what is a virus
genetic informtion (DNA or RNA) wrapped in a protein coat. many are harmless, some are deadly
types of prokaryote viruses (bacteriophages)
virulent phages and temperate phages (only affect bacteria)
virulent phages
preform the lytic cycle in which they attack to the bacteria and insert their viral DNA to be sequenced by the cell until it lyces
temperate phages
goes through the lysogenic cycle in which it inserts it genome into the host. when the host duplicates, so does it. it waits in the host until it senses danger and tries to escape via the lytic cycle
eukaryote viruses
DNA viruses, RNA viruses and RNA Retroviruses. they affect us, could be single or double stranded and have a lipid layer
DNA viruses
goes through lysogenic cycle, doesnt mutate much because od DNA proofreading system in eukaryotes
examples: herpes, smallpox, chickenpox
RNA viruses
preform lytic cycle, mutate frequently because there is no proofreading
examples: common cold, flu, covid-19
RNA retroviruses
converts their RNA into DNA using Reverse Transcriptase to embed their DNA into ours
example: HIV
transposons
genes that copy and paste themselves to other areas of the genome
how to viruses form
antigenic shift and antigenic drift
antigenic shift
mixing of genes from different viruses(fast) (bacterial transfer)
antigenic drift
accumulation of mutations (slow)