Biology 1202B Lecture Notes - Lecture 2: Retrovirus, Lysozyme, Motility
15 Jun 2016
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Document Summary
Infected 500m people: 1/3 of world population, killed 20-50m. 3-5 % of world population: one of the deadliest natural disasters in human history. Small infectious agents which replicate inside the living cells of other organisms: dna or rna genomes, protein coat surrounding, can infect animals, plants, bacteria and archaea. Protein coat repeating protein subunits: virus genome is small. Coat may be surrounded by membrane from host cell: acquired as th virus pass through the host cell membrane, although it may have a membrane not a cell, membrane contains host and viral proteins. Much of what we know about viruses comes from the study of bacteriophage: e coli phages. Virulent bacteriophages: kill host cell every infection cycle. Temperate bacteriophages: enter inactive phase, passed on to daughter cells. Phage is not motile: must randomly collide with appropriate host cell. Phage enzyme lysozyme: digests hole in bacterial cell wall. Protein remains outside: only dna enters. Phage uses host cell transcription and translation machinery.
