State one physical factor that may limit the rate of photosynthesis at Y.
State two features of a dicotyledonous leaf that may affect the rate of photosynthesis.
Explain how the curve changes as light intensity rises from 0 to X.
Name the substance that reacts with carbon dioxide in a chloroplast.
Explain why tube B gives results similar to those of tube A.
Explain why uptake in tube C was lower than uptake in tube B.
Complete the paragraph below by choosing the most suitable words to fill each gap. In a photosystem, several hundred accessory pigment molecules surround a primary pigment molecule, called ...................................., in the .................................... membrane. The position of the primary pigment is also called the ..................................... Light energy is absorbed by the accessory pigments and passed on to the primary pigment. Electrons are raised to a higher energy level. They leave the primary pigment and are captured by electron acceptors and then move along the ...................................., producing ATP.