MET 4 - Glyn Cogen

Question 1

What would you expect the pH to be if measured in the blood of a sprint athlete right after exercise?

(ii) Explain why?
(iii) On his admission to A&E, Glyn’s result are different. Explain why?

[3 marks]

Answer 1

i. pH would be lowered (acidosis) [1]
ii. High level of lactic acid in the blood [1⁄2], produced by anaerobic
metabolism [1⁄2]

iii. There is little to no lactate produced as there is no glucose source* in
the muscle (*glycogen cannot be used) [1]

Question 2

What are the differences between the causes of McArdles and Hers diseases.

What would be the primary symptom on Hers disease? [3 marks]

Answer 2

McArdles is caused by the lack of muscle glycogen phosphorylase enzyme in muscle cells [1] whereas hers disease is caused by the lack of the same enzyme but in the liver [1].

Hers disease results in hypoglyceamia or inability to control blood sugar [1 mark]

Question 3

The concentration of which two factors link muscle contraction to glycogen breakdown?

2 marks

Answer 3

Calcium [1] & AMP levels [1]

Question 4

Glyn could potentially take part in a long distance walk.

(ii) What sources of energy would Glyn use during this long walk?
(ii) Which compound produced inside cells when blood sugar is high helps control the switch to these sources of energy? [2 marks]

Answer 4

He would trigger “second wind” by using blood glucose [1⁄2] and fatty acids [1⁄2] as the source of energy for metabolism in muscle.

Malonyl-CoA [1]