PNB 2265 Exam 50 Questions with
Correct Answers.
Course
PNB 2265
1. Membrane Transport
Question:
Explain the difference between simple diffusion and facilitated diffusion.
Answer:
Simple diffusion: movement of molecules directly through the lipid bilayer without
proteins (e.g., O₂, CO₂).
Facilitated diffusion: movement via carrier or channel proteins, no energy required (e.g.,
glucose via GLUT transporters).
2. Resting Membrane Potential
Question:
What is the main factor responsible for the resting membrane potential?
Answer:
The Sodium-Potassium Pump and selective permeability to potassium ions (K⁺) maintain the
resting membrane potential (~ -70 mV).
3. Action Potential
Question:
What triggers the rapid depolarization phase of an action potential?
Answer:
Opening of voltage-gated sodium channels, causing Na⁺ influx into the cell.
4. Muscle Contraction
Question:
What role does calcium play in skeletal muscle contraction?
, Answer:
Calcium binds to Troponin, causing a conformational change that exposes myosin-binding sites
on actin, enabling contraction.
5. Cardiovascular System
Question:
What determines cardiac output?
Answer:
Cardiac output = Heart rate × Stroke volume.
6. Respiratory Physiology
Question:
What drives oxygen transport from alveoli into the blood?
Answer:
The Partial Pressure Gradient between alveolar air and blood.
7. Renal Physiology
Question:
Where does filtration occur in the nephron?
Answer:
In the Glomerulus within Bowman’s capsule.
8. Endocrine System
Question:
What is the function of insulin?
Answer:
Insulin lowers blood glucose by increasing glucose uptake into cells and promoting glycogen
storage.
9. Nervous System
Correct Answers.
Course
PNB 2265
1. Membrane Transport
Question:
Explain the difference between simple diffusion and facilitated diffusion.
Answer:
Simple diffusion: movement of molecules directly through the lipid bilayer without
proteins (e.g., O₂, CO₂).
Facilitated diffusion: movement via carrier or channel proteins, no energy required (e.g.,
glucose via GLUT transporters).
2. Resting Membrane Potential
Question:
What is the main factor responsible for the resting membrane potential?
Answer:
The Sodium-Potassium Pump and selective permeability to potassium ions (K⁺) maintain the
resting membrane potential (~ -70 mV).
3. Action Potential
Question:
What triggers the rapid depolarization phase of an action potential?
Answer:
Opening of voltage-gated sodium channels, causing Na⁺ influx into the cell.
4. Muscle Contraction
Question:
What role does calcium play in skeletal muscle contraction?
, Answer:
Calcium binds to Troponin, causing a conformational change that exposes myosin-binding sites
on actin, enabling contraction.
5. Cardiovascular System
Question:
What determines cardiac output?
Answer:
Cardiac output = Heart rate × Stroke volume.
6. Respiratory Physiology
Question:
What drives oxygen transport from alveoli into the blood?
Answer:
The Partial Pressure Gradient between alveolar air and blood.
7. Renal Physiology
Question:
Where does filtration occur in the nephron?
Answer:
In the Glomerulus within Bowman’s capsule.
8. Endocrine System
Question:
What is the function of insulin?
Answer:
Insulin lowers blood glucose by increasing glucose uptake into cells and promoting glycogen
storage.
9. Nervous System
