structures always present in bacteria
murein/peptidoglycan cell wall
cell-surface membrane
cytoplasm
circular DNA
70S ribosomes
structures found in SOME bacteria
flagella
capsule
mesosomes (infolding of cell-surface membrane)
plasmids
pili
function of plasmids
the genes they contain can be passed between prokaryotes
function of capsule
protects the bacteria from drying out, protects it from attacks from immune system cells of the host organism
structure of viruses
nucleic acid core
capsid - protein coat
some have a lipid envelope - usually formed from the membrane-phospholipids from the cell they were made in
attachment proteins on the capsid/envelope - these allow the virus to identify and attach to the host cell
viral replication
viruses are parasitic
they use attachment proteins to complementary receptor proteins on the surface of a host cell
they inject their DNA or RNA into the host cell
the ribosomes in the host cell use this nucleic acid to build new viral particles
the host cell bursts open, releasing all of the viral particles
sometimes viral particles leave by budding, when they take a section of the cell-surface phospholipid membrane with them to become their envelope