Please enable JavaScript.
Coggle requires JavaScript to display documents.
Prokaryotes (Bacterial Structure: (They have ribosomes and many types of…
Prokaryotes
Bacterial Structure:
-
They have rigid cell wall that can be 1 or 2 layers thick and is made of a protein-carbohydrate compound called peptidoglycan & may include a membrane covering the peptidoglycan.
they may also form granules of stored nutrients to be used if nutrients in the environment are in short supply.
the presence of this membrane allows biologists to group bacteria into 2 categories using a technique call gram stain.
They have no membrane-bound organelles, but they have genetic material in the form of DNA called plasmids.
2) Chemoautotrophs:
-
if hydrogen-rich chemicals are present, bacteria can form all of their own amino acids & proteins.
-
3)Heterotrophs:
they get both their energy & their nutrients from other organisms. most absorb nutrients from dead organisms, but some are parasites or pathogens.
most live in the presense of oxygen, but some can live without it.
Rhizobium is an important heterotrophic bacterium that converts nitrogen in the air into molecules that can be used by other organisms.
Archaea:
they're found in many places, including extreme environments.
-
-
-
Gram - bacteria
it has a thin layer so it doesn't trap the purple dye. so when the pink dye is added, it's absorbed by the cell wand keep in mind that it's the only dye present in gram-negative bacteria, as a result it appears pink after staining.
the outer membrane of gram-negative bacteria makes them more resistant to host defenses and to medicines.
Gram + bacteria:
it involves 2 colors: dark purple is first because it traps for having a very thick layer of peptidoglycan. pink is also absorbed, but it can't be seen bec. the purple dye is darker. so the test appears purple after staining.
-
-
-