Chapter 18

Question 1

operator

Answer 1

the on off switch when metabolic pathways are being synthesized

Question 2

operon

Answer 2

the operator, the promoter, and the genes they control

Question 3

repressor

Answer 3

protein that can turn an operon off, prevents gene transcription by binding to the operator and blocking RNA polymerase

Question 4

regulatory gene

Answer 4

gene that creates the repressor

Question 5

corepressor

Answer 5

molecule that cooperates with a repressor protein to switch an operon off

Question 6

inducer

Answer 6

inactivates the repressor

Question 7

lac operon

Answer 7

inducible operon and contains genes that code for enzymes used in the hydrolysis and metabolism of lactose

Question 8

cyclic AMP (cAMP)

Answer 8

activates CAP, accumulates when glucose is scarce, and activator

Question 9

activator

Answer 9

protein that binds to DNA and stimulates transcription of a gene

Question 10

negative gene regulation

Answer 10

ex. trp, the process of regulating gene expression by inhibiting the expression of that specific gene

Question 11

positive gene regulation

Answer 11

the binding of specific protein is required for transcription to begin, ex. lac operon process

Question 12

differential gene expression

Answer 12

the expression of different genes by cells with the same genome

Question 13

histone acetylation

Answer 13

the addition of an acetyle group to an amino acid in a histone tail

Question 14

DNA methylation

Answer 14

a different set of enzymes can methylate the DNA itself on certain bases, usually cytosine

Question 15

epigenetic inheritance

Answer 15

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

Question 16

control elements

Answer 16

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

Question 17

enhancers

Answer 17

the more distant distal control elements

Question 18

alternative RNA splicing

Answer 18

different mRNA molecules are produced from the same primary transcript

Question 19

proteasomes

Answer 19

giant protein complexes that bind protein molecules and degrade them

Question 20

MicroRNAs

Answer 20

small single stranded RNA molecules that can bind to complementary mRNA sequences, can degrade or block mrna

Question 21

Small interfering RNA

Answer 21

similar to miRNA and associate with the same proteins

Question 22

RNA interference

Answer 22

used as a means of disabling a specific gene to investigate their function

Question 23

non protein coding DNA

Answer 23

corresponds to the portions of an organisms genome that do not code for amino acids

Question 24

non coding RNA

Answer 24

a functional RNA molecule that is not translated into a protein