BIOL240 Lecture Notes - Lecture 1: Viral Envelope, Intracellular Parasite, Veterinary Virology
11 Feb 2016
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Document Summary
Viruses are acellular particles that are obligate intracellular parasites; they cannot replicate independently but instead use host cell processes and substrates (like amino acids and nucleotides) to make new virus particles. Viruses usually are much smaller than cells but a few exceptions to this rule have been identified. The genomes of most viruses are much smaller than that of any cellular organism. All viruses encase their genomes within a protective protein shell, or capsid. Together, the genome and capsid comprise the nucleocapsid. Some viruses are enveloped; a lipid membrane surrounds their nucleocapsid. Other viruses are non-enveloped: identify the different types of viral genomes. Viruses as a group display remarkable diversity in their genomes, which can consist of either rna or dna and can be either single-stranded or double-stranded. Furthermore, the genomes can be either circular or linear and can consist of a single nucleic acid molecule or several individual fragments: contrast the capsid structures of helical and icosahedral viruses.
