I hope this helps! (i just googled it)
A bactericidal antibiotic, such as penicillin, kills the bacteria. These drugs usually interfere with either the formation of the bacterial cell wall or its cell contents. A bacteriostatic stops bacteria from multiplying.
The heart is an organ (rather than a tissue) because it has an important (and complex) function. Tissues don't have nearly as many things in it as the heart does.
Hope this helps! :)