How could lactic acid production and free fatty acid formation contribute to organelle dysfunction?

When blood flow to human tissue is interrupted, the lack of sufficient blood supply is called ischemia. If ischemia is not restored quickly, the affected tissue may undergo a process called infarction, which involves a series of chemical changes that damage the tissue. The lack of blood supply results in lack of oxygen, and thus lactic acidosis. Mitochondrial dysfunction results. Microscopic examination and chemical analysis of ischemic cells reveal membrane degeneration, excessive calcium (Ca+) inside the cell, and free radical formation, accompanied by a reactive inflammation and free fatty acid formation. A research experiment is designed to evaluate the response of infarcted tissue to intra-arterial administration of an antioxidant. Preliminary results demonstrate that follow-up evaluation of tissue exposed to intra-arterial antioxidant injection resulted, on average, in a smaller area of infarcted tissue after seven days when compared to controls without exposure to the antioxidant. It was noted that 70% of the patients who demonstrated smaller areas of infarction also had a notable decease in edema of the ischemic tissue lasting about 6 to 10 hours after injection.

How could lactic acid production and free fatty acid formation contribute to organelle dysfunction?
A . The acidity of these molecular products, when uncorrected, alters the cell’s pH beyond that which the cell can compensate for. Organelles, containing proteins, denature as a result.
B . Lactic acid production and free fatty acid formation function like free radicals, altering the structure of the molecular components of the organelles.
C . Lactic acids and free fatty acids crowd the organelles within the cells, preventing them from communicating with each other in the cytoplasm.
D . Lactic acids and free fatty acids are hydrophobic and thus can enter the membranes of the organelles, disrupting their function.

View Answer

Answer: A

Explanation:

In small quantities, lactic acids and free fatty acids are tolerable due to the cell’s ability to buffer mild pH changes. However, in an ischemic setting, the cell cannot correct the pH changes, and thus the proteins that form the structural and functional components of the organelles begin to denature. Lactic acids and free fatty acids are acidic, meaning that they contribute hydrogen atoms to the environment, whereas free radicals are deficient in electrons. Although the volume of acidic molecules within the cell is not beneficial for the organelles, their pH is their most harmful characteristic and thus the most immediately damaging consequence. Free fatty acids are hydrophobic and thus may be able to pass through organelle membranes, but they cause organelle dysfunction from outside the organelle in the cytoplasm as well.