Radioactive oxygen gas

[wildsunflower2]

Help!!! I have this "applying the concepts" question and I'm not sure of the answer!! Someone please help........

 

Question

 

Suppose an experiment is performed in which plant 1 is supplied with normal carbon dioxide but with water that contains radioactive oxygen atoms. Plant 2 is supplied with normal water but with carbon dioxide that contains radioactive oxygen atoms. Each plant is allowed to perform photosynthesis, and the oxygen gas and sugars produced are tested for radioactivity. Which plant would you expect to produce readioactive sugars, and which plant would you expect to produce radioactive oxygen gas? Why?

 

I'm so confused!!

[Fishteacher73]

I won't do your homework for you, but it concerns the the two main stages of photosynthesis; the light dependant reactions (light reactions, and the light independent reactions (dark reactions). Each uses different constituants in the begining and has different products. (hint one uses water and one uses CO2, and each will produce a specific radioactive product).

[wildsunflower2]

Thank you for the little hint. You made it a little easier to understand. Your help was appreciated.

[UncleAl]

Look up the half-lives of radioactive oxygen isotopes, CRC Handbook. It's a world-class stupid experiment as stated. The real world answer is that nothing will be radioactive given the procedure. You want to mark with O-17 or O-18 stable isotopes and ID the products by mass spec.

 

I'm so confused!!

Photosynthesis vs. photorespiration and where RuBisCo gets its parts. Why don't you bestir your leaden butt and look up the metabolic charts for C3, C4, and crassulacean acid catabolisms?

 

http://wc.pima.edu/~bfiero/tucsonecology/plants/plants_photosynthesis.htm

[wildsunflower2]

I know this has to do with the two steps of photosynthesis but I can figure out exact how. One plant begins with normal CO2 and the other with normail H2O so I would probably say Plant 1 would produce radioactive sugars and Plant 2 would produce radioactive oxygen gas. Why I think this is because light reaction starts off with water and dark reaction start of with carbon dioxide.

 

Is that correct or am I missing something? Please help me!!!!

[Eclogite]

Wildsunflower,

Does the released oxygen come from the carbon dioxide, the water, or both? That's where your answer lies.

[wildsunflower2]

What do you mean? Sorry I'm not very knowledgable in Science. I just started my first biology class and I'm struggling to understand.

[wildsunflower2]

So are you saying that since radioactive oxygens atoms are used in both that they both would produce radioactive sugars and radioactive oxygen?

[Eclogite]

I am trying to guide you to the answer. If I tell you the answer you have a piece of knowledge. If I guide you to it you have the knowledge, an investigative process, and the satisfaction that comes from learning something rather than being taught it. The reason nobody else has given you the answer is the same. They want you to learn for yourself.

 

Go to your text book or use google to answer my previous question, which I shall simplify: does the released oxygen come from the carbon dioxide or from the water?

[Spider24]

I know that you are trying to guide me to the answer and I have come to my own conclusion. Thanks for the help.

 

Oh yeah and I didn't have to google!