Lesson 2 - Viruses Flashcards
(25 cards)
meaning envelope
a coat around the outside of a virus derived from lipids in the host cell
meaning capsid
the protein coat of a virus
meaning capsomeres
the repeating protein units that make up the capsid of a virus
meaning Virus Attachment Particles (VAPs)
specific antigens that target proteins in the host cell surface membrane
meaning DNA viruses
viruses composed of DNA as genetic material
meaning RNA viruses
viruses composed of RNA as genetic material
meaning retroviruses
type of RNA virus that control the production of DNA corresponding to the viral RNA genome
meaning reverse transcriptase
an enzyme synthesised in the life cycle of a retrovirus that makes DNA molecules corresponding to the viral RNA genome
meaning non-virulent
a term used to describe a microorganism that is not disease-causing
meaning provirus
the DNA that is inserted into the host cell during the lysogenic pathway of reproduction in viruses
meaning lysogeny
the period when a virus is part of the reproducing cell, but does not affect it adversely
meaning latent
the state of the non-virulent virus within the host cell
meaning virulent
a term used to describe a microorganism that is disease causing
viruses are obligate intracellular parasites. What does this mean
can only exist and reproduce as parasites in the cells of other living organisms, and cause damage and disease
what is a capsid made up of
capsomeres arranged in different ways
what are 2 aspects of a virus having a lipid envelope
- makes it easier for viruses to pass from cell to cell
- makes them vulnerable to substances which dissolve the lipid membrane
how do viruses attach to their host cell
the VAPs target proteins on the host cell surface membrane
how do viruses enter animals
the viruses are either taken into the cell by endocytosis, where they release their genetic material. Or, the viral envelope fuses with the host cell surface, releasing the rest of the virus into the cell membrane
how do viruses enter plant cells
use a vector to pierce the cell wall
what are the 2 different routes of infection
the lysogenic pathway and the lytic pathway
how do positive ss RNA viruses replicate the viral RNA
the single strand of RNA acts as a sense strand, and is used directly as mRNA for translation into proteins at the ribosomes. Proteins include viral structural proteins and RNA polymerase
how do negative ss RNA viruses replicate the viral RNA
the single strand of RNA acts as an antisense strand, So, the RNA needs to be transcribed into a sense strand before being translated at the ribosomes. The proteins include RNA replicase
how do negative retroviruses replicate the virla RNA
