Evo 1. The Diversity Of Life, Chapter 26: Introduction to virusses

The [blank_start]funghus Armillaria osteyae[blank_end] is the largest living organism in the world.

Virusses were accidently discovered by [blank_start]Adolf Mayer[blank_end] in an attempt to find the bacteria or toxins causing the [blank_start]mosaic[blank_end] disease in [blank_start]tabacco[blank_end] plants ([blank_start]1889[blank_end]). Later, [blank_start]Martinus Beijerinck[blank_end] coined the term virus ([blank_start]1935[blank_end]).

Virusses can have:

Viruses are made up of nucleic acid (DNA or RNA) enclosed in a protein coat (the capsid) and sometimes wrapped in a membranous envelope. The individual protein subuntis making up the capsid are called capsomeres. Although diverse in size and shape, viruses have many common structural features. (all micrographs are colorized TEMs)

A virus is an intracellular parasite that uses the equipment and small molecules of its host cell to replicate. In this simplest of viral cycles, the parasite is a DNA virus wth a capsid consisting of a single type of protein. Describe what happens to the virus and the host cell in 1 to 4.

After a (Bacterio)phage leaves a host cel in the last stage of infection, they can either destroy the host cell or leave it intact. The infection cycle of a phage that bursts the host cell is called a [blank_start]lytic cycle[blank_end]. These cells [blank_start]cannot[blank_end] be reused for DNA replication and [blank_start]cannot[blank_end] reproduce normally. Phages that ONLY undergo a [blank_start]lytic[blank_end] cycle are called [blank_start]virulent[blank_end] phages. The infection cycle of a phage that leaves the host cell intact is called a [blank_start]lysogene cycle[blank_end]. Phages that undergo a [blank_start]lysogene[blank_end] cycle are called [blank_start]termporate[blank_end] phages. The host cell DNA and the phage DNA intergratie and form a [blank_start]prophage[blank_end]. These cells [blank_start]can[blank_end] reproduce normally. Some [blank_start]prophages[blank_end] do produce harmfull substances. Both the phage genome and enviromental factors can determine the cycle.

The lytic cycle of phage T4, a virulent phage. Drag and drop the correct order of the lytic cycle.

The lytic and lysogenic cycles of phage *lambda*, a temporate phage. Drag and drop the correct cycle.