#Question id: 2865
#Unit 2. Cellular Organization
The trp operon is controlled by repression and attenuation, providing a two-stage response to progressively more stringent tryptophan starvation. But attenuation alone can provide robust regulation: other amino acid operons such as leu and his rely entirely on attenuation for their control. Correct number of codons in leader peptide of leu & his operon in a row;
#Question id: 2867
#Unit 2. Cellular Organization
Deletion in region 3 enhances operon or rate of transcription (in trp operon); Choose an incorrect statement.
#Question id: 2868
#Unit 2. Cellular Organization
Given the following mutants and conditions, predict the expression of the of the lacZ gene (no expression, basal level of expression, or activated level of expression). A mutant of E. coli that has a mutation in the operator of the lac operon that prevents the repressor from binding
Glucose |
Lactose |
Expression |
+ |
- |
1 |
+ |
+ |
2 |
- |
- |
3 |
- |
+ |
4 |
#Question id: 2869
#Unit 2. Cellular Organization
Galactose imported into the yeast cell is converted to galactose 6-phosphate by a pathway involving six enzymes, whose genes are scattered over three chromosomes. Transcription of these genes is regulated by the combined actions of the proteins Gal4p, Gal80p, and Gal3p,
i. GAL3 |
a. Interaction with the Gal80p-Gal4p complex and activates Gal4p. |
ii. GAL4 |
b. Recruits SAGA, Mediator, and TFIID to the galactose promoters, leading to DNA polymerase II recruitment and initiation of transcription |
iii. GAL80 |
c. Transcriptional inhibitor |
d. Transcriptional activator |
#Question id: 2870
#Unit 2. Cellular Organization
In Escherichia coli, the synthesis of tryptophan is controlled by the tryptophan operon that is repressed in the presence of excessive tryptophan. When a mutant strain that has lost the regulatory gene of the tryptophan operon is placed in a medium that contains all nutrients the cells need to grow except tryptophan, which of the following will occur?
#Question id: 2871
#Unit 2. Cellular Organization
With respect to X-chromosome inactivation in females, which, if any, of the following statements is incorrect?