Viruses

nearly 30% of all worldwide mortality; mostly in developing countries

1) sanitization, 2) vaccination (small pox, totally irradiated), and 3) antibiotics (by Flemming, but obviously don’t work against viruses)

not cells, but obligate intracellular parasites; are very small infectious particles consisting of nucleic acid enclosed in a protein coat and, in some cases, a membranous envelope; genome can consist of DNA or RNA; dissasemble during reproductive cycle

largest viral genome, infects amoebas, 1000 Mb

protein shell that encloses the viral genome; can have various (rod-shaped [helical], or icosahedral) structures; built from capsomeres (protein subunits)

some have membranes derived from the membranes of host cells; they surround capsids; fools host's immune system by allowing virus to remain undetected; also facilitates fusion of hte virus wiht the host cell membrane

1) enzymes, 2) ribosomes, 3) tRNAs, 4) amino acids, 5) ATP, 6) other molecules

broadest variety of RNA genomes is found in viruses that infect animals; retrovirus (class of RNA virues) that use reverse transcriptase to copy RNA genome into DNA

the retrovirus that causes AIDS (acquired immunodeficiency syndrome); contains a capsid with two identical strands of RNA and reverse transcriptase, a glucoprotein outer layer, and a viral envelope

a viral DNA integrated into the host DNA

phage inserted into bacterial genome

a range of antiviral products used to prevent viral replication in infected cells; they work by terminating viral DNA Polymerase; ex: AZT

harmless derivatives of pathogenic microbes that stimulate the immune system to mount defenses against the actual pathogen; ex: Jenner injected the less serious cowpox which prevented the contraction of similar but fatal smallpox

circular RNA molecules that infect plants and disrupt their growth

slow-acting, indestructible infectious proteins that cause brain disease in mammals; propogate by converting normal proteins into the prion version

also simply known as phages, are viruses that infect bacteria; MOST complex capsids found in viruses; have an elongated capsid head; protein tail piece attaches the phage to the host and injects phage DNA inside

phage reproductive cycle that culminates in the dealth of the host cell; virulent phage is one that only reproduces by the lytic cycle

allows replication of the phage genome without destroying the host; the viral DNA molecule is incorperated into host chromosome; temperate phages are phages capable of using both types of reproduction within a bacterium

bacteria's defense against phages, cuts up phage DNA when they recognize it as foreign

the genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings

bacteriophages carry bacterial genes from one host cell to another; example of horizontal gene transfer

genetic material is transfered between two bacterial cells that are temporarily joined by sex pili; result of F (fertility) factor