Q: Which of the following best describes the function of the Na\textsuperscript{+}/K\textsuperscript{+} ATPase in maintaining the resting membrane potential of a neuron?

It pumps 3 Na\textsuperscript{+} ions out of the cell and 2 K\textsuperscript{+} ions into the cell, using ATP hydrolysis.

Q: Which of the following is TRUE regarding the phosphoinositide pathway (G\textsubscript{q}-coupled GPCRs)?

Phospholipase C cleaves PIP\textsubscript{2} to generate IP\textsubscript{3} and DAG.

Q: A patient presents with muscle weakness and cardiac arrhythmias. Laboratory tests reveal a defect in the Na\textsuperscript{+}/K\textsuperscript{+} ATPase. Which of the following best explains the pathophysiology?

Impaired Na\textsuperscript{+}/K\textsuperscript{+} ATPase decreases the Na\textsuperscript{+} gradient, reducing action potential amplitude.

Question 1

Which of the following best describes the function of the Na	extsuperscript{+}/K	extsuperscript{+} ATPase in maintaining the resting membrane potential of a neuron?

Accepted Answer

It pumps 3 Na	extsuperscript{+} ions out of the cell and 2 K	extsuperscript{+} ions into the cell, using ATP hydrolysis.

Question 2

A patient is prescribed a statin drug. Which enzyme is directly inhibited by statins, and what is the clinical effect?

Accepted Answer

HMG-CoA reductase; decreased cholesterol synthesis

Question 3

Which of the following statements about omega-3 fatty acids is CORRECT?

Accepted Answer

They have their first double bond at the third carbon from the methyl (omega) end.

Question 4

Which of the following best explains why cholesterol is important for membrane fluidity?

Accepted Answer

Cholesterol disrupts the regular packing of phospholipids, preventing membranes from becoming too rigid or too fluid.

Question 5

A mutation causes a loss of function in the GLUT4 transporter. Which tissue would be most affected and what is the likely clinical consequence?

Accepted Answer

Skeletal muscle; impaired glucose uptake and hyperglycemia

Question 6

Which of the following is a direct effect of activating a G	extsubscript{s} protein-coupled receptor (GPCR)?

Accepted Answer

Activation of adenylyl cyclase and increased cAMP

Question 7

Which of the following best describes the mechanism of action of NSAIDs (non-steroidal anti-inflammatory drugs)?

Accepted Answer

They inhibit cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis.

Question 8

A researcher adds a drug that blocks voltage-gated Na	extsuperscript{+} channels to a neuron. What is the most immediate effect on the action potential?

Accepted Answer

The neuron will be unable to initiate or propagate an action potential.

Question 9

Which of the following is TRUE regarding the phosphoinositide pathway (G	extsubscript{q}-coupled GPCRs)?

Accepted Answer

Phospholipase C cleaves PIP	extsubscript{2} to generate IP	extsubscript{3} and DAG.

Question 10

A patient presents with muscle weakness and cardiac arrhythmias. Laboratory tests reveal a defect in the Na	extsuperscript{+}/K	extsuperscript{+} ATPase. Which of the following best explains the pathophysiology?

Accepted Answer

Impaired Na	extsuperscript{+}/K	extsuperscript{+} ATPase decreases the Na	extsuperscript{+} gradient, reducing action potential amplitude.

Question 11

Which of the following best describes the role of receptor tyrosine kinases (RTKs) in cell signaling?

Accepted Answer

They autophosphorylate on tyrosine residues, initiating downstream signaling cascades.

Question 12

Which of the following is a clinical effect of SGLT2 inhibitors?

Accepted Answer

Decreased glucose reabsorption in the kidney, leading to glycosuria

Question 13

Which of the following best explains why statins are effective in lowering LDL cholesterol?

Accepted Answer

They inhibit HMG-CoA reductase, decreasing cholesterol biosynthesis.

Question 14

Which of the following is a direct effect of increased cAMP in a cell?

Accepted Answer

Activation of protein kinase A (PKA)

Question 15

A patient is given a drug that inhibits phospholipase A2. Which of the following pathways will be directly affected?

Accepted Answer

Synthesis of eicosanoids such as prostaglandins and leukotrienes

Question 16

Which of the following best describes the effect of a mutation that increases the activity of a G	extsubscript{q}-coupled receptor?

Accepted Answer

Increased activation of phospholipase C, leading to increased intracellular Ca	extsuperscript{2+}

Question 17

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

Accepted Answer

They span the lipid bilayer and can function as channels or receptors.

Question 18

Which of the following best describes the effect of a mutation that prevents receptor internalization after ligand binding?

Accepted Answer

Prolonged signaling due to decreased receptor desensitization

Question 19

Which of the following is a direct effect of activating guanylyl cyclase receptors?

Accepted Answer

Increased production of cGMP

Signal Transduction, Membrane Transport, and Lipids: Study Notes for Biochemistry

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