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Question about some home labs!

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Question about some home labs!

Postby biology_newbie » Wed Dec 08, 2004 5:44 am

Hi there,

I am having trouble with a couple of home labs for my biology class...either I am a complete idiot and just couldn't get any of this to work, or something is wrong with these directions because I can't seem to figure out what I'm supposed to be observing.

My first lab dealt with boiling and egg and putting some of the egg white in two test tubes...one with unboiled pineapple juice and one with boiled. I see no difference at all between the tubes. I think I'm supposed to be seeing the egg white getting broken down by the enzymes in the unboiled pineapple juice and not the boiled because the boiling cancels out the enzyme action. Is that right? Would all enzymes that are boiled do the same thing?

The second part of the lab also didn't work. I was supposed to grow some corn seeds in a moistened environment and then take the coleptiles and mash them up with some water and Benedict's solution and then boil it. I'm supposed to see a color change I think and determine which substance was oxidized and which was reduced...I have no idea...I can't see a change.

I also couldn't see a change in color when I took other coleptiles and mixed them with lugol's solution.

Any advice at all? I am so lost...

Thanks,

JJ
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Postby biostudent84 » Wed Dec 08, 2004 5:54 am

Part 1. Go back and boil the juice a little longer. Maybe you didn't denature the enzymes enough.

Part 2. What color is the corn-solution? When Benedict's solution tests positive, it turns yellow. Also, wth Benedict's solution, you need to really boil the stuff as well.

Kyle
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Postby biology_newbie » Wed Dec 08, 2004 6:03 am

Thanks for your reply,

About the pineapple solution...if it were boiled longer, would that mean that it would break down the egg white, or it wouldn't? I've tried this three times each time boiling it longer until finally it was like 3 times longer than it recommended and it started to evaporate.

I'm assuming that boiling it would result in it not having the ability to break down the egg...and I think that would apply for all enzymes. DOes this sound right to you?

Thanks,

JJ
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Postby biostudent84 » Wed Dec 08, 2004 6:23 am

Enzymes are proteins. And as such, they must be kept below a certain temperature. For example, vital enzymes in the human body MUST be kept below 106*F. If this fails to happen, the enzymes (and other proteins) denature...deform. They no longer work properly.

The boiled juice's enzymes are supposed to denature in the same way, yielding a positive result for the unboiled, and a negative for the boiled.

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