1. Respiration This Powerpoint is hosted on www.worldofteaching.com
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3. Foods provide us with calories but they are not the form of energy used by cells.
Food is broken down by enzymes in the digestive system to form glucose.
Celllular Respiration in the mitochondria forms ATP from these sugars.

4. The Chemistry of Respiration
energy and mitochondria clip

5. 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

6. 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

7. Structure of ATP
adenosine Pi

8. 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.

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

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

11. 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) .

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

13. 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.

14. Aerobic respiration = respiration with oxygen.

15. glucose + OXYGEN carbon dioxide + water + ATP C6H12O6 + O2 ――> CO2 + H2O + ATP

16. Aerobic respiration happens in 2 stages:
Stage 1 – Glycolysis
glyco lysis
glucose splitting
This stage occurs in the cytoplasm.

17. Glycolysis does not require oxygen
In glycolysis, a glucose molecule is broken down into pyruvic acid. This process requires 2 ATP to start the reaction.
glucose
series of enzyme
controlled reactions
energy released to make 4 ATP
(-2ATP+4ATP=2ATP)
Net gain of 2ATP
pyruvic acid
Glycolysis does not require oxygen

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

20. pyruvic acid
energy released to make large
quantity of ATP
(~36 molecules)
series of reactions, called
The Kreb Cycle &Electron Transport Chain
carbon dioxide + water

22. ATP production – summary
glucose
2 ADP + 2 P =
2 ATP
pyruvic acid
34 ADP + 34 P =
34 ATP
carbon dioxide + water

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

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

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

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

28. 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.

29. 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

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

31. ethanol + carbon dioxide
glucose
pyruvic acid
2 ADP + 2 P
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

32. Comparison of aerobic and anaerobic respiration
in animals
in plants and yeast
Oxygen required?
yes no
Glycolysis occurs
ATP yield
36ATP
2ATP
Glucose completely broke down?
End products
Carbon dioxide and water
Lactic acid
Ethanol and carbon dioxide