MGY377 FINAL EXAM | 2025-2026 LATEST UPDATED | ACTUAL EXAM QUESTIONS
WITH SOLUTIONS | 100% RATED CORRECT | 100% VERFIED SOLTIONS | ALREADY
GRADED A+
what is transfer DNA essential for - (ANSWER)1. driving bacterial evolution
2. spreading adaptive traits
3. generating new gene variant combinations
L21
ways that bacteria acquire new genes - (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 - (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? - (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? - (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? - (ANSWER)Physiological, genetically programmed state permitting efficient
uptake of DNA
gram+:staphylococcus, bacillus
,gram-:neisseria gonorrhea, haemophilus influenzae
L21
what is artifically induced competence - (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. - (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 - (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 - (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+
WITH SOLUTIONS | 100% RATED CORRECT | 100% VERFIED SOLTIONS | ALREADY
GRADED A+
what is transfer DNA essential for - (ANSWER)1. driving bacterial evolution
2. spreading adaptive traits
3. generating new gene variant combinations
L21
ways that bacteria acquire new genes - (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 - (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? - (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? - (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? - (ANSWER)Physiological, genetically programmed state permitting efficient
uptake of DNA
gram+:staphylococcus, bacillus
,gram-:neisseria gonorrhea, haemophilus influenzae
L21
what is artifically induced competence - (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. - (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 - (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 - (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+
