Exam 4 Quiz 4

Question 1

do all proteins need to be constitutive?

Answer 1

No! They only make the proteins that they need at that time

Question 2

post-translational control

Answer 2

the protein is already made, how the function is limited after its made

Question 3

regulating enzyme activity post-translationally

Answer 3

feedback inhibition

Question 4

feedback inhibition

Answer 4

where you have a series of enzymes that go onto make an end product.
-the end product of a pathway typically interrupts the function of the first enzyme in the pathway

Question 5

first enzyme in the pathway

Answer 5

allosteric enzyme

Question 6

allosteric enzyme

Answer 6

-have a second, important site (allosteric site) along with the active site (the main site)

Question 7

allosteric site

Answer 7

where the end product binds when it is in excess which then goes onto disrupt the active site inhibiting the process from continuing (saves energy)

Question 8

is Feeback reversible

Answer 8

yes

Question 9

concerted feedback inhibition

Answer 9

-involves the use of isoenzymes which are different proteins that catalyze the same reaction but are under different regulatory controls

Question 10

example of concerted feedback inhibition

Answer 10

aromatic AA synthesis, each have a different regulatory control but working towards the same product

Question 11

if more than one end product

Answer 11

all end products must be in excess in order for synthesis to be completely inhibited

Question 12

covalent modification of enzymes

Answer 12

occurs throughout the addition and removal of a particular group/model

Question 13

main groups used to modify enzymes

Answer 13

-Adenosine monophosphate
-Adenosine diphospahte
-inorganic phosphate
-methyl groups

Question 14

Glutamine synthetase

Answer 14

making glutamine, when glutamine levels are staying high AMP is added on which causes the glutamine to reduce

Question 15

regulation of translation at translation level

Answer 15

regulating enzyme synthesis vis:
-riboswitches
-regulatory RNA/small RNA

Question 16

riboswitches

Answer 16

-mRNA contains binding site for specific metabolite
-when metabolite bound it alters folding of mRNA hiding the Shane-Dalgarno sequence

Question 17

aptamer region

Answer 17

specific secondary structure that allows for metabolite bonding

Question 18

when specific metabolite is bound

Answer 18

-translation is blocked
-inhibits the Shine dalgarno sequence from being recognized

Question 19

when no metabolite is bound

Answer 19

shine dalgarno sequence is seen by 30S or 16S rRNA to continue with the process

Question 20

Regulatory RNA/small RNA

Answer 20

binding to an mRNA molecule due to complimentary base pairing

Question 21

small RNA

Answer 21

-40-400 nucleotide bases
-act as regulatory
-exert control through base pairing

Question 22

regulation through 4 different mechanisms

Answer 22

-hides shine dalgarno
-opens shine dalgarno
-increases stability
-decreases stability

Question 23

Regulation of transcription

Answer 23

-at transcription level (only prokaryotes)
-regulating enzyme synthesis
-attenuation

Question 24

regulating enzyme synthesis only occurs in prokaryotes because

Answer 24

transcription and translation need to be occurring at the same time, only seen in prokaryotes bc no nucleus

Question 25

Attenuation

Answer 25

at leader sequence there are tandem tryptophan residues (or whatever AA you need) right next to one another in the N terminal

Question 26

what does the rest of the leading sequence form?

Answer 26

secondary structures

Question 27

leader sequence can fall inot different scenarios based on

Answer 27

what is happening in the cell

Question 28

if tryptophan is plentiful

Answer 28

ribosome will translate leader sequence and inhibit further transcription

Question 29

if tryptophan is in short supply

Answer 29

ribosome will be stalled during translation but transcription will continue

Question 30

when there is excess tryptophan (explain)

Answer 30

-want to turn off transcription
-base pairing is done close to the leader sequence
-RNA polymerase terminates because of the stem loop structure

Question 31

when there is not enough tryptophan

Answer 31

-ribosome gets stopped because there is not enough tryptophan
-secondary structure forms earlier because ribosome takes longer to move
-RNA polymerase can continue because the stem loop structure is further away from the leader sequence