Question 1

Which of the following best describes the main purpose of a muscle biopsy in clinical and research settings?

Accepted Answer

To obtain a sample of muscle tissue for analysis of fiber type, metabolic properties, and pathological changes

Question 2

During a muscle biopsy, which precaution is most important to minimize risk to the patient?

Accepted Answer

Using sterile technique to prevent infection

Question 3

Which of the following is NOT a typical use of muscle biopsy results?

Accepted Answer

Measuring blood glucose levels directly

Question 4

A researcher stains a muscle sample for type I fibers. Which characteristic is most likely associated with type I muscle fibers?

Accepted Answer

High oxidative capacity and resistance to fatigue

Question 5

Which equation best represents the total electrochemical driving force ($$F_{total}) $$acting on an ion across a membrane?

Accepted Answer

$$F_{total} = F_{chemical} + F_{electrical}$$

Question 6

If the chemical driving force and the electrical driving force are equal and opposite, what is the net movement of ions across the membrane?

Accepted Answer

There is no net movement; the system is at equilibrium

Question 7

Which of the following best describes facilitated diffusion through a carrier protein?

Accepted Answer

Passive movement of particles down their concentration gradient via a membrane protein that undergoes conformational changes

Question 8

Which factor does NOT directly affect the rate of simple diffusion across a cell membrane?

Accepted Answer

Number of carrier proteins

Question 9

A patient with type 2 diabetes performs 30 minutes of moderate exercise. Which physiological change is most likely to occur regarding glucose transport?

Accepted Answer

Increased glucose uptake into muscle cells due to enhanced GLUT4 translocation

Question 10

Which process is directly stimulated by insulin binding to its receptor on muscle cells?

Accepted Answer

Exocytosis of GLUT4 transporters to the cell membrane

Question 11

Which of the following is a key difference between simple diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion involves membrane proteins, while simple diffusion does not

Question 12

Which of the following best explains why facilitated diffusion demonstrates saturation kinetics?

Accepted Answer

Carrier proteins can only transport a limited number of particles at a time, and all binding sites can become occupied

Question 13

Which of the following would most likely increase the rate of glucose entry into muscle cells during exercise?

Accepted Answer

Increased translocation of GLUT4 transporters to the membrane

Question 14

Which equation correctly represents the Nernst potential ($$E_c) $$for potassium ions ($$K^+) $$across a membrane?

Accepted Answer

$$E_c = \frac{RT}{zF} \ln \left( \frac{[K^+]_{out}}{[K^+]_{in}} \right)$$

Question 15

A muscle cell is at equilibrium for potassium ions when $$V_m = E_c. $$What does this imply about the net movement of potassium?

Accepted Answer

There is no net movement of potassium ions

Question 16

Which of the following would most likely decrease the rate of passive transport through ion channels?

Accepted Answer

Decreasing the concentration gradient across the membrane

Question 17

Which scenario best illustrates the concept of electrochemical equilibrium in a cell?

Accepted Answer

The chemical and electrical driving forces for an ion are equal and opposite, resulting in no net movement

Question 18

Which of the following is a direct effect of exercise on glucose transport in skeletal muscle of type 2 diabetes patients?

Accepted Answer

Exercise stimulates GLUT4 translocation independently of insulin

Question 19

Which of the following statements about membrane transport proteins is correct?

Accepted Answer

Carrier proteins undergo conformational changes to move specific particles across the membrane

Muscle Biopsy and Transport Across Membranes: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard