5B - Rubisco in C3, C4 and CAM Photosynthesis

Light-dependent stage

 the first stage of photosynthesis, where light energy splits water molecules into oxygen and hydrogen inside the thylakoid membranes. Also known as the light-dependent reactions

Light-independent stage

the second stage of photosynthesis where carbon dioxide is used to form glucose in the stroma of a chloroplast. Also known as the Calvin cycle, the dark stage, or the light-independent reactions

Enzyme

 an organic molecule, typically a protein, that catalyses (speeds up) specific reactions

Rubsico

a pivotal enzyme involved in initial carbon fixation during the light-independent stage of photosynthesis

Carbon Fixation

the process in living organisms where inorganic carbon, typically within carbon dioxide, is converted into organic compounds such as glucose. Carbon fixation is a central part of the light-independent stage of photosynthesis

Inorganic

a compound that does not contain a carbon-hydrogen bond, e.g. carbon dioxide

Organic

a compound containing a carbon-hydrogen bond, e.g. glucose

Substrate

the reactant of a reaction catalysed by an enzyme

Photorespiration

 a wasteful process in plants initiated by Rubisco that limits photosynthesis

Stoma (pl. stomata)

 a small pore on the leaf’s surface that opens and closes to regulate gas exchange

Affinity

 the tendency of a molecule/atom to bind or react with another molecule/atom

C3 plants

plants with no evolved adaptation to minimise photorespiration

Mesophyll cell

a plant cell type found in leaves that contain large amounts of chloroplasts

C4 plants

plants that minimise photorespiration by separating initial carbon fixation and the remainder of the Calvin cycle over space

Bundle-sheath cell

a plant cell type that is the site of most of the Calvin cycle in C4 plants

CAM plants

plants that minimise photorespiration by separating intial carbon fixation and the remainder of the Calvin cycle over time