Figure 13 shows three organisms that live in pond water - Edexcel - GCSE Biology - Question 7 - 2023 - Paper 2
Question 7
Figure 13 shows three organisms that live in pond water.
Oxygen diffuses across the cell membranes of these organisms.
Which row of the table shows the conditi... show full transcript
Worked Solution & Example Answer:Figure 13 shows three organisms that live in pond water - Edexcel - GCSE Biology - Question 7 - 2023 - Paper 2
Step 1
Which row of the table shows the conditions needed for oxygen to diffuse from species A into the pond water?
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Answer
To determine the conditions for oxygen to diffuse from species A into the pond water, we need to identify the scenario in which the concentration of oxygen in species A is higher than in the pond water. From the options given, option B shows a concentration of oxygen in species A as 12 parts per million while the concentration in the pond water is 10 parts per million. Therefore, the correct option is B.
Step 2
Calculate surface area to volume ratio for species B.
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Answer
The surface area to volume ratio is calculated using the formula:
extSurfaceareatovolumeratio=VolumeSurface area
For species B, the surface area is 9000 µm² and the volume is 6000 µm³. Plugging in these values:
Ratio=60009000=1.5
Thus, the surface area to volume ratio for species B is 1.5.
