Microbiology Flashcards
Give the gram stain and structure of Neisseria meningitidis
gram -ve diplococcus
Give the gram stain and structure of streptococcus mutans
gram +ve streptococcus
Give the gram stain and structure of streptococcus pneumoniae
gram +ve diplococcus
Give the gram stain and structure of haemophilus influenzae
gram -ve coccobacillus
Give the gram stain and structure of vibrio cholerae
gram -ve vibrio
Give the gram stain and structure of salmonella typhi
gram -ve rod
Give the gram stain and structure of corynebacterium diptheriae?
gram +ve rod
Give the gram stain and structure of clostridium difficile
gram +ve rod
Categorise s. aureus and s. pyogenes as catalase positive or negative. What does this test mean?
S. aureus = catalase +ve
S. pyogenes (+ all other streps) = catalase -ve
Catalase converts hydrogen peroxide to water and o2.
Which dye is responsible for the colouration of gram +ve bacteria?
Crystal violet - purple
Which dye is responsible for the colouration of gram -ve bacteria?
Safranin
What is the purpose of passing the microscope slide through a Bunsen burner?
This is to fix the bacteria firmly to the slide.
It also kills the bacteria, making it safe to handle, without destroying internal structures.
What are inclusion bodies and where are they found?
They are stores of carbon, fats and phosphates.
They are found in the cytoplasm.
Which environment is most likely to result in a bacteria making a pilus:
low shear force or high shear force
High shear force as the bacteria may want to adhere to the surface so it doesn’t move away from its optimum site.
Why don’t bacteria express pili all the time?
Because it requires a lot of energy and nutrients to make and it reduces the surface area available for metabolic processes.
What type of bacteria are found on the skin mainly?
Gram +ve bacteria
Although behind neck, on hands etc don’t get much air so they are mainly gram -ve
Which protein systems move
a) folded
b) unfolded
proteins across the inner membrane?
folded = sec unfolded = TAT (twin-arginine translocation pathway)
What are slime layers and capsules made of?
What is the difference between the two?
They are made of polysaccharides
Capsules are highly organised and are hard to remove.
Slime layers are disorganised and easy to remove.
Name some encapsulated bacteria and an encapsulated fungus.
Way to remember =
SHiN Kills Some Patients with Capsules
Streptococcus pneumoniae Haemophilus influenzae Neisseria meningitidis Klebsiella pneumoniae Salmonella typhi Pseudomonas aeruginosa Cryptococcus neoformans - only encapsulated fungus
Define these words?
Monotrichous
Amphitrichous
Peritrichous
Monotrichous = one flagellum
Amphitrichous = one flagellum at each end
Peritrichous = spread over entire cell surface
What is the word to describe an organism with clusters of flagella at one or both ends?
Iophotrichous
Give an example of a bacteria with iophotrichous flagella?
Legionella pneumophilia
What sort of flagella does salmonella have?
peritrichous
What type of bacteria usually form endospores?
Gram +ve rods
