Metabolism and hormone control

Question 1

What are the three ways that cells can generate ATP?

Answer 1

1. ATP-PCr
2. The glycolytic system
3. Oxidative phosphorylation
4. In addition to storing ATP directly, cells store creatinine phosphate (phosphocreatinine PCr)
   - The breakdown of ATP creates energy used to male ATP. This is done by the enzyme creatinine kinase.
   - This process does not require oxygen.
   - During the first few seconds of intense muscular activity such as sprinting ATP is maintained at a constant level but the PCr declines as it is used to replenish ATP. The ATP-PCr system can supply the muscles energy needs for 3-15 seonds during a sprint.
5. This is the production of energy through the breakdown of glucose. Glycogen is converted to glucose-1-phosphate and then to glucose-6-phosphate in the glycolysis pathway.
   The conversion of glucose to glucose-6-phosphate costs one ATP. This is not the case for the formation of flucose-6-phosphate from glycogen.
   Glycolysis produces 3 ATP molecules if the starting product is glycogen and 2 molecules of ATP if the starting point is glucose.

• 1 and 2 can function without oxygen and these methods predominate in the early minutes of high intensity exercise.

Anaerobic glycolysis produces lactic acid.

3. The oxidative system. This is an aerobic and it occurs within mitochondria. This system is slow to turn on but can produce lots of energy. This is the primary method of energy production during endurance events, which places a large demand on the cardiorespiratory system.

This method uses the electron transport chain and produces 39 to 30 molecules of ATP.

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Question 2

Describe how the oxidation of fat occurs?

Answer 2

Triglycerides are broken down in a process called lypolysis. This produces three FFA and one glycerol.
The FFA can then enter muscle cells.
FFAs are enzymatically broken down into units of 2 carbons (acetic acid). This is then used to produce Acetyl-CoA for the krebs cycle. The Acetly-CoA then follows the same pathway as oxidative carbohydrate metabolism.

More Acetly-coA is produced from the breakdown of FFA than from glucose.

Question 3

Corollate the type of muscle fibers with the energy metabolism type and why are type one muscles better suited to endurance activities?

Answer 3

p58

More mitochondria and more enzymes of oxidative phosphorylation

Question 4

What’s an easy way to measure aerobic energy production?

Answer 4

Measure the amount of oxygen consumed in the lungs as the amount of oxygen entering the blood is proportional to the amount used by tissues in oxidative metabolism.