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Microbiology Part 10 & 11

Terms in this set (37)

What is the morphology of bacteriophage T4?
Complex
Viruses are sensitive to what?
Interferons
In the T4 life cycle, which step involves the production of early messenger RNA molecules and early proteins?
Transcription and translation
Many viruses "steal" ________ from the host cell's cytoplasmic membrane.
Envelopes
What uses the latent life cycle to infect an E. coli host cell?
Bacteriophage lambda
Which step in the bacteriophage T4 life cycle uses bacteriophage lysozyme?
Penetration
What was the first virus observed in the electron microscope?
Tobacco mosaic virus
The bacteriophage lambda DNA inserted into the genome of the host cell is called?
Prophage
An object that has 20 triangular faces, 12 vertices, and 30 edges is called?
Icosahedron
What is the fourth step in the bacteriophage T4 life cycle?
DNA replication and protein synthesis
What is the fifth step in the bacteriophage T4 life cycle?
Assembly and Maturation
What happens in the Assembly and Maturation stage?
Bacteriophage genetic material is inserted into the head; sheath, base plate, tail fibers are assembled; head is placed on sheath
What is the sixth step in the bacteriophage T4 life cycle?
Release
What happens in the Release stage?
Bacteriophage lysozyme is produced to weaken peptidoglycan, water moves in the e. coli cell (hypotonic environment), e. coli lyses and releases progeny bacteriophages
What happens in the DNA replication and protein synthesis stage?
Early bacteriophage proteins copies the bacteriophage genetic material for progeny, bacteriophage genes are transcribed to make late bacteriophage mRNAs, Late bacteriophage mRNAs are translated to make late bacteriophage proteins (head, sheath tail fiber, proteins)
What are the two bacteriophage infection strategies?
Productive infection and latent/lysogenic infection
Describe productive infection
produces progeny bacteriophages immediately, 2 possible outcomes: lysis of host cell (dies) or the release pathway (remains alive and produces progeny continuously)
Describe the latent/lysogenic infection process
the bacteriophage genome inserts into the host cell genome, the bacteriophage genome is silent (no immediate progeny), later the bacteriophage reactivates and the host cell dies
T4 genome
dsDNA, linear, nonsegmented
T4 shape (morphology)
complex
Is T4 Envelope or naked?
Naked
Host of T4
E. coli
Life cycle of T4
Productive (lytic)
Lambda genome
dsDNA, linear --> circular, nonsegmented
Lambda shape (morphology)
complex
Lambda envelope or naked?
naked
Host of lambda
E. coli
Lifecycle of Lambda
Latent/lysogenic
Describe Attachment phase
T4 tail fibers bind to a receptor on the outer membrane or E. coli
Describe Penetration phase
T4 drills a hole thru the outer membrane, release bacteriophage lysozyme (breaks NAG and NAM bonds in peptidoglycan), drills thru cytoplasmic membrane, injects genetic material into E. coli
Define spike proteins
Hemagglutinin (HA) and Neuraminidase(NA), allow virus to enter the host cell, influenza strains are defined by HA and NA
What is a nucleocapsid made up of?
Capsids and nucleic acids
What is a virus outside of a host cell called?
virion
What is the third step of the latent/lysogenic life cycle of lambda?
The bacteriophage lambda genome is converted from linear to circular
What is the fourth step of the latent/lysogenic life cycle of lambda?
"The choice"
What happens if E. coli is healthy?
transcription/translation, DNA replication and protein synthesis, assembly/maturation, release, e. coli lyses and releases progeny
What happens E. coli is not so healthy?
The bacteriophage genetic material inserts itself into the E. coli chromosome, when E. coli divides the prophage is copied, when an E. coli cell is damaged (UV light) the prophage excises (leaves E. coli), and moves on to transcription/translation, DNA replication/protein synthesis, Assembly/Maturation, Release
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