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Flashcards in Microbiology Deck (29):
1

Give the gram stain and structure of Neisseria meningitidis

gram -ve diplococcus

2

Give the gram stain and structure of streptococcus mutans

gram +ve streptococcus

3

Give the gram stain and structure of streptococcus pneumoniae

gram +ve diplococcus

4

Give the gram stain and structure of haemophilus influenzae

gram -ve coccobacillus

5

Give the gram stain and structure of vibrio cholerae

gram -ve vibrio

6

Give the gram stain and structure of salmonella typhi

gram -ve rod

7

Give the gram stain and structure of corynebacterium diptheriae?

gram +ve rod

8

Give the gram stain and structure of clostridium difficile

gram +ve rod

9

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.

10

Which dye is responsible for the colouration of gram +ve bacteria?

Crystal violet - purple

11

Which dye is responsible for the colouration of gram -ve bacteria?

Safranin

12

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.

13

What are inclusion bodies and where are they found?

They are stores of carbon, fats and phosphates.
They are found in the cytoplasm.

14

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.

15

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.

16

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

17

Which protein systems move
a) folded
b) unfolded
proteins across the inner membrane?

folded = sec
unfolded = TAT (twin-arginine translocation pathway)

18

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.

19

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

20

Define these words?
Monotrichous

Amphitrichous

Peritrichous

Monotrichous = one flagellum

Amphitrichous = one flagellum at each end

Peritrichous = spread over entire cell surface

21

What is the word to describe an organism with clusters of flagella at one or both ends?

Iophotrichous

22

Give an example of a bacteria with iophotrichous flagella?

Legionella pneumophilia

23

What sort of flagella does salmonella have?

peritrichous

24

What type of bacteria usually form endospores?

Gram +ve rods

25

What are AB toxins?

Some exotoxins are AB toxins...

A - has derogatory function on the cell
B - facilitates the uptake of A

26

What is the indole test testing?

It is testing for the presence of tryptophanase which converts tryptophan into indole.

27

Give an example of indole test positive bacteria?

E. coli

28

What is the carbohydrate utilisation test and what is it testing?

Different carbohydrates are placed into the container with bacteria.
It is testing whether or not the bacteria can ferment the carbohydrates, producing a byproduct of acid.
This acid will turn the phenol indicator yellow.

29

What is alpha, beta and gamma haemolysis?

Alpha = partial haemolysis, turns green
Beta = full haemolysis
Gamma = no haemolysis