Antibiotics and Bacteria

Gram-negative bacteria
- Thin layer of peptidoglycan
- Outer membrane is composed of endotoxins
- Outer membrane contains porins that allow certain substances to pass
- Periplasm is the space between the plasma and outer membrane
- Gram-negative cells show up as pink in Gram stains
Gram-positive bacteria
- Thick layer of peptidoglycan
- No outer membrane
- No porins
- Gram-positive bacteria show up as purple in Gram stains

Nucleoid: region in the cytoplasm that contains the bacteria’s DNA molecule
- The bacterial chromosomal DNA is supercoiled
Plasmid: Circular and double-stranded DNA molecules
- Plasmids can be transferred and typically contain genetic material for antibiotic resistance
Ribosomes: facilitate bonding of amino acids for protein synthesis
Cell Wall: Rigid wall that prevents lysis
- Peptidoglycan contributes to the rigidity of the cell wall
Capsule (glycocalyx): allows attachment to surfaces and protection
Flagella: Protein appendages that move the bacteria
Pili: Filamentous appendages that allow for attachment
- Involved in conjugation
Endotoxins: LPS molecules