1. Respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O

2. The Mitochondrion

3. Overview
10 (-2 Phosphorylation of glucose) (-2 for transport of 2NADH2 into the mitochondrion) = 6 6 2 28
Net production of ATP is 36 N.B. Anaerobic respiration only produces 2!

4. Glycolysis Don’t panic!
This can be split into phosphorylation, lysis and oxidation/ATP formation

5. Krebs Cycle
Don’t panic!

6. Exam style explanation of glycolysis
2ATP
2ADP
Glucose 6C P
Glucose diphosphate 6C
phosphorylation
lysis
2 x 3C phosphates
NADH
2 pyruvate 3C
phosphorylation of glucose (ATP expenditure).
splitting of the glucose diphosphate into two 3C phosphates
oxidation by the removal of hydrogen
conversion of NAD to NADH
net production of 2 ATP (2 used and 4 produced)
pyruvate is produced at the end of glycolysis
the NADH can be used to generate further ATP in the mitochondria
This happens in the cytoplasm!
Only the carbon atoms are shown!

7. Exam style explanation to the link reaction
CO2
NAD
NADH
Accounts for 6ATP
2 Acetyl CoA 2C
2 pyruvate 3C
Pyruvate loses CO2 in the link reaction
To form acetyl CoA which enters the Krebs Cycle
Each NADH provides electrons that can pass through the electron transport chain and generate 3 ATP
This happens in the mitochondria!

8. Exam style explanation to the Krebs Cycle
N.B. This happens twice as there are two acetyl CoA molecules from each hexose 2C 6C
4C oxaloacetate
NAD
Accounts for 6ATP
ATP
NADH
KREBS CYCLE
Accounts for 2ATP
CO2
Accounts for 4ATP
Accounts for 12ATP
FAD 5C
CO2
NADH and FADH carry electrons to the ETC to produce ATP

9. Main points Glycolysis occurs in the cytoplasm
Hexose is phosphorylated using ATP
Hexose phosphate is split into two triose phosphates
Triose phosphates are oxidised by the removal of hydrogen
Reduction of NAD to NADH
NADH can enter the mitochondria (at a cost of 1ATP per NADH) and produce 3 more ATPs
2 ATPs used and 4 ATPs produced resulting in a net gain of 2 ATPs
Pyruvate is produced at the end of glycolysis
Pyruvate enters the mitochondria where it loses CO2 in the link reaction and producing NADH
This results in the production of Acetyl CoA (2C) which joins with oxaloacetate (4C) to form citrate (6C)
Further NADH is produced and the removal of CO2 results in the formation of ketoglutarate (5C)
Production of 2 NADH and 1 FADH2 along with the removal of CO2 produces oxaloacetate (4C)
ATP is produced from ADP + Pi
There are two turns of the Krebs Cycle for each hexose molecule
Aerobic respiration/Link reaction + Krebs Cycle produces a high yield of ATP (34)

10. Detail indicated by the IB Biology Guide

11. 8.1.5 Explain oxidative phosphorylation in terms of chemiosmosis.
Every two hydrogen ions that travel through ATP synthase down the electrochemical gradient (chemiosmosis) generate one molecule of ATP
Outer membrane
As the electrons pass along the ETC, hydrogen ions are pumped into the intermembrane space
2H+
2H+
2H+
2H+ e- e- e- e-
ATP Synthase
Inner membrane e-
ADP + Pi
NADH
NAD+
2H+ + e + ½ O2→ H2O
Oxygen is the final
electron acceptor
ATP

12. Summer 2005
Explain the process of aerobic cellular respiration.[8]

13. glucose is broken down to pyruvate in the cytoplasm (glycolysis);
with a small yield of ATP/net yield of 2 ATP;
and NADH;
aerobic respiration in the presence of oxygen;
pyruvate converted to acetyl CoA (link reaction);
acetyl CoA enters Krebs cycle;
Krebs cycle yields a small amount of ATP/one ATP per cycle;
and FADH2 / NADH/ reduced compounds / electron collecting molecules;
these molecules pass electrons to electron transport chain;
oxygen is final electron acceptor/water produced;
electron transport chain linked to creation of an electrochemical gradient/build up of H+ ions in the intra-membrane space;
electrochemical gradient/chemiosmosis powers creation of ATP;
through ATPase;