chapter 16 biology

Question 1

how many DNA binding motifs are there

Answer 1

three

Question 2

identify when gene expression is usually controlled

Answer 2

during transcription initiation

Question 3

describe the usual action of regulatory proteins

Answer 3

they bind to DNA and they can block or stimulate transcription and modulate binding of RNA polymerase to promoter

Question 4

control of gene expression in prokaryotes

Answer 4

Regulate gene expression in response to the environment

Question 5

control of gene expression in eukaryotes

Answer 5

regulate gene expression to maintain homeostasis

Question 6

explain how proteins can interact with base pairs WITHOUT unwinding the DNA helix

Answer 6

the bae pairs have unique accessibility patterns allowing the proteins to bind at the major groove

Question 7

control of gene expression using repression

Answer 7

it is capable of making an enzyme but does not

Question 8

control of gene expression using induction

Answer 8

enzymes for certain pathways are produced in response to substrate

Question 9

explain the control of gene expression in the lac operon

Answer 9

uses a lac repressor to suppress lactose that blocks transcription to operon and CAP as a glucose sensor activating transcription to operon when glucose is low

Question 10

what is the main energy source for lac operon

Answer 10

lactose

Question 11

what does lac operon use to sense lactose

Answer 11

allolactose

Question 12

what is the role of ubiquitin in the degradation of proteins

Answer 12

marks proteins for destruction at proteasome

Question 12

explain control of gene expression in the trp operon

Answer 12

uses trp repressor in a helix turn helix that bind to operator site located adjacent to trp promoter

Question 13

what is the job of the trp operon

Answer 13

biosynthesis of tryptophan

Question 14

what does the trp operator site require

Answer 14

corepressor

Question 15

what are the roles of general transcription factors

Answer 15

initiate transcription by forming the initiation complex

Question 16

what are the roles of specific transcription factors

Answer 16

act in the tissue for time dependent matters to stimulate higher levels of transcription

Question 17

how can transcription factors have an effect from a distance in DNA

Answer 17

they bend DNA to form a loop to position the enhancer closer to the promotor

Question 18

what are 2 types of epigenetic mark

Answer 18

dna methylation and x chromosome modification

Question 19

what happens with dna methylation

Answer 19

high levels correlate with inactive genes

Question 20

what happens with x chromosome modification

Answer 20

female mammals inactivate 1 X chromosome

Question 21

how do small RNAs effect gene expression

Answer 21

after transcription they protect genome RNA silencing pathways implicated in formation of heterochromatin in different organisms