chapter 6

Question 1

Bacterial phenotypes of special interest

Answer 1

ability to:

synthesize essentail macromolecules from minimal media

utilize specific energy sources

resistance to compounds that inhibit growth/ kill

Question 2

ability to synthesize essential macromolecules from minimal media

Answer 2

amino acids of nucleotides —> auxotrophic mutants cannot synthesize their own macromolecules; require additional supplements

Question 3

ability to utilize specific energy sources

Answer 3

ability to use lactose or galatose as C-source —> wily type can generally catabolize a wide variety of molecules;

mutants are more restricted

Question 4

what are minimal media

Answer 4

inorganic salts, carbon source, water

Question 5

resistance to compounds that inhibit growth/ kill

Answer 5

antibiotics, resistant mutants are insensitive

Question 6

key features and properties of bacteria

Answer 6

rapid exponential growth

prokaryotic (no nucleus or membrane-bound organelles)

have only 1 circular chromosomes
-haploid

-do NOT undergo meiosis, no union of cells for sexual reproduction

Question 7

able or unable to synthesize/utilize

Answer 7

able = +

unable = -

Question 8

R =

Answer 8

resistant

Question 9

S =

Answer 9

susceptible

Question 10

bio- =

Answer 10

requires biotin added as a supplement to minimal medium

Question 11

arg- =

Answer 11

requires arginine added as a supplement to minimal medium

Question 12

met- =

Answer 12

requires methionine added as a supplement to minimal medium

Question 13

lac- =

Answer 13

cannot utilize lactose as a carbon source

Question 14

gal- =

Answer 14

cannot utilize galactose as a carbon source

Question 15

str r =

Answer 15

resistant to the antibiotic streptomycin

Question 16

str s =

Answer 16

senstive to the antibiotic streotomycin

Question 17

selective medium:

Answer 17

only certain genotypes can grow

-minimal media selects againt auxotrophs and for prototrophs or antibiotic supplemented medium to test tolerant and senstive bacteria

Question 18

dfferential medium:

Answer 18

everything grows

genotypes grow but can be distinguised from each other based on how the organism grows on the medium
-straining of cells based on their ability to utilize lactose

Question 19

phenotypic screening in bacteria:

Answer 19

replica plating allows idenification of antibiotic resistant or auxotrophic mutants

Question 20

both prototrophic and auxotrophic bacteria can-

Answer 20

grow on complete media

Question 21

auxotrophs dont grow

Answer 21

on minimal media

Question 22

theronine auxotrophs can grow on

Answer 22

minimal media + theronine

Question 23

arginine auxotroph can grow on

Answer 23

minimal media + arginine

Question 24

learn bout conjugation, transformation, and transduction

Question 25

U-tube experiment

Answer 25

proves physical contact is necessary for gene transfer -no increase in growth without cell contact -prototroph growth not because of crossfeeding

Question 26

physcial union of bacterial cells =

Answer 26

conjugation

Question 27

what is used for bacterial cells to connect with eachother

Answer 27

pili (hairs)

Question 28

bacteria DNA transfer requires-

Answer 28

pili and occurs through membrane pores

Question 29

transferred DNA could be

Answer 29

plasmids portions of the bacterial chromosomes (genome)

Question 30

plasmids

Answer 30

extra-chromosomal elements, non-essential under certain conditions

Question 31

properties of the F-factor (plasmid)

Answer 31

enables the production of pili (proteinaceous attachment tube between cells) -prevents conjugation between 2 F+ cells -able to replicate via DNA synthesis during cell division and during conjugation

Question 32

replicate via DNA synthesis during cell divistion and during conjugation

Answer 32

-rolling circle replication of F plasmid in donor -transfer of single-stranded DNA into recipient via pore, second strand synthesized in recipient -results in donor and recipient having F plasmid (F- is converted to F+)

Question 33

What does Hfr mean

Answer 33

high frequency recombinant

Question 34

integration of F plasmid into the bacterial chromosome in Hfr strains

Answer 34

-occurs via insertional sequence (IS) which is a region of homology to bacterial chromosome

Question 35

IS meaning

Answer 35

insertion sequence

Question 36

During conjugation, F plasmid AND chromosomal DNA (called exogenote) from Hfr is-

Answer 36

transferred to the F- strain

Question 37

crossover-like events integrate parts of the transferred donor fragment (exogenote) into-

Answer 37

recipient chromosome (endogenote)

Question 38

mechanism of recombination between Hfr and F- strain

Answer 38

1) conjugation 2) crossover-like events 3) linear DNA left after crossover is lost

Question 39

merozygote

Answer 39

transient, and partially diploid cell

Question 40

F plasmid integrates in

Answer 40

bacterial genome at insertion sites there are several potential insertion sites in bacterial gemome

Question 41

order of tansfer

Answer 41

linear arrangement of genes

Question 42

time of transfer

Answer 42

proportional distance between genes

Question 43

allele exchange in the recipient cell chromosome depends on

Answer 43

transfer and recombination

Question 44

once DNA has transferred, frequency of recombination events depends on

Answer 44

distance between genes (due to crossover-like events)

Question 45

alleles closest to the origin get transferred more effieiciently by

Answer 45

conjugation and are more likely to exchange with chromosomal alleles

Question 46

an odd number of crossover events produce

Answer 46

non-viable exconjugates due to linearization of the chromosome. linear DNA is degraded in bacteria

Question 47

an even number of crossover events produces

Answer 47

circular chromosomes and viable exconjugates

Question 48

freqeuncy of integration is an accurate measure of recombination ONLY IF

Answer 48

the transfer is equal for all genes the exconjugates have 3 genes transferred from an exogenote exconjugates should be selected on the last gene to be transferred.