Exam 23: The Regulation of Gene Expression

In eukaryotes, gene amplification is tolerated well when the amplified gene encodes for RNA products. However, it is rare or detrimental when the product is a protein. Why would it be advantageous for the cell to amplify the RNA- producing genes and not the protein- producing ones?

The trp operon in E. coli is regulated in such a manner as to allow expression of the genes only when cellular levels of tryptophan are low. When tryptophan levels are adequate, the secondary structure of the mRNA halts translation. This form of regulation is known as

Genes associated with embryonic development are known as

One mechanism that may lead to novel disease treatment is , which hinders the translation of specific mRNAs.

The situation in which an active regulatory protein "turns on" expression is an example of

A person with the genotype XXXY would be expected to have how many Barr bodies?

Small molecules that bind directly to mRNAs and effect transcription or translation are binding to regions of the mRNA known as

Genes that are always "turned on" in a cell are referred to as

Inactivated X chromsomes form dark spots in the nucleus known as .

A lac Y- mutant would

The observed "puffs" in the polytene chromosomes of Drosophila are sites of

A certain gene is transformed into a plant cell for potential use as a vaccine delivery system. Upon performing a Northern blot, a good deal of mRNA for the gene is produced. However, the protein product for the gene is not observed. One explanation may be that the

An E.coli cell with the genotype lacOc Z+Y- A- would make which of the following protein products and in what manner?

A bacteria has the following Lac operon genes located on the chromosome: I+P- Z+Y- A+. On a plasmid, this same bacterial cell has the lac genes I- P+Z- Y+A- . Which Lac proteins will be made? What type of protein expression will there be for each protein that is made (induced or constituitive)?

Changes in gene expression that are not the result of changes to the gene itself are known as changes.

The lac repressor is

In the lac operon, Is mutations allow

Within a genome, an enhancer may be located

You are examining an enzyme associated with glycolysis. As such, you would expect

You are studying a biochemical pathway. Preliminary results suggest that this pathway is subject to end- product repression. This pathway is therefore most likely to be a(n)pathway.