FCH 532 Homework 7
1. Indicate the phenotypes of the following E. coli lac partial diploids in terms of
inducibility and active enzymes synthesized.
a. I-P+O+Z+Y-/I+P-O+Z+Y+
b. I-P+OCZ+Y-/I+P+O+Z-Y+
c. I-P+OCZ+Y+/I-P+O+Z+Y+
d. I+P-OCZ+Y+/I-P+OC Z-Y2. Superrepressed mutants, I`, encode lac repressors that bind the operator but do
not respond to the presence of inducer. Indicate the phenotypes of the following
genotypes in terms of inducibility and enzyme production. (a). ISO+Z+ (b). ISOCZ+
(c). I+O+Z+/ ISO+Z+
3. What is the experimental advantage of using IPTG instead of 1,6 allolactose as an
inducer of the lac operon.
4. Indicate the -10 region, -35 region, and the initiating nucleotide on the sense
strand of the E. coli tRNA Tyr promoter shown below.
5’-CAACGTAACACTTTACAGCGGCGCGTCATTTGATATGATGCGCCCCGCTTCCCGATA-3’
3’-GTTGCATTGTGAAATGTCGCCGCGCAGTAAACTATACTACGCGGGGCGAAGGGCTAT-5’
5. What are the main differences between the prokaryotic RNAP and eukaryotic
RNAP?
A. Short answers. Define the following terms in two or three sentences. Be specific.
 Inducible enzyme
 Constitutive enzyme
 Beta galactosidase
 IPTG
 Basal level expression
 Hfr
 F factor
 Bacterial conjugation
 UP element
 Pribnow box
 Shine Dalgaro region
 TATA Box
 Wobble Hypothesis (define it - not give an example)
 Puromycin
 Rifamycin
 -amanitin
 Amber mutation
 Class II topoisomerase
 Primase
 Snurp

Sigma factor

Open complex

Closed complex

Rho factor

Ribozymes, self catalytic RNA enzymes, are often thought to use the lariat model to
remove sections of RNA similar to that described for intron removal in mRNA.
Illustrate and describe the lariat model for intron removal.

What is catabolite repression? Give an example.

What is the PaMaJo experiment? Why was this experiment important for
biochemistry?

What are some structural similarities/motifs used in DNA binding? Explain.

How does attenuation work for trancription regulation?