Prokaryotic Cell Exteriors Flashcards
What is a cell wall?`
A complex, semi-rigid structure that surrounds the plasma membrane.
What is the function of the cell wall?
To protect against hypertonic environments.
What is a gram-positive cell wall?
A cell wall encased in a peptidoglycan shell.
Which protein cuts up peptidoglycan?
Lysosome proteins cut up peptidoglycan.
What is a gram-negative cell wall?
A cell wall made from a thin layer of peptidoglycan and a second phospholipid bilayer..
Where are transport proteins found in gram-negative cells?
In both bilayers.
What are LPS molecules?
LPS stands for lipopolysaccharides. They are attached to the outer face of the outer membrane of gram-negative bacteria.
How can you tell the difference between gram-positive and gram-negative under a microscope?
If the cell turns purple it means the bacteria is gram-positive. If it turns pink it is gram negative.
What is on archea cell walls that makes them unique?
Surface proteins and/or psuedopeptidoglycan.
What is the function of surface proteins on archea?
The act like armour and protect against extreme environments.
What are capsules and slime layers made of?
They are a sticky coating of polysaccharides and/or polypeptides.
What is the function of capsules and slime layers?
They protect against phagocytosis and can colonize surfaces to form heterogenous communtities.
What is the difference between capsules and slime layers?
Capsules are more tightly bound and have definite boundaries whereas slime layers are not as tightly bound to the cell.
What are fimbriae?
They are short protein tubes on the outside of prokaryotic cells that help the cells stick to substrates or other cells.
What are sex pili?
Few, long protein tubes that draw cells together prior to DNA transfer from one cell to another.
