Lecture 1

Question 1

interactions/forces involved in nonspecific adherence

Answer 1

1. hydrophobic interactions
2. electrostatic attractions
3. atomic and molecular vibrations resulting from fluctuating dipoles of similar frequencies
4. Brownian movement (random interactions)
5. recruitment and trapping by biofilm polymers interacting with the bacterial glycocalyx (capsule)

Question 2

nonspecific adherence is ____ and is called ____

Answer 2

reversible; docking

Question 3

specific adherence is ____ and is called _____

Answer 3

irreversible; anchoring

Question 4

adhesins are often found on ____ but can be found in capsules or cell surface

Answer 4

fimbrae (aka pili)

Question 5

why does streptococcus mutans (cause of caries) bind to tooth pellicle?

Answer 5

the adhesin is glucosyl transferase which binds to a salivary protein that is involved in pellicle formation

Question 6

how do bacteria take up nutrients?

Answer 6

1. carrier-mediated diffusion (facilitated)
2. phosphorylation-linked transport (group translocation)
3. active transport (energy dependent)

Question 7

____ can facilitate invasion such as _____

Answer 7

secreted enzymes; hyaluronidase, steptokinase, specific proteins that induce endocytosis/phagocytosis

Question 8

2 different mechanisms for spread

Answer 8

1. lateral propagation to contiguous tissues (multiply then spread)
2. dissemination to distant sites (spread then multiply)

Question 9

endotoxins are a component of the bacteria ____, released when the cell disintegrates; endotoxin term usually reserved for _____

Answer 9

cell wall; lipopolysaccharides

Question 10

exotoxins are ____ substances secreted into _____

Answer 10

soluble; host tissues

Question 11

what makes a microbe a pathogen?

Answer 11

• ability to adhere to host
• ability to colonize the host
• ability to replicate within a given niche
• ability to cause damage (invasion, production of toxin, activation of the immune system)

Question 12

bacterial responses to oxygen

Answer 12

1. strict aerobes- must have oxygen to grow
2. obligate anaerobes- cannot grow in presence of oxygen
3. facultative anaerobes- can grow with or without oxygen (most medically important)

Question 13

microbes that can grow with limited nutrients

Answer 13

oligotrophs

Question 14

microbes that require some oxygen, but lower levels of oxygen

Answer 14

microaerophiles

Question 15

grow well in mild temperatures (15-45 C)

Answer 15

mesophiles

Question 16

difference in envelope structure of Gram + and gram – bacteria

Answer 16

Gram + has thick layer of murein (peptidoglycan) on top which helps cell to maintain shape
Gram - has second lipid bilayer on top

Question 17

murein has a ____ structure to help with rigidity

Answer 17

cross-linked

Question 18

composition of ____ is slightly different for Gram+/- bacteria; Gram negative has ____ terminal

Answer 18

DAP (diaminopimelic acid) –D-alanine

Question 19

between cell membrane and cell wall (murein) is the ____

Answer 19

periplasmic space

Question 20

gram negative has ____ surface structure and gram positive has ____ surface structure

Answer 20

LPS; teichoic acid

Question 21

LPS is made up of ____, ____ and ____

Answer 21

lipid A; core polysaccharide; repeating O-antigen subunits

Question 22

____ is the main reason for the different antigenic specificities among gram negative bacteria

Answer 22

O-antigen

Question 23

structures within bacteria are important bc they are considered ____

Answer 23

pathogen associated molecular patterns (PAMPs)

Question 24

cells of the immune system can recognize PAMPs using _____

Answer 24

pattern recognition receptors (PRRs)

Question 25

_____ recognizes LPS

Answer 25

toll-like receptor 4

Question 26

_____ recognizes peptidoglycan

Answer 26

toll-like receptor 2

Question 27

____ together recognize teichoic acids

Answer 27

toll-receptors 2 and 6

Question 28

involved in the attachment of bacteria to cells and other surfaces

Answer 28

pili (fimbriae)

Question 29

when movement of flagella is directed it is referred to as ____

Answer 29

taxis

Question 30

a substance that surrounds a cell outside the cell wall or lipid membrane

Answer 30

glycocalyx

Question 31

glycocalyx that is well organized and firmly attached is a ____

Answer 31

capsule

Question 32

capsules are usually made of _____ but can include ____ and _____

Answer 32

polysaccharides; monosaccharides; glycoproteins

Question 33

glycocalyx that is not well organized or firmly attached is called a _____

Answer 33

slime layer

Question 34

why would capsules be beneficial to pathogens?

Answer 34

for some bacteria, encapsulation is a necessary virulence factor

Question 35

_____ can recognize flagella

Answer 35

toll-like receptor 5

Question 36

if a microbe is gram negative, you know it has ____ (designated by ____ in the name)

Answer 36

LPS; O-antigen

Question 37

if a microbe is motile, you know it has ____, designated by the ____ in the name

Answer 37

a flagellum (or multiple flagella); H-antigen

Question 38

____ refer to capsules

Answer 38

K-antigens