Bacterial Morphology And Growth Flashcards
What are methods of classifying bacteria?
Size Gross structure Cell wall structure Differential stains Morphology Growth requirements
What are structural components of bacteria?
All bacteria contain DNA Haploid DNA DNA in nucleoid region => not bound to nucleus Ribosome in cytoplasm => different to eukaryotic cells Peptidoglycan membrane No mitochondria No membrane bound organelles \+/- capsule \+/- pilli/flagella
Describe the cell wall of gram positive bacteria?
Thick peptidoglycan layer with lipoteichoic acid
Give an example of gram positive bacteria
Streptococcus pyogenes
Describe the cell wall of gram negative bacteria?
Extra outer membrane with integral lipopolysaccharide
Give an example of gram negative bacteria?
Escherichia Coli
Describe the cell wall of acid fast bacteria?
Thick outer layer of mycolic acids linked by Arabina- galactas
What is gram stain?
A differential cell wall stain dividing bacteria
What colour indicates gram positive bacteria?
Blue/purple
What colour indicates gram negative bacteria?
Red/pink
In acid fast stain, what colour does acid fast bacteria go?
Red
What are factors affecting growth?
Division rate Lag phase time O2 availability Carbon availability Temp pH Inhibitors and growth factors
Growth rate
Describe the different groups based on growth rate
Rapid growers => division every 20-40 mins
Slow growers => division every 30hrs
Dormancy => 18hrs - 80years
What are the different groups of bacteria based on O2 requirements?
Obligate aerobes
Facultative anaerobes
Aerotolerant anaerobes
Obligate anaerobes
What are different groups based on temp requirements for growth?
Pyschrophiles
Mesophiles
Thermophiles
Extreme (hyper) thermophiles
