1. Higher Human Biology Subtopic 7 (a) Respiration
Metabolic Pathways
Higher Human Biology
Subtopic 7 (a)
Respiration

2. Learning Intentions State the equation of respiration
Describe the structure of ATP
State the role of ATP in the transfer of energy
Discuss the 3 stages in aerobic respiration

3. What can we remember?
Respiration is a series of enzyme controlled reaction that releases the energy in food to make ATP.

4. Why do cell need energy? Growth Cell division Repair
Movement (e.g. muscular contraction)
Chemical reactions (e.g. protein synthesis)
Remember ATP links catabolic and anabolic reactions.

5. Adenosine tri phosphate
ATP
Adenosine tri phosphate
Energy currency of the cell
Stores energy
1 adenosine + 3 inorganic phosphates
ADENOSINE Pi

6. Adenosine di phosphate
Energy Release
The energy stored in ATP is released when the bond to the last phosphate is broken to produce…………
Adenosine di phosphate
ADENOSINE Pi
Energy

7. ATP is a link between anabolic and catabolic reactions.
The Reversible Reaction
There is a constant supply of ATP in our cells as it is synthesised as fast as it is used.
REMEMBER……
ATP is a link between anabolic and catabolic reactions.

8. Phosphorylation An enzyme controlled process
Involves the addition of a phosphate group
Also occurs when the Pi and energy from ATP are transferred.

9. Respiration The Process

10. ANAEROBIC RESPIRATION
The Equations
AEROBIC RESPIRATION
- Presence of oxygen
ANAEROBIC RESPIRATION
- Lack of oxygen

11. Overview (aerobic respiration)
Energy rich substance (e.g. glucose) is broken down and used to make ATP
Enzyme controlled steps
3 stages :
1. Glycolysis
2. Citric Acid Cycle
3. Electron Transport Chain (ETC)
Requires the enzyme ATP synthase

12. Overview (aerobic respiration)
Cristae (folds in the inner membrane)
Central matrix (fluid filled interior)

13. Stage 1 : Glycolysis Occurs in the cytoplasm Doesn’t need oxygen
Splits 6C glucose into 2 × 3C pyruvates
Hydrogen ions and electrons removed
Net gain of 2 ATP

14. The energy investment stage
Phosphorylation happens twice (step 1 and step 3)
Step 3 uses the enzyme phosphofructokinase

15. The energy payoff stage
4 ATP generated here (2 needed in energy investment stage) so NET GAIN of 2 ATP
H+ ions and electrons released by the action of a dehydrogenase enzyme and picked up by the coenzyme NAD to form NADH
NADH goes to the ETC

16. Textbook page 103
If there is no oxygen present then the reaction does not proceed to TCA

17. Stage 2 : Citric Acid Cycle
Occurs in the matrix of the mitochondria
Needs oxygen
Converts pyruvate into Acetyl which combines with coenzyme A to make acetyl coenzyme A

18. Stage 2 : Citric Acid Cycle
Acetyl coenzyme A is broken down in a series of steps releasing H+ ions, electrons and carbon dioxide
The H+ ions and electrons are picked up by NAD / FAD

19. Stage 3 : Electron Transport Chain
Occurs on the cristae of the mitochondria
Contains a group of proteins attached to the inner membrane and the enzyme ATP synthase
Proteins
ATP Synthase
Intermembrane space
Matrix

20. Stage 3 : Electron Transport Chain
The NADH / FADH2 release their high energy electrons
The electrons release their energy which is used to pump H+ across the membrane (matrix to inter membrane space)
This forms a gradient (more H+ in intermembrane space)
The H+ flow back through the enzyme ATP synthase synthesizing
ADP + Pi ATP
The electrons, a pair of H+ and oxygen combine to form water.

22. TOTAL ATP = 38 ATP Production 2 ATP from glycolysis
36 ATP formed in the rest of the cycle (nearly all in the ETC)
TOTAL ATP = 38
ETC clip

23. Put the following statements under the correct stage in respiration…..
It ends with the production of water
It brings about the breakdown of glucose to pyruvate
It involves the production of CO2
It begins with acetyl coA combining with oxaloactetate
It involves a cascade of electrons, which are finally accepted by oxygen
It results in the production of ATP
It has an energy investment and an energy payoff stage
It results in the production of NADH

24. Learning Intentions State the equation of respiration
Describe the structure of ATP
State the role of ATP in the transfer of energy
Discuss the 3 stages in aerobic respiration