Exam 1 - (2) Surface Structures

Question 1

Gram + bacteria express ______ on their outermost surface. Gram - express ______.

Answer 1

• Teichoic acid

- LPS

Question 2

Two types of teichoic acid are:

Answer 2

• Glycerol Teichoic acid

- Ribotol Teichoic acid

Question 3

_______ are embedded deeper in the the peptidoglycan layer of Gram + bacteria than the similar teichoic acids.

Answer 3

-Lipoteichoic acids

Question 4

Describe the structure of Lipopolysaccharide (LPS):

Answer 4

-Lipid A attached to a core polysaccharide attached to am O-antigen

Question 5

What is a Lipid A (within LPS)?

Answer 5

fatty acids attached to a phosphorylated disaccharide

Question 6

Describe a polysaccharide core (within LPS)?

Answer 6

It is similar between Gm- bacteria, but with unique sugars.

Question 7

Describe the O-antigen within LPS’s structure:

What is it the main reason for?

Answer 7

• highly variable repeating sugar subunits.

- antigenic specificity among Gm- bacteria

Question 8

What type of toxin is LPS?

Answer 8

Endotoxin

Question 9

In regards to immunology, what is important about the pathogenic surface structures?

Answer 9

-They are considered pathogen assc. molecular patterns (PAMPS)

Question 10

What do cells of the immune system use to recognize PAMPs?

Answer 10

pattern recognition receptors (PRRs)

Question 11

Name 3 “Toll-like” PRRs and what they recognize:

Answer 11

• Toll-like receptor 4 -> LPS
• Toll-like receptor 2 -> peptidoglycan
• Toll-like receptor 2 and 6 together -> teichoic acids

Question 12

What are pili/fimbriae involved in?

Answer 12

attachment of the bacteria to cells and other surfaces

Question 13

What specialized proteins can be found on the tips of fimbriae and what are they developed for?

Answer 13

• Adhesins

- adherence

Question 14

What are sex pili for? ;)

Answer 14

conjugation/transference of genetic material between adjacent bacteria

Question 15

name there types of fimbriae/flagella arrangements:

Answer 15

1-Monotrichous (one squiggly, like a sperm)
2-Lophotrichous (a few squigglys)
3-Peritrichous (covered with squigglys)

Question 16

The base for a flagella/fimbriae is _____ in all layers of the bacterial mebrane/cell wall via specific ______ and ______.

Answer 16

• embedded
• rings (superficial to deep L, P, MS, C)
• proteins

Question 17

Flagella play a role in bacterial motility and can rotate clockwise and counter clockwise to achieve this.

Answer 17

cool

Question 18

Movement by a flagellum can be ______ or ______.

Answer 18

• random

- directed

Question 19

Directed flagellar movement is called______. It can be towards something good or away from something bad.

Answer 19

Taxis

Question 20

Name 4 types of taxis:

Answer 20

1-Chemotaxis (toward chemoattractant or away from chemorepellant.
2-Aerotaxis
3-Osmotaxis
4-Thermotaxis

Question 21

What is a Glycocalyx?

Answer 21

a substance that surrounds the cell

Question 22

What type of glycocalyx is referred to as a capsule?

Answer 22

one that is well organized and firmly attached

Question 23

What is the chemical makeup of a capsule?

Answer 23

polysaccharides typically, but sometimes monosaccharides and glycoproteins.

Question 24

What is a glycocalyx that is not well organized or firmly attached?

Answer 24

a slime layer

Question 25

Why are capsules beneficial to pathogens?

Answer 25

for some bacteria, encapsulation is a necessary virulence factor. (S. pneumoniae only causes pneumonia with a capsule).

Question 26

Can the immune system recognize capsules?

Answer 26

YES!!!!!

Question 27

Toll-like receptor 5 recognizes _________, and sometime the _______ can be recognized by the immune system.

Answer 27

• flagella

- capsular polysaccharide

Question 28

What happens when the immune system recognizes a microbe?

Answer 28

-macrophagy, release of leukocytes, learning by T-cells, a bunch of stuff.

Question 29

A notorious hamburger pathogen is given the serological designation: E. coli O157:H7. What can this tell us?

Answer 29

• O157: the 157th type of O antigen that was characterized (gram negative b/c LPS)
• H7: the 7th type of H antigen that was characterized (present in flagella, so it is motile)
• it doesn’t have a capsule (K antigens refer to capsules)