Chapter 13

Question 1

nucleoid body

Answer 1

the single chromosome folded up in a bacterium

Question 2

capsule

Answer 2

a thick, mucus-like coating in addition to the cell wall

Question 3

pathogen

Answer 3

a bacterial strain that causes disease in the host organism

Question 4

bacterial chromosome

Answer 4

a single molecule of double-helical DNA arranged in a circle

Question 5

the approximately 1000 genes that are shared by all E.coli strains

Answer 5

core genome

Question 6

pangenome

Answer 6

the core genome plus all of the other genes that are found in some strains but others

Question 7

What kind of plasmid allows the bacterial cells that carry them to make contact with another bacterium and transfer genes?

Answer 7

F. episomes

Question 8

metagenomics

Answer 8

the collective analysis of genomic DNA from a community of microbes sampled from normal environments

Question 9

the human microbiome project

Answer 9

a metagenomics analysis of the bacteria that lives in the human body

Question 10

petri dish

Answer 10

liquid media or on media solidified by agar in a plate

Question 11

genetic screen

Answer 11

an examination of each colony in a population for its phenotype

Question 12

horizontal gene transfer

Answer 12

traits involved are not transferred by inheritance from parents to offspring, rather, they are introduced from unrelated individuals from different species

Question 13

What are the three different mechanisms of gene transfer in bacteria?

Answer 13

transformation, conjugation, and transduction

Question 14

donor

Answer 14

provides the genetic material for transfer

Question 15

recipient

Answer 15

receives the material

Question 16

transformation

Answer 16

DNA from a donor is added to the bacterial growth medium and is then taken up from that medium by the recipient

Question 17

conjugation

Answer 17

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

Question 18

tranduction

Answer 18

the donor DNA is packaged within the protein coat of a bacteriophage and is transferred to the recipient when the phage particle infects it

Question 19

What is the recipient in transformation called?

Answer 19

transformants

Question 20

What is the recipient in conjugation called? tranduction?

Answer 20

exconjugates; tranductants

Question 21

natural transformation

Answer 21

take up DNA fragments spontaneously from their surrounding

Question 22

artificial transformation

Answer 22

take up DNA only after laboratory procedure make their cell wall and membranes permeable to DNA

Question 23

competent

Answer 23

able to take up DNA from the medium

Question 24

cotransformation

Answer 24

the simultaneous transformation of two or more genes

Question 25

bacterial conjugation

Answer 25

a one way DNA transfer from donor to recipient that requires cell-to-cell contact and that is initiated by conjugative plasmids in donor strains

Question 26

F plasmid

Answer 26

first conjugative plasmid to be discovered

Question 27

origin of transfer

Answer 27

the specific site that an F plasmid is nicked

Question 28

Hfr bacteria

Answer 28

cells whose chromosomes carry an integrated plasmid produce a high frequency of recombinants for chromosomal genes when they are mated with F- strains

Question 29

F' plasmid

Answer 29

the newly formed plasmid carrying most of the genes of the F plasmid plus some bacterial DNA

Question 30

merodiploids

Answer 30

the exconjugants from mating F'- carrying cells with F- cells that contain two copies of some bacterial gene-- one of the F' and the other in the bacterial chromsome

Question 31

lytic cycle

Answer 31

cycle resulting in cell lysis and release of progeny phage

Question 32

lysate

Answer 32

the population of phage particles released from the host bacteria at the end of the lytic cycle

Question 33

generalized transduction

Answer 33

the process which can result in the transfer of any bacterial gene between related strains of bacteria

Question 34

virulent

Answer 34

after infecting a host, they always enter the lytic cycle, multiplying rapidly and killing the cell

Question 35

lysogenic cycle

Answer 35

DNA integrates into the host genome and multiplies along with it, doing no harm to the host

Question 36

prophage

Answer 36

integrated copy of the temperate bacteriophage DNA

Question 37

bacterium containing a prophage

Answer 37

lysogen

Question 38

specialized transducing phages

Answer 38

viruses produced by the faulty exclusion of a lysogenic virus from the bacterial genome

Question 39

specialized transduction

Answer 39

the phage-mediated transfer of a few bacterial genes

Question 40

genomic islands

Answer 40

large segments of DNA whose properties suggest that they originated from transfer of foreign DNA into a bacterial cell

Question 41

pathogenicity islands

Answer 41

genomic island in pathogenic bacteria