Your name ______________
BCH 609 Plant Biochemistry
FINAL EXAM May 3, 2001
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1. The shikimate pathway is critically important and is known to occur in both
prokaryotic microorganisms and plants. Discuss reasons why this pathway is so
important and even essential for all organisms, including animals. In your answer,
emphasize the role of the pathway as a “supplier” of several distinct classes of
metabolites. (6 pts)
BCH 609 FINAL EXAM
Your name ______________
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2. As stated in question 1 above, the shikimate pathway exists in prokaryotes and plants
and therefore shares many common similarities. However, differences clearly exist
between certain aspects of these pathways in the two kingdoms, some of which are
subtle and some obvious. Discuss several of the aspects that distinguish the plantbased shikimate pathway from that present in bacteria, specifically listing examples
to illustrate: (A) a regulatory distinction, particularly in regard to enzymatic activity;
(B) a distinction regarding a structural aspect of an enzyme (not herbicide
sensitivity); (C) a distinction at the level of an enzyme in regard to herbicide
sensitivity; (D) distinctions in gene level regulation (e.g., including spatial regulation
and how this is achieved). (8 pts)
3. The elucidation of many plant secondary pathways has been greatly assisted by the
isolation of informative mutants. For example, the “tt” mutants, which block steps in
the general phenylpropanoid pathway and lead to the synthesis of flavonoids
including anthocyanins. Describe some general reasons why such a fairly large
number of mutants have been easily obtainable for such pathways. (5 pts)
BCH 609 FINAL EXAM
Your name ______________
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4. Coordinate or integrated control is becoming a hallmark of biochemical pathway
regulation. Describe some basic experiments and their results if you were
investigating a new pathway that consists of several enzymatic steps, and arrived at
the conclusion that there was indeed coordinate regulation. Assume that you have in
hand the means to detect pathway products (metabolites), appropriate enzymatic
assays, and genes encoding these enzymes. (11 pts)
BCH 609 FINAL EXAM
Your name ______________
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5. It has been observed in the floral industry that, in the process of breeding and
selecting for the best visual traits for ornamentals, many popular flowers have
actually lost their fragrances. It has recently been found that this is due to the lack of
function of only one or two genes. Given that the distinctive aroma of many flowers
is in fact due to the collection of many molecules that, in combination, make up the
these pleasant odors, explain how the production of such a large number of
compounds might be affected by only one or two genes. (6 pts)