PLEASE ANSWER ALL QUESTIONS 1. __________ distance or thickness of the membrane,
ID: 3508066 • Letter: P
Question
PLEASE ANSWER ALL QUESTIONS
1. __________ distance or thickness of the membrane, ________ surface area of the membrane, _________ molecular weight of the substance, and __________ lipid solubility of the substance ALL act to DECREASE the rate of diffusion of a substance through a membrane.
A) Increased, increased, increased, increased
B) Decreased, decreased, increased, decreased
C) Increased, decreased, increased, increased
D) Decreased, decreased, increased, increased
E) Increased, decreased, increased, decreased
2. Starting with depolarization, which of the following lists the numbered events that occur during the action potential in the most correct order?
1. depolarization
2. opening of voltage gated K+ channels
3. repolarization
4. threshold reached
5. closing of voltage gated K+ channels and K+ permeability back to permeability at RMP
6. after hyperpolarization
7. opening of activation gates of voltage gated Na+ channels
8. closing of inactivation gates of voltage gated Na+ channels
A) 1, 7, 8, 4, 2, 3, 5, 6 B) 1, 7, 4, 8, 2, 6, 3, 5 C) 1, 2, 4, 8, 7, 5, 6, 3 D) 1, 7, 4, 8, 2, 3, 6, 5
3. Hyperkalemia (above normal concentration of K+ in the blood) causes _______________ of the resting cell membrane because _____________ K+ leaves the cell (compared to normal), because the concentration gradient for K+ is ________________ (compared to normal).
Hypokalemia (below normal concentration of K+ in the blood) causes ___________ of the resting cell membrane because ___________ K+ leaves the cell (compared to normal), because the concentration gradient for K+ is _______________ (compared to normal). In ________________ the resting cell is further from threshold than normal.
A) depolarization, more, increased, hyperpolarization, less, decreased, hyperkalemia
B) hyperpolarization, less, increased, depolarization, more, decreased, hyperkalemia
C) hyperpolarization, less, decreased, depolarization, more, increased, hyperkalemia
D) hyperpolarization, more, increased, depolarization, less, decreased, hypokalemia
E) depolarization, less, decreased, hyperpolarization, more, increased, hypokalemia
Explanation / Answer
1. Option E is the correct answer. Rate of diffusion decreases with increase in membrane thickness and molecular weight of the diffusing substances. Rate of diffusion increases with increase in surface area and lipid solubility of the diffusing substances.
2. Option D is the correct answer. An action potential starts with depolarization followed by influx of sodium ions through opening of sodium ion channel. After depolarization a threshold of positive membrane potential (30mV) acheived followed by opening of potassium ion which allow outflux of potassium ion and causes repolarization. Outfluxing of potassium ion continued beyond the resting membrane potential which leads to hyperpolarization. After hyperpolarization, closing of potassium channel occurs and resting membrane potential is acheived.
3. Option E is the correct answer.In case of hyperkalemia, the concentration of potassium ion into blood is increases which allow less potassium ion to leave the cell and since potassium ion is having positive charge, it will cause depolarization and the concentration gradient for potassium ion is decreased. In case of hypokalemia, the concentraion of potassium ion into the blood is decreased which allow cells to leave more potassium ion which results in hyperpolarization of the cell and the concentration gradient for potassium ion is increased. In hypokalemia the resting cell is further from threshold from the normal because the cell is hyperpolarized in case of hypokalemia.
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