Problem 16
From fatty acid to ketone body. Write a balanced equation for the conversion of stearate into acetoacetate.
Problem 20
An accurate adage. An old biochemistry adage is that fats burn in the flame of carbohydrates. What is the molecular basis of this adage?
Problem 21
Missing acyl CoA dehydrogenases. A number of genetic deficiencies in acyl CoA dehydrogenases have been described. A deficiency in acyl CoA dehydrogenase presents itself early in life or after a period of fasting. Symptoms include vomiting, lethargy, and, sometimes, coma. Not only are blood levels of glucose low (hypoglycemia), but also starvation-induced ketosis is absent. Provide a biochemical explanation for the last two observations.
Problem 22
Missing ingredient. Why are liver cells not capable of using ketone bodies as a fuel?
Problem 23
Finding triacylglycerols in all the wrong places. Insulindependent diabetes is often accompanied by high levels of triacylglycerols in the blood. Suggest a biochemical explanation for the high blood levels of triacylglycerols.
Problem 24
Leaner times might follow. Why can't animals convert fats into glucose? Why are plants capable of such a conversion?
Problem 25
Losing protein. What is the purpose of protein degradation during the initial stages of starvation?
Problem 27
After lipolysis. During fatty acid mobilization, glycerol is produced. This glycerol is not wasted. Write a balanced equation for the conversion of glycerol into pyruvate. What enzymes are required in addition to those of the glycolytic pathway?
Problem 29
Ill-advised diet. Suppose that, for some bizarre reason, you decided to exist on a diet of whale and seal blubber, exclusively. (a) How would a lack of carbohydrates affect your ability to utilize fats? (b) What would your breath smell like? (c) One of your best friends, after trying unsuccessfully to convince you to abandon this diet, makes you promise to consume a healthy dose of odd-chain fatty acids. Does your friend have your best interests at heart? Explain.
Problem 32
Sleight of hand. Animals cannot affect the net synthesis of glycogen from fatty acids. Yet, if animals are fed radioactive lipids \(\left(^{14} \mathrm{C}\right),\) over time, some radioactive glycogen appears. How is the appearance of radioactive glycogen possible in these animals?
