Question

Please help with these questions!

1. A messenger to a receptor protein blocks the translation of sodium leak channels in a neuron. What happens to the membrane potential and why? Hint: think about permeability and use the equations from class. ( i know that it blocks the membrane potential but I'm not sure why)

2. How many molecules of ATP are in the cytosol, in the intermembrane space, and in the mitochondrial matrix after reacting 1 molecule of glucose through all three stages of aerobic respiration? (I believe there is is 2 molecules of ATP in the cytosol but I'm not sure about the intermembrane space or the mitochondrial matrix)

Answer 1

1) The membrane potential is blocked since the sodium leak channels are blocked, the membrane potential starts with the open of the sodium channels since there is no leak there is no change in the polarity of the membrane and no membrane potential.

2) first in the cytosol we have glycolosis producing 2 ATP and 2 NADH.

In the mitochondrial matrix during the link reaction to Acetil-CoA we have 2 NADH, then in the krebs cycle we have 2 ATP, 6 NADH and 2 FADH.

In the intermembrane space occurs the ETC (Electron transport chain) where the NADH and the FADH are transformed to ATP, 3 for each NADH molecule and 2 for each FADH. Using all the NADH and FADH from the previous steps we have 2 NADH (4-6 ATP) from the glycolysis (since this step is in the cytosol it goes through a shuttle system meaning that it only goes for 2 ATP to 3 ATP for each NADH) + 2 NADH (6 ATP) from the link reaction + 6 NADH (18 ATP) + 2 FADH (4 ATP) from Krebs cycle. In total 34 ATPs at the intermembrane space

For a total of 2 in the cytosol, 2 in the mitochondrial matrix and 32-34 in the intermembrane space, for a theorical yield of 36/34 ATPs