Microbiology

Microbiology: ‘The Correct handling of Micro-organisms’
1. Devise a title for each of the two experiments you did :
(i), Experiment 1 demonstrated the growth of bacteria when placed in liquid nutrient broth culture, the number of species present had increased in growth.
.(1)
(ii) Experiment 2 illustrated the growth of bacteria when placed on different surfaces of solid agar plates which included: nutrient agar, CLED agar and MacConkey agar; the number of species present also had increased in growth.
(1)
2(A). Experiment 1: Choose 2 words that describe the appearance of the pre –incubation broth:
(i) Straw yellow (½) (ii) Transparent .(½)
2 (B). Choose two words that describe the appearance of the post-incubation broth:
(i) Turbidity .(½) (ii) Pellicle formation (½)
3. Complete the table below to show your post-incubation observations in Experiment 2

Nutrient Agar

CLED Agar

MacConkey Agar

Appearance of agar before incubation
Pale yellow
Green
Red

Appearance of the colonies for each species on each type of agar

E.coli – Shiny white/clear with rough outer edges.

P.aeruginosa – Matte white/clear with smooth outer edges

B.subsilis – Matte white/clear with rough outer edges.
E.coli – opaque yellow colony produced.

P.aeruginosa – green colony produced

B.subsilis – pale blue colony produced
E.coli – orange colony produced

P.aeruginosa – white colony produced

B.subsilis – pale orange colony produced.

Appearance of Agar surrounding each species following incubation

Transparent
E.coli – Yellow
P.aeruginosa – Blue
B.subsilis – Pale Blue
E.coli – Orange
P.aeruginosa – Orange
B.subsilis – Orange
(7)
4 (A). Describe what is meant by the term aseptic