Biology 207 - Practice Questions 3 - Answers
Question 1 What is the purpose of:
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Question 2 Consider the experiment in Lecture 5 section 4c.
a) The symbol '+' is used to represent three different things. What are they?
A functional, wild type allele.
Growth of the cells.
b) Positive and negative controls are done so that we know that an experiment has worked
the way it should. Which control(s) in the table allow us to know that we didn't make the
Question 3 Students often confuse biochemical pathway analysis with complementation
tests. To illustrate the differences consider this synthesis pathway from S. cerevisiae. You
have isolated three mutant strains unable to synthesize compound “B”. The blocked step in
each mutant strain is shown. Mutations 1 and 3 are in the same gene. Complete both tables with the expected results where + indicates growth and - indicates no
growth. Also identify positive controls and negative controls.
a) Biochemical pathway analysis results
b) Complementation test results
Question 4 You have isolated five Neurospora mutant strains that are unable to synthesize
an essential compound, C. In order to determine the biochemical pathway that synthesizes C
you tested each of the five mutant lines for their ability to grow on minimal media (MM) and
minimal media supplemented with compounds D, E, and C. (Compounds D and E are similar
in structure to compound C.) The results of growth (+) or no growth (-) were:
Strain MM MM+D MM+E MM+C
mutant 1 -