Question

Your teacher wants you to mix up the enzymes and substrates necessary to perform the Calvin cycle in a test tube. In order to control the reactions, you wish to do this in the absence of the light reactions, whole chloroplasts, and cells. What components do you need to put into the test tube?

- ATP, NADPH, and an extract from chloroplast stroma
- ATP, NADPH, and CO2
- ATP, CO2, and an extract from chloroplast stroma
- ATP, CO2, and intact thylakoids
- ATP, CO2, NADPH, and a light source
- ATP, NADPH, and intact thylakoids

Answer 1

Conduct the Calvin cycle in a test tube, you must add ATP, NADPH, CO2, and an extract from the chloroplast stroma, which includes necessary enzymes for the cycle such as RuBisCO.

Step-by-step explanation:

To perform the Calvin cycle in a test tube without the light reactions, whole chloroplasts, or cells, you need to add ATP, NADPH, and CO2 along with an extract from the chloroplast stroma which contains the necessary enzymes, including RuBisCO, for the cycle to occur.

The Calvin cycle is a light-independent process used to convert CO2 into organic compounds, namely glyceraldehyde-3-phosphate (G3P), which can later become glucose. The cycle has three stages: fixation, reduction, and regeneration. During the fixation stage, CO2 is attached to RuBP by the enzyme RuBisCO, initiating the cycle.



ATP and NADPH produced during the light reactions provide the energy for the subsequent reduction stage, leading to the production of G3P. Finally, some G3P is used to regenerate RuBP, perpetuating the cycle. As the light-dependent reactions—which happen in the thylakoids—provide ATP and NADPH, these molecules are required in the test tube for the Calvin cycle, but a light source or the thylakoid structures themselves are not necessary since we are focusing on the light-independent reactions.