Lecture 5

Question 1

glycol tetrapeptide

Answer 1

structure of repeating unit in peptidoglycan found in coli and most gram neg. bacteria

Question 2

glycol tetrapeptide repeating units

Answer 2

N-acetylglucosamine and N-acetylmuramic acid

Question 3

glycosidic bonds

Answer 3

X direction

Question 4

peptide bonds

Answer 4

Y direction

Question 5

Gram pos. cells walls can contain up to ___%peptidoglycan

Answer 5

90%

Question 6

Gram pos. cell walls are common to have ____________ embedded in their walls.

Answer 6

teichoic acids

Question 7

lipoteichoic acids

Answer 7

teichoic acids covalently bound to membrane lipids

Question 8

Examples of prokaryotes that lack cell walls?

Answer 8

• mycoplasmas

- thermoplasmas

Question 9

mycoplasmas

Answer 9

group of pathogenic bacteria

Question 10

thermoplasma

Answer 10

species of archaea

Question 11

Gram geg. bacteria walls contain ___% peptidoglycan.

Answer 11

10

Question 12

Most of the cell wall of gram neg. bacteria walls are composed of…

Answer 12

lipopolysaccharide (LPS) layer

Question 13

LPS consists of…

Answer 13

core polysaccharide and O-polysaccharide

Question 14

LPS replaces most phospholipids in the….

Answer 14

outer half of outer membrane

Question 15

endotoxin

Answer 15

the toxic components of LPS

Question 16

Lipid A

Answer 16

releases endotoxin when gram neg. cells are lysed

Question 17

periplasm

Answer 17

gel like consistency space located between cytoplasmic and outer membranes that houses many proteins

Question 18

How wide is the periplasm

Answer 18

~15nm

Question 19

porins

Answer 19

channels for movement of hydrophilic low-molecular-weight substances

Question 20

Archaea has no…

Answer 20

peptidoglycan and outer membrane

Question 21

pseudomurein

Answer 21

• polysaccharide similar to peptidoglycan composed of N-acetylglucosamine and N-acetylalosaminuronic acid
• found in cell walls of certain methanogenic archaea

Question 22

T/F all archaea cell walls contain pseudomurein

Answer 22

some cell walls lack pseudomurein

Question 23

S layers

Answer 23

• present outside other layers of the cell wall
• not in all species
• made of protein

Question 24

Archaea and the S layer

Answer 24

In some archaea, the S layer is the only cell wall

Question 25

Capsules and slime layers are made of...

Answer 25

carbohydrate polymers

Question 26

Capsules and slime layers....

Answer 26

- assist in attachment to surfaces - protect against phagocytosis - resist desiccation

Question 27

fimbriae

Answer 27

-filamentous protein structures that enable organisms to stick to surfaces or form pellicles

Question 28

pili

Answer 28

filamentous protein structures typically longer than fimbriae

Question 29

What do pili do

Answer 29

- assist in surface attachment - facilitate genetic exchange between cells - motility

Question 30

Which pili is involved in twitching motility

Answer 30

type IV

Question 31

conjugation

Answer 31

facilitate genetic exchange between cells

Question 32

polyphosphates

Answer 32

accumulations of inorganic phosphate

Question 33

sulfur globules

Answer 33

composed of elemental sulphur

Question 34

carbonate minerals

Answer 34

composed of barium, strontium, and magnesium

Question 35

magnetosomes

Answer 35

can orient themselves specifically within a magnetic field

Question 36

gas vesicles

Answer 36

spinal-shaped, gas filled structures made of protein that confer buoyancy in planktonic cells by decreasing cell density -impermeable to water

Question 37

gas vesicles are composed of which two proteins?

Answer 37

GvpA and GvpC

Question 38

endospores

Answer 38

dormant, highly differentiated cells resistant to heat, harsh chemicals and radiation

Question 39

Ideal dispersal of endospores

Answer 39

via wind, water, or animal gut

Question 40

Endospores are present only in..

Answer 40

some gram pos. bacteria

Question 41

types of endospores

Answer 41

terminal, subterminal, and central

Question 42

endospore structure

Answer 42

- contains dipicolinic acid - enriched in Ca2+ - core contains small acid-soluble spore proteins (SASP)

Question 43

Spore formation is...

Answer 43

highly regulated

Question 44

flagella

Answer 44

assists in swimming moving by rotation | -helical in shape

Question 45

different flagellar arrangements

Answer 45

peritrichous, polar, lophotrichous

Question 46

flagella composed of..

Answer 46

flagellin

Question 47

flagellar structure of archaea

Answer 47

- half the diameter of bacterial flagella - composed of several different proteins - move by rotation

Question 48

flagellar synthesis in bacteria

Answer 48

- several genes required - MS ring made first - then proteins and hook - filament grows from tip

Question 49

Flagella increase or decrease rotational speed in relation to strength of the....

Answer 49

proton motive force

Question 50

Differences in swimming motions

Answer 50

- peritrichous: move slow in straight line | - polarly flagellated: move more rapidly and typically spin

Question 51

gliding motility

Answer 51

- flagella-independent motility - slower and smoother than swimming - movement along long axis of cell - requires surface contact

Question 52

mechanisms of gliding motility

Answer 52

- excretion of polysaccharide slime - type IV pili - gliding-specific proteins

Question 53

taxis

Answer 53

directed movement in response to chemical or physical gradients

Question 54

chemotaxis

Answer 54

response to chemicals

Question 55

phototaxis

Answer 55

response to light

Question 56

aerotaxis

Answer 56

response to oxygen

Question 57

osmotaxis

Answer 57

response to ionic strength

Question 58

hydrotaxis

Answer 58

response to water

Question 59

chemotaxis attractants and receptors sensed by..

Answer 59

chemoreceptors