AQA A-Level Biology 2025/6

Biology • A-Level

Question 1 of 40

0% Complete

A potted bean plant is kept at a constant temperature of 25 °C and a constant CO₂ concentration of 400 ppm. The light intensity is gradually increased from very low to very high levels. How will the rate of photosynthesis change as light intensity rises?

Hint: Consider what happens to the chloroplast pigments when they receive more photons than they can use.

It will increase rapidly at first and then level off once the light‑saturation point is reached It will increase initially but then decline at very high light intensities because the plant is damaged It will continue to increase proportionally with light intensity across the whole range It will remain unchanged because light intensity does not affect the rate of photosynthesis

Points Available

AQA A-Level Biology 2025/6

A potted bean plant is kept at a constant temperature of 25 °C and a constant CO₂ concentration of 400 ppm. The light intensity is gradually increased from very low to very high levels. How will the rate of photosynthesis change as light intensity rises?

A potted bean plant is kept at a constant temperature of 25 °C and a constant CO₂ concentration of 400 ppm. The light intensity is gradually increased from very low to very high levels. How will the rate of photosynthesis change as light intensity rises?