Energy systems

Question 1

Describe how energy is provided for the repeated maximal contractions during weight lifting

Answer 1

• ATP PC system (anaerobic)
• Coupled reaction
• Phosphocreatine (PC) is broken down into phosphate and creatine and energy
• Energy then used for ATP resynthesis
• Energy + ADP + P produces ATP

Question 2

How the proportions of carbs and fat during a period of exercise of increasing intensity changes

Answer 2

• At a low level of exercise, some energy comes from fats and some from carbs
• As the intensity of the exercise increases, less fats are used and more carbohydrates are used. This is because fats require more oxygen to breakdown and so are during during aerobic exercise
• During high intensity exercise, there is less oxygen available and so less fat can be used as energy
• Therefore, carbohydrates are used
• This involves glycogen being broken down into glucose (glycolysis) with the enzyme PFK

Question 3

What are the main energy sources used by an athlete during a 400m spring? Explain the predominant energy system used during this time

Answer 3

• The main energy sources used by the athlete is glucose and the main energy system used is the lactic acid system (anaerobic)
• Glycogen broken down into glucose
• 2 ATP formed
• This then produces pyretic acid and lactic acid

Question 4

Name the main energy system used in the 100m and explain how this system provides energy for the muscles

Answer 4

• ATP PC system (anaerobic)
• Fuel for this system is PC which is found in the muscles
• Coupled reaction
• Phosphocreatine is broken down into phosphate and creatine and energy
• Energy combines with ADP and phosphate to produce ATP

Question 5

Explain how the majority of energy during a marathon would be provided

Answer 5

• Aerobic system
• Glycogen broken down into glucose (glycolysis) which produces 2 ATP
• Produces pyruvic acid
• Pyruvic acid then converted into acetyl co enzyme A which is fed into the krebs cycle
• Fats combine with oxygen and fed into krebs
• Produces 2 ATP
• Hydrogen ions removed and fed into the electron transport chain
• 34 ATP produced

Question 6

Sprinters stop accelerating at 7-8 seconds into a 100m, why?

Answer 6

• ATP PC is the main energy system
• Coupled reaction where phosphocreatine is broken down into phosphate and creatine and energy
• This energy then combines with phosphate and ADP to produce ATP
• As PC is used up, performance starts to deteriorate and starts to change to the lactic acid system
• Lactic acid system provides energy more slowly