Question

What happens to carbon atoms during photosynthesis?

Answer 1

It's a long explanation, but from what I know, it involves the Calvin Cycle:


Step 1: Carbon Fixation. This phase begins when a carbon dioxide molecule is attached to a 5 carbon sugar, ribulose biphosphate (RuBP).

This reaction is catalyzed by the enzyme RuBP carboxylase (rubisco) one of the most abundant proteins on earth.

The products of this reaction is an unstable 6 carbon compound that immediately splits into 2 molecules of 3-phosphoglycerate.

For every 3 molecules of carbon dioxide that enter the cycle via rubisco, 3 RuBP molecules are carboxylated forming 6 molecules of 3-phosphoglycerate.

Step 2: Reduction. This endergonic reduction phase is a 2 step process that couples ATP hydrolysis with the reduction of 3-phosphoglycerate to glyceraldehyde phosphate.

An enzyme phosphorylates (adds a phosphate) 3-phosphoglycerate by transferring a phosphate from the ATP. The product is 1-3-bisphosphoglycerate.

Electrons from the NADPH reduce the carboxyl group of the 1-3-bisphosphoglycerate to the aldehyde group of glyceraldehyde-3-phosphate.

For every three carbon dioxide molecules that enter the Calvin cycle, 6 glyceraldehyde-3-phosphates are produced, only one can be counted as a net gain. The other 5 are used to regenerate 3 molecules of RuBP.

Step 3: Regeneration of RuBP. A complex series of reactions rearranges the carbon skeletons of 5 glyceraldehyde-3-phosphate molecules into 3 RuBP molecules.

These reactions require 3 ATP molecules.

RuBP is thus regenerated to begin the cycle again.

Answer 2

Please check out Calvin cycle to know how CO2 is used
It goes through a series of reaction , first joining with RuBP, eventually gives G3P, and the cycle continues

loulagman, please cite the source that u get it from
Since this is not your own typed answer, you must need to provide the source it is from

Answer 3

http://answers.yahoo.com/question/index?qid=20110913131907AAmH1v3

Sorry! I nearly forgot! Thanks cmkc109 (:

Answer 4

i saw that but its for an online class and if i copy and past they have this thing that says that i did that and the lesson they gave me is not helping me.

Answer 5

Do you have a specific you dont understand?? It is very long to explain the whole process of calvin cycle

Answer 6

to answer your question briefly, it just combines with RuBP with the help of rubisco , which forms G3P (sugar)

Answer 7

i read that yahoo post and nothing thats on there is said on the lessons, and also what part is the carbon atom ughh i think ima quit =( and its like 64 freaking assiments i gotta do or else i dont graduate...

Answer 8

Didnt see ur lesson..so I'm not sure what is on ur lesson
which part is carbon on, then is carbon fixation

the yahoo answer actually explains pretty clearly

Answer 9

maybe ill just use that and some from yahoo answer and put into my own words, thanks guys =]

Answer 10

The Calvin cycle may be divided into 3 steps.

Step 1: Carbon Fixation. This phase begins when a carbon dioxide molecule is attached to a 5 carbon sugar, ribulose biphosphate (RuBP).

This reaction is catalyzed by the enzyme RuBP carboxylase (rubisco) one of the most abundant proteins on earth.

The products of this reaction is an unstable 6 carbon compound that immediately splits into 2 molecules of 3-phosphoglycerate.

For every 3 molecules of carbon dioxide that enter the cycle via rubisco, 3 RuBP molecules are carboxylated forming 6 molecules of 3-phosphoglycerate.

Step 2: Reduction. This endergonic reduction phase is a 2 step process that couples ATP hydrolysis with the reduction of 3-phosphoglycerate to glyceraldehyde phosphate.

An enzyme phosphorylates (adds a phosphate) 3-phosphoglycerate by transferring a phosphate from the ATP. The product is 1-3-bisphosphoglycerate.

Electrons from the NADPH reduce the carboxyl group of the 1-3-bisphosphoglycerate to the aldehyde group of glyceraldehyde-3-phosphate.

For every three carbon dioxide molecules that enter the Calvin cycle, 6 glyceraldehyde-3-phosphates are produced, only one can be counted as a net gain. The other 5 are used to regenerate 3 molecules of RuBP.

Step 3: Regeneration of RuBP. A complex series of reactions rearranges the carbon skeletons of 5 glyceraldehyde-3-phosphate molecules into 3 RuBP molecules.

These reactions require 3 ATP molecules.

RuBP is thus regenerated to begin the cycle again.