TLS Online TPP Program

#Question id: 1111


If a pharmaceutical company wished to design a drug to maintain low blood sugar levels, one approach might be to design a compound that does which of the following?

#Unit 4. Cell Communication and Cell Signaling
  1. increases glycogen phosphorylase activity in liver cells

  2. activates adenylyl cyclase in liver cells

  3. stimulates G protein activity in liver cells

  4. increases phosphodiesterase activity in liver cells

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TLS Online TPP Program

#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;

TLS Online TPP Program

#Question id: 2867

#Unit 2. Cellular Organization

Deletion in region 3 enhances operon or rate of transcription (in trp operon); Choose an incorrect statement.

TLS Online TPP Program

#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


TLS Online TPP Program

#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

TLS Online TPP Program

#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?

TLS Online TPP Program

#Question id: 2871

#Unit 2. Cellular Organization

With respect to X-chromosome inactivation in females, which, if any, of the following statements is incorrect?