Quiz 8 Gene transfer and Genetic Engineering
What does RecA contain?
A homology (similarity) searching function that match the strand and when it find one it facilitates repair
What is the temperate phage?
A phage that goes through the lysogenic cycle and eventually goes into the lytic cycle
What is the virulent phage?
A phage that reproduces only by a lytic cycle.
What is the effect of F' plasmids?
A plasmid and whatever bacterial gene adhere to it when it leaves a bacterium are transferred
What can be packed into a cell during generalized transduction?
Each bacterial fragment from the host cell chromosome has an equal chance of accidentally becoming a part of phage particles during the phage's replication cycle
What is a fertility plasmid?
F plasmid; direct the synthesis of proteins that self assemble into conjugation pili
Which F cell is the donor cell?
F+
Which of the following cells is capable of making a sex pilus or conjugation pilus? F- F+ F neutral None of these choices All of these choices
F+
What makes an F pilus?
F+ cell
What are the cells used in conjugation?
F+= contains the F plasmid F-=does not contain the F plasmid
Which F cell is the recipient or female cell?
F-
What is the F cell in conjugation?
Fertility plasmid, contains info required to form F pilus
What is transferred during generalized transduction?
Fragments of host bacterial DNA of variable length and number are packed into the head of a virus
How can you change transposed plasmids?
From its stand aloneWhat form in the cytoplasm into a chromosome and you can take it out of the chromosome and change it back into its stand alone form
What does agrobacterium cause?
Galls (tumors on plant roots, branches, and stems)
When a bacteriophage moves random pieces of DNA from one host to another, it is called? Conjugation Generalized transduction Specialized transduction Transposition Transformation
Generalized Transduction
What does a virulent phage do?
Phage nucleic acid enters the cell and directs cells to synthesize phage specific nucleic acids and proteins. When the cell becomes filled with phages, phage enzymes rupture the cell relasing newly formed phages into the environment to infect more cells
What is enterococcus vocalese controlled by?
Pheromone receptor repressor system
What are bacteriocinogens?
Plasmids that carry the proteins that can kill or inhibit the growth of other bacteria
What is conjugation called when it entails the F pilus?
Promiscuous
A virus which incorporates its DNA into the DNA of its host organism is existing as a _____. virulent phage prophage lytic phage none of these
Prophage
Viral DNA lying within a bacterial chromosome is called a ________ while the combination of a bacterial cell and its temperate phage is called a ________. prophage, lysogen plaque, lysogen lysogen, prophage prophage, retrovirus
Prophage, Lysogen
What are bacteriocin plasmids?
Proteins that inhibit the growth of other bacteria
Removing the cell walls from two different strains of organisms and then allowing the membrane bound cells to combine with one another best describes: genetic fusion protoplast fusion cell fusion DNA fusion
Protoplast fusion
What is a resistance plasmid?
R Plasmid; contains up to 10 resistance genes and can be resistant to antibiotics, and toxic metals
What is the equivalent to RecA in humans?
Rad 54 and Rad A
Where do transposable elements insert themselves?
Randomly and is not controlled with no homology searching
The combining of genes from two different sources is known as: Genetic transfer Genomics Recombination Replication Conjugation
Recombination
What two mechanisms could conjugation be?
Repair or replacement
Why would you want to induce conjugation?
Repair; to get fixed copies of the genes that may have been damaged
What do injectosomes do? What is another name for them?
Secretion systems: made of two proteins that combine to form a structure resembling a needle and acts that way so that it can inject toxins into other cells
How is RecA useful in repair?
Simultaneously binds single strand DNA to double strand DNA.
What is transferred with F+ plasmid?
Single plasmid
What did joshua lederberg use to discover conjugation
Used mutated strains of E. Coli that were unable to synthesize certain substances and that not all E. coli will conjugate
What is the difference between a temperate phage and a virulent page? Virulent phages destroy host cells, but temperate phages can enter into a lysogenic state with their host cells. Temperate phages destroy host cells, but virulent phages can enter into a lysogenic state with their host cells. Virulent phages can cause cancer while temperate phages cannot cause cancer. Virulent phages can provide immunity to the host cell from infection by other phages of the same type. None of these.
Virulent phages destroy host cells, but temperate phages can enter into a lysogenic state with their host cells.
Why do conjugation pili look bigger when stained?
Virus' attach to the strands
Outside of yogurt what do we use CRISPR for?
We realized that enzymes that do this work, that take fragments of DNA and insert them into specific places can also be used to cut out specific pieces. It has become a huge tool in genetic engineering.
What is specialized transduction?
When a phage particle transfers specific genes from one bacterial cell to another
When are bacteriocins usually expressed?
When cells get into a high concentration, causes danger for population crash
When does transduction happen?
When some bacterial DNA from infected bacterium goes along for the ride
What is cytotoxin?
imbedding in the outer membrane and they can inhibit cell protein synthesis and cause problems with the hosts calcium efflux pumps
Transposed plasmids can be where in the chromosome?
in or out
What are extracellular virulence factors?
virulence factors made inside the cell that do their work on the outside
What are five categories of virulence factors?
1. Those that will enhance a microbes ability to colonize their host 2. Immunoevasion 3. Immunosuppression 4. Allow the microbe to get nutrients from the host 5. For pathogens that have to live inside of cells: factors that facilitate movement into and out of their host
A transposon differs from a transposable element based on the presence of which of the following? A transposon contains genes or sequences other than those needed for transposition, whereas a transposable element contains only the sequence and genes needed for transposition A transposon has insertion sequences and a transposable element does not A transposon encodes transposase and a transposable element does not A transposon contains an origin of replication and a transposable element does not
A transposon contains genes or sequences other than those needed for transposition, whereas a transposable element contains only the sequence and genes needed for transposition
What are two things competence factors can do?
Added to cultures that aren't expressing the DNA and you can make non-competent bacteria out of a competent bacterium
In a culture containing both F- and F+ cells, which of the following will occur if we wait long enough? No conjugation will occur The cells will all become genetically identical All F- will become F+ cells All F+ cells will become F- cells
All F- will become F+ cells
Which of the following describes a plasmid? Extrachromosomal DNA Circular Double stranded Self replicating All of these choices
All of these choices
Which of the following is a method of lateral gene transfer? Conjugation Transformation Transduction All of these choices None of these choices
All of these choices
What is the affect of high frequency recombination?
An initiating segment of a plasmid and a linear sequence of bacterial DNA that follows the initiating segment are transferred
What do H antigens do?
Assists cell in adhering to their hosts and can prevent phagocytic binding
What is the single stranded DNA vulnerable to?
Attack by nucleases and can only enter the cell if the nucleases on the cell surface have somehow been inactivated
What is plasmid displacement?
Bacteria that eject their own plasmids or digest their own plasmids
Where can you find virulence factors?
Bacterial chromosome or in a virulence plasmid, or both
What is transduction affected by?
Bacteriophage
Why would phage therapy be preferential compared to the use of antibiotics? Bacteriophages will attack all bacteria in the host versus attacking only specific bacteria like antibiotics. Bacteriophages attack only targeted bacteria leaving potentially beneficial bacteria in the host unharmed. Bacteriophages do not replicate like other viruses so they can not infect host cells. Antibiotics can kill bacteria but bacteriophages do not. Bacteriophages can kill bacteria but antibiotics do not.
Bacteriophages attack only targeted bacteria leaving potentially beneficial bacteria in the host unharmed.
How can you induce a competence factor in transformation?
By heating them or exposing them to cold or a strong electric field
How can you make competent bacteria out of non-competent?
By running a charge through it that pokes holes and inserts foreign DNA
What is a genetic engineering tool founded by Fransisco Mojica?
CRIPR - CAS 9
What does Cas stand for?
CRISPR-associated
What are virulence plamsids?
Carries virulence factors on plasmids; cause disease signs and symptoms i.e. shigella flex nuri = causes dysentery
What are Tumor inducing plasmids?
Cause tumor formation on plants i.e. agrobacterium
Which of the following statements is true? High frequency recombination depends on a cell having multiple F plasmids. Promiscuous plasmids can only be transferred between the same species. Cells containing an F´ plasmid have multiple copies of some genes. An F pilus is needed for bacterial transformation.
Cells containing an F´ plasmid have multiple copies of some genes.
What is released into a medium during transformation?
Competence factor
A transgenic organism: contains DNA from two different species of organism contains a plasmid is resistant to viral infection contains DNA which allows it transfer plasmids from its cells to other cells
Contains DNA from two different species of organism
Without restriction endonucleases, it would be impossible to _____. insert plasmids into bacteria bring about muations in bacteria replicate DNA in a recombinant cell cut the DNA of plasmids
Cut the DNA of plasmids
What can bacterocins do?
Destroy DNA Interfere with ribosomes which messes up protein synthesis Inhibit active transport menaing you are starving cells of needed nutrients Increase/decrease iron permeability (impair the cells ability to change its charge potential which is important for making ATP)
What do enterotoxins cause?
Diarrhea
How does a temperate phage differ from a virulent?
Does not cause disruptive infection
A bacterium that is transformed: cannot form a conjugation pilus has acquired naked DNA from the environment will probably die within 48 hours if injected, it always will result in the death of a mouse
Has acquired naked DNA from the environment
How did Moijca discover CRISPR
He was looking at genomes of certain bacteria and he found areas that DNA sequences read the same backwards and forwards, that were repeated and short, regularly interspaces, and not found all over the genome just in clusters
When an F plasmid is incorporated into the chromosome of an F- cell, the cell becomes a/an: F+ cell Hfr cell F- cell Hfr cell and F- cell None of these choices
Hfr Cell
Transformation is a response to what in a cells growth cycle?
High cell density and depletion of nutrients (cell undergoes stress)
What do the T-Plasmids do?
Horizontally transfers to the plant and randomly inserts into the plants chromosomes, it breaks the programmed cell death cycle which is why you get galls because the cells keep reproducing
Some viruses have a lipid bilayer, also known as the viral envelope. The viral envelope is most likely to come from the following source: host cell plasma membrane host membrane bound organelles host nucleus another virus
Host cell plasma membrane
What is a virulent phage capable of?
Infection and eventually destruction and death of a bacterial cell
What happens when a cell in the lysogenic cycle becomes active?
It goes into the lytic cycle
What is important about the discovery of MRSA during transduction?
It shows that some cells gain abilities they didn't originally have (lysogenic conversion) Some bacteriophages bring counter measures for other ones It will bring tools to the ell that it doesn't allow other phages to invade the same cell Space in a virus is limited so they don't use much DNA
What was found about CRIPR in 2007?
It was recognized to be a bacterial immune system based in nucleic acids
Who discovered conjugation?
Joshua Lederberg
What does conjugation transfer in relation to transformation and transduction?
Larger quantities of DNA (occasionally whole chromosomes)
When does generalized transduction occur?
Later in lytic cycle
What happens in transformation?
Less than 1% of cells DNA transferred Requires competence factor. It changes certain characteristics of an organism depending on which genes are transferred
Which of the following is not true? All viruses require a host cell in which to replicate Many viruses contain both DNA and RNA Certain viruses can cause cancer Animals, plants, and bacteria can all be infected by viruses
Many viruses contain both DNA and RNA
What is a type of transposition?
Mitosis
Do transposons replicate on their own?
No
What is transferred during specialized transduction?
Only genes near the prophage are transferred to another bacterium
How many strands enter a cell during transformation?
Only one
What cycle does specialized transduction occur in?
Only the lytic cycle
How does a temperate phage reproduce?
Phage DNA is incorporated into a bacterium's DNA and is replicated with it every time the cell divides
What happens rarely in specialized transduction?
Phage contains one or more bacterial genes that were adjacent to the phage DNA when it was part of the bacterial chromosome
What happens during specialized transduction?
Phage inserts at a specific location when they integrate with a chromosome, genes of the phage form a loop and are exsised from the bacterial chromosome in order to manufacture new phage componenets
Recombination occurs during the process of transformation only when Double stranded DNA is taken up by a recipient cell Single stranded DNA is taken up by a recipient cell Double stranded DNA is integrated into the recipient cell chromosome Single stranded DNA is integrated into the recipient cell chromosome None of these choices
Single stranded DNA is integrated into the recipient cell chromosome
What is a transposable element?
Smallest bit of genetic information that can-do transposition
Transduction is highly ___________?
Species specific
What bacterium did danisco use to immunize their yogurt?
Streptococcus thermophiles
Why is avian flu a concern for public health officials if the virus is entirely avian in nature? Swapping of gene segments may occur between human and avian influenza strains and may produce mutants that are easily passed between humans thereby leading to an uncontrolled pandemic. Avian flu may be passed from waterfowl to chickens thereby infecting worldwide food stocks. Swapping of gene segments may occur between human and avian influenza strains and may produce mutants that are easily passed between waterfowl leading to an uncontrolled pandemic among wild birds. All of these choices. None of these choices.
Swapping of gene segments may occur between human and avian influenza strains and may produce mutants that are easily passed between humans thereby leading to an uncontrolled pandemic.
What do agrobacterium carry?
T-plasmid or Ti-Plasmid
Competence refers to a bacterium's ability to _____. synthesize a protein from another species gene that has been engineered undergo conjunction with an F+ cell take up DNA fragments be infected by a phage
Take up DNA fragments
Which type of phage would be best for recombination via the process of transduction? Lytic Temperate Zoonotic Specialized None of these choices
Temperate
What is affected in conjugation?
The plasmid
How do archaea undergo conjugation?
They are induced if you expose them to UV. They will sprout fibrae and pili and start undergoing conjugation
In specialized transduction the bacterial genes transduced tend to be: those genes in greatest use by the bacteria those genes that are currently not being transcribed those genes that are located close to the site of the prophage insertion those genes that are small enough to fit in the viral head
Those genes that are located close to the site of the prophage insertion
What two things is conjugation used for?
To swap genetic diversity and to decentralize information that is useful for survival
Where can transposition move information?
To/from a plasmid To/from another plasmid To/from the chromosome To/from another place in the chromosome
A ________ is a genetic sequence able to move from one location in a chromosome to another. Plasmid F factor Transposon R factor
Transposon
Which of the following represents the correct order of steps in a typical virus replication cycle? maturation --> adsorption --> penetration --> release --> synthesis adsorption --> penetration --> release --> maturation --> synthesis adsorption --> penetration --> synthesis --> maturation --> release adsorption --> penetration --> maturation --> synthesis --> release
adsorption --> penetration --> synthesis --> maturation --> release
What happens generalized transduction?
as phage directs synthesis and assembly of new phage particles, it packages DNA by the headful allowing bacterial DNA fragment occasionally to be incorporated into a phage particle.
What is O Antigen?
binding target that can inhibit phagocyte killing: found in syphilis infection
What is virulence?
capacity of an organism to cause disease
what is enterococcus vocalese solicitation mechanism?
cells that dont have virulence plasmids make small proteins that they expel out of the cell into the environment. If there is another bacteria around that has the virulence plasmids they will detect the protein and will initiate conjugation and give plasmids to the one that was sending the signal. When they are recieved the signals stop
What is the capsule layer?
composed of glycoproteins, glycolipids, and polysaccharides which can inhibit phagocyte binding and antibody binding sites
What does conjugation require?
contact between donor and recipient cells
What do endonucleases do?
cut double stranded DNA into units of 7,000 to 10,000 nucleotides
What does a fertility plasmid contain?
everything needed to transfer itself to other bacteria
What are agrobacterium?
genus of bacteria that does horizontal gene transfer with plants
What do flagella do?
help bacteria move from site to site through their host. They also contain H antigens
What is RecA?
multifunction DNA repair enzyme found in every bacterial species that it has been looked for in and Archea
What is lipopolysaccharide?
outer membrane of a gram negative cell: antigen that can create fever, and systemic shock
What is lysogeny?
persistence of a prophage without replication and destruction of the bacterial cell, cells containing a prophage are said to be lysogenic
What is a prophage?
phage DNA that is incorporated into the hosts bacterium's DNA at a specific place
What are siderophores?
proteins secreted by pathogens that have a strong affinity for iron
What is an antiphagocytic protein?
proteins that dont cover over binding sites, they actively break phagocyte bonding and prevent it from bonding
What are bacteriocins?
proteins that inhibit the growth of conspecific bacteria
What do transposons imply?
that its has genes to move and some other information comes with it
What is conjugation?
transfer of DNA between bacteria using a pilus
What is transduction?
transfer of DNA from one bacterium to another by a bacteriophage
What are type I fimbre?
type of pili that contains adhesion that enhance the stickiness of a bacterium
What do you use catabolic enzymes for?
use new nutrients that you couldnt use before
