Viruses And Bacteria Flashcards
What is the outer coat of protein called on a viral structure?
Capsid
What are the two possible replication cycles that a virus can enter?
The Lytic cycle and the Lysogenic cyle
What is the lytic cycle/
Once inside, the host cell’s DNA is destroyed and the viral genes take over the host cell’s machinery to produce more viruses
The host cell bursts open, killing it in the process, and the viruses are free to infect other cells.
What is the lysogenic cycle?
The first two steps (attachment and DNA injection) occur just as they do for the lytic cycle.
once the phage DNA is inside the cell, it recombines with a particular region of the bacterial chromosome. This causes the phage DNA to be integrated into the chromosome.
The integrated phage DNA, called a prophage, is not active: its genes aren’t expressed, and it doesn’t drive production of new phages. However, each time a host cell divides, the prophage is copied along with the host DNA, getting a free ride.
How does the lysogenic cycle turn into the lytic cycle?
Under the right conditions, the prophage can become active and come back out of the bacterial chromosome, triggering the remaining steps of the lytic cycle
What are retroviruses?
Uses an enzyme, reverse transcriptase, to produce viral DNA from it’s viral RNA.
The viral DNA, now a provirus, is then integrated into the host cell’s DNA and replicates along with the host cell’s DNA
What are the few linear DNA bacteria?
Borrelia, Streptomyces, and Agrobacteria
What are polyribosomes?
Simultaneous translation of a transcript (even while that transcript is still being made).
Specific to prokaryotes only
What is polycistronic mRNA
In bacteria, related genes are often found in a cluster on the chromosome so they can be transcribed as a single unit for efficiency
