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Flashcards in Bugs in the system Deck (15):
0

What is the bacterial reproduction mechanism in broth?

-Binary fission

1

Define infection

The establishment of an organism on/in a host associated with multiplication and destruction/dysfunction of the host

2

What can cause infection?

Bacteria, archea, protozoa, fungi, prions, viruses

3

What are the possible mechanisms of infection transmission

-Air borne droplets (coughing/sneezing)
-Direct contact (exchange of bodily fluids)
-Animal transmission
-Contaminated products
-Maternal->foetal

4

Describe the concept of gram staining

-Stain cells with crystal violet
-Add iodine which forms complexes with crystal violet
-Add acetone to decolourise cells by removing complexes. Those cells which thick peptidoglycan wall (i.e. gram positive bacteria) will retain crystal violet-iodine complexes as they will be too large to pass through
-Counterstain with safranin
-View under microscope to see staining colour

5

Why are acid fast stains useful and what type of bacteria do they stain?

-Stain bacteria which do not have thick peptidoglycan wall content and also have an extra cell membrane
-Mycobacterium Tb and Leprosy

6

Define pathogen

-Any micro/organism which parasitises a host and causes disease

7

Why are bacterial cell walls of interest and significance?

-Used in detection and diagnosis
-Can be a target for antibiotics
-Gram -ve have LPS with endotoxin effects

8

Name the most common gram +ve cocci

-Streptococcus
-Staphlococcus

9

Name the most common gram -ve cocci

-Neisseria

10

Name the most common gram +ve bacilli

-Clostridium

11

Name the mose common gram -ve bacilli

-Escherchia Coli
-Pseudomonas
-Helicobacter
-Salmonella

12

Which microorganisms are prokaryotic and which are eukaryotic?

-Bacteria and Archea are prokaryotic
-Protozoa and Fungi are Eukaryotic

13

List the main differences between prokaryotes and eukaryotes

Prokaryotes
-No membrane bound organelles
-1 Chromosome
-Coupled biochemical reactions
-V.labile mRNA
-30s and 50s ribosomal subunits

Eukaryotes
-Membrane bound organelles
-Many chromosomes
-Compartmentalised reactions
-mRNA stable
-40s and 60s ribosomal subunits

14

Name the main mechanisms by which bacteria aquire antibiotic resistance

-Antibiotic inactivation by hydrolysis, group transfer or redox
-Target modification
-Efflux pumps
-Target Bypass
-Mutations
-Horizontal transfer of plasmids