2.4

Question 1

Outer membrane

Answer 1

only gram negative
the second membrane outside cell wall

Question 2

what does outer membrane consist of

Answer 2

LPS, lipopolysaccharide, and phospholopid

Question 3

outer membrane symmetry

Answer 3

asymmetrical
the outer leaflet is mostly LPS with little phospholipid
the inner leaflet is phospholipids

Question 4

what are the three parts of LPS

Answer 4

lipid A- within memb
core polysaccharide- connecting
o-specific polysaccharide- outer

Question 5

lipid A structure

Answer 5

-hydrophobic tails anchor lipid A in OM, this is the base of LPS
phosphates confer a negative charge

Question 6

what is lipid A also known as?

Answer 6

endotoxin, sensed by immune system and leads to potent immune response causing septic shock

Question 7

o specific polysaccharides also called

Answer 7

o antigen

Question 8

o specific polysaccharides structure

Answer 8

-diverse sugar subunits connected and branched
-repeating combination of sugar

Question 9

o antigen diversity and its importance

Answer 9

can be used to identify specific bacterium as they are highly variable from lineage to lineage

Question 10

what anchors the cell wall to the outer membrane

Answer 10

brauns lipoprotein

Question 11

where are brauns lipoproteins abundant?

Answer 11

gram negative cells

Question 12

how does brauns lipoprotein work>

Answer 12

lipid anchors in OM and the other end is covalently attached to peptidoglycan

Question 13

what are porins

Answer 13

-protein channels in OM that are channels for entrance/ exit of small molecules
-can be specific or non specific

Question 14

what are the functions of the outer membrane

Answer 14

provide mechanical strength to cell using ionic bonds between LPS molecules via divalent metal ions
- important barrier
-antibiotic sensitivity, closes porins for certain molecules
-protects cell wall(ie. from lysozym that chews it)
-enables periplasmic space

Question 15

Periplasm

Answer 15

gram negative bacteria
space between inner/ outer membrane

Question 16

periplasm functions

Answer 16

-buffer b/w environment and cell
-good for detoxification
-protein folding
-high affinity binding protein for
nutrients
-break down macromolecules for uptake

Question 17

what bond is important for protein folding

Answer 17

disulfide bond formation

Question 18

S layers

Answer 18

-protein coat
rigid/ permeable monolayer or glycoprotein
-self organized repeating structure
-outermost layer of cell

Question 19

functions of S layer

Answer 19

protective layer, protects from bacteriophages or bacterio pathogens
-provides periplasmic space or keep external proteins from accessing OM or CW

Question 20

what domains produce s layers

Answer 20

more common in archaea
some bacteria

Question 21

what are capsules or slime layers

Answer 21

coats of polysaccharides around cell surface

Question 22

difference between capsule and slime layer

Answer 22

capsules: organized into matrix and attach to cell
slime layers loosely attaches and less organized

Question 23

functions of capsules and slime layers

Answer 23

adjearing to surface, protection from host immune cells (bacterial pathogens), protection from dehydration

Question 24

pili

Answer 24

protein filaments that extend from cell surface

Question 25

how many bacteria produce pili

Answer 25

most bacteria and particularly gram -ve

Question 26

conjugative pili

Answer 26

important for conjugation and transfer of genetic material between pilus bridge

Question 27

what is a fimbria considered

Answer 27

a type of pilus

Question 28

fimbria function

Answer 28

mediates attachment to surface or another cell, shorter and more abundant than pilus