11.3 Light independent reaction

Question 1

What are the products from the LDR that are important in the LIDR

Answer 1

ATP and reduced NADP

Question 2

Why is ATP and reduced NADP important in the LIDR

Answer 2

Because they are used to reduce glycerate-3-phosphate (GP)

Question 3

Does the LIDR require light energy, and what is the technicality

Answer 3

The LIDR doesnt require light energy

But it does require the products of the LDR for it to occur. Therefore technically light does need to be present for the cycle to constantly continue

Question 4

Where does the LIDR occur

Answer 4

In the stroma of chloroplasts

Question 5

What are the stages of the Calvin Cycle

Answer 5

1. CO2 from the atmosphere diffuses through the stomata and dissolves into the water surrounding the mesophyll cellls. It then diffuses through the cell-surface membrane, cytoplasm and chloroplast membranes into the stroma of the chloroplast
2. In the stroma, CO2 reacts with Ribulose Bisphosphate (RuBP) catalysed by Rubisco
3. The reaction between CO2 and RuBP produces two molecules of 3-carbon glycerate-3-phosphate (GP)
4. Reduced NADP from the LDR is used to reduce GP to Triose phosphate using energy supplied by ATP
5. The NADP is re-formed and enters the LDR again to be reduced by accepting protons again
6. Some triose phosphate molecules are converted to organic substances that the plant requires. e.g. Starch, cellulose, nucleotides, amino acids, lipids and glucose
7. Most triose phosphate is used to regenerate RuBP, using ATP from the LDR

Question 6

What are the adaptations of the chloroplasts beneficial for the light dependent reaction

Answer 6

1. The fluid of the stroma contains all the enzymes needed to carry out the LDR. The fluid is membrane bound, so a chemical environment can be maintained within it
2. The stromal fluid surrounds the grana and so the products of the LDR quickly diffuse into the stroma
3. In contains DNA and ribosomes so it can quickly make the proteins involved in the LDR