Public health microbiology - David allison

Question 1

what are the general properties of microorganisms?

Answer 1

• microscopic dimensions
• ubiquitous (found everywhere)
• independent growth and survival
• exist as single cells / cell clusters

Question 2

name some characterisation methods:

Answer 2

specific staining techniques

- electron microscopy (TEM & SEM)

Question 3

Which are prokaryotic cells?

Answer 3

bacteria, algae

Question 4

which are eukaryotic cells?

Answer 4

animals, plants, fungi, protozoa

Question 5

general properties of bacteria:

Answer 5

• size is 0.12 - 5 micrometer .
• shape (cocci, rod, ovoid, filamentous)
• cell arrangement (unicellular, chains, pairs, clusters)

Question 6

structures in bacteria that are found in ALL bacteria:

Answer 6

cell wall, cell membranes, DNA, plasmid, ribosomes, mesosomes

Question 7

structures in bacteria that are found in SOME bacteria:

Answer 7

slime, capsule, fimbriae, pili, flagella,

Question 8

cell wall in prokaryotes vs eukaryotes

Answer 8

cell wall in prokaryotes is made of peptidoglycan, cell wall in eukaryotes is made of cellulose

Question 9

which structure regulates the penetration of macromolecules?

Answer 9

cell wall

Question 10

how can we study the structure of bacterial cell walls?

Answer 10

initially differential staining technique - gram stain - be able to differentiate sliced cells horizontally
Transmission Electron Microscopy
X-Ray crystallography / enzymic digests

Question 11

what are the Gram stain colours

Answer 11

Gram positive cells - stain purple
Gram negative cells - stain red
Staining depends on ultrastructure of cell wall

Question 12

what does the cell wall of gram positive bacteria contain?

Answer 12

A thick peptidoglycan layer,
teichoic acids,
cell membrane
cytoplasm

Question 13

what does the cell wall of gram negative bacteria contain?

Answer 13

• an outer membrane
• a periplasm
• much thinner peptidoglycan layer
• cell membrane
• cytoplasm

Question 14

how does knowing the cell wall structure help us?

Answer 14

by knowing the cell wall structure, we can be more specific with anti microbial chemotherapy.

Question 15

how is the peptidoglycan stopped from being washed away in gram positive bacteria?

Answer 15

it is anchored into the cytoplasm by lipoteichoic

Question 16

where are Lipopolysaccharide (LPS) found?

Answer 16

embedded into the outer membrane of ONLY gram negative bacteria.

Question 17

where are lipoproteins found?

Answer 17

only in gram negative bacteria

Question 18

why is LPS important?

Answer 18

bc its fever causing, high levels are bad