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A student investigated the movement of water in potatoes - Edexcel - GCSE Biology Combined Science - Question 5 - 2023 - Paper 1
Question 5
A student investigated the movement of water in potatoes. The student used three identical cubes of potato. The size of a cube is shown in Figure 6. Calculate the v... show full transcript
Worked Solution & Example Answer:A student investigated the movement of water in potatoes - Edexcel - GCSE Biology Combined Science - Question 5 - 2023 - Paper 1
Step 1
Step 2
Step 3
Explain the mass change in the cube in the concentrated salt solution.
Answer
When placed in a concentrated salt solution, water moves out of the potato cube through osmosis, as the concentration of solute (salt) outside the cube is greater than inside. This leads to a decrease in mass as water exits the cube to equalize solute concentrations across the semi-permeable membrane.
Step 4
Describe how the student could modify this investigation to find this concentration.
Answer
To determine the concentration of salt solution where the potato cube does not change mass, the student could perform a series of experiments using different salt concentrations until finding one where the mass of the potato cube remains constant after immersion for a specified time. This would indicate that osmosis has reached equilibrium.
Step 5
Explain why potato cells do not burst when placed in water.
Answer
Potato cells do not burst when placed in water due to the presence of a rigid cell wall, which provides structural support and limits the extent of expansion as water enters the cells. This prevents cell lysis despite the influx of water.