concept 19.1: a virus consists of a nucleic acid surrounded by a protein coat

is a virus a cell

no

what is a virus

a very small infectious particle that consists of a nucleic acid enclosed in a protein coat and sometimes a membranous envelope

which is simpler, a virus or a prokaryotic cell

a virus

what are viruses incapable of carrying out on their own

they cannot reproduce or carry out metabolism outside of a host cell

what are viruses beleived to have evolved from

they are beleived to be evolved as bits of cellular nucleic acid

what are plasmids and transposons

mobile genetic elemnts

what is tobacco mosaic disease

stunts the growth of tobacco plants and gives their leaves a mosaic coloration

what was the original hypothesis of what caused tobacco mosaic disease

very small bacteria

adolf mayer

discovered that he could transmit a disease by rubbing the sap extracted from one diseased leaf to a healthy plant

dimitri ivanowsky

he passed infected tobacco mosaic sap through a filter that was meant to filter out bacteria, and discovered that the filtered sap was still able to cause the disease, and reasoned that the bacteria were either very very small or they produced toxins that were very small

martinus beijernick

discovered that the infectious agent in the tobacco mosaic plant sap was able to reproduce only within the host that is infected and reasoned that the agent was smaller and simpler than bacteria and was then credited with the discovery of bacteria

wendell stanly

confirmed the hypothesis of martinus beijernick by crystalizing the infectious particle

what make up a virus

nucleic acid, a capsid (protein coat surrounding the viral genome, and sometimes a membranous envelope, and will consist of either double or single stranded DNA or double or single stranded RNA

where are some viral evelopes found on bacteria found

on influenza and many other viruses found in animals

bacteria phases aka phages

viruses that infect bacteria, and have the most complex capsids found among viruses

how does a phage infect bacteria

a protein tail piece attaches the phage to the host and injects the phage DNA inside