Lecture 39 Viruses Flashcards
Viruses
infectious non-cellular agents
What do viruses no have?
nucleus, organelles, or cytoplasm
True or False: viruses contain only RNA
False! viruses can contain either DNA or RNA (but NEVER both)
Can viruses replicated outside of the host cell?
No!
Do viruses have metabolic processes such as digestion?
No!
Nucleic Acid
either DNA or RNA (single or double stranded); huge variation in genome size; circular and linear
Capside
protein coat that encloses and protect nucleic acid core
What are capsids composed of?
capsomeres (they give proteins their distinctive shape)
Viron
complete virus particle = nucleic acid + capsid + envelope
Naked virus
have nucleic acid core and capsid (nucleocapsid)
Enveloped virus
have nucleocapsid and envelope
Envelope
phospholipid bilayer with proteins that can be used for attachment to host cell; derived from host cell so it is difficult for immune system to detect
What are the spike-like projections of an enveloped virus used for?
used to bind to/attach to receptors on the host cell surface
What are the spike-like projections of an enveloped virus made of?
proteins and/or carbohydrates
What are some examples of larger viruses?
smallpox and measels
What are som examples of smaller viruses?
yellow fever and polio
Morphological types of viruses
1) polyhedral
2) helical
3) complex
Polyhedral shaped virus example
Herpes
Helical shaped virus example
Ebola, rabies
How are complex viruses special?
can recognize specific hosts through their specifically defined tail fibers
How can complex viruses be used by us?
can be helpful against antibiotic resistant bacteria
Components of a complex virus
- capsid head
- sheath
- tail fiber
- pin
- baseplate
What do family names of viruses end in?
-viridae
What do genus names of viruses end in?
-virus
