DP Biology (first assessment 2025)

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Question 23M.2.SL.TZ2.1b

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Date May 2023 Marks available [Maximum mark: 1] Reference code 23M.2.SL.TZ2.1b
Level SL Paper 2 Time zone TZ2
Command term Estimate Question number b Adapted from N/A
b.
[Maximum mark: 1]
23M.2.SL.TZ2.1b

Samples of feces were collected from 40 individuals and were immediately frozen to preserve them. The numbers of bacteria in the feces (cell counts / 1011 cells g-1) were later measured and the enterotype was determined. The box plot shows this data. Each data point shows the cell count from one fecal sample.

[Source: Material from: Vandeputte, D., Kathagen, G., D’hoe, K. et al., Quantitative microbiome profiling links
gut community variation to microbial load, published 2017, Nature, reproduced with permission of SNCSC.]

(b)

Estimate the median number of bacterial cells per gram of feces in the R enterotype.

[1]

Markscheme

1.9 × 1011 / 190000 million / 190 billion (cells per gram);

Cells per gram not needed as in stem. Accept 1.80 × 1011 to 1.95 × 1011.

Syllabus sections