a negative membrane potential. –
Correct Answer :(b) preventing Ca2+ from altering the activity of molecules in the cytosol.
Which of the following occur without coupling transport of the solute to the movement of a second
solute?
(a) import of glucose into gut epithelial cells
(b) export of Ca2+ from the cytosol
(c) export of H+ from animal cells for pH regulation
(d) the export of Na+ from cells to maintain resting membrane potential –
Correct Answer :(b) export of Ca2+ from the cytosol
Which of the following best describes the behavior of a gated channel?
(a) It stays open continuously when stimulated.
(b) It opens more frequently in response to a given stimulus.
(c) It opens more widely as the stimulus becomes stronger.
P a g e 4 | 61
PCB 3023 Final Exam 1: (Latest Update 2026 /
2027) Molecular Cell Biology | Questions &
Answers | Grade A | 100% Correct - UCF
Pumps are transporters that are able to harness energy provided by other components in the cells to
drive the movement of solutes across membranes, against their concentration gradient. This type of
transport is called _____________.
(a) active transport.
(b) free diffusion.
(c) facilitated diffusion.
(d) passive transport. –
Correct Answer :(a) active transport.
Active transport requires the input of energy into a system so as to move solutes against their
electrochemical and concentration gradients. Which of the following is not one of the common ways
to perform active transport?
P a g e 1 | 61
, PCB 3023 Final Exam 08/27/2026
(a) Na+-coupled
(b) K+-coupled
(c) ATP-driven
(d) light-driven –
Correct Answer :(b) K+-coupled
The Na+-K+ ATPase is also known as the Na+-K+ pump. It is responsible for maintaining the high
extracellular sodium ion concentration and the high intracellular potassium ion concentration. What
happens immediately after the pump hydrolyzes ATP?
(a) Na+ is bound
(b) ADP is bound
(c) the pump is phosphorylated
(d) the pump changes conformation –
Correct Answer :(c) the pump is phosphorylated
The Aeroschmidt weed contains an ATP-driven ion pump in its vacuolar membrane that pumps
potentially toxic heavy metal ions such as Zn2+ and Pb2+ into the vacuole. The pump protein exists in
a phosphorylated and an unphosphorylated form and works in a similar way to the Na+-K+ pump of
animal cells. To study its action, you incorporate the unphosphorylated form of the protein into
phospholipid vesicles containing K+ in their interiors. (You ensure that all of the protein molecules are
in the same orientation in the lipid bilayer.) When you add Zn2+ and ATP to the solution outside such
vesicles, you find that Zn2+ is pumped into the vesicle lumen. You then expose vesicles containing the
pump protein to the solutes shown in Table Q12-25A.
Table Q12-25A
P a g e 2 | 61
, PCB 3023 Final Exam 08/27/2026
You then determine the amount of phosphorylated and unphosphorylated ATP-driven ion pump
protein in each sample. Your results are summarized in Table Q12-25B, where a - Correct Answer :(d) A
small amount of Zn2+ will move into the vesicle; no K+ will move out of the vesicle; the protein will
become unphosphorylated.
You have generated antibodies that recognize the extracellular domain of the Ca2+-pump. Adding
these antibodies to animal cells blocks the active transport of Ca2+ from the cytosol into the
extracellular environment. What do you expect to observe with respect to intracellular Ca2+?
(a) Ca2+-pumps in vesicle membranes keep cytosolic calcium levels low.
(b) Ca2+-pumps in the endoplasmic reticulum membrane keep cytosolic calcium levels low.
(c) Ca2+-pumps in the Golgi apparatus keep cytosolic calcium levels low.
(d) Ca2+ concentrations in the cytosol increase at a steady rate. –
Correct Answer :(b) Ca2+-pumps in the endoplasmic reticulum membrane keep cytosolic calcium
levels low.
Cells make use of H+ electrochemical gradients in many ways. Which of the following proton
transporters is used to regulate pH in animal cells?
(a) light-driven pump
(b) H+ ATPase
(c) H+ symporter
(d) Na+-H+ exchanger –
Correct Answer :(d) Na+-H+ exchanger
Which of the following statements is true?
(a) Amoebae have transporter proteins that actively pump water molecules from the cytoplasm to the
cell exterior.
(b) Bacteria and animal cells rely on the Na+-K+ pump in the plasma membrane to prevent lysis
resulting from osmotic imbalances.
P a g e 3 | 61
, PCB 3023 Final Exam 08/27/2026
(c) The Na+-K+ pump allows animal cells to thrive under conditions of very low ionic strength.
(d) The Na+-K+ pump helps to keep both Na+ and Cl- ions out of the cell.
- Correct Answer :(d) The Na+-K+ pump helps to keep both Na+ and Cl- ions out of the cell.
Ca2+-pumps in the plasma membrane and endoplasmic reticulum are important for _____________.
(a) maintaining osmotic balance.
(b) preventing Ca2+ from altering the activity of molecules in the cytosol.
(c) providing enzymes in the endoplasmic reticulum with Ca2+ ions that are necessary for their
catalytic activity.
(d) maintaining a negative membrane potential. –
Correct Answer :(b) preventing Ca2+ from altering the activity of molecules in the cytosol.
Which of the following occur without coupling transport of the solute to the movement of a second
solute?
(a) import of glucose into gut epithelial cells
(b) export of Ca2+ from the cytosol
(c) export of H+ from animal cells for pH regulation
(d) the export of Na+ from cells to maintain resting membrane potential –
Correct Answer :(b) export of Ca2+ from the cytosol
Which of the following best describes the behavior of a gated channel?
(a) It stays open continuously when stimulated.
(b) It opens more frequently in response to a given stimulus.
(c) It opens more widely as the stimulus becomes stronger.
P a g e 4 | 61
