Ch. 16

Question 1

gene expression is controlled by

Answer 1

regulatory proteins binding to specific DNA sequences

Question 2

regulatory proteins

Answer 2

block or stimulate transcription

Question 3

prokaryotic organisms regulate gene expression in response to

Answer 3

their environment

Question 4

eukaryotic cells regulate gene expression to

Answer 4

maintain homeostasis

Question 5

to regulate prokaryotes use

Answer 5

operons

Question 6

positive control of transcription initiation

Answer 6

increases when activators bind DNA

Question 7

negative control of transcription initiation

Answer 7

reduces transcription when repressors bind to operators

Question 8

promoter

Answer 8

positions and orients polymerase correctly

Question 9

operator

Answer 9

is where repressor binds

Question 10

operons negative regulation

Answer 10

uses repressor protein
can be inducible or repressible

Question 11

operons positive regulation

Answer 11

uses activartor protein
activators: glucose, cAMP, and CAP

Question 12

trp operon

Answer 12

encodes genes for the biosynthesis of tryptophan
not expressed with sufficient amounts of tryptophan
expressed when levels are low

Question 13

trp operon is ______ regulated by trp repressor protein

Answer 13

negatively
presence of tryptophan (high levels) causes activation of repressor

Question 14

lac operon

Answer 14

contains genes to breakdown lactose as an energy source
regions include:
CAP binding site
promoter
operator

Question 15

lac operon is _______ regulated by repressor protein

Answer 15

negatively
action is induction

Question 16

lac operon: if glucose is present

Answer 16

RNA pol poorly binds to lac operon promoter,
operon needs help from CAP

Question 17

lac operon: no glucose around

Answer 17

cAMP goes up and binds with CAP activating it
CAp thus helps RNA pol attach to promoter

Question 18

controlling the expression of eukaryotic genes requires

Answer 18

transcription factors

Question 19

what are required for the function of transcription factors

Answer 19

coactivators and mediators

Question 20

eukaryotic regulation

Answer 20

transcription factors bind to promoter region
RNA pol II binds to promoter to begin transcription

Question 21

gene expression can be controlled after transcription with

Answer 21

RNA interference RNAi
alternative splicing
RNA editing
mRNA degradation

Question 22

alternative splicing

Answer 22

introns spliced out of pre-mRNAs to produce mature mRNA that is translated

Question 23

RNA editing

Answer 23

creates mature mRNA that are not truly encoded by the genome

Question 24

posttranscriptional regulation: transportation

Answer 24

movement of the mRNA may be interfered with

Question 25

translation repressor proteins

Answer 25

interfere with translation

Question 26

degradation of mRNA

Answer 26

loss of poly-A tail

Question 27

protein degradation

Answer 27

proteins are produced and degraded continually in the cell

Question 28

miRNA

Answer 28

micro RNA
22 nucelotides in length
involved in repression of a gene

Question 29

siRNA

Answer 29

small interfering RNA
20-24 nucleotides

Question 30

circRNA

Answer 30

small circular RNA

Question 31

piRNA

Answer 31

piwi-interacting RNA
largest non-coding RNA
help form RNA-protein complexes
many subtypes

Question 32

RNA interference (RNAi)

Answer 32

biological process in which RNA molecules inhibit gene expression or translation by neutralizing targeted mRNA molecules