photosynthesis Flashcards
what does photosynthesis do?
transforms solar energy into the chemical energy of carbohydrates
equation for photosynthesis
6CO2+6H2O –> C6H12O6+6O2
where does carbon dioxide enter the leaves through
stomata
where does carbon dioxide and water diffuse to?
chloroplast, the site of photosynthesis
what does the stroma contain
numerous flat thylakoid disk arranged in stacks called grana
2 reactions involved in photosynthesis are…?
-light reactions
-calvin cycle
what are the 3 events involved in the light reaction?
chlorophyll-absorbs solar energy, which energized electrons and splits H20
ATP- produced using an electron transport chain
NADP+ -a coenzyme, accepts electrons to become NADPH
what are the events involved in the Calvin Cycle?
CO2- taken up by one of the substrates in the cycle
ATP and NADPH-from the light reactions change CO2 to a carbohydrate
solar energy can be described in terms of its…?
wavelength and energy content
two primary pigments used during photosynthesis are…?
chlorophylls and carotenoids
what colors do chlorophylls absorb and reflect
absorb- violet, red, and blue wavelengths
reflect- green light
what do carotenoids absorb and reflect?
absorb- violet, blue, and green
reflect- yellow and orange wavelengths
what color are Xanthophylls?
yellow
what do the electron pathways in the light reactions produce?
ATP and NADPH
Parts to a photosystem
-pigment complex, or light antenna
-special chlorophyll pigment, the reaction center
-electron acceptor molecules
how do electrons gain energy in photosynthesis?
by being boosted up an energy hill
what is light energy converted into after providing a boost for electrons?
chemical energy, which is stored in the chemical bonds of sugar molecules
what happens to photosystem II (PS II)absorbs solar energy?
energized electrons get passed to electron acceptors
what does PSII do?
splits water molecules to recover the electrons passed to the electron acceptors
as electrons are passed down an electron transport chain, energy is release and stored in the form of a …?
Hydrogen ion (H+) gradient
what happens when photosystem I (PSI) absorbs solar energy?
energized electrons are passed to different electron acceptors
the electron acceptors in PSI pass the electrons to..?
NADP+ to form NADPH
what does the thylakoid space or lumen become during photosynthesis?
an H+ reservoir
what is NADP+
a coenzyme that accepts H+ from a substrate
How and when is NADPH formed
it is formed during the light reactions by accepting electrons from the electron transport pathway and then picks up H+
the 3 steps of the calvin cycle
-carbon dioxide fixation
-carbon dioxide reduction
-regeneration of RuBP
what happens during the first step of the calvin cycle
CO2 from the air is attached to RuBP
-the enzyme for this reaction is carboxylase oxygenase (rubisco)
what does Rubisco do?
splits the resulting 6-carbon molecule to form two 3-carbon molecules
during reduction of carbon dioxide, what do NADPH and ATP provide?
NADPH-provides electrons for the reduction
ATP- provides the energy
what is the product of the calvin cycle
gylceraldehyde-3-phosphate (G3P)
what is the primary advantage of CAM photosynthesis?
conservation of water
