Identify the incorrect statement regarding the enzyme PEP carboxylase:
1. PEP carboxylase has a lower Km for bicarbonate ions, hence, higher affinity — than RuBisCO.
2. ${\mathrm{O}}_2$ is a very poor substrate for this enzyme.
3. It plays an important role in ${\mathrm{C}}_4$ cycle but not in CAM plants.
4. PEP carboxylase is also significant in non-photosynthetic metabolic pathways.

What can occur during both photosynthesis and respiration?

Identify the correct statement:
1. The light reactions provide ATP and NADPH to the Calvin cycle.
2. The light reactions provide ${\mathrm{CO}}_2$ to the Calvin cycle.
3. The light reactions supply oxygen to the Calvin cycle.
4. Calvin cycle is in no way dependent on the light reactions.

What is true for both light reactions and the Calvin cycle of photosynthesis in plants?
1. Production of molecular oxygen
2. Depend directly or indirectly on light
3. Requirement of ATP
4. Production of NADPH

Neither light dependent reaction nor Calvin cycle in photosynthesis in plants require:

If chloroplasts are illuminated with sunlight, the lowest pH would be observed in:

To establish a proton gradient across the thylakoid membrane, the protons are provided by:

Identify the correct statement:
1. The pH within the thylakoid is less than that of the stroma.
2. The pH of the stroma is higher than that of the other two measurements.
3. The pH of the stroma is higher than that of the thylakoid space but lower than that of
the cytosol.
4. The pH of the thylakoid space is higher than that observed anywhere else in the cell.

Radioactive carbon [${}^{14}\mathrm{C}$] was fed to a plant during the day and after a short time was traced to oxaloacetate. The plant used in the experiment will be:

${\mathrm{C}}_4$ plants are able to photosynthesize with no apparent photorespiration because of:
1. absence of Calvin cycle.
2. use of PEP carboxylase for primary carbon dioxide fixation.
3. absence of RuBisCO.
4. presence of tissues that do not require oxygen.