The photograph shows a magnified image of bacterial cells from a human intestine - Edexcel - GCSE Biology - Question 3 - 2017 - Paper 1
Question 3
The photograph shows a magnified image of bacterial cells from a human intestine.
(a) Which of the statements about cells are true?
1. Bacterial cells and plant cel... show full transcript
Worked Solution & Example Answer:The photograph shows a magnified image of bacterial cells from a human intestine - Edexcel - GCSE Biology - Question 3 - 2017 - Paper 1
Step 1
Which of the statements about cells are true?
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Answer
The only correct answer is A.
Bacterial cells and plant cells have a cell wall, making statement 1 true. However, bacterial cells do not have a nucleus, so statement 2 is false. Therefore, the correct option is A.
Step 2
Compare the mass of prebiotic chemical A with that of prebiotic chemical B in these foods.
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Answer
In onions, prebiotic chemical A has 17.3 g while chemical B has 16.9 g. In dandelion leaves, A is 15.8 g compared to B's 11.8 g. For garlic, A is 12.5 g while B has 5.0 g. Finally, artichokes have 18.0 g of A and 11.5 g of B. Overall, prebiotic chemical A is consistently higher in mass compared to chemical B across all four foods.
Step 3
Which food shown in the table would cause the greatest increase in the number of beneficial bacteria in the intestines?
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Answer
Based on the mass of prebiotic chemicals, onions would likely cause the greatest increase due to having the highest masses of both prebiotic A and B among the options provided.
Step 4
How much time will it take for 10 g of beneficial bacteria to increase to 80 g?
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Answer
The bacteria double every hour. Starting with 10 g, it takes 3 hours to reach 80 g:
At 0 hours: 10 g
At 1 hour: 20 g
At 2 hours: 40 g
At 3 hours: 80 g
Therefore, the time required is 3 hours.
Step 5
Complete the sentence by putting a cross (✗) in the box next to your answer.
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Answer
The only correct answer is C. Oligosaccharides are prebiotic chemicals that provide health benefits by promoting beneficial gut bacteria.
Step 6
Describe how scientists would investigate this claim.
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Answer
Scientists could conduct controlled clinical trials where participants consume probiotic yoghurt and then assess health parameters over time. They would compare results with a control group not consuming the yoghurt to evaluate any positive effects on health.
