Bacteria grown in a liquid medium is called a bacterial culture - Edexcel - GCSE Biology - Question 7 - 2020 - Paper 1
Question 7
Bacteria grown in a liquid medium is called a bacterial culture.
As the number of bacteria increases the bacterial culture becomes opaque.
This is because light is a... show full transcript
Worked Solution & Example Answer:Bacteria grown in a liquid medium is called a bacterial culture - Edexcel - GCSE Biology - Question 7 - 2020 - Paper 1
Step 1
Give two aseptic techniques the scientist should use when taking samples from the bacterial culture.
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Answer
Use a sterile pipette to transfer the sample, ensuring no contamination.
Flame the mouth of the culture container to sterilize and prevent airborne bacteria from entering.
Step 2
Calculate the time taken for the amount of light being absorbed by the bacterial sample to double from 0.5 to 1.0 arbitrary units.
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Answer
From Figure 8, the absorption at 40 minutes is 0.5 arbitrary units, and it reaches 1.0 arbitrary units at 100 minutes. Therefore, the time taken to double is:
100 minutes - 40 minutes = 60 minutes.
Step 3
Give one improvement the scientist could make to view the bacteria more clearly.
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Answer
Use a higher magnification lens, such as x2000, to improve clarity and detail when observing the bacteria.
Step 4
What method is used to insert the gene from the bacteria into the crop plant?
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Answer
The method used is C genetic engineering.
Step 5
Discuss the advantages and disadvantages of growing crop plants that produce a toxin that can kill insects.
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Advantages:
Less damage to crops due to insect pests.
Increased yield, leading to more food production.
Reduced need for chemical pesticides, which can benefit the environment.
Disadvantages:
Insects may develop resistance to the toxin over time.
Potential higher costs for production and initial implementation.
Concerns about cross-contamination with non-GMO plants.
Possible detrimental effects on beneficial insects and the wider ecosystem.
