Bke2 Biochemistry Exercises

Group exercise: Metabolism 2

The pentose-phosphate shunt

What are the two most important products obtained from the pentose-phosphate shunt?
In what way is the pentose-phosphate shunt coupled to glycolysis?
What determines the speed of the pentose-phosphate shunt?
In which tissues are the pentose-phosphate shunt activities greatest?

Gluconeogenesis

Explain the difference between glycolysis and gluconeogenesis.
Biotin (one of the B vitamins) plays a decisive role in gluconeogenesis - please elaborate.
In contrast to glycolysis, there are certain enzymatic steps in gluconeogenesis also in the mitochrondria. What are these steps?
What is the 'cost' in terms of ATP when synthesizing glucose from pyruvate?
Gluconeogenesis and glycolysis are reciprocally regulated. Explain what this means and list the regulating molecules.
During strong muscular exertion some muscles work anaerobically, which results in the formation of lactic acid. How can lactate form glucose?

Glycogen metabolism

What is the structural difference between glycogen and glucose?
Why can't the glycogen present in skeletal muscles be used by other tissues in the body, in contrast to the case with the liver?
How are synthesis and degradation of glycogen regulated?

Fatty acid metabolism

What is meant by saturated and unsaturated fatty acids?
In everyday speech, fat usually means the same as triacylglycerol. What does a molecule of this kind consist of?
How can glycerol residues from fat be utilised as energy?
How are fatty acids broken down for use as energy?
Describe how fatty acids are transported into the mitochondrion for further oxidation.

Amino acids and urea metabolism

How is a surplus of amino acids used by the body? Where does this take place in the body?
Which enzymatic steps are included when the a-amino group in an amino acid is spiked off?
Explain the function of pyridoxal phosphate in amino acid metabolism.
How do terrestrial vertebrates handle a surplus of ammonium? Which organs metabolise ammonium?
In which way is the urea cycle linked to the citric acid cycle?
What is meant by a glycogen and a ketogen amino acid?

Reading material: Horton, Chapters 13, 16, 17.

Lectures:
Glucose metabolism
Oxidative phosphorylation
Pentose phosphate pathway and fatty acid metabolism
Metabolism of amino acids

Links:
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