Investigating Cells - Questions and Answers
STANDARD GRADE
BIOLOGY
CREDIT LEVEL
REVISION QUESTIONS
INVESTIGATING CELLS
1. In an investigation, three 25 g samples of sultanas were put into separate beakers of distilled water, as shown below:
After 24 hours, the sultanas were removed from the water, blotted on filter paper and reweighed. The results are shown in the table:
|Sample |Mass after 24 hrs (g) |Percentage change in mass |
|1 |32.5 |30.0 |
|2 |32.2 |28.8 |
|3 |32.4 |29.6 |
a) Complete the table with the percentage change in mass of the sultanas in sample 3.
32.4 g – 25 g = 7.4g
(7.4 / 25) = 0.296
0.296 x 100 = 29.6 %
b) The change in mass of the sultanas was caused by the movement of water.
i) Name this process.
Osmosis
ii) Explain the results in terms of water concentrations.
The water moved from an area of high water concentration outside the cell to an area of low water concentration inside the cell. 1. Continued
c) Which of the following is the best reason for blotting the sultanas before reweighing? Tick the correct box.
| |To stop them sticking together | |To remove external sugar solution |
| | | | |
|X |To remove external water | |To make sure the sultanas were dried |
2. Plant cells and animal cells were left in water or 10% sucrose solution for 10 minutes. The cells were then examined under the microscope: The appearance of
BIOLOGY
CREDIT LEVEL
REVISION QUESTIONS
INVESTIGATING CELLS
1. In an investigation, three 25 g samples of sultanas were put into separate beakers of distilled water, as shown below:
After 24 hours, the sultanas were removed from the water, blotted on filter paper and reweighed. The results are shown in the table:
|Sample |Mass after 24 hrs (g) |Percentage change in mass |
|1 |32.5 |30.0 |
|2 |32.2 |28.8 |
|3 |32.4 |29.6 |
a) Complete the table with the percentage change in mass of the sultanas in sample 3.
32.4 g – 25 g = 7.4g
(7.4 / 25) = 0.296
0.296 x 100 = 29.6 %
b) The change in mass of the sultanas was caused by the movement of water.
i) Name this process.
Osmosis
ii) Explain the results in terms of water concentrations.
The water moved from an area of high water concentration outside the cell to an area of low water concentration inside the cell. 1. Continued
c) Which of the following is the best reason for blotting the sultanas before reweighing? Tick the correct box.
| |To stop them sticking together | |To remove external sugar solution |
| | | | |
|X |To remove external water | |To make sure the sultanas were dried |
2. Plant cells and animal cells were left in water or 10% sucrose solution for 10 minutes. The cells were then examined under the microscope: The appearance of