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Module 4
1. Provide an overview of the relationship between genotype and
phenotype.
2. With the use of a diagram, provide an overview of the general
regulation strategies available to a bacterial cell.
3. Feedback inhibition is a reversible and dynamic process. Explain.
4. Compare and contrast repressible and inducible operons.
5. Site 3 examples of global control. Include the system name,
environmental signal, the regulatory molecule and its activity and the
number of genes regulated.
6. What is catabolite repression and how dies it work?
7. What is Quorum sensing?
8. Chemotaxis is an example of signal transduction. Explain, with the use
of diagrams.
9. What are the two main mechanisms by which bacteria regulate enzyme
activity and how do they differ?
10. Define the following terms:
(a) enzyme
(b) active site
(c) allosteric enzyme
(d) ligand
(e) modulator
(f) allosteric inhibition
(g) competitive inhibition
11. Describe the processes involved in catalysis of a substrate by an
enzyme and how competitive and allosteric inhibition affect this
catalysis.
12. What role do allosteric effectors play in allosteric inhibition?
13. Allosteric effectors tend to resemble the substrate or products
involved in the reactions that they effect. True or false and explain.
14. How do positive and negative allosteric effectors differ?
15. Describe feedback inhibition and give an example where this
mechanism is involved in the regulation of a biosynthetic pathway.
16. Explain the central dogma of molecular biology.
17. Gene expression can be regulated at several levels. Explain.
18. Gene expression can be regulated at the levels of transcription and
translation. Discuss each with respect to energy efficiency of each
mechanism.
19. Define the following terms:
(a) operon
(b) promoter
(c) regulator
(d) inducer
(e) repressor
(f) terminator
(g) operator
20. What is autogenous regulation and with what genes is it generally
associated?
21. Transcription termination generally involves one of two mechanisms.
What are they and which one is used in the regulation of gene
expression?
22. What is posttranscriptional regulation and how does it usually work?
23. How does histidine regulate its own synthesis?
24. Corynebacterium glutamicum is used for the commercial production of
lysine over other, more highly studied organisms such as E. coli. What
elements make it more suited for this purpose than E. coli? (This is a
BIG question and requires a BIG answer)
25. Feedback inhibition and repression both play a role in the regulation of
lysine biosynthesis in E. coli. True or false and explain.
26. What controls the synthesis of threonine over lysine in
Corynebacterium glutamicum?
27. Regulation of aspartakinase can control the production of all the
aspartate family of amino acids. Explain.
28. What are the members of the aspartate family of amino acids and why
are the classified like this?
29. Explain the regulation of enzymes in the production of lysine and
threonine in Corynebacterium glutamicum under the following
conditions:
(a) high threonine, high lysine
(b) high threonine, low lysine
(c) low threonine, high lysine
(c) low threonine, low lysine
30. What elements make up the lac operon and what roles do they play?
31. The lac operon is an inducible operon. Why and what does this mean?
32. Describe the process of induction in the lac operon. You should
discuss both the induced and uninduced states.
33. The lac repressor completely stops transcription of the lac operon
structural gene. True or false and explain.
34. The trp operon is an inducible operon. True or false and explain.
35. Describe the process of repression in the trp operon.
36. TrpL does not produce a functional protein. True or false and explain
the role of the trpL gene.
37. Explain the process of attenuation in the trp operon under conditions
of low and high tryptophan levels.
38. All secondary structures formed in the trp operon attenuator can act
as transcription terminators. True or false and explain.