举一反三
- Carnitine is: A: an essential cofactor for the citric acid cycle. B: essential for intracellular transport of fatty acids. C: one of the amino acids commonly found in protein. D: present only in carnivorous animals.
- Some athletes believe that dietary carnitine supplements will enhance their ability to perform aerobic exercise. Which statement BEST describes the “scientific” basis of this belief? A: Carnitine is required in the transport of medium and long-chain fatty acids into the mitochondrial matrix, and so increasing the amount of carnitine will increase the rate of transport. B: Carnitine activates carnitine-acyl transferase-1 (CAT-I) thereby increasing the rate of transport of fatty acids into the mitochondrial matrix. C: Carnitine levels in the cytoplasm are reduced when large amounts of fatty acyl carnitine are transported into the mitochondrial matrix. D: Carnitine enhances the activation of fatty acids to fatty acyl-CoA, thereby increasing the rate of their transport into the mitochondrial matrix.
- The synthesis of fatty acids USES carnitine to transport acetyl-CoA from the mitochondria to the cytoplasm.（）
- What would be the consequences of inhibiting the carnitine shuttle which transports fatty acids into the mitochondria? A: accumulation of fat droplets in liver and muscle. B: Increase in blood glucose concentration. C: Increase in fatty acid synthesis in the liver. D: Low levels of long chain free fatty acids in the blood.
- The average molecular weight of oil can be reflected by measuring ( ) A: Saponification value B: Peroxide value C: Free fatty acids D: Trans fatty acids
内容
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The inhibition of carnitine acyltransferase I by malonyl-CoA ensures that the oxidation of fatty acids is inhibited whenever the liver is amply supplied with glucose as fuel and is actively making triacylglycerols from excess glucose.
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We evaluated the associations between serum omega-3 and omega-6 poly-unsaturated fatty acid levels and colon cancer risk in a study conducted between 1997 and 2002. We included 363 cases of colon cancer and 498 disease-free controls. Serum omega-3 poly-unsaturated fatty acid levels were inversely associated with colon cancer risk. Subjects in the upper 33% of serum omega-3 poly-unsaturated fatty acids had a 33% lower risk of colon cancer as compared with subjects in the lower 33% of serum omega-3 poly-unsaturated fatty acids. In contrast, the risk of colon cancer was increased by omega-6 poly-unsaturated fatty acids by 68%. This is the first study that simultaneously finds an inverse association of serum omega-3 poly-unsaturated fatty acids and a positive association of omega-6 poly-unsaturated fatty acids with colon cancer. The study design is a:
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The final products of digestion are ? A: fatty acids, starch, glucose B: protein, amino acids, glucose C: protein, fat, carbohydrate D: glucose, amino acids, fatty acids
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Carnitine, a zwitterionic compound derived from lysine, is involved in fatty acid metabolism and is required at which two points in the transport of fatty acids from the cytoplasm to the mitochondria (see Figure 3-5) A: A and E B: A and C C: B and C D: B and D E: E and D
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In food, the best ratio of saturated fatty acid, monounsaturated fatty acids, polyunsaturated fatty acid should be ( )