Multiple choice

The first step in dark reaction of photosynthesis is the

  1. formation of ATP

  2. ionisation of water

  3. attachment of carbon dioxide to pentose sugar

  4. excitement of electron of chlorophyll by a photon of light

  5. --

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ribulose Bisphosphate Carboxylase (RuBP Carboxylase) catalyses CO2 fixation. Ribulose-1,5-bisphosphate + CO2 ----------------> 2 copies of 3-phosphoglycerate