State one physical factor that could limit the rate of photosynthesis at Y.
State two characteristics of a dicotyledonous leaf that can influence the rate of photosynthesis.
Explain the shape of the curve as light intensity increases from 0 to X.
Name the substance that combines with carbon dioxide in a chloroplast.
Explain why the results in tube B are similar to those in tube A.
Explain why the uptake in tube C was less than the uptake in tube B.
Complete the paragraph below by using the most suitable words for the gaps. 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 excited to a higher energy level. They are emitted from the primary pigment and are captured by electron acceptors and eventually pass along the ................................ , producing ATP.