In this lab you learned that plants remove carbon dioxide fr

In this lab, you learned that plants remove carbon dioxide from the atmosphere during pho-to synthesis as part of the carbon cycle. Use your textbook or other resources to identify three different processes that contribute carbon dioxide to the atmosphere.

Solution

1. One process is aerobic respiration in which plant cells oxidize glucose to produce CO₂ and energy.

2. a) Second process is photorespiration during this process ribulose bisphosphate carboxylase catalyzes the addition of O₂ instead of CO₂.

b) As a result 3-phosphoglycerate and phosphoglycolate are formed.

c) Phosphoglycolate is converted to glycolate and transferred to peroxysome, where it is oxidized and converted to glycine.

d) Glycine is transferred to mitochondria converted to serine with the loss of CO₂ and NH₃.

e) This serine is converted to glycerate in peroxisome then transferred to chloroplast.

f) So photorespiration not beneficial for the plant it is reverse of photosynthesis- O₂ is consumed and CO₂ is released without gain of ATP.

3. a) Third process is CAM ( Crassulacean Acid Metabolism).

b) During the night open stomata to collect CO₂. This CO₂ is stored in vacuole as four carbon compound called malate.

c) During the day time this malate is transported to chloroplast to convert into CO₂, which is then used in photosynthesis.

4. Apart from this other process like fermentation, during the formation of fossil fuels, burning of fuels, etc are other process which contribute CO₂ from plants into the atmosphere.