aerobic organism anaerobic organism bacteria bacterial cell structure bacterial disease bacterial outer membrane biofilm cell capsule cell envelope cell membrane cell wall coccobacillus cochineal diaminopimelic acid diplococcus exotoxin facultative anaerobic organism genus glycocalyx gonorrhea gram-negative bacteria gram-positive bacteria gut flora human flora lipophilic bacteria lipopolysaccharide lipoteichoic acid lysogenic cycle meningitis microaerophile microbiology microorganism n-acetylglucosamine n-acetylmuramic acid nanaerobe neisseria obligate anaerobe pathogen pathogenic bacteria peptidoglycan periplasmic space pilus pneumonia sinusitis skin flora slime layer sphere staphylococcus streptococcus teichoic acid toxic shock syndrome urinary tract infection vaginal flora