Photosynthesis Flashcards
Can you describe how carbon dioxide absorbed by the plant is incorporated into organnic molecules
carbon dioxide reacts with ribulose bisphosphate (RuBP) to form two molecules of glycerate 3-phosphate (GP). This reaction is catalysed by the enzyme rubisco
ATP and reduced NADP from the light-dependent reaction are used to reduce GP to triose phosphate
some of the triose phosphate is used to regenerate RuBP in the Calvin cycle
some of the triose phosphate is converted to useful organic substances.
Can you describe the role of ATP and reduced NADP in the light dependent reaction
The light-independent reaction uses reduced NADP from the light-dependent reaction to form a simple sugar. The hydrolysis of ATP, also from the light-dependent reaction, provides the additional energy for this reaction
Can you describe the events of the calvin cycle
The Calvin cycle has three stages.
In stage 1, the enzyme RuBisCO incorporates carbon dioxide into an organic molecule.
In stage 2, the organic molecule is reduced.
In stage 3, RuBP, the molecule that starts the cycle, is regenerated so that the cycle can continue.
Can you describe how the plant leaf is adapted to carry out photosynthesis
Can efficiently absorb sunlight-upper part of leaf contains tightly packed palisade mesophyll cells; cells have large vacuole which pushes chloroplasts to the edge of leaf and well developed cytoskeleton to push chloroplasts to the side of the cell receiving the most light.
Rapidly carries out gaseous exchange-spongy mesophyll layer contains lots of air spaces, meaning there is a lot of surface area for CO2to diiffuse into cells and oxygen to diffuse out. Leaf is also very thin, so there is a very short diffusion distance for gases.
Chloroplasts well adapted for photosynthetic reaction-organisation of thylakoids into grana creates a large surface area for reactions to take place on. Thylakoid double membrane contains many photosystems allowing it to effectively channel light energy.
