Testing for glucose in the water which leaf is in?

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annalovesyou
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Testing for glucose in the water which leaf is in?

Post by annalovesyou » Fri May 01, 2009 7:33 am

In Biology class, the teacher has required students to make up their own experiment.
It has to be based around photosynthesis or cellular respiration.

My partners and I have decided to do the affects of light on photosynthesis.
We have decided to test for glucose in each test dimple using Clinistix.
Every test dimple has a few drops of water and one Elodea leaf.
3 test dimples will be placed in a cupboard. 3 underneath a low-light lamp. 3 underneath a high-light lamp.




Will the single Elodea leaf use all of the glucose it produces?
Will unused glucose just stay in the leaf, or will it seep into the water?
Will the amounts of glucose in each test dimple be good enough to show contrasting results? I want to be able to see the differences in colour of the Clinistix, so I can compare them.



Thanks.

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MrMistery
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Post by MrMistery » Sat May 02, 2009 12:52 am

plants don't let their sugar go into the water, just like you wouldn't keep your money on your front lawn.
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mith
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Post by mith » Sat May 02, 2009 5:16 am

You'd have to cut the phloem but the glucose concentration at a leaf doesn't indicate photosynthesis activity.
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Post by annalovesyou » Sat May 02, 2009 12:39 pm

I know I wouldn't keep my money on the lawn, but what if I had a hole in my pocket? After all, the Elodea leaf is separated from its stem, resulting in a hole where things can flow out of... Please comment on this statement!

And I'd also like to know why glucose concentration of a leaf doesn't indicate photosynthesis activity. I'm not trying to be a smart-alec, I'm just confused since I was taught that photosynthesis is the synthesising of sugars and it requires light.


What else can I make up an experiment on? It has to be based on photosynthesis or cellular respiration, and it must not be too complicated.

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Post by MrMistery » Sun May 03, 2009 3:11 am

grrr complicated.
first of all plants don't transport their sugars under the form of glucose but under the form of sucrose.
Second, it's not that easy. you see the direct product of photosynthesis are organic trioses (sugars with 3 carbons). if these trioses are kept in the chloroplast, they are used to make starch. If they are exported into the cytoplasm, they are used to make sucrose, which is then exported from the leaf. Your experiment would only catch the fructose and not the starch, and this would not be a very good result: if you have low sucrose in the water, it may be because the plant is not carrying out photosynthesis or it may be because the plant is synthesizing starch with all the sugars it makes.

I don't know who told you glucose is very important for plants, but it's not.
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Post by annalovesyou » Sun May 03, 2009 8:53 am

Ooooooohhhh
What can I do my experiment on then? It has to be on either cellular respiration or photosynthesis!

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mith
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Post by mith » Thu May 07, 2009 2:25 am

try testing yeast growth, you can count the cells

http://biology.clc.uc.edu/fankhauser/La ... actice.htm

Think of treatments you can do to them, growth media, temperature, pH, C02 conc etc
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Post by AstusAleator » Thu May 21, 2009 5:23 am

You should be able to calculate carbohydrate production very neatly by simply monitoring the CO2 levels in your samples.
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Post by annalovesyou » Tue Jun 02, 2009 8:06 am

Oh it doesn't matter anymore. I talked to my teacher and we figured something out. Thanks anyway.

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