Bacteria Structure

Question 1

What is the shape of the Vibrio Cholera?

Answer 1

Spiral shaped.

Question 2

What is the shape of Strep?

Answer 2

Chains of Spheres

Question 3

What is the shape of Staph?

Answer 3

Grape-like Clusters (Spheres)

Question 4

Difference between gram positive and negative?

Answer 4

Positive = Thick Peptidoglycan Layer
Negative = Thin Peptidoglycan layer with an outer membrane

Question 5

What are the steps in Gram Stain?

Answer 5

1. Crystal Violet = stains purple
2. Gram’s Iodine
3. Alcohol - removes stain from gram negative due to porins allowing the purple to be removed
4. Safarin Red - dyes the colorless microbes red/pink and if purple will stay purpse
   Gram Positive = Purple
   Gram Negative = Pink

Question 6

Gram Positive cell wall characteristics?

Answer 6

Thick Peptidoglycan and Teichonic Acid

Question 7

Gram Negative cell wall characteristics?

Answer 7

Thin Peptidoglycan
Outer Membrane
- Lipopolysacchrides
- Porins

Question 8

What kind of bacteria can have a capsule?

Answer 8

Both kinds of bacteria can have a capsule. The capsule would be outside of the other membranes.

Question 9

Which kind of bacterium have more cross-linking of peptidoglycan?

Answer 9

Gram Positive

Question 10

What unique structure is used on gram positive outer membrane for Toll-Like Receptor recognition?

Answer 10

Teichonic Acid

Question 11

What are the parts of LPS and what kind of bacteria?

Answer 11

Gram Negative Only. Recognized by innate immune system.
Most Outer level is variable the O-Antigen (recognized)
Lipid A at the base, induces fever/endotoxin

Question 12

What are the PAMPs of both gram positive and negative bacteria?

Answer 12

Positive = Lipoteichonic Acid
Negative = Lipopolysaccharide

Question 13

What are the function of fimbriae and pili?

Answer 13

Adherence to cells and are virulence determinants. Unique to come types of bacteria.

Question 14

What are the differences between flagella of enteric bacteria and pseudomonads?

Answer 14

Pseudomonads - single polar flagella

Enteric - multiple flagella over the cell

Question 15

What do the types of secretions mechanisms do?

Answer 15

Type II - secrete protein
Type III - delivers toxins
Type IV - delivers DNA
–virulence factors–

Question 16

How does having a capsule benefit the bacterium?

Answer 16

Can prevent the bacteria from getting phagocytosed and can hide the antigens.

Question 17

What is the primary virulence factor of Haemophilus and where does it infect?

Answer 17

Type B Polysaccharide Capsule and primary infection site is usually the nasopharynx

Question 18

Who does Haemophilus primarily effect and what does it cause?

Answer 18

Highest incidence of Meningitis in 3 month to 2 year olds.

3 months because that’s after Ab protection from mother wears off

Question 19

Why are capsules poor immunogens?

Answer 19

Due to the repetitive sequence unable to elicit a strong immune response.

Question 20

What is a conjugate vaccine and how did they use it for Haemophilus?

Answer 20

Conjugate vaccine is when they pair another antigen with the capsule antigen to elicit a strong response to get a T-cell dependent response.