Calvin cycle 2 Flashcards
The diagram shows Melvin Calvin’s Lollipop experiment for
identifying the products of the Calvin Cycle. Why was radioactive
hydrogen carbonate supplied to the algae?
So that the substances into which the CO2 is incorporated can
be identified
Describe the Calvin Cycle
CARBON FIXATION - Rubisco enzyme catalyses the
reaction of RuBP with CO2 to produce 2x Glycerate-3-
Phosphate (G-3-P).
2. REDUCTION - NADPH reduces G-3-P into 2x Triose
Phosphate (TP) with energy being provided by ATP
3. REGENERATION - 2x TP are converted into orgnaic
compounds e.g. glucose OR ATP is used to convert TP
into RuBP for more turns of the Calvin cycle.
How many carbon aotms in Ribulose
Bisphosphate(RuBP)?
5
Name the enzyme that catalyses the fixation of carbon dioxde
into RuB to produce glycerate-3-phosphate.
Rubisco
How many turns of the calvin cycle take place to produce 1
molecule of glucose?
6
How many carbon atoms in glycerate-3-
phosphate?
3
What are the proudcts of every 6 turns of the
carbon cycle?
1 × glucose molecule
5 x RuBP
What are the light independent reactions of photosynthesis
sometimes referred to as?
The Calvin Cycle
What are the products of the Calvin cycle
(LIR)?
Organic compounds e.g. glucose, amino acids, lipids
RuB (Ribulose Bisphosphate)
How many carbon atoms in triose
phosphate?
3
The diagram shows Melvin Calvin’s Lollipop experiment for:
identifying the products of the Calvin Cycle. Why is a fast flow
tap used in this experiment?
To terminate the reactions immediately.
The diagram shows Melvin Calvin’s Lollipop experiment fors
identifying the products of the Calvin Cycle. Why is hot methanol
supplied to the algae?
algae
High temp will denature enzymes that catalyse
reactions.
Methonal could denature the enzymes.
Does the Calvin Cycle require light to
function?
No
BUT
The reactions will stop eventually in the absence of
light because essential ATP and NADPH from light
reactions will run out.
During the light-independent reaction of photosynthesis, carbon
dioxide is converted into organic substances. Describe how. (6
marks)
- Carbon dioxide combines with ribulose
bisphosphate/RuBp: - Produces two glycerate-3-phosphate / GP;
- GP reduced to triose phosphate / TP;
- Using reduced NAP; and.
5.
…..Using energy from ATP;
Triose phosphate converted to glucose / RuBP
/ ribulose bisphosphate
Heat stress decreases the LDR - why does this lead to a decrease
in the LIDR?
Less ATP
Less reduced NADP
