MMI133 Lecture Notes - Lecture 4: Rna Virus, Papillomaviridae, Hepadnaviridae
18 Jun 2018
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Viruses
● Infectious particles that are not living things
● Transmitted from host to host (blood, mucus, food, aerosols, water, fomite/infectious
material,vector carriers)
● Only a minority causes human disease (due to the host range of specificity)
● Can only multiply within a host cell (obligate intracellular)
● Contains DNA or RNA (Never both!)
● Very few enzymes
● No ribosomes or enzymes for metabolising and must depend on the host cell for a source of
protein
Virion - complete infectious viral particle with nucleic acid surrounded by protein coat
● RNA or DNA (single or double stranded) + capsid (protein coat composed of capsomer protein
particles)
● The complete unit is known as a nucleocapsid
● Some have lipid envelope outside of nucleocapsid , which has been derived from host cell
membranes
● Some have glycoproteins or spikes inserted in envelopes or capsid
●
Bacteriophages
● Viruses that infect bacteria that can transfer genes from one bacteria to the other
● Can be used for genetic information (e.g. production of insulin)
● Transfer genes for a production of toxin
Classifying Viruses
● Grouped into families based on RNA or DNA composition and structure
●RNA viruses mutate quickly
(which makes us unable to create a vaccine) due to lack of
proofreading
DNA Viruses
1. Papillomaviridae (HPV) *can be Oncogenic
2. Adenoviridae
3. Hepadnaviridae (Hepatitis)
4. Herpesviridae (HSV)
5. Poxviridae (Poxes, but not Chicken Pox)
6. Parvovirus (B-19)
Document Summary
Infectious particles that are not living things. Transmitted from host to host (blood, mucus, food, aerosols, water, fomite/infectious material,vector carriers) Only a minority causes human disease (due to the host range of specificity) Can only multiply within a host cell (obligate intracellular) No ribosomes or enzymes for metabolising and must depend on the host cell for a source of. Virion - complete infectious viral particle with nucleic acid surrounded by protein coat. Rna or dna (single or double stranded) + capsid (protein coat composed of capsomer protein. The complete unit is known as a nucleocapsid. Some have lipid envelope outside of nucleocapsid , which has been derived from host cell protein particles) membranes. Some have glycoproteins or spikes inserted in envelopes or capsid. Viruses that infect bacteria that can transfer genes from one bacteria to the other. Can be used for genetic information (e. g. production of insulin) Transfer genes for a production of toxin.
