The following exercises are available in this section
Experiments with isolated liver cells - the citric acid cycle and warming up post-operative patients
By the end of this exercise you should be able to:
- Describe the citric acid cycle and explain its central role in metabolism
- Explain why acetyl CoA arising from fatty acid oxidation cannot be a net source of glucose
- Explain how an amino acid infusion can prevent post-operative hypothermia
Selection of fuels for muscle contraction
By the end of this exercise you should be able to:
- Describe and explain the sources and metabolism of the different fuels available to muscle (muscle glycogen, blood glucose, triacylglycerol from plasma lipoproteins, plasma non-esterified fatty acids, and ketone bodies);
- Explain how the intensity of physical work influences muscle fuel selection
- Explain how metabolic state (fed or fasting) influences muscle fuel selection
- List and explain the regulatory mechanisms involved in muscle fuel selection under different conditions
- Explain the role of creatine phosphate in muscle contraction
- Explain the difference between aerobic and anaerobic exercise, and the relative importance of each in weight reduction and prevention of obesity.
Hyperammonaemic coma due to liver failure
By the end of this exercise you should be able to:
- Explain the origin of plasma enzymes that can be used to assess liver function, and why it is important to know the Km of an enzyme in order to measure it in plasma.
- Explain why the elevated transaminases in plasma are different in alcoholic and non-alcoholic liver disease
- Explain how measurement of bilirubin in plasma can differentiate between obstructive jaundice and jaundice due to liver disease.
- Explain how hyperammonaemia leads to loss of consciousness, and how lactulose can be used to lower blood ammonia in cases of liver failure.
An unconscious child with keto-acidosis and a skin rash
By the end of this exercise you should be able to:
- Describe the role of biotin in carboxylases and its attachment to the apoenzyme
- Explain how a single genetic defect can lead to defective activity of multiple carboxylases
- Explain how impaired activity of carboxylases can lead to ketosis even in the fed state