Respiration C6H12O6 + 6O2 → 6CO2 + 6H2O

The Mitochondrion

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!

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

Krebs Cycle Don’t panic!

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!

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!

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

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)

Detail indicated by the IB Biology Guide

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

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

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;