Chapter 19 (The Virus) Flashcards
Are viruses cells?
no, they are called “intracellular parasites”
What is a dead cell?
a cell that has no more of a capacity to make energy
What types of cells do viruses infect?
they are able to infect EVERY single type of life form, a virus can infect one type of cell or organism but not others
what macromolecules are viruses made of?
nucleic acids and proteins
What is unique about how viruses survive?
they evolve very fast which is driven by the mistakes in the genetic blueprint that don’t have a mechanism to get fixed
What do viral genomes consist of?
double or single-stranded DNA or RNA and sometimes a viral envelope
What is the capsid?
the capsid is the protein shell that encloses the viral genome
What is the capsid built from?
capsomere proteins
Some viruses also have these that contain capsid
some viruses also have lipid membranes that contain capsid
What is the lipid membrane in some viruses called?
viral envelope
What are the benefits of a lipid membrane in some viruses?
entry/attachment into the healthy cell plasma membrane
What are the viruses that infect bacterial cells?
bacteriophages
What are the two reproductive mechanisms for viruses?
lysogenetic and lytic cycle
What is the lytic cycle?
it destroys the host cell almost immediately
What types of phages use the lytic cycle?
virulent phages, able to spread more
What is the cycle of the lytic cycle?
attachment, injection of DNA, digestion, production, release of progeny viruses
As a defense, what do cells have?
restriction enzymes
What can restriction enzymes do?
they can degrade foreign nucleic acids at a specific part of the sequence
What is the lysogenic cycle?
replicates the genome without destroying the host cell