Bacteriophage lambda can reproduce in two alternative modes of growth.
In the lytic mode, the phage infects a bacterial cell, reproduces many copies of itself, lyses the host cell, and circulates through the environment to infect another host cell
.
Can phages be lytic and lysogenic?
Some phages can only reproduce via a lytic lifecycle, in which they burst and kill their host cells.
Other phages can alternate between a lytic lifecycle and a lysogenic lifecycle, in which they don’t kill the host cell
(and are instead copied along with the host DNA each time the cell divides).
Is lambda a lytic phage?
Lambda strains, mutated at specific sites, are unable to lysogenize cells; instead, they grow and enter the lytic cycle after superinfecting an already lysogenized cell
. The phage particle consists of a head (also known as a capsid), a tail, and tail fibers (see image of virus below).
Which kind of transduction occurs by bacteriophage lambda?
Specialized transduction
is a process where a special set of genes are transferred to another bacterium which takes place by site-specific recombination. The lambda phage has two cos sites which help the phage to ligate. When lambda DNA is introduced in E. coli it gets cyclized due to cos sites.
How is the replication cycle of lambda phage different from that of T4?
How is the replication cycle of lambda phage different from that of T4? The genome of lambda phage can integrate in the bacterial genome and replicate in concert with the bacterial DNA. T4 can not do this but undergoes a replication cycle that results in cell lysis.
What is lytic and lysogenic cycle?
The lytic cycle involves the reproduction of viruses using a host cell to manufacture more viruses; the viruses then burst out of the cell. The lysogenic cycle involves the incorporation of the viral genome into the host cell genome, infecting it from within.
Why is lambda phage called temperate phage?
Bacteriophage λ is a temperate phage, which,
upon infection of Escherichia coli, enters either the lytic or lysogenic replication pathway
. The latter is defined by the integration of the λ prophage within the bacterial host genome, where it is quiescently inherited by daughter cells.
What is the life cycle of lambda phage?
λ phages are commonly used in DNA cloning. They can have either
lytic or lysogenic cycle
, depending on the environment. In the lytic cycle, λ phages replicate rapidly and eventually cause lysis of the host cell. In the lysogenic cycle, the viral DNA circularizes and integrates into the host DNA.
What are lambda phage vectors?
Bacteriophage lambda,
a bacterial virus that infects E. coli
, has been widely used as a cloning vector. As described in Ch. 21, lambda is a well-characterized virus with both lytic and lysogenic alternatives to its life cycle. Although lambda DNA circularizes for replication and insertion into the E.
Can lytic cycle change to the lysogenic cycle?
Lysogens can remain in the lysogenic cycle for many generations but
can switch to the lytic cycle at any time via a process known as induction
. During induction, prophage DNA is excised from the bacterial genome and is transcribed and translated to make coat proteins for the virus and regulate lytic growth.
How are lysogenic phages different from lytic phages?
The lytic cycle involves the reproduction of viruses using a host cell to manufacture more viruses; the viruses then burst out of the cell.
The lysogenic cycle involves the incorporation of the viral genome into the host cell genome, infecting it from within
.
What determines whether or not the lytic cycle or lysogenic cycle is entered?
What determines whether or not the lytic cycle or lysogenic cycle is entered?
If the host cell bursts, it is the lytic cycle
. If the virus inter grates a becomes a chromosome, it can duplicate and be released into the daughter cells, this is the lysogenic cycle.
When a transducing phage interacts with a new host cell?
The DNA from the previous host can recombine with the new host chromosome. When a transducing phage interacts with a new host cell,
Conjugation does not result in the formation of new offspring
. Bacterial conjugation is often referred to as bacterial sex.
What does bacteriophage lambda infect?
Bacteriophage lambda is a virus that infects
E. coli
. The typical infection cycle results in the lysis of the E. coli cell and the release of about 100 progeny phage particles, each capable of infecting another cell.
Which type of phage replication can lead to transduction?
Transduction happens through either the
lytic cycle or the lysogenic cycle
. When bacteriophages (viruses that infect bacteria) that are lytic infect bacterial cells, they harness the replicational, transcriptional, and translation machinery of the host bacterial cell to make new viral particles (virions).
Is T4 phage lytic or lysogenic?
T4 is capable of undergoing only a lytic lifecycle
and not the lysogenic lifecycle. The T4 Phage initiates an E. coli infection by recognizing cell surface receptors of the host with its long tail fibers (LTF).
How is the T2 phage different from the lambda phage quizlet?
How is the T2 phage different from the lambda phage?
The lambda phage is capable of entering the lysogenic cycle, T2 phage are strictly lytic
.
Who determine the sequence of lambda phage?
Explanation: The phage DNA molecule, unlike the bacterial plasmid DNA, exists usually in a linear conformation and DNA is a duplex molecule. 3. Who determined the sequence of Lambda phage? Explanation: The exact sequencing of lambda phage of 49 kb was done with
Sanger sequencing method
in 1982.
What is lytic phage?
Lytic phages
take over the machinery of the cell to make phage components
. They then destroy, or lyse, the cell, releasing new phage particles. Lysogenic phages incorporate their nucleic acid into the chromosome of the host cell and replicate with it as a unit without destroying the cell.
How does the lysogenic cycle differ from the lytic cycle quizlet?
What is the main difference between a lytic and lysogenic cycle? In the lytic cycle, the viral genome does not incorporate into the host genome. In the lysogenic cycle, the viral genome incorporates into the host genome and stays there throughout replication until the lytic cycle is triggered.
How are lytic and lysogenic cycles similar?
Both initiated by the binding of the virus to a host cell receptor molecule
. Both require the cellular machinery of the host cell. Both the lytic and lysogenic cycles have the capacity to produce several viral particles from a single one that infected the host cell.
How do bacteriophages replicate?
During a lytic replication cycle
, a phage attaches to a susceptible host bacterium, introduces its genome into the host cell cytoplasm, and utilizes the ribosomes of the host to manufacture its proteins.
What is the major difference between a lytic phage such as t2 and a temperate phage like lambda?
One key difference between the lytic cycle and the lysogenic cycle is that
the lysogenic cycle does not lyse the host cell straight away
. Phages that replicate only via the lytic cycle are known as virulent phages while phages that replicate using both lytic and lysogenic cycles are known as temperate phages.
How are temperate and virulent the same?
Temperate phages replicate via both lytic and lysogenic cycles. Virulent phages show generalized transduction, and they are capable of killing the host bacterium after each infection cycle
. Temperate viruses show specialized transduction, and they do not kill the host bacterium immediately after the infection.
How many base pairs are there in lambda phage?
Abstract. The sequence of
72 base pairs
of the rightward operator (O-R) of bacteriophage lambda is presented as determined with simple and rapid methods for direct DNA sequencing.
When the DNA of lambda phage gets integrated with the bacterial DNA it is?
Lambda phage exists as a phage but also integrates into the E. coli chromosome at the attB site to form
a prophage
. The integration reaction occurs when integrase makes staggered cuts in the center of the phage attP site and in the center of the bacterial site attB.
