Chapter 18

Question 1

Differential gene expression

Answer 1

the expression of different genes by cells with the same genome.

Question 2

Operator

Answer 2

A segment of DNA that is an On / OFF switch

Question 3

Operon

Answer 3

The operator, promotor and genes they control

Question 4

Repressor

Answer 4

Protien that can switch off the trp operon by binding to the operator

Question 5

Regulatory gene

Answer 5

long bacterial genes that are expressed continously

Question 6

Corepressor

Answer 6

a small molecule that cooperates with the repressor protien to switch an operon off

Question 7

Inducer

Answer 7

inactivates the repressor

Question 8

activator

Answer 8

a protein that binds to DNA and stimulates transcription of a gene

Question 9

Histone acetylation

Answer 9

addition of a acetyl group to an amino acid in a histone tail which promotes transcription

Question 10

DNA methylation

Answer 10

is a biological process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter, DNA methylation typically acts to repress gene transcription.

Question 11

Epigenetic inheritance

Answer 11

inheritance of traits transmitted by mechanisms not involving the nucleotide sequence itself

Question 12

Multiple control elements

Answer 12

segments of noncoding DNA that serve as binding sites for proteins called transcription factors

Question 13

Alternative RNA splicing

Answer 13

different mRNA molecules are produced from the same primary transcript