Page 167 - KOMPILASI ARAHAN TUGASAN PEKA SPM KINTA UTARA 2022

(g) Graph

Graph of size of clear area against concentration of antibiotic

3.5

3

2.5
size of clear area (cm) 1.5
2

PANITIA SAINS DAERAH KINTA UTARA
1

0.5

0
distilled water low high concentration of antibiotic

1. High concentration of antibiotic inhibit growth of bacteria more than low concentration of
antibiotic.
2. The higher the concentration of antibiotic, the larger the size of clear region formed.
3. Antibiotic is a substance that produces clear area on the surface nutrient agar.
4. The hypothesis is accepted. The higher the concentration of antibiotic, the lower the growth of
bacteria.
5. Antibiotic kills /prevent/inhibit the growth of bacteria and thus the area is clear.
6. Make sure the nutrient agar is sterile, all the apparatus used also must be sterilised before use,
and seal the nutrient agar tightly after introduced with bacteria
7. Yes, this is because clear are is formed in the presence of antibiotic disc and there is no clear
area formed in the distilled water disc.

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