Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!samsung!uunet!tdatirv!sarima
From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: sci.bio
Subject: Re: Quiz time
Message-ID: <212@tdatirv.UUCP>
Date: 25 Apr 91 19:51:59 GMT
References: <1991Apr24.134105.25827@pa.dec.com>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 49

In article <1991Apr24.134105.25827@pa.dec.com> mikkelson@breakr.enet.dec.com (snopes) writes:
> A "high-energy bond"
 
>  a) absorbs a large amount of free energy when the phosphate group is
>     attached during hydrolysis.
>  b) is formed when ATP is hydrolyzed to ADP and one phosphate group
>  c) is usually found in each glucose molecule; that is why glucose is
>     chosen as the starting point for glycolysis.
>  d) none of the above

I choose (a).
(b) is simply backwards, and (c) is essentially irrelevant, though
I suppose a (weak) case might be made for (d) on the grounds that (a)
is worded rather poorly.

>When NAD combines with hydrogen, the NAD is
 
>  a) reduced  b) oxidized  c) phosphorylated  d) denatured  e) none of these

It is (a) reduced.
Taking on hydrogen is the opposite of taking on oxygen.
[I.e. it is energetically equivalent to *losing* oxygen].
And since, in chemistry, the word for loss of oxygen is 'reduction',
thus NADH is the reduced form of NAD.
The NAD form of the molecule is the oxidized form, and there is no phosphate
involved, so phosphorylation is not involved.

>The oxygen released in photosynthesis comes from
 
>  a) carbon dioxide  b) glucose  c) ribulose biphosphate 
>  d) water  e) atmospheric oxygen

The answer here is (d) water.  The hydrogen in the water ends up on the NAD
(or a related molecule), leaving raw oxygen.
The oxygen in the carbon dioxide is retained in the resulting glucose.
(Sugars do, after all, contain oxygen as well as carbon and hydrogen).

Ribulose biphosphate is not involved in photosynthesis (it sounds like
a early precurser to RNA).

>Which of the following has the most energy?
 
>  a) AMP  b) ADP  c) ATP  d) glucose  e) NADPH

The answer is (d) glucose, because it can be oxydized into carbon dioxide
to produce a great many ATP molecules (I think about 30 in aerobic respiration).
-- 
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uunet!tdatirv!sarima				(Stanley Friesen)