micriobial genetics

Question 1

replicon plasmid meaning

Answer 1

plasmids can autonmously replicate

Question 2

episome plasmid meaning

Answer 2

plasmids that can integrate in the host chromosome

Question 3

transposons def

Answer 3

mobile DNA sequences that can move between plasmids and the chromosome

Question 4

what is the repository for many antibiotic resistance genes

Answer 4

transposons

Question 5

degradative plasmids

Answer 5

contains genes that code for enzymes involved in catabolism of complex compounds

Question 6

Col plasmids

Answer 6

contain genes that code for bacteriocins, proteins that can kill other bacteria

Question 7

pathogenicity islands (PAIs)

Answer 7

sections of DNA that encode virulence factors w originated from another organism

Question 8

what is a bacteriophage

Answer 8

virus that replicates inside a bacteria
consists of nucleic acid encapsulated in a protein coat

Question 9

infection of bacteria by virulent phage will result in what

Answer 9

result in death by cell lysis (releases newly replicated phage particles)

Question 10

prophage

Answer 10

in the lysogenic state the phage genome integrates in the bacterial chromosome and will be replicated w the bacterial genome

Question 11

conjugation gene transfer

Answer 11

cell-cell contact
form cytoplasmic bridge
requires sex pilus hair like projection

Question 12

conjugation gene transfer

Answer 12

cell-cell contact
form cytoplasmic bridge
requires sex pilus hair like projection
must have 1 F+ cell and the F- recipient will then become F+

Question 13

Hfr vs F+

Answer 13

F+ strains and Hfr is that F+ strains have F plasmids in the cytoplasm freely without integrating into bacterial chromosomes while Hfr strains have F plasmids integrated to their chromosomes.

Question 14

transduction gene transfer

Answer 14

via phage vector w/o cell-cell contact
phage will infect recipient
can be generalized transduction or specialized transduction

Question 15

generalized transduction vs specialized transduction

Answer 15

generalized - phage DNA to be completely replaced by the bacterial DNA

specialized transduction - DNA consists of both phage DNA and bacterial DNA

Question 16

transformation gene transfer

Answer 16

transfer of genes by means of naked DNA
the recipient must be competent (have structures on its cell wall that can bind the DNA and take it intracellularly)

Question 17

Griffith experiment results and methods

Answer 17

isolated streptococcus pneumonia
lead to discovery of DNA as genetic material

capsules produced “smooth” (S) mucoid colonies (lethal)

mutants w/o capsules grow as “rough” (R) colonies (non lethal)

Question 18

spontaneous mutations

Answer 18

due to uncorrected errors in DNA replication

Question 19

induced mutations

Answer 19

caused by mutagens which are agents that elevate the level of spontaneously occurring mutations

Question 20

what does 5-bromouracil do to induce mutations

Answer 20

substitute for T, occasional faulty pairing w G

Question 21

what does acridines, ethidium bromide (intercalative dyes) do to induce mutations

Answer 21

insert between 2 base pairs

Question 22

what does radiation do to induce mutations

Answer 22

pyrimidine dimer formation

Question 23

fermentation mutants

Answer 23

no longer able to use a specific carbon source

Question 24

auxotrophs

Answer 24

mutants that are unable to synthesize a particular organic compound required for growth
cannot grow on defined minimal medium w/o some nutritional additive

Question 25

antibiotic/bacteriophage mutant

Answer 25

mutants that have acquired resistance to common antibiotics or bacteriophage

Question 26

virulence mutant

Answer 26

mutants that have LOST the ability to produce a virulence factor

Question 27

replica plating is used to do what

Answer 27

detect auxotrophic mutants

Question 28

transition vs transversion point mutation

Answer 28

transition -purine to purine etc
transervsion - purine to pyrimidine etc

Question 29

conservative vs non-conservative missense mutation

Answer 29

conservative - same type/class mutation

Question 30

ames test for mutagenicity use

Answer 30

used for screening potential carcinogens by testing for mutagenesis
used to test many chemicals
relies on observation that most common cause of cancer are mutations by DNA damage

(new mutations that reverse effect of og mutation)