Are microorganisms introduced to closed biological systems from the external world also a bacteria can be either benign or pathogenic.

Pathogenic bacteria can enter a closed biological system and cause disease such as Cholera, which is induced by waterborne microbe that infects the human intestine.

Can be introduced into a closed ecosystem as well and have mutualistic benefits for both the microbe and the host.

also known as bacterial flora, which is defined as bacteria that naturally reside in a closed system.

Disease can occur when microbes included in normal bacteria flora enter a sterile area of the body such as the brain or muscle. This is considered an endogenous infection (True/False)

A relation between two organisms in which at least one organisms is dependent on the other, one of the organism's benefits, and the other is unaffected. Many of the microorganisms that make up our normal microbiota are commensals.

inhabit the surface of the eye

inhabit the ear and external genitals

These bacteria live on secretions and sloughed-off cells and they bring no apparent benefit or harm to the host.

Is a type of symbiosis that benefits both organism.

the large intestine contains bacteria, such as E. coli that synthesize vitamin K and some B vitamins. These vitamins are absorbed into the bloodstream and distributed for use by cells. In exchange, the large intestine provides nutrients used by the bacteria, resulting in their survival

What bacteria found in intestines

E. coli synthesize what type of vitamins

One organism benefits by deriving nutrients at the expense of the other

live in the human intestinal tract in numbers approaching 1 billion per gram of feces. These are nonmotile and do not form endospores.

Infections often result from puncture wounds or surgery and are a frequent cause of peritonitis.

an inflammation resulting from a perforated bowel.

derived from the organism’s ability to form propionic acid. Some species are important in the fermentation of Swiss cheese.

Propionibacterium has the ability to form

are bacteria that are commonly found on human skin and implicated as the primary bacterial cause of acne.

long and slender, with pointed rather than blunt ends.

In humans, they’re found most often in the gingival crevice of the gums and may be responsible for some dental abscesses