H: Growth in a Natural Environment

Question 1

What percentage of microbes have been culture

Answer 1

1%

Question 2

Why is it complicated

Answer 2

not a pure culture

Question 3

in nature bacteria naturally aggregates with other bacteria to form ___

Answer 3

biofilms

Question 4

What are biofilms

Answer 4

composed of organized regions of bacterial cells embedded in an exoploymeric substance (EPS) formed on solid liquid interfaces

Question 5

What happens as biofilms mature

Answer 5

develop channels to permit the exchange of nutrients and waste

Question 6

Benefits of biofilms (4)

Answer 6

prevent bacteria from being washed away, provide protection, facilitates food web, bacteria able to communicate w/in pop

Question 7

How do biofilms facilitate food webs, give example

Answer 7

allows diff species to interact w/each other. one will use antoher’s waste as source of nrg

Question 8

What do biofilms provide portection from

Answer 8

UV light and chemicals

Question 9

Give examples of biofilms (5)

Answer 9

corroded/clogged pipes, used in waste water treatment to speed up process, on surface of food can cause food-borne illness, dental biofilms cause plaque, medical devices like artificial joints or catheters (protected from antibiotics)

Question 10

Describe biofilm formation

Answer 10

free living cells adhere to a surface using fimbriae. secretion of polysaccharides help adhere them. flagellated bacteria stop synthesizing flagella and become non-motile. various pop can become part of 1 biofilm. EPS exo polymeric substance is porduced, biofilm matures. single cells released into water, can form biofilm on another surface