Chapter 15.2 Flashcards
contains either DNA or RNA
viral genome
called the capsid; some have spikes that aid in attaching/entering the host cell
protein coat
composed only of a nucleocapsid, a capsid with enclosed genome
naked virus
viruses surrounded by an envelope
enveloped viruses
a completely assembled, infectious virus outside its host cell
virion
viruses with a rod or filament shape
helical
viruses with a capsid that has 20 triangular sides
isocahedral
other viruses that are not helical or isocahedral are considered to have what type of symmetry
complex
retroviruses are replicated indirectly through a DNA intermediate using a what
reverse transcriptase enzyme
use reverse transcriptase to transcribe their RNA to DNA
retroviruses
what are the five steps of viral replication
- attachment
- entry
- biosynthesis
- assembly
- release
the virion binds to the host cell using surface proteins that bind to the specific protein receptors on the host cell surface
attachment
the viral nucleic acid and sometimes the whole nucleocapsid gains access to the cell cytoplasm. the freed nucleic acid is transported to the site at which it will be expressed and replicated
entry
the viral nucleic acid is replicated, and the viral proteins, including capsid and tail fiber/spike proteins are made
biosynthesis
capsid proteins and viral nucleic acid are assembled into nucleocapsids. if the virus is enveloped, the envelope may be acquired as the nucleocapsid buds from a cytoplasmic membrane
assembly
