Energy systems

1. Energy systems Learning outcomes: • All are able to demonstrate understanding of the energy sources required for ATP resynthesis • All are able to describe the Lactic Acid energy system • Most are able to explain the use of PCr in ATP resynthesis • Most are able to apply their understanding of the lactic acid system to sporting examples. • Some can analyse the lactic acid and determine advantages and disadvantages

2. Starter activity • In two teams use the activity to demonstrate your knowledge and understanding of the ATP-PC system. • Complete one of your partners exam questions (homework).

3. 100m sprint- ATP split to drive away from blocks PCr supplies energy for rest of race Quick recap • Site of reaction – • Fuel used – • Active enzyme – • Molecules of ATP produced - ATP SPLITTING • muscle cell • ATP • ATPase ATP-PC SYSTEM • muscle cell • Phosphocreatine • Creatinekinase • 1 molecule

4. Homework • Complete the worksheet on OBLA and its relationship with VO2max. • Use p22-24 of your text book • Watch videos on my weebly site: 1. Introduction to VO2max 2. Factors affecting VO2max 3. VO2max and OBLA

5. Energy systems • The conversion of these fuels into energy which can then be used to resynthesise ATP occurs through one of 3 energy systems: • 1-The ATP-PC System • 2- The Lactic Acid System • 3- The Aerobic system

6. The Energy Systems Immediate: ATP-PCr Short-term: Lactic acid (glycolysis) Long-term: Aerobic

7. Activity • Using the pictures demonstrate your understanding of the Lactic Acid system (Anaerobic glycolysis). • One person in your group will move to another group to share your understanding and gain further knowledge. • Summarise your understanding of the Lactic Acid system. • Extension - analyse the system and determine its advantages and disadvantages

8. Lactic Acid System • Most activities last for longer than 10 secs. • Once phosphocreatine is depleted the lactic acid system (anaerobic glycolysis) takes over and re synthesises ATP from the breakdown of glucose. • Glucose is stored in the muscles and liver as glycogen. • In order to provide energy to make ATP glycogen has to be converted to glucose. This process is called glycolysis. (Sarcoplasm)

9. Lactic Acid System • Glucose is broken down into 6 phosphates (2 ATP) and pyruvic acid. • The main enzyme responsible for the break down of glucose is phosphofructokinase (PFK) activated by low levels of phosphocreatine • Pyruvic acid is converted into lactic acid in the absence of oxygen.

10. Lactic Acid system • Overall summary: • C6H12O6 (glucose)  2(C3H6O3) (pyruvic acid) + ENERGY • ENERGY  2ADP + 2Pi  2ATP • The energy released from the breakdown of each molecule of glucose is used to make two molecules of ATP • The lactic acid system actually provides sufficient energy to re-synthesise three molecules of ATP but the process of glycolysis itself requires energy (one molecule) • The lactic acid system provides energy for high-intensity activities lasting up to 3 minutes but peaking at 1 minute, for example the 400m

11. Lactic Acid System Advantages Disadvantages • Few chemical reactions so ATP can be resynthesises quickly • Anaerobic so do not need to wait for the 3 minutes or for sufficient oxygen • Lactic acid can be converted back into liver glycogen • can be called upon to produce an extra burst of energy (10,000m) • If lactic acid accumulates in the muscle, the pH of the body is lowered and this has an effect on enzyme action. PFK, the controlling enzyme, is then inhibited and the ability to re-generate ATP is reduced. This affects performance, for example ‘burning out’ at the end of a race • Only a small amount of energy (5%) locked inside a glycogen molecule can be released in absence of oxygen.

12. Quick recap 400m race First 10 secs ATP-PC Lactic Acid will provide for the rest • Site of reaction – • Fuel used – • Active enzyme – • Molecules of ATP produced - • Sacroplasm of muscle cell • Glycogen (stored CHO) • Phosphofructokinase • 2 molecules

13. Exam Question • What are the main energy sources used by an athlete during a 400M sprint? Explain the predominant energy system used during this time. (7 Marks) Make notes on your own to answer this question. Share with the person beside you. Share with the whole class.

14. Candidate A • The main energy sources used by a 400m runner are carbohydrate and phosphocreatine. The ATP/PC system is used for the first part of the race and is a simple system to use. It uses phosphocreatine as the fuel and there are no fatiguing by products. The energy yeild is ATP. After 10 seconds the lactic acid system is used.

15. Candidate B • The energy sources used by the sprinter are phosphocreatine and glucose. The main energy system is the lactic acid system. This is anaerobic and glucose is broken down into pyruvic acid. Two molecules of ATP are formed and lactic acid is the by product.This system takes place in the sarcoplasm.

16. Energy systems Learning outcomes: • All are able to demonstrate understanding of the energy sources required for ATP resynthesis • All are able to describe the Lactic Acid energy system • Most are able to explain the use of PCr in ATP resynthesis • Most are able to apply their understanding of the lactic acid system to sporting examples. • Some can analyse the lactic acid and determine advantages and disadvantages

17. Plenary Activity • All write down one question and answer that would demonstrate the progress you have made in this lesson.