Genetics Exam 3

True or false? Two genes in a bacterial cell may be expressed at different levels, but each individual gene is expressed at the same level under all environmental conditions.

False

Which of the following interact with DNA in a non-sequence specific manner?

a - Histones

True or False? DNA binding proteins involved in the regulation of gene expression bind covalently and irreversibly to specific DNA sequences.

False

If a bacterial gene is regulated by both positive and negative control which of the following sites would you find in the DNA?

d- A and B

When considering gene regulation in bacteria which of the following is TRUE of inducible genes?

b- inducible genes are typically involved in catabolic pathways

The lac operon consists of three genes: lacZ, lacY, and lacA. How many promoters are required to express these three genes?

b - 1

Which of the following is TRUE of the lac operon when lactose is present?

d - A and B

Which of the following is TRUE of positive control when considering the regulation of the lac operon?

d - A, B and C

Consider the regulation of the lac operon in E. coli. Which of the following is TRUE when the cell is in the presence of both glucose and lactose?

d - A and B

True or False? The same positive control mechanism for the lac operon regulates other sugar utilization operons in E. coli.

True

True or False? The trp operon is a repressible operon regulated by both negative and positive control.

False

Which of the following is TRUE when there is an excessive amount of tryptophan present in the cell?

b - Free Tryptophan serves as the corepressor and binds to the repressor protein

Which of the following is involved in the attenuation mechanism in the regulation of the trp operon?

d - A, B and C

Consider the regulation of the trp operon, which of the following is TRUE when there is no tryptophan present and coupled transcription-translation is occurring?

d - A and B

True or False? The attenuation mechanism of the Trp operon in E. coli relies on two codons that code for tryptophan in the leader region. Similarly, for other amino acid synthesis operons in E. coli, only two codons coding for their respective amino acids are required

False

True or False? Consider the methylation of H2A in the histone octamer. This will promote a tighter association of the DNA with the histone octamer.

False

Which of the following is TRUE of epigenetic changes in gene expression?

d - A and B