This question is about cells and transport - AQA - GCSE Biology - Question 7 - 2010 - Paper 1

The function of chloroplasts is to carry out photosynthesis, allowing the plant to absorb sunlight and convert it into glucose and oxygen.

One type of cell in a potato plant that does not contain chloroplasts is a root hair cell.

The independent variable in the investigation is the concentration of salt solution.

The student dried the surface of each potato piece to ensure that only the mass of the potato was measured. If any excess water or solution was left on the potato, it would affect the mass and the results of the investigation.

To calculate the percentage increase in mass of the potato piece, use the formula:

First, calculate the increase in mass:

Increase in mass = End mass - Starting mass = 2.7 g - 2.5 g = 0.2 g

Now, substituting into the formula:

To complete Figure 9, label the x-axis as 'Concentration of salt solution (mol/dm³)', ensure the scale is suitable and covers at least 50% of the grid, plot the data from Table 6 accurately, and draw a smooth line of best fit through the points.

The concentration of salt solution equal to the concentration of the solution inside the potato pieces is approximately 0.3 mol/dm³, based on the data represented in Figure 9.

The potato pieces in the 0.4 mol/dm³ salt solution decreased in mass because water moves out of the potato cells by osmosis. In this case, the concentration of the salt solution outside the cells is higher than that inside, causing water to flow out to balance the concentration, resulting in a loss of mass.