Bke2 Biochemistry Exercises

Group exercise: Metabolism I

Glycolysis

Which compound is, generally, the carrier of free energy in the body? Name three important body processes that need a continuous supply of energy.
What does glycolysis mean? What characterises the intermediaries in glycolysis? Where in the cell does glycolysis take place?
Where in the glycolysis is ATP consumed? Where in the glycolysis are NADH and ATP formed? How large is the net production of ATP when converting 1 mole of glucose to 2 moles of pyruvate?
Why does the cell form ethanol (yeast cells) or lactic acid (animal cell) during glycolysis under anaerobic conditions?
Apart from glucose, other sugar species such as fructose and galactose can be used as energy, please explain how?

The citric acid cycle

Where in the cell does the citric cycle take place? Which enzymatic step forms the link between glycolysis and the citric acid cycle?
Describe the metabolic process that characterises the citric acid cycle?
Which step in the citric acid cycle is considered to regulate the flow of substrate through the cycle? Which compound has the greatest effect on the rate of the citric acid cycle?
In which way does succinate dehydrogenase differ from other enzymes in the citric acid cycle?
Give examples of intermediaries in the citric acid cycle that are used in biosynthesis. State also the type of biosynthesis.
If oxaloacetate is used in biosynthesis, what happens to the citric acid cycle? In what way can a lack of oxaloacetate in the citric acid cycle be compensated.
Why can the citric acid cycle function only under aerobic conditions?
How is the citric acid cycle regulated, which are the key enzymes?

Oxidative phosphorylation

The electron transport chain consists of three large protein complexes - please name them. What is the role of ubiquinone?
Where in the electron transport chain are there proton pumps? How are these pumps linked to ATP production?
How is NADH transported from cytosol to the mitochrondrion's matrix? Give examples.
How is ATP transported from the mitochrondrion's matrix to the cytosol?
How many ATP are obtained from NADH and FADH2 ? Give examples.
How many ATP's are formed during aerobic oxidation of glucose? List the different steps that give ATP (glycolysis, citric acid cycle, oxidative phosphorylation).
How is oxidative phosphorylation regulated?
What happens when the oxidative phosphorylation is uncoupled? Does this uncoupling occur naturally? If so, where?
What is meant by the P:O ratio?

Reading material: Horton, Chapters 10-12, 14

Lectures:
Carbohydrates, vitamins, glycolysis
The citric acid cycle and oxidative phosphorylation

Links:
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