2.8 Flashcards
membrane bound organelles
eukaryotic cells, concentrate and separate enzymes and reactants in a lesser volume, increasing productivity of chemical reactions
describe prokaryotes
unicellular and small, organized, has a cell wall, small, dna in nucleoid, single ring chromosome, cell division by budding or fission, no membrane bound organelles
what does the prokaryotic cell wall do (3)
maintains shape, protects cell, prevents cell from bursting
what do bacterial cell walls contain
peptidoglycan- polymer composed of modified sugars cross linked by short polypeptides
gram positive bacteria
simple cell walls composed of a thick layer of peptidoglycan
gram negative bacteria
more resistant to drugs, less peptidoglycan and structurally more complex- outer membrane (protects from body’s defenses) that contains lipopolysaccharaides (carbs bonded to lipids- toxic)
capsule
sticky layer of polysaccharide or protein that surrounds cell wall of prokaryote
endospores
cell produces copy of chromosome surrounded by multilayered structure water is removed and metabolism halts (harsh conditions)
how do prokaryotes stick to things
they stick to a substrate or one another by means of hair like appendages called fimbriae (shorter and more numerous than pili)
taxis
directed movement to or from a stimulus (ex flagella)
are flagella similar in different types of organisms
different in bacteria, archae, and eukaryotes
bacterial flagellum
evolved in steps, main parts: motor hook and filament composed of 42 different kinds of proteins
exaptation
process in which structures originally adapted for 1 function take on another
prokaryote organization
prokaryote cells lack complex compartmentalization associated with organelles but some prokaryotes have specialized membranes that perform metabolic functions
prokaryote chromosome and where it is located
prokaryotes typically have 1 circular chromosome and lack a nucleus, chromosome located in nucleoid region of cytoplasm not membrane enclosed