Biofilms

Question 1

The (blank) ensures (blank) by constantly adding and removing equal amounts of (blank).

Answer 1

chemostat, logarithmic growth, culture medium

Question 2

What allows growth and growth conditions to be highly controlled?

Answer 2

chemostat, which allows detailed study of microbes in natural settings

Question 3

Bacteria are communal creatures true or false?

Answer 3

true

Question 4

In nature, prokaryotes do not grow as single unicellular entities, true or false?

Answer 4

true

Question 5

Most prefer to grow in communities that stick together on organic or inorganic surfaces, true or false?

Answer 5

true, this forms structures called biofilms

Question 6

Biofilms cannot form on a range of surfaces true or false?

Answer 6

false

Question 7

Complex and elaborate assemblages of bacterial micro colonies attached to surfaces and surrounded in a porous, sticky adhesive EPS secreted by microbial cells.

Answer 7

biofilm

Question 8

EPS

Answer 8

extracellular polysaccharide matrix

Question 9

How are biofilms formed?

Answer 9

there are 5 steps

Question 10

Step 1 of biofilm formation: (draw)

Answer 10

reversible attachment of single unicellular bacteria

Question 11

Step 2 of biofilm formation: (draw)

Answer 11

formation of micro colonies

Question 12

Step 3 of biofilm formation: (draw)

Answer 12

EPS secretion

Question 13

Step 4 of biofilm formation: (draw)

Answer 13

biofilm maturation

Question 14

Step 5 of biofilm formation: (draw)

Answer 14

dissolution and dispersal (revert to planktonic state)

Question 15

Part 1 of the biofilm life cycle.

Answer 15

form when/where nutrients are plentiful (bacteria attach themselves to surfaces via their cell envelope)

Question 16

Part 2 of the biofilm life cycle.

Answer 16

once nutrients become scarce, individuals detach themselves from the community to forage for new nutrients

Question 17

Biofilms in nature can take many different forma and serve different functions for different species, true or false?

Answer 17

true

Question 18

Single species biofilms=

Answer 18

pathogenic bacteria

Question 19

Formation of biofilms cannot be cued by different environmental signals in different species, true or false?

Answer 19

false

Question 20

Biofilm formation is regulated by what?

Answer 20

quorum-sensing

Question 21

the processes of assessing bacterial density in the neighbourhood

Answer 21

quorum-sensing

Question 22

What is quorum-sensing?

Answer 22

involves signalling/communication molecules or autoinducers that are secreted into the surrounding environment

Question 23

Extracellular concentration of inducer concentration increases with increase in cell population density, true or false?

Answer 23

true

Question 24

What do autoinducers do?

Answer 24

freely diffuse in and out of bacterial cells and bind to a cytoplasmic receptor protein

Question 25

At a certain (blank), the transcription regulator is activated and binds to DNA activating (blank) regulated genes.

Answer 25

inducer concentration, quorum-sensing

Question 26

Different microenvironments develop in different layers of the biofilm, true or false?

Answer 26

true

Question 27

What is the difference in layers based on?

Answer 27

gradients of oxygen concentration, nutrients availability, by-products, etc

Question 28

What are some examples of bacteria exhibiting different physiological states?

Answer 28

growth rates, stress response, metabolic activity

Question 29

What are some pros of biofilms?

Answer 29

allow microbes to work together efficiently, normal microbiota biofilms of plants and animals are essential

Question 30

What are some cons of biofilms?

Answer 30

damage equipment and infrastructure, colonize abiotic surface put into body, biofilms of pathogenic bacteria are a huge problem in medicine, highly resistant to antimicrobials

Question 31

Bacteria faced with environmental stress do not undergo complex molecular reprogramming that includes changes in cell structure, true or false?

Answer 31

false

Question 32

Can some prokaryotes undergo cell differentiation?

Answer 32

yes

Question 33

(blank) differentiates into specialized cells called (blank).

Answer 33

anabaena, heterocysts

Question 34

What is an anabaena?

Answer 34

specialized structure that houses the nitrogen fixing enzyme

Question 35

What is a heterocyst?

Answer 35

a molecule that contains an oxygen-binding complex

Question 36

Actinomycete bacteria form filamentous mycelia and aerial sporangia, true or false?

Answer 36

true

Question 37

As nutrients decline aerial hyphae divide into arthospores that are resistant to drying, true or false?

Answer 37

true

Question 38

Some species when starved trigger an elaborate process to produce endospores, true or false?

Answer 38

true

Question 39

What are endospores?

Answer 39

dormant structures containing highly complex cell walls that are resistant to killing by dry heat