Could someone check if I answered these questions correctly? (Biology)

• student93
In summary, the resting membrane potential is -72.88 mV, while the Nernst potentials for Na+, K+, and Cl- are 69.91 mV, -96.88 mV, and -21.10 mV, respectively. At the resting potential, Na+ ions try to enter the cell, K+ ions try to leave, and Cl- ions try to leave. Adding 30 mM of K+ to the extracellular environment would depolarize the cell, with a new resting membrane potential of -38.95 mV. However, if the K+ channel is blocked, the cell will depolarize even further, with a new resting membrane potential of 35.02 mV.
student93
Information Given:
Resting Membrane Potential: -72.88 mV
Na+ Nernst Potential: 69.91 mV
K+ Nernst Potential: -96.88 mV
Cl- Nernst Potential: -21.10 mV

1. At the resting potential, what is the direction of net movement for Na+, K+, and Cl-.

The Na+ ions are trying to get inside the cell since the Na+ ions would like to bring resting membrane potential closer to their own Nerst Potential of 69.91 and thus depolarize the cell. The K+ ions are trying to get outside the cell since the Na+ ions would like to bring resting membrane potential closer to their own Nerst Potential of -96.88 and thus hyperpolarize the cell to. The Cl+ ions are trying to get outside the cell since the Cl+ ions would like to bring resting membrane potential closer to their own Nerst Potential of -21.10 and thus depolarize the cell.

2. A commonly used strategy to depolarize the neurons is to add K+ in the bath. What would be the resting membrane potential of this cell if you add K+ so that the total extra-cellular K+ becomes 30 mM?

Extracellular K+ Concentration: 30 mM
Intracellular K+ Concentration: 155 mM

New Nernst Potential of K+: (61/1)(Log(30/155)) = -43.51 mV -> Thus, the K+ ions will try to get inside of the cell to bring the cell’s resting membrane potential value of -72.88 mV to a value closer to -43.31 mV and consequently depolarize the cell.

New Resting Membrane Potential: 61log(((1x30)+(0.04x140)+(0.01x40))/((1x155)+(0.04x10)+(0.01x120))) = -38.95 mV

3. Suppose this cell is now poisoned by a spider toxin that blocks the K+ channel (PK becomes 0.0), will the cell be depolarized or hyperpolarized? Why?

The cell will depolarize since the internal K+ ions within the cell will accumulate and become more concentrated within the cell and won’t be able to leave the cell since the K+ channel has been blocked by the spider toxin. The cell membrane will deviate from its approximate value of -70 mV to a more positive value.

New Resting Membrane Potential when PK=0: 61log(((0)+(0.04x140)+(0.01x40))/((0)+(0.04x10)+(0.01x120))) = 35.02 mV

This new potential is more positive than the original resting membrane potential of -72.88 mV, indicating that the cell has depolarized.

1. What is the purpose of having someone check my answers in biology?

The purpose of having someone check your answers in biology is to ensure that the information you have provided is accurate and correct. This can help you improve your understanding of the subject and identify any areas where you may need further clarification or review.

3. Is it important to have my answers in biology checked?

Yes, it is important to have your answers in biology checked. Biology is a complex subject and having someone review your answers can help you identify any mistakes or misunderstandings you may have. This can ultimately improve your understanding of the subject and your performance on exams or assignments.

4. How can I find someone to check my answers in biology?

There are a few ways you can find someone to check your answers in biology. You can ask a classmate or friend who is knowledgeable in the subject to review your answers. You can also reach out to a biology teacher or tutor for help. Additionally, there are online forums and study groups where you can ask for feedback on your answers.

5. What should I do if my answers in biology are consistently incorrect?

If your answers in biology are consistently incorrect, it may be helpful to seek additional help and review from a teacher or tutor. You can also try practicing with different resources and asking for feedback on your answers. It is important to identify any areas where you may need further clarification or review in order to improve your understanding and performance in biology.

Replies
2
Views
2K
Replies
1
Views
3K
Replies
1
Views
1K
Replies
2
Views
3K
Replies
4
Views
8K
Replies
2
Views
3K
Replies
7
Views
6K
Replies
2
Views
25K
Replies
2
Views
5K
Replies
7
Views
9K