Excercise lab questions

Question 1

Explain why there might be a difference in blood glucose concentration between the three groups (water, cordial with sugar, cordial without sugar)? At which time points? Why?

Answer 1

No change at 0 minutes
The BGC of the water and cordial without sugar should be lower than cordial with sugar at the 60 mins mark.
Cordial with sugar causes a higher BGC because the sugar is absorbed into the blood and not to the liver/muscles as glucose. The pancreas secretes insulin to the glucose spike, then it will eventually plateau.

Question 2

What are the three ways that muscle fibres can form ATP during contractile activity? Which of these ways was the major source of ATP during this cycling activity?

Answer 2

1. Phosphorylation of ADP by creatine phosphate
2. Phosphorylation of ADP by glycolysis in cytosol
3. Oxidative phosphorylation of ADP in mitochondria

The major source of ATP in exercise is phosphorylation of ADP via glycolysis in cytosol

Question 3

Explain how glucose is used to provide energy in the form of ATP during aerobic exercise.

Answer 3

Under anaerobic conditions, ATP is formed through oxidative phosphorylation. Reduced electron carriers (NADH and FADH2) pass electrons through the ETC. Hydrogen ions are pumped into the mitochondrial membrane space, providing energy for ADP to ATP. The electron carries oxidised NAD+ and FAD and O2 breaks down to H2O

Question 4

Explain how triglycerides are used to provide energy in the form of ATP during aerobic exercise.

Answer 4

Low glucose levels cause triglycerides to be converted into Acetyl CoA molecules to generate ATO through AEROBIC metabolism

Question 5

For the cyclists who drank either water or cordial without sugar, explain how their bodies can keep using glucose as a fuel source after the blood glucose has been depleted.

Answer 5

Because the liver goes through glycogenolysis to breakdown glycogen into glucose through enzymes, phosphorylase kinase/glycogen to maintain glucose homeostasis

Question 6

What is the difference between aerobic and anaerobic glycolysis?

Answer 6

Anaerobic glycolysis is the absence of oxygen. Glycolysis proceeds but pyruvate is converted to lactate and the total net gain is 2ATP per glucose.

In comparison, aerobic glycolysis is the presence of oxygen. The glycolysis proceeds, pyruvate is converted into Acetyl CoA. Involves the citric acid cycle and oxidative phosphorylation. Overall net gain of 38ATP per glucose.

Question 7

Name 3 ways muscle fibres forms ATP during activity

Answer 7

creatine phosphate,
anaerobic glycolysis, and
aerobic metabolism.