MGY377 Questions and Answers A+
Graded (2025)
what .is .transfer .DNA .essential .for .- .CORRECT .ANSWER-1. .driving .bacterial
.evolution
2. .spreading .adaptive .traits
3. .generating .new .gene .variant .combinations
L21
ways .that .bacteria .acquire .new .genes .- .CORRECT .ANSWER-1. .transformation .-
.uptake .from .environment
2. .conjugation .- .plasmid .transfer .from .one .bacteria .to .another
3. .transduction .- .spread .via .bacteriophage
L21
what .is .griffith .expt .- .CORRECT .ANSWER-showed .that .bacteria .are .able .to
.transfer .things .to .each .other. .
mouse .inoculated .with .heat .killed .S .strain .and .live .R .strain .died. .shows .that
.perhaps .the .S .strain .transfering .something .to .transform .the .live .R .strain .to .be
.able .to .be .virulent
L21
What .is .the .Avery-MacLeod-McCarty .experiment? .- .CORRECT .ANSWER-The
.Griffith .led .to .the .Arthur .McClout .McCarthy .experiment, .and .it .discovered .the
.transformaing .principle .of .DNA.
-Mixing .live .R .cells .with .S .cell .DNA .leads .to .virulent .S .cells
L21
What .is .competence? .- .CORRECT .ANSWER-a .bacteria's .ability .to .take .up .DNA
.from .the .environment .and .be .transformed .(have .a .genetic .change)
Note: .in .the .lab, .a .phenotypic .change .is .usually .needed .to .detect .successful
.transfection
,L21
what .is .natural .competence? .examples? .- .CORRECT .ANSWER-Physiological,
.genetically .programmed .state .permitting .efficient .uptake .of .DNA
gram+:staphylococcus, .bacillus
gram-:neisseria .gonorrhea, .haemophilus .influenzae
L21
what .is .artifically .induced .competence .- .CORRECT .ANSWER-when .bacteria .are
.made .to .be .competent .via .chemical .or .physical .alteration
L21
describe .competence .in .gram+ .bacteria. .give .example .of .how .it .is
.CONTROLLED .in .a .bacteria. .- .CORRECT .ANSWER--controlled .by .Quorem
.sensing .like .mechanism. .gram+ .bacteria .only .become .competent .when .there
.are .sufficient .other .similar .bacteria .in .the .environment .to .ensure .safe .uptake .of
.DNA.
In .staphylococcus:
-comC .produces .pre-CSP .which .is .processed .and .secreted .by .comAB
.transporter .as .CSP. .this .occurs .at .a .basal .rate .in .all .staph.
-when .sufficient .staph .in .environment, .CSP .in .environment .will .be .high .and .will
.reach .threshold .of .comD .histidine .kinase. .This .leads .to .autophosphorylation
.and .then .phosphorylation .of .comE .intracellularly. .
-comE-P .activates .early .competence .proteins .like .comAB .and .comCDE. .It .also
.activates .comX, .a .minor .sigma .factor .for .the .synthesis .of .late .competence
.machinery, .RecA, .and .negative .feedback .inhibition
L21
describe .gram+ .competence .machinery .- .CORRECT .ANSWER-1. .membrane
.spanning .pseudopilis .reels .in .DNA .to .help .attach .it .to .comEA, .a .DNA .binding
.protein
2. .nuclease .induce .ds .breaks .in .DNA.
3. .comEA .brings .DNA .to .comEC, .a .pore .on .cytoplasmic .membrane
4. .comFA, .an .ATPase .attached .to .comEC, .uses .proton .gradient/ATP .hydrolysis
.to .pull .in .DNA .from .3' .end .into .the .cell. .comFA .also .acts .as .helicase .to .unwind
.and .pull .in .DNA. .
5. .DNA .enters .cytoplasm .3' .end .first .through .comEC .and .binds .to .ssDNA
.binding .proteins. .(5' .end .is .chopped .into .nucleotides .in .the .cell .wall)
6. .DNA .can .be .added .to .genome .using .RecA .homologous .recombination, .or
.can .be .used .as .a .food .source.
L21
Describe .transformation .in .gram- .cells .- .CORRECT .ANSWER-1. .Use .DNA .uptake
.Sequence
,2. .DUS .binds .to .unknown .receptor .DR
DNA .is .passed .through .PilQ .secretin .complex**
3. .DR .feeds .the .DNA .to .comE .in .the .periplasm
4. .comE .delivers .DNA .to .comA, .cytoplasmic .membrane .protein
5. .DNA .is .pushed .into .cell .via .force .similar .to .gram+
L21
What .are .the .2 .ways .to .artificially .induce .competence? .- .CORRECT .ANSWER-1.
.Calcium .Induced
2. .Electroporation
L21
describe .Calcium .Induced .competence .- .CORRECT .ANSWER-add .high
.concentration .calcium .ion .and .then .heat .shock .in .cold .temp .to .induce .low
.efficiency .competence
>10% .cells .become .competent
works .for .dsDNA .and .plasmids. .
good .because .doesn't .require .special .equipment
exact .mechanism .not .known
L21
describe .Electroporation .- .CORRECT .ANSWER-apply .a .voltage .pulse .to .disrupt
.the .cell .membrane. .induces .transient .pores .in .the .membrane. .
95% .of .cells .become .competent, .but .there .is .high .cell .death
special .equipment .is .needed .with .sophisticated .power .supply
single .or .ds .DNA
L21
Reasons .bacteria .are .naturally .competent, .and .evidence .and .potential .problems
.with .each .reason .- .CORRECT .ANSWER-1. .Use .DNA .as .food
Problem: .doesn't .make .sense .why .there .is .special .machinery .to .import .DNA. .
Evidence: .E. .coli .without .competence .machinery .(homologue) .cannot .use .DNA
.as .food .source .to .grow .on. .
2. .DNA .repair .
Yes, .true .via .HR, .but .it .has .been .shown .that .when .cells .are .put .in .stress
.condition, .competence .is .not .induced.
Evidence: .it .has .been .shown .that .the .advantage .of .damage .induced
.competence .is .offset .by .reduced .performance. .
, 3. .Acquire .new .genes/functions
*Most .widely .accepted. .Competence .machinery .can .be .used .to .test .out .new
.DNA .from .environment
4. .Biofilm
-Newer .theory, .as .shown .that .DNA .is .important .in .early .biofilm .formation, .and
.that .cells .without .functional .competence .machinery .can .develop .small .biofilm,
.but .no .DNA .is .implicated .in .their .biofilm. .
(Psedopilis .important .in .biofilm .formation). .For .DNA .to .be .involved .in .biofilm,
.pseudopilis .must .be .present. .
L21
Describe .plasmids .- .CORRECT .ANSWER--small .circular .supercoiled .piece .of
.DNA
-use .host .cell .machinery .for .replication
-conjugated .between .bacteria
-have .own .replication .origin
-dispensable .for .growth .but .they .usually .provide .some .benefit .to .the .host, .such
.as .Ab .resistance
L22
Ways .that .plasmids .maintain .themselves .in .a .host .- .CORRECT .ANSWER-1.
.Provide .benefit .to .the .host .(like .Ab .resistance)
2. .Copy .number .control .- .RNAI/RNAII
3. .Addiction .system .- .CCdb/ccda
4. .Partition .system .- .ParM
-low .copy .# .plasmid .need .addiction .system .of .partition .system
L22
Relation .between .plasmid .size .and .copy .number .- .CORRECT .ANSWER-as .size
.increase .(kb), .copy .number .decrease
L22
What .is .the .origin .of .replication .on .plasmid? .- .CORRECT .ANSWER-oriV, .site
.where .DNA .replication .begins
The .way .a .plasmid .initiates .and .progresses .through .replication .depends .on .the
.type .of .oriV .it .has
Can .proceed .uni .or .bi .directionally
L22
what .types .of .replication .proteins .do .plasmids .use? .- .CORRECT .ANSWER-they
.can .use .either .host .or .plasmid .encoded .proteins
-most .rely .on .host .(bacterial) .replication .enzymes .to .copy .themselves .though
.(DNApol)
Graded (2025)
what .is .transfer .DNA .essential .for .- .CORRECT .ANSWER-1. .driving .bacterial
.evolution
2. .spreading .adaptive .traits
3. .generating .new .gene .variant .combinations
L21
ways .that .bacteria .acquire .new .genes .- .CORRECT .ANSWER-1. .transformation .-
.uptake .from .environment
2. .conjugation .- .plasmid .transfer .from .one .bacteria .to .another
3. .transduction .- .spread .via .bacteriophage
L21
what .is .griffith .expt .- .CORRECT .ANSWER-showed .that .bacteria .are .able .to
.transfer .things .to .each .other. .
mouse .inoculated .with .heat .killed .S .strain .and .live .R .strain .died. .shows .that
.perhaps .the .S .strain .transfering .something .to .transform .the .live .R .strain .to .be
.able .to .be .virulent
L21
What .is .the .Avery-MacLeod-McCarty .experiment? .- .CORRECT .ANSWER-The
.Griffith .led .to .the .Arthur .McClout .McCarthy .experiment, .and .it .discovered .the
.transformaing .principle .of .DNA.
-Mixing .live .R .cells .with .S .cell .DNA .leads .to .virulent .S .cells
L21
What .is .competence? .- .CORRECT .ANSWER-a .bacteria's .ability .to .take .up .DNA
.from .the .environment .and .be .transformed .(have .a .genetic .change)
Note: .in .the .lab, .a .phenotypic .change .is .usually .needed .to .detect .successful
.transfection
,L21
what .is .natural .competence? .examples? .- .CORRECT .ANSWER-Physiological,
.genetically .programmed .state .permitting .efficient .uptake .of .DNA
gram+:staphylococcus, .bacillus
gram-:neisseria .gonorrhea, .haemophilus .influenzae
L21
what .is .artifically .induced .competence .- .CORRECT .ANSWER-when .bacteria .are
.made .to .be .competent .via .chemical .or .physical .alteration
L21
describe .competence .in .gram+ .bacteria. .give .example .of .how .it .is
.CONTROLLED .in .a .bacteria. .- .CORRECT .ANSWER--controlled .by .Quorem
.sensing .like .mechanism. .gram+ .bacteria .only .become .competent .when .there
.are .sufficient .other .similar .bacteria .in .the .environment .to .ensure .safe .uptake .of
.DNA.
In .staphylococcus:
-comC .produces .pre-CSP .which .is .processed .and .secreted .by .comAB
.transporter .as .CSP. .this .occurs .at .a .basal .rate .in .all .staph.
-when .sufficient .staph .in .environment, .CSP .in .environment .will .be .high .and .will
.reach .threshold .of .comD .histidine .kinase. .This .leads .to .autophosphorylation
.and .then .phosphorylation .of .comE .intracellularly. .
-comE-P .activates .early .competence .proteins .like .comAB .and .comCDE. .It .also
.activates .comX, .a .minor .sigma .factor .for .the .synthesis .of .late .competence
.machinery, .RecA, .and .negative .feedback .inhibition
L21
describe .gram+ .competence .machinery .- .CORRECT .ANSWER-1. .membrane
.spanning .pseudopilis .reels .in .DNA .to .help .attach .it .to .comEA, .a .DNA .binding
.protein
2. .nuclease .induce .ds .breaks .in .DNA.
3. .comEA .brings .DNA .to .comEC, .a .pore .on .cytoplasmic .membrane
4. .comFA, .an .ATPase .attached .to .comEC, .uses .proton .gradient/ATP .hydrolysis
.to .pull .in .DNA .from .3' .end .into .the .cell. .comFA .also .acts .as .helicase .to .unwind
.and .pull .in .DNA. .
5. .DNA .enters .cytoplasm .3' .end .first .through .comEC .and .binds .to .ssDNA
.binding .proteins. .(5' .end .is .chopped .into .nucleotides .in .the .cell .wall)
6. .DNA .can .be .added .to .genome .using .RecA .homologous .recombination, .or
.can .be .used .as .a .food .source.
L21
Describe .transformation .in .gram- .cells .- .CORRECT .ANSWER-1. .Use .DNA .uptake
.Sequence
,2. .DUS .binds .to .unknown .receptor .DR
DNA .is .passed .through .PilQ .secretin .complex**
3. .DR .feeds .the .DNA .to .comE .in .the .periplasm
4. .comE .delivers .DNA .to .comA, .cytoplasmic .membrane .protein
5. .DNA .is .pushed .into .cell .via .force .similar .to .gram+
L21
What .are .the .2 .ways .to .artificially .induce .competence? .- .CORRECT .ANSWER-1.
.Calcium .Induced
2. .Electroporation
L21
describe .Calcium .Induced .competence .- .CORRECT .ANSWER-add .high
.concentration .calcium .ion .and .then .heat .shock .in .cold .temp .to .induce .low
.efficiency .competence
>10% .cells .become .competent
works .for .dsDNA .and .plasmids. .
good .because .doesn't .require .special .equipment
exact .mechanism .not .known
L21
describe .Electroporation .- .CORRECT .ANSWER-apply .a .voltage .pulse .to .disrupt
.the .cell .membrane. .induces .transient .pores .in .the .membrane. .
95% .of .cells .become .competent, .but .there .is .high .cell .death
special .equipment .is .needed .with .sophisticated .power .supply
single .or .ds .DNA
L21
Reasons .bacteria .are .naturally .competent, .and .evidence .and .potential .problems
.with .each .reason .- .CORRECT .ANSWER-1. .Use .DNA .as .food
Problem: .doesn't .make .sense .why .there .is .special .machinery .to .import .DNA. .
Evidence: .E. .coli .without .competence .machinery .(homologue) .cannot .use .DNA
.as .food .source .to .grow .on. .
2. .DNA .repair .
Yes, .true .via .HR, .but .it .has .been .shown .that .when .cells .are .put .in .stress
.condition, .competence .is .not .induced.
Evidence: .it .has .been .shown .that .the .advantage .of .damage .induced
.competence .is .offset .by .reduced .performance. .
, 3. .Acquire .new .genes/functions
*Most .widely .accepted. .Competence .machinery .can .be .used .to .test .out .new
.DNA .from .environment
4. .Biofilm
-Newer .theory, .as .shown .that .DNA .is .important .in .early .biofilm .formation, .and
.that .cells .without .functional .competence .machinery .can .develop .small .biofilm,
.but .no .DNA .is .implicated .in .their .biofilm. .
(Psedopilis .important .in .biofilm .formation). .For .DNA .to .be .involved .in .biofilm,
.pseudopilis .must .be .present. .
L21
Describe .plasmids .- .CORRECT .ANSWER--small .circular .supercoiled .piece .of
.DNA
-use .host .cell .machinery .for .replication
-conjugated .between .bacteria
-have .own .replication .origin
-dispensable .for .growth .but .they .usually .provide .some .benefit .to .the .host, .such
.as .Ab .resistance
L22
Ways .that .plasmids .maintain .themselves .in .a .host .- .CORRECT .ANSWER-1.
.Provide .benefit .to .the .host .(like .Ab .resistance)
2. .Copy .number .control .- .RNAI/RNAII
3. .Addiction .system .- .CCdb/ccda
4. .Partition .system .- .ParM
-low .copy .# .plasmid .need .addiction .system .of .partition .system
L22
Relation .between .plasmid .size .and .copy .number .- .CORRECT .ANSWER-as .size
.increase .(kb), .copy .number .decrease
L22
What .is .the .origin .of .replication .on .plasmid? .- .CORRECT .ANSWER-oriV, .site
.where .DNA .replication .begins
The .way .a .plasmid .initiates .and .progresses .through .replication .depends .on .the
.type .of .oriV .it .has
Can .proceed .uni .or .bi .directionally
L22
what .types .of .replication .proteins .do .plasmids .use? .- .CORRECT .ANSWER-they
.can .use .either .host .or .plasmid .encoded .proteins
-most .rely .on .host .(bacterial) .replication .enzymes .to .copy .themselves .though
.(DNApol)
