L2 Systematic bacteriology 1

Question 1

How do we distinguish between prokaryotes or eukaryotes?

Answer 1

gram stain-distinguishes according to cell wall structure
gram +ve= purple
gram -ve=pink

Question 2

What does spore mean?

Answer 2

Insert structures to physical and chemical challenge

Question 3

What are the limitations of gram stains?

Answer 3

• not all organisms stain well with gram stain

- eg Mycobacterium tb- organism that causes tb has a lipid rich/waxy cell wall that does not take up a stain

Question 4

What does obligate aerobe and obligate anaerobic oxygen mean?

Answer 4

Obligate aerobes- require oxygen

obligate anaerobes-killed by oxygen

Question 5

How do obligate anaerobic bacteria be killed by oxygen?

Answer 5

• respiration uses electron acceptor other than oxygen
• smaller reduction potential than o2
• less proton motive force across membrane (ATP synthase)
• less energy released per molecule oxidised

Question 6

How to identify streptococcus spp via haemolysis or hemolysis?

Answer 6

-alpha-greening of colonies-s.pneumonia and viridans group
-beta-colony size- large-pyogenic small (s.milleri
gamma-no heamolysis-

Question 7

how do serological tests work in bacterial identification?

Answer 7

1- host immune response to Ag BY THE raising of Abs.
2- Ab specific to microbe/virus (polyclonal), or signle component
3-detect presence of specific IgM Ab to virus/microbe
4-demonstrate in vitro by agglutination (aggregation) reaction
5- rapid detection of viruses
6- can identify serotypes of bacteria