Scientists believe that stimulating growth of algae and other organisms can reduce carbon dioxide amounts in the atmosphere. Where is carbon dioxide consumed in a plant cell?

Question

A.  Matrix in mitochondria
B.  Cellulose in cell wall
C.  Stroma in chloroplasts
D.  Number of amyloplasts
E.  Central vacuole

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?
 
Gather Content
· What do you know about plants using carbon dioxide? How does it relate to the question?

Consider Possibilities
· What other information is related to the question? Which information is most useful?

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

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.  Stroma in chloroplasts

Clarify Question
· What is the key concept addressed by the question?
        o The question asks about carbon dioxide consumption in plant cells.
· What type of thinking is required?
        o You are being asked to apply your knowledge about different organelles to explain which would be involved in removing carbon dioxide from the atmosphere.
· What key words does the question contain and what do they mean?
        o Reduce carbon dioxide amounts in the atmosphere – this means that increased algae growth will take carbon dioxide from the atmosphere and convert it into molecules in the algae.
 
Gather Content
· What do you know about plants using carbon dioxide? How does it relate to the question?
        o Plants use carbon dioxide during photosynthesis, converting carbon dioxide and water into glucose and oxygen.  By increasing algae growth and photosynthesis, the theory is that carbon dioxide levels would decrease.

Consider Possibilities
· What other information is related to the question? Which information is most useful?
        o Amyloplasts and the vacuole store starch and water in plant cells.
        o Cellulose is made of glucose, so the carbon dioxide that is made into glucose will end up in cellulose (and in starch) eventually.  However, these are the end products of the reaction, not the location where the reaction occurred.
        o Mitochondria are responsible for the reverse reaction, using oxygen to break glucose into water and carbon dioxide.  So increased mitochondria would lead to increased carbon dioxide release into the atmosphere.

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Photosynthesis occurs in chloroplasts, and specifically in the stroma of a chloroplast.  As more algae grow they will produce more chloroplasts and more carbon dioxide will be converted into glucose, removing the carbon dioxide from the atmosphere.

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?
        o This question asked you to apply your understanding of different organelles to explainwhy an increase in algae would lead to a decrease in carbon dioxide in the atmosphere. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you understand that the reaction that plants use to remove carbon dioxide from the atmosphere was photosynthesis?  Did you know that photosynthesis occurs in the stroma of chloroplasts?  Did you realize that mitochondria perform the reverse reaction and release carbon dioxide into the atmosphere?  Did you think that the storage of glucose in starch or cellulose would explain the decrease in carbon dioxide in the atmosphere, although the question asked where this would occur?