Chapter 20.2 Flashcards
Are viruses considered living(4)?
No, although they have genetic material, they cannot reproduce on their own, they do not carry out metabolic activities, they do not have cytoplasm or organelles, and do not maintain homeostasis
Do viruses grow?
No, they are assembled into their full size
What two structures do all viruses have?
Nucleic acid and a capsid
What is a capsid?
A protein sheath that surrounds the nucleic acid core
What is a envelope and what does it do?
A membrane-like layer that covers the capsid of some viruses, helps the cell gain entry
Can the genetic material of a DNA virus remain seperate?
Yes
How does a DNA virus reproduce?
DNA inserted-> viral DNA-> mRNA-> viral proteins-> baby virus
What are the two ways a RNA virus can reproduce and what are those types of viruses called?
RNA-> viral mRNA-> viral protiens-> baby virus
RNA-> viral DNA through reverse transcriptase-> viral mRNA-> viral proteins-> baby virus
Retroviruses
How do viruses recognize their hosts?
Specific proteins on a host cells surface that match proteins on the capsid of the virus
What is the envelope made of?
Proteins, lipids, and glycoproteins(proteins with attached carbohydrate molecules)
What are viruses that infect bacteria called and what extra structure do they have?
Bacteriophages or phages, tail fibers
What is the function of the tail fibers?
Injection of the viral DNA into the bacteria
What is the lytic cycle?
Genetic material enters the cell, the virus uses the host cell’s organelles, enzymes, and raw materials to replicate the virus’s DNA and to make viral protiens, the cell breaks open to release the new viruses and dies.
What are the viruses formed from the lytic cycle called?
Virulent
What is the lysogenic cycle?
Genetic material enters the cell, when the cell replicates it also replicates the provirus, after time the provirus may leave the host’s DNA and enter a lytic cycle, or, if it does not enter the lytic cycle it may become a permanent part of the host’s genome
