wildsunflower2 Posted September 8, 2005 Report Share Posted September 8, 2005 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!! Quote Link to comment Share on other sites More sharing options...
Fishteacher73 Posted September 8, 2005 Report Share Posted September 8, 2005 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). Quote Link to comment Share on other sites More sharing options...
wildsunflower2 Posted September 8, 2005 Author Report Share Posted September 8, 2005 Thank you for the little hint. You made it a little easier to understand. Your help was appreciated. Quote Link to comment Share on other sites More sharing options...
UncleAl Posted September 8, 2005 Report Share Posted September 8, 2005 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 Quote Link to comment Share on other sites More sharing options...
wildsunflower2 Posted September 10, 2005 Author Report Share Posted September 10, 2005 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!!!! Quote Link to comment Share on other sites More sharing options...
Eclogite Posted September 10, 2005 Report Share Posted September 10, 2005 Wildsunflower, Does the released oxygen come from the carbon dioxide, the water, or both? That's where your answer lies. Quote Link to comment Share on other sites More sharing options...
wildsunflower2 Posted September 10, 2005 Author Report Share Posted September 10, 2005 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. Quote Link to comment Share on other sites More sharing options...
wildsunflower2 Posted September 10, 2005 Author Report Share Posted September 10, 2005 So are you saying that since radioactive oxygens atoms are used in both that they both would produce radioactive sugars and radioactive oxygen? Quote Link to comment Share on other sites More sharing options...
Eclogite Posted September 11, 2005 Report Share Posted September 11, 2005 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? Quote Link to comment Share on other sites More sharing options...
Spider24 Posted September 12, 2005 Report Share Posted September 12, 2005 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! Quote Link to comment Share on other sites More sharing options...
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