Problem::

I need help answering these questions:

Problem 1: Newborn mammals and mammals that hibernate both have a large amount of brown fat. This fat is brown because of the very large number of mitochondria. Some of the electron transport chain molecules contain iron. It is all this iron that makes the tissue appear brown relative to the more typical white adipose tissue.

The physiological function of brown fat is to keep animals warm. The mitochondria in this fat are slightly different from those in all other cells in that these mitochondria generate heat but do not make ATP. This does not mean the animals produce no ATP. All the other cells of the organism contain mitochondria that function in the way we have described.

In the inner membrane of these brown fat mitochondria, in addition to all the other molecules we learned about, there is an extra protein. This protein allows protons to pass from the intermembrane space to the matrix, but there is no ATP synthesis coupled to the transfer.

Required:

Question 1: How does this system generate more heat than conventional mitochondria?

Question 2: Would oxygen still be required for this heat-generating process? Explain.

Problem 2:

Question: Explain in your own words WHY oxygen is necessary for ATP production in the mitochondria. Include every relevant step between oxygen (and what happens to it) and ATP production.

Consider the situation in cells of a man with emphysema. His lungs have very little functioning surface area for oxygen to enter his blood. As a result, there is less oxygen in his tissues compared to a similar-aged man with normal lungs.

You examine the nicotinamide electron carriers in both men. In the man with normal lungs you find 50% NADH and 50% NAD+.

Question: What ratio of these molecules would you expect to find in the man with emphysema? Explain your answer.

Any help would be greatly appreciated!