Chemistry 2211a - Tutorial #7 – Magnesium
Question:
Why is photosynthesis important?
How do plants protect against too much
sunlight?
What is a chloroplast made of?
What is the overall reaction?
What is reduced and by how much?
Where does the oxygen from glucose
and water come from?
Where do the oxygen atoms (O) from
molecular oxygen (O2) come from?
What are the systems in
photosynthesis?
What is the overall order of
photosynthesis ?
Answer:
- Produces food (glucose) from CO2, water
and sunlight (photons).
- Chloroplast
- Carotenoids
- Anthocyanin
These molecules protect in auto-oxidation of
photosynthetic machinery, which would render the
plant unable to produce food.
- Stroma Æ the thick fluid found in between
grana. This is the site of the light
independent reactions (the Calvin Cycle)
- Grana Æ stacks of thylakoids
- Thylakoid Æ membrane-bound
compartment inside the chloroplasts. These
compartments are the site of the lightdependent reactions of photosynthesis.
6CO2 + 12 H2O Æ C6H12O6 + 6H2O + 6O2
Carbon is reduced from an oxidation state of +4 to
an average oxidation state of 0
Oxygen atoms are oxidized from 2- to 0
CO2
H2O
PSII Æ photosystem II
It absorbs 680 nm light and promotes an electron to
photosystem I. This electron is replaced by H2O Æ
O2.
Helps maintain the proton gradient in the thylakoid
lumen
PSI Æ photosystem I
It absorbs 700 nm light and reduces NADP+ to
NADPH. Helps maintain the proton gradient in the
thylakoid lumen. This gradient produces ATP used
for carbon fixation.
Dark reaction cycle (Calvin Cycle)
fixes CO2 in the form of sugars.
Photon Æ PSII Æ photon Æ PSI ÆNADPH
ATP produced with H+ Æ Calvin Cycle (CO2
fixation) using energy
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Chemistry 2211a – Tutorial Qu and Answers – Tutorial 7
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