prokaryotes Flashcards
tree of life
bacteria, archaea, then eucarya branched off of archaea
prokaryotes lack membrane bound nucleus and organelles but have a
cell wall
cell wall contains
peptidoglycan
function of cell wall
maintains shape, provides protection, prevents osmotic bursting
2 types of cell walls
gram negative: thin peptidoglycan, lipopolysaccharide (endotoxin) and bilayered membrane, red
gram positive: thick peptidoglycan, single cell (plasma) membrane, purple
cell membrane/ plasma membrane
infolds for respiration/ photosynthesis
cell membrane function
selectively permeable; regulates movement in/out of cell
synthesis of cell wall components
assists w DNA replication
secretes proteins
contains flagella
what is cell membrane composed of
phospholipid bilayer, carbohydrates and proteins
capsule
coating of molecules external to the cell wall, made of sugars and/or proteins
capsule function
adhesion to substrate, cohesion, biofilms, protection against host immune system, camouflage from WBCs
centre of cell membrane is ____ and outer is ____
hydrophobic, hydrophilic
pili and fimbriae
when they are short an abundant the function is adhesion
when they are long and sparse the function is conjugation (joins one bacterium to another)
flagellum
allow bacteria to move, can rotate clockwise or anticlockwise, can be outside or inside the cell and when cell flexes moves in corkscrew motion
nucleoid
bacterial chromosome, single ring of DNA (haploid)
what exists in the cytoplasm
Ribosomal DNA
DNA on plasmids
-small circles of DNA, not essential for survival but advantageous in stressful conditions
bacillus shape
rods
coccus shape
balls