Chapter 16.4-16.6

Question 1

Transformation

Answer 1

> 30 pathways

Question 2

Stress response systems help bacteria

Answer 2

Bacteria take up foreign genetic material (naked DNA) from their environment; acquire genes that make it better able to survive

Question 3

In transformation, recipient cell must be

Answer 3

competent

Question 4

competent

Answer 4

able to take up DNA from the medium

Question 5

Mechanism of natural transformation

Answer 5

1. Donor DNA binds to the recipient cell at the receptor site
2. One donor strand is degraded. The admitted donor strand pairs with the homologous region of the bacterial chromosome
3. The donor strand is integrated into the bacterial chromosome
4. After cell replication, one cell is identical to original recipient; the other carries the mutant genes

Question 6

Contransformation

Answer 6

can occur at a high frequency when two genes are close together in the genome

Question 7

Cotransformation efficiency

Answer 7

indicator of whether genes are genetically linked

Question 8

Bacterial cells can be artificially transformed by

Answer 8

treating the cells with
reagents that make the cell membrane/cell wall permeable to DNA

Question 9

Treatments for artificially transformation

Answer 9

*Calcium chloride at cold temperature followed by a heat shock
*Electroporation (electric pulse)

Question 10

What kind of DNA can be transformed into cells

Answer 10

linear and circular

Question 11

Conjugation

Answer 11

donor carries a special type of plasmid that allows it to transfer DNA directly when it comes in contact with the recipient

Question 12

Conjugation recipient

Answer 12

exconjugant

Question 13

conjugative plasmids

Answer 13

plasmids that initiate conjugation because they carry the genes that allow the donor to transfer genes to the recipient.

Question 14

F plasmid

Answer 14

conjugative plasmid that carries many genes required for the transfer of DNA

Question 15

Cells carrying an F plasmid

Answer 15

F+ cells

Question 16

Genes carriedby F plasmid

Answer 16

Formation of appendage (pilus) by which a donor cell contacts a recipent cell
Endonuclease enzyme that nicks the F plasmid’s DNA at a specific site

Question 17

origin of transfer

Answer 17

during bacterial conjugation, the spot on the F plasmid where replicative transfer of DNA from the donor to the recipient cell initiates (formed by endonuclease enzyme)

Question 18

F pilus

Answer 18

hollow protein tube that protrudes from an F+, Hfr, or F’ bacterial cell and binds to the cell wall of an F− cell. Retraction of the pilus into the F+ cell draws the two cells close together in preparation for gene transfer.

Question 19

The process of conjugation

Answer 19

1. The pilus consists of a protein that binds specifically to the cell walls of F-
2. Attachment to F- cells and retratcs and cells are drawn together
3. Gene transfer: A single strand of DNA travels from the male to the female cell
4. In the original F+ cell, newly synthesized DNA replaces the single strand transferred to the previously F- cell

Question 20

Chromosomal integration of F plasmid
by HOMOLOGOUS RECOMBINATION

Answer 20

~1 in 105 F+ cells becomes an Hfr cell

Question 21

Hfr

Answer 21

High Frequency of Recombinants
for chromosomal genes

Question 22

episomes

Answer 22

plasmids, like the F plasmid, that can integrate into the host genome.

Question 23

Gene transfer from Hfr cells to F- cells

Answer 23

cells remains F- but carries some genes from Hfr chromosome

Question 24

Rarely, F’ plasmids are formed upon

Answer 24

recombination between
genomic DNA flanking the integrated F factor

Question 25

F’ plasmid

Answer 25

F plasmid + some bacterial chromosomal genes

Question 26

A rare recombination event between regions of limited sequence similarity permits

Answer 26

out-looping of F factor including trp+ locus

Question 27

Transfer of F’ plasmid to an F－cell can generate

Answer 27

merodiploid

Question 28

Merodiploid

Answer 28

partially diploid bacterium (carries a second copy of part of its genome)

Question 29

Merodiploids are useful for

Answer 29

complementation studies

Question 30

If the merodiploid containing trp-yand trp-xis able to grow without tryptophan added to the medium ->

Answer 30

mutations are in different genes

Question 31

Generalized transduction

Answer 31

transfer of any random fragment of donor DNA to the recipient

Question 32

Temperate phages Virulent

Answer 32

Enter lytic cycle and lysogenic cycle

Question 33

lysogenic cycle

Answer 33

the integration of a bacteriophage into the bacterial host genome as a prophage, which does no immediate harm to the cell.

Question 34

prophage

Answer 34

a phage genome integrated into the bacterial host genome

Question 35

lysogen

Answer 35

a bacterial cell that carries a prophage.

Question 36

integrated cop of the temperate bacteriophage DNA is

Answer 36

lysogen with prophage

Question 37

specialized transducing phages

Answer 37

bacteriophage carrying mainly phage DNA but also one or a few of the bacterial genes that lie near the site of prophage insertion. They can transfer these genes to another bacterium in the process known as specialized transduction.

Question 38

specialized transduction

Answer 38

transfer of donor genes close to the prophage excision sites to the recipient

Question 39

Mistakes during excision of prophage DNA result in

Answer 39

specialized transducing phages

Question 40

Mistakes during excision of prophage DNA result in

Answer 40

specialized transducing phages

Question 41

genomic islands

Answer 41

large DNA segments transferred from one bacterial species to another.

Question 42

pathogenicity islands

Answer 42

segments of DNA in disease-causing bacteria that encode several genes involved in pathogenesis.

Question 43

Pathogenicity islands appear to have been transferred into the bacteria by horizontal gene transfer from

Answer 43

differet species

Question 44

Recombinant mariner transpoon and mariner transposase gene introduced on plasmid lacking

Answer 44

replication origin

Question 45

Inverse PCR to identify

Answer 45

transposon insertion sites

Question 46

Gene targeting via homologous recombination

Answer 46

To examine functions of genes by making null (or other types of) mutations

Question 47

Penicillin-binding proteins (PBPs

Answer 47

catalyze the formation of the peptide cross-links

Question 48

Penicillin inhibits

Answer 48

enzymatic activity of PBPs in bacterial cell wall

Question 49

Mutations that cause penicillin resistance

Answer 49

penA, penB, mtr

Question 50

mtr

Answer 50

increased number of efflux pumps expel more penicillin

Question 51

penB

Answer 51

mutant proin protein decreases penicillin entry

Question 52

penA

Answer 52

mutant PBP cannot bind penicillin

Question 53

Metagenomics

Answer 53

study of collective bacteria within a community