If the antenna complex did not exist in a particular plant mesophyll cell, what effect would that have on photosynthesis?

Question

A.  There would be no expected effect on photosynthesis
B.  These cells would be unable to absorb any light energy
C.  These cells would have a reduced capacity to generate glucose
D.  These cells would be able to fix more carbon dioxide

Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?

  Gather Content
What do you already know about the light reactions, photo systems, and antenna complexes? What other information is related to the question?

  Choose Answer
Do you have the necessary information to dissect the problem?

  Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did theprocess break down or lead you astray? How can you revise your approach to produce a more desirable result?
 

Answer 1

C.  These cells would have a reduced capacity to generate glucose

Clarify Question
What is the key concept addressed by the question?
        · The question asks you to determine what would happen to photosynthesis if a particular plant mesophyll cell lacked an antenna complex?
What type of thinking is required?
· You are being asked to dissect, or analyze, the photosynthetic outcome for a plant cell lacking an antenna complex.

  Gather Content
What do you already know about the light reactions, photo systems, and antenna complexes? What other information is related to the question?
        · The first phase of photosynthesis includes the light reactions, where energy from the sun is captured using chlorophyll to remove electrons from water, excite them to a higher energy level, and to use redox reactions in order to produce ATP and NADPH. The ability to capture solar energy depends on photosystems, which are collections of many pigment molecules, some of which have specialized functions.
        · Antenna complexes contain hundreds of chlorophyll molecules and have the specialized ability to vastly increase the amount of energy that can be harvested by the plant. The antenna complex serves to harvest and direct its energy so that the electrons stripped from water can move to the reaction center complex of the photosystem. Considering the importance of the antenna complex, what do you suppose would happen in a mesophyll cell that lacked an antenna complex? How might this affect the light reactions and photosynthesis in that cell?

  Choose Answer
Do you have the necessary information to dissect the problem?
        · Keep in mind for this question we are only talking about a single cell that lacks the antenna complex out of many that are perfectly fine. That said, let’s consider several options provided by the question. Considering how important an antenna complex is to the light reactions, it will certainly have some effect; the question is how much.
        · Is the cell that lacks the antenna complex incapable of harvesting light energy at all? Not so. The affected mesophyll cell is still capable of harvesting light, but poorly compared to cells with antenna complexes. Considering that there would be reduced energy capture due to a lack of antenna complexes, that means less energy to participate in electron transport, less proton pumping and a lower gradient, and ultimately less ATP and NADPH.
        · For the affected cell, less ATP and NADPH means less potential energy to drive the Calvin cycle, and less glucose will be produced as a result.

  Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did theprocess break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · Answering this question correctly depended on your ability to analyze the photosynthetic outcome on a mesophyll plant cell lacking antenna complexes.
        · If you got a correct answer, well done! If you got an incorrect answer, did you recall that the light reactions rely on photosystems? Did you remember that photosystems contain antenna complexes and reaction centers? Were you able to infer that less ATP and NADPH in the affected mesophyll cell would mean less energy for the Calvin cycle to fix carbon and would produce less glucose as a result?