Exam 11: Regulation of Gene Expression

In a fly,the transcription rates of a gene that codes for an enzyme vary tremendously among different cell types.The most likely reason for these differences is that different cell types have different

Transcription factors are

In the worm C.elegans,lin-4 acts as a negative regulator of lin-14.Which statement about lin-4 is true?

Suppose that a certain enzyme is synthesized whenever the solution in which the cells are growing lacks substance X.When substance X is present,the enzyme is produced only under certain environmental conditions.This phenomenon would most likely be an example of _______ gene regulation.

Without maintenance methylase,the changes made by DNA methylase would not

Some metabolic pathways are regulated in part by changes in the rate of degradation of key enzymes.This is an example of

In a bacterial cell, $\beta$ -galactosidase is at high concentrations but $\beta$ -galactoside permease is at very low concentrations.What is the most likely explanation?

A virus-encoded protein called Tat is

In a repressible operon,the repressor molecule

What is the main difference between eukaryotic and prokaryotic gene regulation?

Which statement about the early genes in the T4 bacteriophage is false?

The presence of a Barr body indicates

An inducer

The binding of an enhancer

In eukaryotes,the earliest stage of regulatory control that occurs largely outside of the nucleus is

In eukaryotes,a promoter is the region of

In negative regulation,

Ubiquitin forms a complex with proteins and then binds with _______,forming a sort of "molecular chamber of doom" where proteins are digested into small peptides and amino acids.

Supplying nematodes with an excess of the product of lin-4 would most likely lead to a(n)_______ of lin-14 product,with the phenotypic consequences of _______.

The drought stress response in plants is an example of