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13.2 Structure and function of chloroplasts - Coggle Diagram
13.2 Structure and function of chloroplasts
General information/structure
Located mainly in palisade and spongy mesophyll
Double membrane
Stroma
Site of light-independent phase of photosynthesis
Background fluid in a chloroplast
Thylakoids
Site of light-dependent phase of photosynthesis
Membrane-enclosed fluid-filled sacs
Stacks of thylakoids are called grana
The membranes connecting thylakoids and grana are called lamellae
Pigments and photosystems
Photosynthetic pigments are embedded in lamellae and thylakoid membranes
Pigments are arranged in clusters called photosystems, which also contain proteins
Photosystem I - main wavelength absorbed = 700nm
Photosystem II - main wavelength absorbed = 680nm
Energy absorbed from light is channelled to reaction centre
Each reaction centre contains two chlorophyll a molecules - primary pigment
Other pigments help to channel harvested energy to chlorophyll a - accessory pigments
Accessory pigments increase energy level of electrons travelling to primary pigments
Action spectrum
Shows rate of photosynthesis at different wavelengths
The sum of the absorbances of different pigments
Chromatography
Crush leaves with propanone and petroleum ether
Filter to obtain dark green solution of pigments
Mark with pencil 2cm from base of chromatography paper
Use capillary tube to dot concentrated spot of green solution
Place paper in glass with solvent and mark solvent front
Calculate Rf values for each pigment (distance travelled by pigment/distance travelled by solvent)