Bacteria Flashcards
What do prokaryotes lack?
nucleus and membrane-bound organelles.
Can prokaryotes be found in extreme habitats?
YES
Are prokaryotes autotrophs or heterotrophs?
BOTH
What are the two domains of prokaryotes?
bacteria and archaea
Are prokaryotes larger or smaller than eukaryotes generally?
smaller
Are prokaryotes more simple or more complex when compared to eukaryotes?
more simple
What is the function of a cell wall in bacteria?
shape, protection, prevention from bursting in hypotonic environment.
What is the polymer made of sugars cross-linked by short polypeptides that composes the cell wall?
Peptidoglycan
How do prokaryotes reproduce?
binary fission
What can rapid proliferation of prokaryotes produce?
colonies
What are the three classifications of bacteria based on their shape?
Cocci (spherical) Bacilli (rods) Spirilla (helices, corkscrews)
Why do gram-positive bacteria remain blue even after destain and counterstain? What is the purpose of the iodine?
Their cell walls have a much thicker peptidoglycan layer which allows them to retain more CV, the iodine binds to the CV and helps to trap it in the cell wall.
Who discovered penicillins?
Fleming - inhibit cross-links in peptidoglycan, preventing formation of functional cell wall.
Why do gram-negatives appear pink?
Their thin peptidoglycan walls do not retain the CV dye through the destaining process.
Why are gram-negative more dangerous?
They have out lipopolysaccharide layer that covers thin peptidoglycan layer, may contain endotoxins there.
Know the colors of gram +and gram - at each step of stain, picture provided on other side of card.
