1. ATP

2. ATP • Adenosine Triphosphate • referred to as the energy currency or energy carrier of living organisms • NOT an energy storage molecule • Nucleotide-comprised of a purine base (adenine) attached to C1of a ribose sugar backbone and the phosphates are attached to C5

3. Structure of ATP

4. ATP • ATP is thermodynamically unstable thus it is readily hydrolysed to ADP, Pi and 30.6kJ of energy HYDROLYSIS (ATPase) • ATP + H2O ADP + Pi+ CONDENSATION 30.6kJ of energy per mole of ATP • ADP • AMP

5. ATP • exists in very small quantities in the cell in equilibrium with ADP • 30.6kJ of energy is evolved per mole of ATP hydrolysed • Mobile, easily transported (universal energy ‘carrier’ and is easily diffused to carry energy to energy consuming processes • ATP releases energy quickly without having to go through any complicated metabolic pathways

6. ATP • found in all living cells and cell types, hence energy ‘currency’-reduces the amount of cell machinery and materials required to manufacture different energy carriers • Formed during photosynthesis and respiration

7. Uses of ATP • Anabolic processes- provides energy needed to build macromol.eg. polysaccharide, proteinsyhthesis, DNA replication • Movement-muscle contraction, ciliary action • Active transport • Secretion of vesicles • Activation of chemicals- phosphorylation of glucose at start of glycolysis

8. Photosynthetic Pigments Two main types: • Chlorophyll- a and b • Carotenoids- carotenes and xanthophylls • These absorb light enery converting it into chemical energy

9. Chlorophyll • absorb mainly red and blue-violet light reflecting green which explains why plants appear green • flat porphyrin head with a magnesium atom at the center which acts as the “sunlight trap” or “solar panel” • hydrophobic (water-hating/lipid loving) tail which is embedded into the lipid rich thylakoid membrane • Chlorophyll a most abundant

10. Chlorophyll a Structure

11. Carotenoids • yellow, orange, red or brown pigments • absorb strongly in the blue violet region • referred to as accessory pigments because they pass the solar energy they absorb to the chlorophyll • protect the chlorophyll from oxidation by O2 produced during photosynthesis • they protect the chlorophyll from damage due to excess light

12. Carotenoids • Found in flowers and fruits • Beta carotene most common-carrots • Their basic structure comprises two small rings linked by a long hydrocarbon chain

13. Carotenoid Structure

14. Absorption spectra:- shows the relative amount of light absorbed at different wavelengths • Action spectra:- shows the effectiveness of different wavelengths in promoting photosynthesis