Bacterial envelope handout

Question 1

What envelope structures can be found on both Gram+ and Gram- bacteria?

Answer 1

Capsule (slime and glycocalyx)
Cell wall (peptidglycan, murein, mucocomplex)
Cytoplasmic membrane (inner membrane, cell membrane, plasma membrane)

Question 2

What is the chemical composition of the capsule?

Answer 2

Polysaccharide gel

Question 3

What is the function of the capsule structure?

Answer 3

Pathogencity factor protecting against phagocytosis

Immunogenic- **EXCEPT streptococcus pyogens which is hyaluronic acid and non-immunogenic.

Question 4

What is the chemical composition of the outer membrane structure? And is it Gram+ or Gram-?

Answer 4

Lipopolysaccharide Lipid A
Polysaccharide
Phospholipids
Proteins (porins and outer membrane proteins)

IT IS GRAM-

Question 5

This protein on top of the gram + cell structure make it stronger?

Answer 5

Peptidoglycan

Question 6

Only gram +/ - has an outer membrane composed of LPS which is responsible for endotoxic shock?.

Answer 6

gram -

Question 7

Gram stains work best at what layer?

Answer 7

The peptidoglycan layer

Question 8

If the stain is violet, what does it mean?

Answer 8

Means it is very small to let in, so put some iodine to allow it to coagulate

Question 9

5. A lab tech forgets the iodine fixation step staining strep. The organism will appear pink/blue/colorless?

Answer 9

Appear pink

Question 10

With iodine Gram +/- locks in the purple/blue color and is extrememly crosslinked whereas a gram +/- releases the color with iodine?

Answer 10

Gram + locks in the color and gram – releases the color

Question 11

Endotoxin shock associated with septicemia caused by…?

Answer 11

neisseria meningitides

Question 12

What is bacterial log phase?

Answer 12

When the cells increase in number by 2’s

Question 13

What is lag phase?

Answer 13

no growth in cell

Question 14

What is the generation time?

Answer 14

The time it takes for a bacteria to go from 1 bacterium to 2 daughter cells

Question 15

What is a stationary phase?;

Answer 15

no increase in the number

nutrients used up -toxic products like acid and alkalis begin to form

Question 16

Aerobes can/ cannot ferment. Anaerobes are/ are not fermenter.

Answer 16

Aerobes cannot ferment and anaerobes are fermentors.

Question 17

What are the ABC bacterium?

Answer 17

A-actinomyces,
B-bacteroides,
C- clostridium

Question 18

Capsules have a ___ layer which allow them to be non-phagocytic?

Answer 18

slime layer

Question 19

What is ferritin?

Answer 19

Storage form of iron (rmmber ferum in a tin)

Question 20

List the following from nonbioavalable to most bioavaliable form:
calcim citrate,
calcium glucamate,
calcim carbonate?

Answer 20

Calcium carbonate-calcium citrate-calcium glucamate

Question 21

LPS (lipopolysacchrides) are the only endotoxins, true/false?

Answer 21

true

Question 22

Gram + have a mesosome, true/false?

Answer 22

true

Question 23

Where do gram – have endotoxins?

Answer 23

Outer membrane

Question 24

Acid fast have what kind of chemical composition?

Answer 24

Mycolic acids : whose function is acid-fsatness and resistence to drying and chemicals.

Question 25

In Peptidoglycan layer, what two antibiotics inhibit cell wall synthesis?

Answer 25

PCN and cephalosporins