Bacterial Structure and Physiology

opportunistic pathogen

microorganism that doesn’t typically cause disease in a healthy individual, but can become harmful when in a certain location or when a person has a compromised immune system

cocci

spherical shaped bacteria

bacilli

rod shaped bacteria

spirillum (spirochaete)

spiral shaped bacteria

nucleoid region

contains chromosomal DNA (all bacteria have)

plasmids

extra pieces of DNA (not all bacteria have this)

ribosomes

make proteins (all bacteria have)

cytosol

fluid component, site of all metabolism (all bacteria have)

plasma membrane

regulates entry and exit of materials (all bacteria have)

cell wall

protection (all bacteria have)

flagella

propeller-like structures used only for motility

axial filaments

found only on spirochetes (G-), used for motility, wrap around cell to give it a corkscrew shape

capsule

tightly attached to cell wall and used for protection, attachment, and sometimes nutrition

slime layer

loosely attached to cell wall and used for attachment and nutrition

fimbriae

multiple hair-like projections involved in adherence

how can pili assist with movement?

give bacteria motility through twitching/gliding movements or through extension and retraction

pili can…

help develop biofilms

do pili help with attachment?

yes

pili can transfer….

genetic material from one bacterial cell to another

virulence

refers to how harmful a pathogen is to the host