U3A2: 5C effects on the rate of photosynthesis

Question 1

effect of light on the rate of photosynthesis

Answer 1

rate of photosynthesis increases towards saturation point due to exposure to greater light energy. rate reaches saturation point and then it plateaus.

Question 2

effect of temperature on the rate of photosynthesis

Answer 2

rate of photosynthesis increases towards enzymes optimal temperature due to frequent enzyme-substrate collisions. above the optimal temperature, the enzymes begin to denature.

Question 3

effect of pH on the rate of photosynthesis

Answer 3

above and below the optimal pH, enzymes denature. the graph is more symmetrical.

Question 4

effect of carbon dioxide on the rate of photosynthesis

Answer 4

rate of photosynthesis increases towards saturation point due to chloroplats having higher concentration of carbon dioxide for light-independant stage. rate reaches saturaion point and then it plateaus.

Question 5

effect of water on the rate of photosynthesis

Answer 5

to prevent water loss, plants close stomata so water does not evaporate out of the leaves.
C4 and CAM plants are not affected unless unavailability is extreme.

Question 6

effect of enzyme inhibition on the rate of photosynthesis

Answer 6

competitive inhibitors bind to the active site of enzymes to prevent the catalysis of substrates. (steadily increase until reaches saturation point at which it plateaus)
non-competitive inhibitors bind to an allosteric site of an enzyme, causing conformational change to the active site so the substrate cannot bind. (quickly reaches saturation point at half the rate of uninhibited enzymes and plateaus)
(uninhibited enzymes quickly reach the saturation point at double the rate of non-competitive inhibitors and plateaus)