Download photosynthesis sample questions markscheme File

1.
(a)
(b)
(c)
more chlorophyll / photosystems;
so more light absorbed;
2
insufficient light / poor absorption hence low rate of photosynthesis;
higher leaves absorb majority of red and blue wavelengths;
only green / orange / yellow wavelengths available for lower leaves;
2 max
catalysis of reaction in the Calvin cycle;
RuBP carboxylase not very effective so much needed / reference
to photorespiration;
used for carbon fixation;
carbon fixation is vital to the plant / carbon dioxide needed
for photosynthesis;
2 max
[6]
2.
(a)
(b)
substrate binds / approaches active site;
shape of active site changes;
bonds in substrate weaken;
activation energy decreases;
explains broad specificity of some enzymes;
eg proteases;
(i)
(ii)
3 max
oxygen;
NADPH / NADPH + H+ / NADPH2;
ATP;
2 max
occurs in stroma of chloroplast;
ribulose disphosphate / RuBP / 5-C sugar combines with CO2;
catalyzed by rubisco / ribulose biphosphate carboxylase;
splits into two 3-C sugars / glycerate 3-phosphate;
ATP and NADPH supply energy and H;
3-C sugars join to form glucose / 6-C sugar;
RuBP regenerated (with use of ATP);
4 max
[9]
3.
(a)
(b)
Award [1] for each of the following structures clearly
drawn and correctly labelled.
thylakoid membrane / grana;
double outer membrane / envelope;
ribosomes; circular DNA;
lipid globules / starch granules;
stroma;
3 max
large surface area of thylakoids for light absorption / photosynthesis;
(small) space in the thylakoids to accumulate protons;
fluid stroma for enzymes of the Calvin cycle /
light independent reaction;
2 max
1
(c)
ATPase location in the thylakoid membrane
(lets protons across the membrane);
protons go down concentration gradient;
protons move from the thylakoid to the stroma;
energy is used to synthesize ATP;
Accept any of the above points if clearly explained using a
suitably labelled diagram.
2 max
[7]
2