Like what you see? Comment, Follow, and Subscribe!

Friday, December 18, 2009

Anatomy of an Exam

Yesterday, I took the least satisfying exam I have ever had the misfortune of encountering.  (Note that this isn't a case of sour grapes on my part; I scored fine, and my cumulative marks are safely in the 'good range'.)

The Content
Some of the questions on this 25-question, multiple-choice molecular genetics final included:
Q: "Which domain(s) recognize(s) methylated histone tails?"
a) Chromo domains    b) Bromo domains     c) Both Chromo and Bromo domains

Q: "Yeast Gal4 is one of the most well-characterized transcription factors in eukaryotes. What type of activating region does Gal4 have?"
a) Gln-rich region      b) Acidic region      c) Pro-rich

Q: "6S RNA in E. coli cells downregulates gene expression in the stationary phase.  What protein is the target for 6S RNA binding?"
a) Large ribosomal subunit    b) Sigma70 RNA polymerase holoenzyme    c) Aminoacyl-tRNA synthetase

The answers are a, a, and... it doesn't matter; the minutiae addressed in this exam are completely irrelevant to understanding the course topic, to the point of this being discernible to someone unaffiliated with the biological sciences.  The professor has wasted his one opportunity to determine whether students understood the important concepts covered in the course, in favor of testing for the ability to memorize thousands of unrelated facts.  Asking questions such as these in molecular biology is akin to testing a geography student on their ability to match countries with their capitol cities, instead of on their knowledge of, say, geography's effects on the development of civilization.  This only reinforces my suspicion that many professors do not know what the main concepts are in the courses that they are assigned to teach.  This is probably a side-effect of the extremely narrow focus of most professors' research.

The Format
Exam format is also at issue.  Four multiple choice, 25-question exams are the only method of evaluation in this 400-level junior/senior class.  While I understand that this is partially due to the course's size (120+ students), this limitation does not prevent the questions themselves from being much better than they are.  All 25 questions had only three possible answers, turning the whole affair into something of a stochastic crapshoot.  It's not like we pay a lot for this or anything.  I really hope this professor is a class-A researcher.

With such a simple format, proofreading also would have been fairly straightforward and much appreciated:
     "Answer which one determines the copy number of plasmid."
     a) an origin of replication      b) selection marker      c) multiple clorning site

It's Not That Hard
Writing decent exam questions that actually address concepts is not difficult; as an unpaid undergraduate TA last spring, I came up with:

"In the DNA, G can be converted to 8-oxo-G and 5-methyl-C to T by various biochemical mechanisms.  What is a 'failsafe glycosylase'?  How would you design a failsafe glycosylase to address the two base conversions described above?"

"Consider the structure of RNA versus that of DNA.  How do their structural differences reflect their different functions in the cell?"

"The Gibbs free energy is used to evaluate the thermodynamics of biochemical transformations in living organisms.  How is this thermodynamic potential an appropriate choice for this application?"

"The partial hydrolysis of a nucleotide triphosphate into a nucleotide monophosphate and a pyrophosphate is only moderately favorable (X kJ/mol), while the hydrolysis of pyrophosphate is more favorable (Y kJ/mol).  How does a difference of (Y-X) kJ/mol influence the equilibrium position of these reactions?  Why is this important in the process of DNA synthesis?"

The topics of these questions have a lot of overlap with the material covered in this molecular genetics course, and I think they're sufficient to illustrate the point.


So what do you think: do I have a point here?
Why is it so hard to get your money's worth at a university these days?


  1. Yea it may not be hard to write the exam questions but put into consideration the endless number of other exams students have going on that week as well. Using multiple choice question format deals with familarity...not actual understanding....they have grad school or med school to actually learn that stuff...

  2. I have seen some decent conceptual multiple choice exams. But the tendency is that they are very easy for any one who was actually paying attention in class. BS minutia questions on the other hand make a very nice bell curves for minimal effort.