PHOTOSYNTHESIS Flashcards
Photosynthesis
Photochemical reaction
Electron transfer
Biochemical reaction (carbohydrates)
Light reaction
thylakoid membranes
the capture of light energy as ATP and reducing power, NADPH
Carbon-fixing reaction
chloroplast stroma
the transfer of energy and reducing power from ATP and NADPH to CO2
starting products
carbon dioxide and water
products
3 carbon sugar and O2
Photosynthesis vs respiration
endergonic
potential energy of substrate < product
exergonic
potential energy of substrate > product
Chlamydomonas
pyrenoid: carbon fixing reactions take place
Oxygenic photosynthesis
electron from H2O and product is O2
reduction of CO2 to carbohydrate
plants, algae and cyanobacteria
Anoxygenic photosynthesis
do not extract electrons from water
electrons from H2S
purple sulfur bacteria and green sulfur bacteria
Plastids
Proplastid–> undifferentiated (seeds, embryonic)
Etioplast–> dark grown photosynthetic tissue
Chloroplast–> pigments
Chromoplast –> red and yellow pigment
Leucoplast –> amyloplast, elaioplast, proteinoplast (storage of starch, oils, proteins)
Plastid conversions
light induces conversion from etioplast to chloroplast
Light absorption spectra of photosynthetic pigments
all chlorophyll-based photosynthesis systems use chlorophyll a
Chlorophylls
harvest the light energy and transduce it into chemical energy
amphipathic molecules
thylakoid membrane
chlorophyll biosynthesis
glutamic acid –> protoporphyrin IX00> chlorophyll synthase attaches phytol tail
Protoporphyrin IX *
a precursor of Mg-containing chlorophyll and containing heme
