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Streptococcus mutans is one species of bacteria which causes tooth decay - Edexcel - GCSE Biology - Question 4 - 2021 - Paper 1
Question 4
Streptococcus mutans is one species of bacteria which causes tooth decay. A scientist tested the effectiveness of toothpaste at killing this species of bacteria. T... show full transcript
Worked Solution & Example Answer:Streptococcus mutans is one species of bacteria which causes tooth decay - Edexcel - GCSE Biology - Question 4 - 2021 - Paper 1
Step 1
Which word describes the techniques used to prevent contamination of the agar jelly plate?
Answer
The correct answer is C aseptic. Aseptic techniques are vital in preventing contamination in microbiological work. Other options are not applicable since:
- A. clinical is not a technique.
- B. diagnostic refers to identifying diseases rather than preventing contamination.
- D. lysogenic pertains to a phase in the viral lifecycle.
Step 2
Give two precautions needed to prevent contamination of the agar jelly plate.
Answer
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Keep the lid on at all possible times: This minimizes exposure to airborne contaminants and prevents unwanted bacteria from settling on the agar.
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Use sterile equipment: Utilizing sterilizing methods, such as flaming loops or disinfecting the working area, is crucial to avoid introducing contaminants during inoculation.