Systematic bacteriology Flashcards
How are microorganisms classified
Appearance
enzyme/ metabollic tests
growth requirements
molecular tests
How can microorganisms be identified under a microscope
pure culture?
shape/size
grouping
structures
staining
What are the common shapes of bacteria
cocci - spheres
bacilli - rods
spiral shaped
what does a division in 1 plane for a coccus produce
diplococcus
how can cocci produce chains
division in 1 plane to produce 4-20 cocci
How do cocci produce clumps
division in 3 planes
How do chains of bacilli form
delayed separation of the cell wall
which form of bacteria are more commonly found in chains
gram positive
what shape are fuse-form pathogens
long slender rods
What are the types of spiral-shaped bacterium
rigid
flexible
what makes a spiral shaped bacteria flexible
flagella attached at one end and corkscrews along the inside - better mobility
What is a spore?
A structure from a bacteria that allows it to spread and survive in an unfavourable environment
What does a spore consist of
Contains a chromosome in the centre surrounded by a membrane made up of proteins
Are spores alive
no - therefore are difficult to degrade
Which types of pathogens produce spores
anaerobic
What is a gram stain
distinguishes between gram negative and gram positive bacteria due to their cell walls
Why does gram staining not work on all bacteria
if they have a lipid rich/waxy cell wall - will not take up stain
How are microorganisms classed
appearance
growth requirements
enzyme/metabolic tests
molecular tests
Which types of organisms require oxygen in lab
obligate aerobes
Which type of bacteria can grow in absence or presence of oxygen
facultative anaerobes
How is a selective media used for growth of specific prokaryotes
By containing the presence of specific substances that permit growth of one organism
What type of media can facilitate identification of prokaryotes
differential media
What are the ways haemolysis occurs on blood agar plates
alpha - partial
beta - complete
gamma - no haemolysis
What types of biochemical reactions can be used to identify prokaryotes
utilisation of carbon sources
utilisation of amino acids
coagulase (enzyme production)
How are serological tests used
demonstrate specific antigens or antigen-binding interactions
Agglutination
How is agglutination used to identify bacteria
Antibody + signal are mixed, Antigen will either bind or remain suspended in solution
