Chapter 15 Review Quiz

Nitrogen Metabolism II: Degradation

. What types of molecules serve as the starting materials for synthesis of uric acid?

. Frogs begin life as tadpoles and then mature into four-legged creatures capable of moving on land. As they grow, their nitrogen metabolism:

. Maple syrup urine disease results from an inborn error of metabolism of certain types of amino acids. Which ones?

. Biochemists consider animals to be wasteful of nitrogen. Metabolism of nitrogen in animals differs from metabolism in plants in this way:

. In order to relieve depression, psychiatrists may attempt to prevent destruction or reuptake of neurotransmitters. Monoamine oxidase affects levels of tyramine, a neurotransmitter which also acts as a hypertensive agent in brain. In order to avoid vascular accidents in the brain, persons who are prescribed MAO are advised to avoid old wines, hard cheeses, and pickled foods which may contain tyramine. Monoamine oxidase relieves depression by:

. Catabolism of amino acids usually follows one of two paths, depending upon the types of degradation products they form. Amino acids are said to be:

. A number of toxins such as those found in puffer fish or the Red Tide organisms interfere with metabolism of acetylcholine. Directly after the firing of a synapse in voluntary muscle, acetylcholine is destroyed by:

. Ubiquinated proteins are transferred to large proteolytic machines for cleavage to smaller fragments. The proteolytic machine is known as a:

. One type of protein which you would expect to have a relatively short half-life would be:

. Metabolism of fats and carbohydrates differs from nitrogen metabolism in that:

. Urea is synthesized in:

. One amino acid which is non-essential for humans is not only essential for cats, but is the most common amino acid found in white blood cells. Which one?

. Degradation of proteins is facilitated by a process known as:

. The major defect in patients suffering myasthenia gravis is:

. In hyperammonemia, excess ammonia builds up in blood and threatens brain tissue. Hyperammonemia may be treated by intravenous administration of arginine glutamate. The arginine stimulates the ornithine cycle, converting ammonia to urea, and the glutamate helps by:

. Destruction of protein by bacteria converts most of the nitrogen into ammonia or nitrate, which may be used by other organisms. Under some circumstances, the end product of degradation of proteins to nitrogen products may result in a substance which is very difficult for other organisms to metabolize. What substance might this be?

. Most molecules in the body are formed and destroyed at controlled rates. One of the fates of aging hemoglobin is formation for excretion of 250-400 mg daily of this pigment:

. The initial step in cellular catabolism of amino acids is usually:

. Sedentary persons who consume rich diets sometimes suffer gout, a condition which may cause toes to swell and joints to become painful due to an accumulation of:

. Native American trackers were famous for their skill at following minute clues to track persons or animals through grasslands, forests, and across deserts. One of the clues used by these trackers was the feces deposited by animals or humans. In addition to predicting the species (it was always nice to know whether one were tracking a human or a grizzly), the trackers could predict the time when the feces were deposited by the temperature and color. A good candidate for the orange compound in feces which darkens on exposure to air is:

. Unlike many physiological substances, metabolism of ammonia is under very strict control because:

. Blood capillaries are fragile and may break upon impact (such as a slap in the kisser), allowing components of blood to spill into the interstitial spaces, where they degrade slowly. The resulting "black" eye might be due to a greenish pigment called:

. Degradation of ketogenic amino acids results in two-carbon fragments which may be formed into ketone bodies or fatty acids, or oxidized to carbon dioxide and water by:

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