Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!uunet!tdatirv!sarima
From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: sci.bio
Subject: Re: Quiz time
Message-ID: <222@tdatirv.UUCP>
Date: 27 Apr 91 18:04:37 GMT
References: <1991Apr24.134105.25827@pa.dec.com> <212@tdatirv.UUCP> <1991Apr26.185708.19178@alchemy.chem.utoronto.ca>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 117

In article <1991Apr26.185708.19178@alchemy.chem.utoronto.ca> mroussel@alchemy.chem.utoronto.ca (Marc Roussel) writes:
<In article <212@tdatirv.UUCP> sarima@tdatirv.UUCP (Stanley Friesen) writes:
<>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.
<>> ...
<>I choose (a).
<>...
<>I suppose a (weak) case might be made for (d) on the grounds that (a)
<>is worded rather poorly.
 
<It's a little worse than that.  Hydrolysis is the process in which a
<chemical group is removed by the action of water.  (a) is therefore
<nonsense.

Oops, I guess I didn't read that very carefully!!  This is one of those cases
where the intended meaning was so obvious to me that I didn't analyze it in
detail.

What is the term used in biochemistry for the process of dissociating
water into H and O?

<>>  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].
<> ..
<This definition of reduction is bizarre to say the least.  Oxidation and
<reduction have to do with electrons, not with oxygen.  

Well, I currently you are indeed correct, that is how it is defined *now*.
But historically the term 'oxidation' refered to a reaction in which oxygen
was added to another compound.  And I think that at a beginning level it is
important to base the descriptions on this intuitive definition of oxidation
rather than jumping right into talking about electrons.  [I mean the
beginner is likely to say 'but what do electrons have to do with oxygen?'].

In a sense my comment was not a 'definition' so much as a description.
It is after all true, that oxygen and hydrogen are opposite in thier
affinities for electron, and thus impose opposite oxidation/reduction
states.
[For you beginners - the most natural ion of oxygen is (2-), the most
natural ion of hydrogen is (+) - the bare proton, thus two hydrogens
have exactly the opposite effect as one oxygen]

Then of course one may go on from here and notice that pH is the log of
the hydrogen ion concentration and relaize that acid/base reactions are
closely related to oxydation/reduction reactions  (in fact in some senses
they are the same thing).

As I said, this can get quite confusing to the beginner, going from oxygen
to alkali.

<>>Which of the following has the most energy?
<>>  a) AMP  b) ADP  c) ATP  d) glucose  e) NADPH
<
<As someone else pointed out, this question is bizarre.  What kind of
<energy are we talking here?  Free energy?  (Probably...)
<     As I promised, I now wish to start a meta-discussion around this exam.
<I have always thought of service courses as a mistake of monumental
<proportions: the content is usually watered down and the emphasis is all
<wrong.  I think that this exam is an ideal example of what happens to
<students whose exposure to a subject comes via a service course: they
<get a muddled view of the field.  Note that I'm not just talking about Stanley
<(who probably gave more or less the answers the original instructor
<expected), but about the instructor who set this exam.

Yeah, I suppose I did, I am real good at that.

I also like to try to present things in a simple way for the beginner.
Sometimes I suppose I get carried away and make things *too* brief.

<     I speak partly from experience as an instructor in one particular
<service course.  The problems as I see them are many and varied.  The
<root problem however is class sizes.  Administrators like service
<courses because they see it as appropriate for these to have very high
<student to teacher ratios.

Oh, just *lovely*, the *worst* possible criterion!  A high student/teacher
ration is just asking for poor education.

The best courses are always the ones with relatively *few* students, so
the teacher can give everyone some time and attention.
(And so everyone can ask all the questions they want).

< This makes it difficult to set a high
<standard (because one is then forced to prepare fairly standard exams to avoid
<spending all of one's time marking) and even more difficult to get the kind
<of feedback one needs to decide how appropriate one's approach to a subject
<is for the particular group being taught.  As a result of the generally
<low standards in service courses, the large publishing houses seem to
<have decreed that all textbooks intended for them shall be thoroughly
<pablumized.  The whole experience seems to be designed to turn students off, no
<matter how hard an individual instructor tries to find ways to reach
<them.

Yeah, its true I can scarcely stand most bginning texts.

<     I think about these questions a lot these days.  I have no solutions, but 
<I'd love to hear from you if you have any ideas.  Should we do away
<with service courses altogether or just think up new and more creative
<ways to deliver them?  Should we replace them with frequent
<extradepartmental guest lectures in mainstream courses?  I await your
<opinions.

I do not know the answer here.   It is difficult to figure out.

Of course the most boring class I ever took was when I (stupidly)
decided to take the non-calculus physics rather than the calculus physics.
(Dumb - I bet even the calculus intro to physics course would have been
- in your words - pablum).
-- 
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uunet!tdatirv!sarima				(Stanley Friesen)