The light-independent reaction

Question 1

What is the Calvin cycle?

Answer 1

• occurs in the storms
• produces one carbon per cycle
• RuBp joins CO2 to produce GP using rubisco
• GP produces TP using energy from NADPH and ATP
• the NADPH is reduced and the ATP hydrolysed into ADP and sent back to the LDR
• TP then is used to reproduce RuBP so the cycle can continue
• one carbon atom is also lost which is used by the remaining TP to produce biological molecules

Question 2

How are chloroplasts adapted to carrying out the light-independent reaction of photosynthesis?

Answer 2

• the fluid of the stroma contains all the enzymes needed to carry out the light-independent reaction
• it also contains membrane-bound organelle so a high concentration of enzymes and substrates can be maintained within it
• the stroma fluid surrounds the grana and so the products of the light-dependent reaction can readily diffuse into the stroma
• it contains both DNA and ribosomes so it can quickly and easily manufacture some of the proteins involved in the light-independent reaction

Question 3

What is Calvin’s lollipop?

Answer 3

• algae is held in a Petri dish lollipop
• the hot methanol under the algae kills it to stop photosynthesis
• chromatography roadsters the compounds which are labelled by radioactive carbon to identify carbon containing compounds
• the valve under the petrified allows the sample to be removed quickly to keep the order of the compounds

Question 4

what are limiting factors?

Answer 4

• enzymes are impacted by temperature
• CO2 concentration to convert GO to TP
• light to produce ATP and NADPH in the LDR to make TP