1. The Chemistry of Respiration
energy and mitochondria clip

2. Adenosine triphosphate
The energy released during respiration is not used directly by cells.
Instead it is used to make a molecule called ATP which stores the energy until it is needed.
ATP = Adenosine triphosphate

3. What does ATP do?
ATP supplies energy for all the processes that need it.
For example:
movement
chemical reactions
growth.
slow twitch/fast twitch investigation

4. Structure of ATP
adenosine Pi

5. Formation of ATP
ATP is made when another molecule called adenosine diphosphate (ADP) is bonded to a third inorganic phosphate (Pi) using the energy released from glucose.

6. adenosine + Pi adenosine Pi Enzymes Energy from respiration
Energy Rich bond formed

7. Summarised as: ADP + Pi ATP
The whole process is under the control of enzymes

8. The role of ATP
ATP stores the energy in the third bond of the molecule
The energy is released when that bond is broken to release the third inorganic phosphate (Pi) .

9. adenosine Pi
ATP
Enzymes Pi
adenosine +
ADP
Energy released to do work

10. Summary ATP energy (out)
cellular respiration
cell activities
ATP
ADP + Pi
energy
(out)
(in)
cellular respiration
cell activities
The whole process is an enzyme controlled reaction.

11. Aerobic respiration = respiration with oxygen.

12. glucose + OXYGEN energy + carbon dioxide + water (to make ATP)

13. Aerobic respiration happens in 2 stages:
Stage 1 – Glycolysis
glyco lysis
glucose splitting

14. Glycolysis does not require oxygen
In glycolysis, a glucose molecule is broken down into pyruvic acid.
glucose
series of enzyme
controlled reactions
energy released to make small quantity of ATP
(2 molecules)
pyruvic acid
Glycolysis does not require oxygen

15. Stage 2 – Breakdown of pyruvic acid
The pyruvic acid made in glycolysis (stage1) still contains a lot of energy
It can only be broken down to release the rest of the energy in the presence of oxygen.

16. pyruvic acid
energy released to make large
quantity of ATP
(36 molecules)
series of enzyme controlled reactions
carbon dioxide + water

17. ATP production – summary
glucose
2 ADP + 2 Pi =
2 ATP
pyruvic acid
36 ADP + 36 Pi =
36 ATP
carbon dioxide + water

18. Summary of ATP production
Stage 1 and 2 release all the chemical energy in one molecule of glucose to make a total of 38 ATP molecules.
2 molecules ATP from glucose  pyruvic acid
36 molecules ATP from pyruvic acid  carbon dioxide + water
Total 38 molecules ATP

19. Anaerobic Respiration (in animals)
anaerobic = in the absence of oxygen

20. In low oxygen conditions or during heavy exercise, when not enough oxygen can be supplied, muscle cells swap to anaerobic respiration

21. in absence of oxygen pyruvic acid is turned into lactic acid.
glucose
glycolysis still happens as it does not require oxygen
2 ADP + 2 Pi
2 ATP
pyruvic acid
in absence of oxygen pyruvic acid is turned into lactic acid.
lactic acid

22. A build up of lactic acid produces muscle fatigue
A build up of lactic acid produces muscle fatigue. Muscle fatigue makes muscles ache and contract less powerfully. A recovery period is needed. During this time more oxygen is taken in to convert the lactic acid back into pyruvic acid again. The volume of oxygen needed is called the oxygen debt.

23. Summary oxygen debt e.g. during hard exercise oxygen debt
glucose
pyruvic acid
oxygen debt
e.g. during hard exercise
oxygen debt
repaid during recovery time
lactic acid

24. Anaerobic Respiration in plants
The same process occurs in plants and yeast in low oxygen conditions, e.g. muddy, flooded soils.

25. ethanol + carbon dioxide
glucose
pyruvic acid
2 ADP + 2 Pi
2 ATP
glycolysis still happens, producing
2 ATP molecules
This time in absence of oxygen, pyruvic acid is turned into carbon dioxide and ethanol
This is irreversible
ethanol + carbon dioxide

26. Comparison of aerobic and anaerobic respiration
in animals
in plants and yeast
Oxygen required?
yes no
Glycolysis occurs
ATP yield
38ATP
2ATP
Glucose completely broke down?
End products
Carbon dioxide and water
Lactic acid
Ethanol and carbon dioxide