lab 9 Flashcards
(23 cards)
What is the diameter of viruses?
between 10 and 300nm
What is a virus?
small infectious agent that replicates only inside living cells of other organisms. it infects animals, plants, microorganisms including bacteria
what is a viron ?
free viral particles (outside the cell or in the process of infecting a cell).
what is genetic material?
DNA or RNA
What is capsid?
protein coat
what is envelope of lipids?
surrounding the capsid
what are bacteriophages?
viruses that infect bacteria
what is procapsid?
capsid in precursor form
What is a concatomer?
a long continuous DNA molecule that contains multiple copies of the same DNA sequences linked in series
what happens if DNA is too large ? what modifys it?
it wont fit into the procapsid. an enzyme cuts the DNA.
what is Lytic virus P1?
bacteriophage dsDNA that infects E. coli and other bacteria
what is lysogenic cycle?
the phage genome exists as a plasmid in the bacterium
What is the first stage of the lytic cycle?
Attachment: phage attaches to host cell
what is the second stage of the cycle ?
Penetration: phage penetrates host cell and injects its DNA
what is the third stage?
biosynthesis: phage DNA directs synthesis of viral components by the host cell.
the fourth stage?
maturation: assembly of phage particles called virions.
the fifth stage ?
phage lysozyme breaks cell wall due high number of virions produced.
what is a prophage?
bacteriophage genome inserted and integrated into the circular bacterial DNA chromosome or existing as a plasmid
Rolling circle replication
Process of unidirectional nucleic acid replication that can rapidly synthesize multiple copies of circular molecules of DNA.
What is a capsid ? (protein coat)
protection of nucleic acid from destruction by DNAses
Nucleic acid core
phage genome carrying genetic information necessary for replication of new phage particles.
Spiral protein sheath
retracts so that nucleic acid can pass from capsid into host cell’s cytoplasm
End plate and tail fibers-
attachment of phage to specific receptor sites on a susceptible host’s cell wall.
