2.2 Bacterial Appendages

Question 1

bacteria produce two different types of protein appendages, what are they

Answer 1

pili and fimbriae

Question 2

pili

Answer 2

are long and less numerous on outside of cell

Question 3

fimbriae

Answer 3

are more numerous and shorter

Question 4

the tips of pili and fimbriae are able to do what.

Answer 4

are able to interact with proteins or lipids on the surface of epithelial cells in the gut to help the bacterial cell attach to that host cell

Question 5

capsule

Answer 5

dense, well-defined polysaccharide or protein layer closely surrounding the cell.

Question 6

what functions do capsules serve

Answer 6

protection and can bind to water – may enable cell to resist the process of drying out or losing water

Question 7

capsules can aid in bacterial cell to cell contact, promoting…

Answer 7

biofilm formation

Question 8

flagella –what is it simple

Answer 8

a bacterial appendage that mediates motility. – rotates like a propeller on a motorboat

Question 9

flagella are what shape

Answer 9

helical

Question 10

when bacterial cells invade the human body, the flagellum..

Answer 10

is recognized by the innate immune system and promotes an inflammatory or immune response.

Question 11

pathogens sometimes alter the featueres of flagella – why

Answer 11

the flagella will not be expressed during infections therefore they are able to evade the immune system

Question 12

base of flagellum has a wide section called thre

Answer 12

hook

Question 13

the hook connects the

Answer 13

filament to the flagellar motor in the base

Question 14

flagellar motor

Answer 14

anchored in the cytoplasmic membrane and the cell wall
– consists of a control rod that passes through a series of bushings or rings, – this rotoe and motor are within the basal body

Question 15

basal body

Answer 15

uses protein motive force as the energy source to rotate the flagella.

Question 16

the four flagellar arrangements

Answer 16

monotrichous, amphitrichous, lophotrichous, peritrichous

Question 17

monotrichous

Answer 17

single flagellum protruding from one end of the cell

Question 18

amphitrichous

Answer 18

two flagella, one protruding from each end of the cell

Question 19

lophotrichous

Answer 19

a tuft of flagella all at one end of the cell

Question 20

peritrichous

Answer 20

flagella are found all around the cell

Question 21

flagella mediate what kind of movement

Answer 21

directional

Question 22

when flagella rotate clockwise

Answer 22

called tumbling

Question 23

tumbling - motility

Answer 23

when flagella rotate in a clockwise direction, they are no longer bundled and the cell ceases its forward motion. allows for quick and useful durectional movement.

Question 24

when flagella rotate counter clockwise

Answer 24

running

Question 25

running- motility

Answer 25

in a cell with peritrichous flagella, the flagella bundle when rotated in counter clockwise direction results in what is called a run -- the bacteria are moving in a particular direction -- moving forward

Question 26

bacteria display chemotactic behaviour -- what does this mean

Answer 26

means that they can move toward or away from substances within their immediate environment

Question 27

bacteria move toward

Answer 27

- food and resources - signals provided by other bacteria - sometimes chemicals that are attractive

Question 28

bacteria move away from

Answer 28

- toxic micro environments

Question 29

chemotaxis is mediated by flagella -- describe diagram

Answer 29

first, the flagella rotate counter clockwise, running. then, bacteria sense that are moving AWAy from the attractant in the environment -- it then rotates clockwise in a tumble with no directional movement. after tumble, counter cloockwise rotation is initiated gain, and if bacteria is pointing towards attractant, counter clockwise rotation occurs to extend towards the attractant.

Question 30

some gram positive bacteria produce what

Answer 30

endospores

Question 31

what are endospores' function

Answer 31

is a mechanism for survival in deleterious environments -- like where nutrients are low

Question 32

sporulation and endospore production steps

Answer 32

1. DNA replicates -- then its segregated to opposite ends of the cell 2. membranes form around the DNA 3. forespore forms additional membrane 4. protective cortex forms around the spore 5. protein coat forms around cortex 6. mothjer cell dies, spore remains viable -- it is released

Question 33

what is the spore that is made from endispore productions

Answer 33

a differentiated cell that is highly resistant to heat, cold, chemicals, and even radiation

Question 34

what happens whens pores sense conditions have improved

Answer 34

they will germinate and resume growth

Question 35

there are some gram positive bacteria that produce endospores, and these endospores are present health concerns -- why?

Answer 35

they become really difficult to kill

Question 36

example of gram positive endospores.

Answer 36

clostridium difficile is found on hospital equipment. it causes botulism or food poisoning.