L24 - Photosynthesis 1 Flashcards
What 2 processes make up the carbon cycle?
Respiration and Photosynthesis
Describe a chloroplast
Sub-cellular organelles
About 2.5x’s larger than mitochondria
Have a high level of internal structure
In green plants where does photosynthesis take place?
In chloroplasts
Describe what each is and what happens at each:
a) Inner chloroplast membrane
b) Outer chloroplast membrane
c) Thylakoid membrane
d) Stroma
e) Grana/granum
f) Thylakoid disc
g) Stromal lamellae
h) Thylakoid space
a) transport for phosphate and sucrose pre-cursors
b) permeable to small molecules
c) absorption of light by chlorophyll, synthesis of ATP4-, NADPH, and electron transport
d) enzymes that catalyse CO2 fixation and starch synthesis
e) Stacks of thylakoid discs
f) The central thylakoid space is surrounded by the thylakoid membrane (derived from inner chloroplast membrane)
g) connections between grana
h) site of light reactions of photosynthesis
What are the different types o chlorophyll in:
a) green plants
b) algae
c) bacteria
a) chl.a chl.b
b) chl a, c,d,e
c) bacteriochlorophyll
What part of the spectrum does chlorophyll absorb light from?
extreme parts of the spectrum
In Chlorophyll A there is a side group of CH3, what is this replaced by to get to Chlorophyll B?
CHO
What secures chlorophyll to the thylakoid membrane?
Long hydrocarbon tail secures the molecule to hydrophobic proteins embedded in the thylakoid membrane
What are antenna systems?
Chlorophylls are arranged into light harvesting complexes called antenna systems. One chlorophyll acts as the reaction centre receiving energy from surrounding pigment molecules
What is the reaction centre in Photosystem 1 called and what does it contain?
P700 - contains chlorophyll A
Describe photoreduction
A Fe-S protein (FX) is the primary electron acceptor which transfers its electrons via FA and FB to ferredoxin (FD)
NADP+ subsequently reduced to NADPH+H+ by NADP reductase
2NADP+ + 4e- + 4H+ ———-> 2NADPH+H+
