Photosynthesis
Lamellae used as spacer to maximise light capture
Photosynthetic pigments
Chlorophyll a -> main photosynthesising pigment involved in light dependent stage
made up of porphyrin ring with magnesium centre and hydrocarbon tail
absorbs blue-violet and red-orange light(visible spectrum only)
magnesium ion gets excited when one of its electrons gets energy from a photon
releases an excited electron to primary acceptor molecule
Accessory pigments - chlorophyll b, xanthophyll + carotene(carotenoids) and
phaeophytin
light-harvesting pigments + used to increase range of wavelengths absorbed to be
used in photosynthesis
Not involved in photosynthesis
Transfer energy absorbed to chlorophyll a to be used in photosynthesis
Absorption spectrum: wavelengths of light that a particular photosynthetic pigment
absorbs(graph of absorbance)
Action spectrum: wavelengths of light that bring about photosynthesis in a particular
plant (graph of rate of photosynthesis)
Pigments arranged in photosystems in thylakoid membranes
pigment molecules are clustered into antenna complexes
arranged in a complex to channel light energy to one molecule of chlorophyll a
Chlorophyll a + primary acceptor molecule = reaction system
Photosystem = reaction centre + other light harvesting molecules
, 2 types of photosystem: P1 and P2
P1 = reaction centre is called P700 - chlorophyll a max absorption of 700nm(red)
P2 = reaction centre is P680 - chlorophyll a max absorption of 680nm(orangey red)
work together in light-dependent stage
PS1 = NADPH producing
PS2 = water splitting
Light-Dependent stage
occur in thylakoid membranes in grana
ADP converted to ATP - Photophosphorylation
Water molecules split into H+ and O2 - Photolysis
NADP reduced to NADPH
1. Photons from sunlight excite magnesium particles in chlorophyll a in photosystem 2
high energy state + electron leaves chlorophyll molecule
Lamellae used as spacer to maximise light capture
Photosynthetic pigments
Chlorophyll a -> main photosynthesising pigment involved in light dependent stage
made up of porphyrin ring with magnesium centre and hydrocarbon tail
absorbs blue-violet and red-orange light(visible spectrum only)
magnesium ion gets excited when one of its electrons gets energy from a photon
releases an excited electron to primary acceptor molecule
Accessory pigments - chlorophyll b, xanthophyll + carotene(carotenoids) and
phaeophytin
light-harvesting pigments + used to increase range of wavelengths absorbed to be
used in photosynthesis
Not involved in photosynthesis
Transfer energy absorbed to chlorophyll a to be used in photosynthesis
Absorption spectrum: wavelengths of light that a particular photosynthetic pigment
absorbs(graph of absorbance)
Action spectrum: wavelengths of light that bring about photosynthesis in a particular
plant (graph of rate of photosynthesis)
Pigments arranged in photosystems in thylakoid membranes
pigment molecules are clustered into antenna complexes
arranged in a complex to channel light energy to one molecule of chlorophyll a
Chlorophyll a + primary acceptor molecule = reaction system
Photosystem = reaction centre + other light harvesting molecules
, 2 types of photosystem: P1 and P2
P1 = reaction centre is called P700 - chlorophyll a max absorption of 700nm(red)
P2 = reaction centre is P680 - chlorophyll a max absorption of 680nm(orangey red)
work together in light-dependent stage
PS1 = NADPH producing
PS2 = water splitting
Light-Dependent stage
occur in thylakoid membranes in grana
ADP converted to ATP - Photophosphorylation
Water molecules split into H+ and O2 - Photolysis
NADP reduced to NADPH
1. Photons from sunlight excite magnesium particles in chlorophyll a in photosystem 2
high energy state + electron leaves chlorophyll molecule
