Respiration

In the cytoplasm of cells • Glucose is phosphorylated to glucose phosphate using 2 ATP molecules • Glucose phosphate splits into 2 triose phosphate • Dehydrogenase catalyses the oxidation of triose phosphate into pyruvate with a net gain of 2 ATP and NADH (reduced NAD)

Pyruvate is actively transported into the mitochondrial matrix • Dehydrogenase catalyses oxidation of pyruvate (3C) into acetate (2C), producing NADH (reduced NAD) • Decarboxylase catalyses loss of CO2 in the process • Acetate combines with coenzyme A to produce acetyl coenzyme A • Acetylcoenzyme A reacts with a 4 carbon molecule, releasing co enzyme A and producing a 6C molecule that enters the kerbs cycle

For both acetylcoenzyme A in the matrix • Acetylcoenzyme A reacts with a 4 carbon molecule, releasing co enzyme A and producing a 6C molecule • Dehydrogenase catalyses the oxidation of 6C molecule producing NADH (reduced NAD) • Decarboxylase catalyses the loss of CO2 in the process • Dehydrogenase catalyses the oxidation of 5C molecule producing 2 NADH and FADH • Decarboxylase catalyses the loss of CO2 in the process • ATP generated by substrate-level phosphorylation

Chemiosmotic theory at inner mitochondrial membrane • NADH and FADH release electrons to electron transfer chain (ETC) • Electrons pass through ETC by a series of redox reactions • Energy released used to pump H+ (protons) across inner mitochondrial membrane into intermembrane space • H+ ions diffuse down electrochemical gradient, through ATP synthase embedded in the membrane, back into the matrix • ATP synthase catalyses ATP by condensing ADP and Pi in oxidative phosphorylation • O2 acts as a terminal electron acceptor from ETC producing water

Glycolysis • Pyruvate reduced by NADH to lactate • This regenerates NAD • NAD used in glycolysis

Glycolysis • Pyruvate reduced by NADH to ethanol and CO2 • This regenerates NAD • NAD used in glycolysis