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7 Exercise Biochemistry
You must have read Chapter 16 and 18 before joining this discussion group.
What happens metabolically when we exercise and when should we exercise? Watch the video below before entering the discussion.
Answer the following questions related to this video.
Question: Adrenaline/Epinephrine is released by the sympathetic nervous system during exercise what does it do?
Adrenaline initiates multiple biochemical processes that provide energy. It increases Glycogenolysis, upregulates glycolysis and initiates the breakdwon of fat deposits. It has numerous other effects on heart rate, blood pressure etc. that are not discussed in this book.
Where does cAMP come from, what does it do?
Adrenaline exerts its actions through G-protein coupled receptors (GPCR), which activate adenylate cyclase. Adenylate cyclase converts ATP into cyclic AMP (cAMP), which in turn activates protein kinase A.
Why is AMP kinase activated during exercise and what are the consequences?
AMP kinase is activated by AMP. AMP is generated during exercise by the enzyme adenylate kinase which converts to molecules of ADP into one molecule of ATP and one molecule of AMP. This partially restores ATP levels and in addition generates the signalling molecule AMP, which activates AMP kinase.
AMP kinase upregulates a multitude of processes that provide energy, while blocking those that use energy. See Figure 9 in chapter 18.
How are insulin levels regulated during exercise?
Insulin activates a multitude of processes that require energy, such as glycogen synthesis, protein synthesis, and fat synthesis. Adrenaline suppresses insulin release.
Why is lactate generated during exercise?
During heavy exercise blood flow to muscles is insufficient to provide muscle with oxygen and glucose. As a result, glycogen is mobilised to generate large amounts of glucose, which cannot be completely oxidised. Instead, glycolysis is diverted to lactate to recycle NADH in the cytosol without using oxygen.
When you want to lose weight, why should you train when fasted? Identify the incorrect answer.
- Insulin levels are low, reducing fat biosynthesis
- Lipolysis is enhanced by glucagon and adrenaline, reducing body fat.
- Fatty acid oxidation is enhanced, due to low levels of malonyl-CoA
- Glycolysis is enhanced by adrenaline, burning glucose.
- Muscle build-up is increased due to insulin.
5. Muscle build-up is increased due to insulin.
