Bacterial Cell

Question 1

What are the main functions of the capsule?

Answer 1

Layer that functions in adherence and immune evasion

Question 2

What are strong antigens on bacteria?

Answer 2

Flagella

Question 3

What is the cell wall like for Gram +?

Answer 3

It is a thick peptidoglycan wall

Question 4

What is the cell wall like for Gram -?

Answer 4

It is a thin peptidoglycan wall

Question 5

What is the function of pili in virulence?

Answer 5

Pili confer virulence by promoting attachment to the host.

Question 6

What is the function of flagella in virulence?

Answer 6

Motility

Question 7

What does the envelope consist of?

Answer 7

The envelope consists of an inner membrane, a cell wall (the peptidoglycan) and, in the case of Gram - envelopes, an outer membrane.

Question 8

Inner Membrane

Answer 8

The inner membrane is common to both Gram - and Gram + envelopes. It consists of a lipid bilayer comprising phospholipids and proteins.

Question 9

Outer Membrane

Answer 9

The outer membrane is unique to the Gram - envelope. Like the inner membrane, it is a bilipid layer, but the outer leaflet has lipopolysaccharide (LPS) molecules instead of phospholipids.

Question 10

Porins

Answer 10

Porins are structures unique to the outer membrane that allow passive entry and exit of small molecules.

Question 11

What makes LPS toxic?

Answer 11

Lipid A

Question 12

How do Clostridium perfringens spores cause disease?

Answer 12

The production of a spore by a stressed cell will directly result in disease as in food contamination

Question 13

How do Bacillus anthracis spores cause disease?

Answer 13

Spores must convert back to a normal growing cell (germination) before they cause disease symptoms

Question 14

Mycoplasma

Answer 14

A very simple cell type that has only an inner membrane, of special composition. Because it lacks the peptidoglycan, it can have a variety of shapes.

Question 15

Biofilms

Answer 15

Biofilms are organized multicellular bacterial

communities that coordinate via pheromones and are difficult to deal with as they are protected from antibiotics

Question 16

How do the biofilms change in the GI tract and why?

Answer 16

In human, biofilms are most prominent in the proximal colon and appendix. Biofilm levels decline toward the distal colon.

Possibly, the interactions between biofilms and IgA differ between the proximal and distal colon. If some feature of IgA allows it to better bind bacteria in the distal colon, this could inhibit bacterial deposition at that site.

Question 17

What is the difference in the flagella of ETEC bacteria?

Answer 17

ETEC flagella replace the cap with an adhesin.

Question 18

What is a therapeutic strategy to defeat biofilms?

Answer 18

Apply a drug that blocks pheromone communication among bacteria in the biofilm.