8. METABOLISM Flashcards
Explain the processes by which light energy is converted into chemical energy.
- through photosynthesis
- light dependent reaction in the thylakoid membrane in the chloroplast
- light absorbed by chlorophyll in photosystem II
- excites an electron which is passed from carrrier to carrier
- pumping of protons against the concentration gradient into the thylakoid space
- ATP synthase synthesizes ATP through chemiosmosis ( generated proton gradient)
- electrones pass from PS II to PSI thorugh carriers
- electrones from PSI are used to reduce NADP
- photolysis of water replaces an electron to the photosystem
- products (ATP and NADPH) are then used in light- Independent reaction which uses CO2 to synthesize glucose
Calvin cycle
Ribulose Bisphosphate + CO2
glycerate 3 phosphate reduced to
triose phosphate
Describe the role of oxygen in aerobic cell respiration.
- final electron acceptor ( highly electronegative ) at the end of electron transport chain
- binds to protons maintaining the proton gradient in intermembrane space (water as the waste product)
- allows for maximum ATP production ( maximum energy yield from oxidation of glucose) and can breakdown fats
- prevents buildup of lactic acid
Example of competitive and non-competitive inhibitor
Relenza - competitive, neuraminidase, influenza virus, prevents cleavage of the docking protein and the release of virions
Cyanide - non-competitive, cytochrome oxidise in electron transport chain
End -product inhibition example
Threonine converted to isoleucine, isoleucine functions as non-competitive inhibitor
Explain Calvin’s experiment and what was discovered about photosynthesis through his work.
a. Calvin cycle is light-independent ✔
b. carbon fixation
OR
carboxylation of ribulose bisphosphate/RuBP occurs ✔
c. algae placed in thin glass container/“lollipop” apparatus ✔
d. given plenty of light and bicarbonate/ CO2 ✔
e. at start of experiment algae supplied radioactive carbon/HCO3-/14C ✔
f. samples taken at intervals / heat/alcohol killed samples ✔
g. C-compounds separated by chromatography ✔
h. 14C/radioactive-compounds identified by autoradiography ✔
i. showed that RuBP was phosphorylated ✔
j. after five seconds/immediately more glycerate-3-phosphate/3-PGA labelled than any other compound ✔
k. shows glycerate-3-phosphate/3-PGA first «carboxylated» compound/the first stable product ✔
l. next compound to be detected containing radioactive carbon was triose phosphate/G3P/glyceraldehyde 3 phosphate ✔
m. showed that a wide range of carbon compounds was quickly made in sequence ✔
n. showed that a cycle of reactions was used to regenerate RuBP ✔
