Photosynthesis Case

Metabolism

All chemical reactions in a cell → arranged into metabolic pathways

Intermediates in these pathways are called metabolites

Catabolic reactions (e.g. respiration) release energy

Anabolic reactions (e.g. photosynthesis) use up energy

Leaf Structure

Phototropism → growth towards light

Large leaf surface area → captures more light

Thin leaves → few cell layer → more light captured by chlorophyll

Leaf mosaic increases leaf exposure to light

Internal Structure

Cuctile → reduces H2O loss by evaporation

Palisade mesophyll → chloroplast can move around cell for max light absorption

Spongy mesophyll → allows diffusion of gases through leaves

Phloem sieve tube → removes products of photosynthesis

Chloroplast

Thylakoid membrane: light-dependent → large surface area

Associated with chlorophyll, accessory pigments, ETC, enzymes

Grana: stacks of thylakoid membranes

Enclose hydrogen reservoir used in chemiosmosis

Lamella: tubular extensions forming a network between grana

Stroma: RuBP carboxylase catalyses light independent reaction