Organization of the Bacterial Cell pt.3

Question 1

what antibiotic only works on mycobacteria

Answer 1

ethambutol blocks synthesis of arabinan

Question 2

why do mycobacteria grow super slowly

Answer 2

the waxy envelope is way less permeable to everything including nutrients

Question 3

what is the S-layer / what does it do

Answer 3

is the protein/glycoprotein component of the cell envelope / has large pores to allow a lot of things into the cell

Question 4

what is the S-layer linked to in gram-positive cells / gram negative cells

Answer 4

peptidoglycan / LPS

Question 5

what is a slime layer

Answer 5

a glycocalyx that is loosely associated with the cell wall

Question 6

what is a capsule

Answer 6

a glycocalyx that is a discrete layer outside the cell wall

Question 7

what do capsules and slime layers do

Answer 7

they assist with attachment & adhesion, protect from desiccation, protect from phagocytosis

Question 8

why are capsules required for disease

Answer 8

because they protect the bacterial cell from phagocytosis

Question 9

how do peritrichous flagella move

Answer 9

they bundle together behind the swimming cell (kinda like a ponytail)

Question 10

how do flagella move

Answer 10

in a circular rotation movement - only in a clockwise or counterclockwise fashion

Question 11

how is the energy required for the flagella made

Answer 11

generated though proton motive force

Question 12

what is chemotaxis

Answer 12

is the biased random walk that bacterium do - when spinning counterclockwise the cell is running (towards attractants), clockwise the cell is tumbling and changes direction

Question 13

how do chemoreceptors influence the biased random walk

Answer 13

they trigger the flagellum to go either clockwise or counterclockwise (can sense the attractants)

Question 14

what are pili used for

Answer 14

adherence and twitching mobility

Question 15

how do bacteria grow

Answer 15

have to increase in length/mass before can separate and divide into two identical daughter cells (binary fission)

Question 16

what is the rate of bacterial growth / how do cells have a growth rate that is faster than their replication rate

Answer 16

exponential / in fast growing cells replication can start before termination of the previous round

Question 17

what regulates cell division

Answer 17

DNA replication

Question 18

how does bacteria replication begin

Answer 18

the origin of replication replicates

Question 19

where is the terminator sequence located

Answer 19

in the center of the cell

Question 20

what is the Z-ring / what triggers its formation

Answer 20

the septum that divides the two daughter cells / the replication of the terminator sequence

Question 21

what two things direct synthesis of new peptidoglycan to the division site

Answer 21

transglycosylases and transpeptidases

Question 22

what occurs before a cell may divide / what is used for it

Answer 22

elongation of the cell / through new peptidoglycan being added along the wall

Question 23

what is the difference between MreB and FtsZ

Answer 23

MreB forms around the entire rod of bacterium & FtsZ is only at the division site

Question 24

what is the cause of dispersed zonal growth

Answer 24

MreB forms a spiral around the cell so it new peptidoglycan is added in stripes along the cell

Question 25

how many zones of growth are in a circular cell

Answer 25

one because there is only FtsZ

Question 26

what is polar growth

Answer 26

when new peptidoglycan is only added at one pole

Question 27

what two parts determine the shape of the cell

Answer 27

the cytoskeleton sue to addition of peptidoglycan and the turgor pressure on the cell wall