Red Cross Lifeguarding
Genetics WSU MBIOS/BIOL 301, Exam3,
Dr. Julie Stanton, Spring Fall Newest
Solution
Describe the two types of media that bacteria can be grown in. - ANS ✔✔ - Minimal Media: ONLY carbon
and ion sources.
Complete Media: EVERYTHING bacteria need to survive.
Define Prototrophic and Auxotrophic bacteria. - ANS ✔✔ - Prototrophic: Can grow in minimal media.
Auxotrophic: Cannot grow on minimal media.
Describe the "replica plating technique." - ANS ✔✔ - Plate the same cells on two different types of
media. Then, look for a colony that grow on one media and not the other.
Describe the 3 types of bacterial genetic transfer. - ANS ✔✔ - Conjugation: Transfer between cells via a
physical connection.
Transduction: Transfer of genetic material via a virus.
Transformation:Uptake of genetic material from the environment (Dead Bacteria).
Describe the discovery of conjugation. - ANS ✔✔ - The auxotrophic strains met- bio- thr+ leu+ thi+ and
met+ bio+ thr- leu- thi- were studied. On minimal media, the mixed bacteria survived, and the unmixed
died.
When placed in a U-Shaped tube with a filter separating the two strains, they died when later placed on
minimal media.
1
, Red Cross Lifeguarding
What is the mechanism of conjugation? - ANS ✔✔ - 1) Sex pillus forms to connect cells.
2) Conjugation bridge forms for passage of DNA
3) Endonuclease nicks F factor (Cut strain called "T-Strain")
4) T-DNA is separated and transferred across
5) Complementary DNA is synthesized from T-DNA (Both cells will have double stranded F factor)
6) Ligase joins ends (DNA is circularized)
7) Cells separate ("Exconjugants")
What are Hfr Cells? - ANS ✔✔ - "High frequency" of recombination cells. Have F factor integrated in
chromosome. Can transfer genomic DNA during conjugation.
Not all of the F factor sequence is transferred, so the recipient usually remains F-
How was the first genetic map of E. coli created? - ANS ✔✔ - Via conjugation mapping. The units are
minutes.
What are F' Cells? - ANS ✔✔ - Formerly Hfr cells that have excised their F factor from the bacterial
chromosome.
Describe the Lytic cycle. - ANS ✔✔ - Phage injects DNA into host cell.
Host cell helps make many phages.
Phages lyse host cell.
Phages infect other cells.
Describe the mechanism of transduction. - ANS ✔✔ - 1) Phage infects host, Host DNA is fragmented
2) Phage can pick up host DNA during assembly
3) One strand of DNA pairs with the host DNA, The other strand is degraded.
2
Genetics WSU MBIOS/BIOL 301, Exam3,
Dr. Julie Stanton, Spring Fall Newest
Solution
Describe the two types of media that bacteria can be grown in. - ANS ✔✔ - Minimal Media: ONLY carbon
and ion sources.
Complete Media: EVERYTHING bacteria need to survive.
Define Prototrophic and Auxotrophic bacteria. - ANS ✔✔ - Prototrophic: Can grow in minimal media.
Auxotrophic: Cannot grow on minimal media.
Describe the "replica plating technique." - ANS ✔✔ - Plate the same cells on two different types of
media. Then, look for a colony that grow on one media and not the other.
Describe the 3 types of bacterial genetic transfer. - ANS ✔✔ - Conjugation: Transfer between cells via a
physical connection.
Transduction: Transfer of genetic material via a virus.
Transformation:Uptake of genetic material from the environment (Dead Bacteria).
Describe the discovery of conjugation. - ANS ✔✔ - The auxotrophic strains met- bio- thr+ leu+ thi+ and
met+ bio+ thr- leu- thi- were studied. On minimal media, the mixed bacteria survived, and the unmixed
died.
When placed in a U-Shaped tube with a filter separating the two strains, they died when later placed on
minimal media.
1
, Red Cross Lifeguarding
What is the mechanism of conjugation? - ANS ✔✔ - 1) Sex pillus forms to connect cells.
2) Conjugation bridge forms for passage of DNA
3) Endonuclease nicks F factor (Cut strain called "T-Strain")
4) T-DNA is separated and transferred across
5) Complementary DNA is synthesized from T-DNA (Both cells will have double stranded F factor)
6) Ligase joins ends (DNA is circularized)
7) Cells separate ("Exconjugants")
What are Hfr Cells? - ANS ✔✔ - "High frequency" of recombination cells. Have F factor integrated in
chromosome. Can transfer genomic DNA during conjugation.
Not all of the F factor sequence is transferred, so the recipient usually remains F-
How was the first genetic map of E. coli created? - ANS ✔✔ - Via conjugation mapping. The units are
minutes.
What are F' Cells? - ANS ✔✔ - Formerly Hfr cells that have excised their F factor from the bacterial
chromosome.
Describe the Lytic cycle. - ANS ✔✔ - Phage injects DNA into host cell.
Host cell helps make many phages.
Phages lyse host cell.
Phages infect other cells.
Describe the mechanism of transduction. - ANS ✔✔ - 1) Phage infects host, Host DNA is fragmented
2) Phage can pick up host DNA during assembly
3) One strand of DNA pairs with the host DNA, The other strand is degraded.
2
