Final Exam : Exam 5 pt 2

Question 1

Why is it not enough to control regulation of sugars individually

Answer 1

because the sugars often have a preferred substrate

Question 2

Global regulatory mechanisms

Answer 2

-complex control system that regulates expression of cellular processes in microorganisms
-one event that triggers all proteins

Question 3

best sugar

Answer 3

glucose

Question 4

global regulatory mechanisms also called

Answer 4

catabolite repression

Question 5

Catabolite repression

Answer 5

• mechanism that controls sugar usage
  -helps us use glucose above all else

Question 6

Catabolite repression is an example of

Answer 6

-positive of control of transcription
-activator protein

Question 7

activator protein of catabolite repression

Answer 7

Cyclic AMP receptor protein

Question 8

Cyclic AMP receptor protein

Answer 8

-common regulatory nucleotide
-also called cyclic GMP, di-GMP, and guanosine tetraphosphate

Question 9

effector protein

Answer 9

cyclic AMP, tied to glucose

Question 10

Cyclic AMP when glucose is present:

Answer 10

-Low cyclic AMP
-glucose inhibits adenylate cyclase (inhibit cAMP production)
-glucose causes the transport of remaining cAMP out of cell
-no RNA polymerase brought in bc no binding to activator
**seen before Lac operon

Question 11

Cyclic AMP when glucose is abscent

Answer 11

-High cyclic AMP
-cAMP acts as inducer and draws in RNA polymerase

Question 12

Glucose and lactose present

Answer 12

-no lactose utilization enzymes
-only glucose enzymes

Question 13

No glucose but lactose is present

Answer 13

-no inhibition of adenylate cyclase
-lactose utilization genes will be made

Question 14

if neither lactose or glucose present

Answer 14

repressor will be sitting on the operator

Question 15

diauxic growth

Answer 15

-more exponential growth seen with glucose
-lag phase
-then less exponential growth w lactose

Question 16

lag phase

Answer 16

when glucose runs out and have to wait for lactose to be brought in

Question 17

two compartment regulatory system

Answer 17

links events occurring outside the cell to the regulation of gene expression inside the cell

Question 18

two players in two compartment regulatory systems

Answer 18

-sensor kinase proteins
-response regulator proteins

Question 19

sensor kinase proteins

Answer 19

-inside cell membrane (integral protein)
-autophosphorylation upon recognition of environmental cue

Question 20

kinase

Answer 20

-phosphorylate proteins
-typically phosphorylate themselves (autophosphorylation)

Question 21

categories of kinases

Answer 21

-serine-threonine
-tyrosine
-histidine

Question 22

what residue doe phosphorylation occur at in sensor protein kinases

Answer 22

histidine residue

Question 23

response regulator protein

Answer 23

-Cytoplasmic
-DNA binding protein
-effector is passing of phosphorylation

Question 24

how do you reset system

Answer 24

feedback loop and phosphotase

Question 25

phosphatase

Answer 25

removing phosphate from response regulator at a constant rate

Question 26

mutations

Answer 26

-inherited change in the nucleotide base sequence of the genome -relatively rare bc of proofreading mechanisms -driving force of evolution

Question 27

how often is there a mutation

Answer 27

every 108-109 base pairs

Question 28

what do we have to fix mutations

Answer 28

repair mechanisms

Question 29

why do we see more in prokaryotes than eukaryotes

Answer 29

-no backup copies of genes: haploid -replicate very fast

Question 30

mutant strain

Answer 30

-bacteria carrying mutation strain -genotype will differ, phenotype may not differ

Question 31

point mutations

Answer 31

when one base pair is substituted for another

Question 32

silent mutation

Answer 32

-different sequence but allows for same amino acid to be coded for -occur in wobble site

Question 33

nonsense mutation

Answer 33

mutation allows a stop codon to be placed there causing for a incomplete protein

Question 34

missense

Answer 34

-add in a different amino acid -different amino acid than before

Question 35

frameshift mutations

Answer 35

-when base pairs are inserted or deleted -alters the reading frame

Question 36

reverse mutations

Answer 36

when an earlier mutation is reversed by a second mutations

Question 37

two types of reverse mutations

Answer 37

1. same-site (true) reversion 2. second-site reversion

Question 38

same site reversion

Answer 38

converts the mutant nucleotide sequence back to original sequence

Question 39

second site reversion

Answer 39

a second mutation occur at a different site in the DNA and causes the first mutation to be restored

Question 40

second mutation found in

Answer 40

same gene or another gene

Question 41

spontaneous mutation

Answer 41

-random change in DNA arising from errors in replication -intrinsic -quite slow (10^-6 - 10^-8)

Question 42

induced mutations

Answer 42

-exposure to mutagens (physically or chemically) that interact with DNA in a disruptive manner

Question 43

base analogs

Answer 43

-compounds that look similar to base used in DNA but have an extra group that attaches that modifies and causes a stable mutation -point mutations -need to be actively growing bc it cant be incorporated into dormant cell

Question 44

DNA modifying agents

Answer 44

-mutagens that change the baes structure and therefor alter its base pairing -addition of a group that attaches to a base that's already there

Question 45

Intercalating agents

Answer 45

-planar molecules that insert themselves between the stacked bases of the helix to induce single nucleotide pair insertions and deletions -frameshift mutation -disrupts DNA polymerase

Question 46

non-ionizing Radiation

Answer 46

-excites an atom to a higher energy state -UV radiation (260nm) -not as penetrating a ionizing -absorbed by DNA and targets pyrimidines bases forming pyrimidine dimers

Question 47

ionizing radiation

Answer 47

-radiation ejects orbital electrons from an atom and causes ions to form -gamma rays (most) -X rays -cathode rays (least)

Question 48

why must we have repair mechanisms

Answer 48

-because mutations can alter nucleotide sequences, they must be able to repair any lethal changes

Question 49

nucelotide excision repair

Answer 49

-UvrABC enzyme detects issue and cleaves out section -fills in with DNA poly I -DNA ligase makes final connection

Question 50

base excision repair

Answer 50

-DNA glycosylase removes just the base yielding an apurinic/apyrimidinic site (AP site)

Question 51

AP endonucleases

Answer 51

-recognizes AP site, and nicks the DNA backbone -DNA poly I put in correct nucleotide -DNA ligase makes final connection

Question 52

Direct repair

Answer 52

photoactivation

Question 53

photoactivation

Answer 53

-light activated repair -photolyase -used for dimers

Question 54

SOS repair system

Answer 54

-seen in extreme conditions and a lot of errors -Rec A protein -Lex A protein -Sfi A -Translesion DNA synthesis genes

Question 55

Rec A protein

Answer 55

-activated due to stalls in replication -triggers Lex A repressor to cleave itself to initiate gene transcription -increases transcription of genes for excision repair -produces Sfi A

Question 56

Lex a repressor

Answer 56

found in operator region of SOS gene

Question 57

Sfi A

Answer 57

blocks cell division

Question 58

Translesion DNA synthesis

Answer 58

breakage and no longer have a template, use DNA poly IV and V which have no proofreading capabilities

Question 59

selection mutant isolation

Answer 59

-confers to an advantage for the organism -antibiotic resistance

Question 60

screening mutant isolation

Answer 60

-examining large numbers of colonies for certain types of mutations -non-selectable -nutrient deficiencies

Question 61

Replica plating

Answer 61

used ti detect auxotrophic mutants

Question 62

A lysine auxotroph only grows on

Answer 62

lysine supplemented media