LQB292 Lecture 5: Viruses
7 Nov 2018
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Lqb292 principles of infection and immunity viruses. Humans, animals, plants, bacteria, fungi, algae, protozoa. Characteristics of a virus: viruses come in many shapes and sizes. The viral genome (nucleic acid) is protected by a capsid. Capsid composed of many subunits called capsomers: the capsomers are protein, often a single type of protein, sometime the capsids is made of 2-4 different proteins assembled. Rule 2: the viral genome is rna or dna: rna viruses are the only organisms to use rna as genetic material. Rule 3: the nucleocapsid is icosahedral or helical: helical rod shaped in appearance. Helical symmetry, capsomers are arranged in helical pattern around a central core. Helical nucleocapsids tend to be rod-shaped rather than spherical. Rule 4: they are either enveloped or unenveloped viruses. The nucleocapsid can either have no envelop or be enveloped. The envelope is lipid from the host cell membrane: unenveloped virus common cold, human papillomavirus. Enveloped virus hb, hepatitis c, measles, influenza.
