A2 PE Anaerobic Energy Systems

Question 0

Briefly outline the main stages of the lactic acid system

Answer 0

Glucose is broken down by PFK into pyruvic acid
2 mols of ATP are produced
In the absence of sufficient oxygen, pyruvic acid is converted by LDH into lactic acid

Question 1

Briefly outline the process of the ATP-PC system

Answer 1

PC is broken down by creatine kinase to release energy
This energy is used to resynthesise ATP
PC = P + C + energy
ADP + P + energy = ATP
This is called the ‘coupled reaction’ as they happen almost simultaneously

Question 2

How much stored ATP is in the muscles?

Answer 2

Enough for up to 3 seconds of activity

Question 3

What are the advantages of the ATP-PC system to the athlete?

Answer 3

Immediate release of energy so suitable for working at a high intensity.
ATP-PC can be enhanced by creatine monohydrate supplements.
ATP-PC replenishes quickly during recovery (takes 2-3 minuets to replenish)
No fatiguing by products.

Question 4

What are the disadvantages of the ATP-PC system to the athlete?

Answer 4

Limited stores of PC only allows activity to be sustained at high intensity for 10 seconds.
Requires recovery time and oxygen to replenish (fast component of EPOC).
Inefficient as one molecule of PC rebuilds one molecule of ATP.

Question 5

Why is pyruvic acid not be fed into the Kerbs cycle following anaerobic glycolysis?

Answer 5

A lack of sufficient oxygen levels due to high intensity will mean the enzyme LDH converts pyruvic acid into lactic acid.

Question 6

What are the advantages of the Latic acid system to the athlete?

Answer 6

Lactic acid can be converted into liver glycogen (Cori Cycle).
Provides energy for up to 3 minutes of high intensity exercise.
ATP can be regenerated fairly quickly as few chemical reactions are required during anaerobic glycolysis.

Question 7

What are the disadvantages of the Latic acid system to the athlete?

Answer 7

Lactic acid is a fatiguing byproduct.
The build up of the lactic acid denatures enzymes and prevents them from working correctly.
Only a small amount of energy can be released from glycogen under anaerobic conditions (5% compared with 95% under aerobic conditions)

Question 8

Define OBLA

Answer 8

Onset of blood lactate accumulation

Question 9

How can a coach measure the level of lactic acid in the blood and when will they have reached OBLA?

Answer 9

Lactate sampling - by taking blood samples.
When blood lactate reaches 4 mmols/litre OBLA has been reached.
This happens at higher percentages of VO2Max for elite athletes.

Question 10

Give an example of an activity which would use the ATP-PC system as its major source of energy production

Answer 10

Any activity which has a duration of 10 seconds or less;
A sprint finish of a race
Throwing the javelin
A sub-10 second 100m race
Long or triple jump

Question 11

Give an example of an activity which would use the lactic acid system as its main source of energy production

Answer 11

Any activity which is over 10 seconds but under 3 minutes;
400m sprint (4x400m relay)
800m
Gymnastic events like the floor

Question 12

Which enzyme is used to break down phosphocreatine?

Answer 12

Creatine kinase

Question 13

What are the causes of fatigue during exercise?

Answer 13

Depletion of PC stores
Build up of lactic acid (OBLA)
Depletion of glycogen stores
Dehydration; reduced blood flow (viscosity) / loss of electrolytes
Lack of calcium (ions for cross bridge formation)
Lack of acetylcholine for nerve impulses

Question 14

If a performer is completing a 100m sprint, how will energy be provided for the race?

Answer 14

ATP stores (first 2-3 seconds)
ATP PC system (up to 10 seconds)

Question 15

If a performer is running the 800m, how will energy be provided for the race?

Answer 15

ATP stores (First 2-3 seconds)
ATP PC system (up to 10 seconds)
Lactic acid system (up to 3 minutes)