Why are penicilins often more effective against gram-positive bacteria than gram-negative bacteria?

Because Gram negative bacteria have an extra protective layer of lipopolysaccharide surrounding their cell wall!

Explanation:

Mechanism of action of penicillin is:

Effect on gram negative :

As you can see in the image, the gram negative bacteria has an extra layer of protection on its cell wall by lipopolysaccharide. Penicillin can't reach the cell wall to bind to the D-D Transpeptidase, so it is more effective on gram positive bacteria than gram negative bacteria.

auricle

explanation:

the flaps on the front of the atria are called the auricle.

probably since the potency of the cocaine, not a lot, but i've never done any research on cocaine so i wouldn't know, but i would also guess it would determine on the gap between sniffs or if you did it all at once, so i really don't know.