Chapter 10: Energy Carriers Leaving Certificate Biology Higher Level

Oxidation - Reduction Oxidation is the loss of electrons Reduction is the gain of electrons Use the mnemonic, “OILRIG”, to remember Oxidation – reduction (redox) reactions are very important for living organisms as energy can be transferred very efficiently from one form to another – i.e. chemical energy to heat, kinetic, sound energy

Oxidation - Reduction Energy carriers take part directly in metabolic reactions by: Gaining high energy electrons (reduction) Losing electrons that have given up their energy (oxidation)

Energy Carriers ATP (adenosine triphosphate) Is the ‘energy currency’ of the cell Composed of: Adenine Ribose 3 phosphates

ELECTRON TRANSPORT CHAIN Energy Carriers NAD+ (nicotinamide adenine dinucleotide) Electron carrier used in aerobic respiration Picks up energised electrons (reduction) after a bond is broken and carries them to the electron transport chain where they release their energy in an enzyme-controlled environment to produce ATP NAD+ + 2e– + H+ → NADH ELECTRON TRANSPORT CHAIN

Energy Carriers NADP (nicotinamide adenine dinucleotide phosphate) Electron carrier used in photosynthesis Picks up energised electrons (reduction) that originated from chlorophyll molecules that were hit by light and transfers them along with protons to the dark stage in order that CO2 may be reduced (addition of H+ and e–) to form glucose NADP + 2e– → NADP– + H+ → NADPH DARK STAGE