Final Exam: Exam 5

Question 1

Regulation of transcription

Answer 1

DNA binding proteins

Question 2

DNA binding proteins

Answer 2

-homodimeric
-specific protein domains

Question 3

homodimeric

Answer 3

2 protein subunits that are the same

Question 4

specific protein domain

Answer 4

-helix turn helix
-zinc finger
-leucine zipper

Question 5

helix turn helix

Answer 5

-2 alpha helix connected by small turn (about 3 AA)
-most commonly seen

Question 6

first alpha helix

Answer 6

recognition helix, usually glycine

Question 7

second alpha helix

Answer 7

stabilizing helix

Question 8

zinc finger

Answer 8

alpha helix that binds zinc at the end

Question 9

leucine zipper

Answer 9

regularly spaced leucine residues within alpha helix that allow them to fit together like a ziper

Question 10

DNA proteins will bind to the

Answer 10

-major grooves and look for inverted repeats within the groove
-NO stem loop

Question 11

how can DNA binding proteins act

Answer 11

As repressors or activators

Question 12

repression can cause

Answer 12

repression or induction (both negative control)

Question 13

repression

Answer 13

when end product is present then end product will repress synthesis of enzymes needed to make it

Question 14

when is repression seen the is

Answer 14

synthesis of anabolic reactions

Question 15

the repressor needs to

Answer 15

bind to the DNA and inhibit transcription

Question 16

binding of the repressor is controlled by

Answer 16

co-repressor or effector protein

Question 17

activation

Answer 17

an enzyme or enzymes will only be made if their substrate is present

Question 18

the effector protein of the co-repressor is the

Answer 18

-end product
-relay message that DNA binding protein needs to binds

Question 19

DNA binding proteins are

Answer 19

Allosteric, have two binding sites

Question 20

upon binding a co-repressor

Answer 20

conformational change will occur within repressor which allows binding to the DNA at the operator

Question 21

When argenine (enzyme) is absent

Answer 21

want RNA polymerase to make argenine

Question 22

when arginine is present

Answer 22

arginine acts as co-repressor or effector molecule

Question 23

corepressor binds to the

Answer 23

repressor which then binds to DNA and blocks the RNA polymerase from making more of the enzyme

Question 24

Induction

Answer 24

-negative control
-type of repression where substrate becomes present so mechanisms needs to be turned on

Question 25

induction is seen in ______ reactions

Answer 25

catabolic

Question 26

induction in absence of lactose

Answer 26

repressor bound bc there isnt any lactose that needs broken down

Question 27

induction in presence of lactose

Answer 27

need to remove repressor so lactose can be broken down

Question 28

what is the effector in induction

Answer 28

-wahtever is being used (lactose)

Question 29

in induction effector will bind to….

Answer 29

repressor then releases the DNA binding protein from DNA so RNA polymerase can continue

Question 30

positive control

Answer 30

DNA binding protein is acting as an activator

Question 31

activator

Answer 31

promotes initiation of transcription

Question 32

activator binding site

Answer 32

where activator binds

Question 33

activator binding site is located

Answer 33

upstream the promoter

Question 34

in positive control of transcription the promoter site is

Answer 34

weak

Question 35

since promoter is weak so

Answer 35

RNA polymerase needs helping determining where to bind

Question 36

when activator protein binds in positive control then

Answer 36

modification of the DNA can occur or it can physically interact with RNA polymerase to allow binding

Question 37

in presence of sugar

Answer 37

activator binds to activator binding site to pull in RNA polymerase, inducer (sugar) binds to allosteric site allowing for activator to bind and pull RNA poly in to make all genes needed to break down sugar

Question 38

the promoters of positively controlled genes have

Answer 38

nucleotide sequences that bind RNA poly weakly and have poor consensus sequences

Question 39

operon

Answer 39

cluster of genes where expression is under control of a single operon

Question 40

regulon

Answer 40

more than one operon is under the control of a single regulatory protein