6 exam-style questions with full mark schemes and model answers. Write your own answer and the AI examiner marks it against the mark scheme.
Learn this properly: Plant and Animal CellsA microbiologist examines a drop of soil water and identifies two organisms: a soil bacterium (a prokaryote) and a single-celled soil amoeba (a eukaryote that engulfs and digests food).
Compare the structures of the prokaryotic bacterial cell and the eukaryotic amoeba cell. In your answer you should describe both similarities and differences, and refer to named sub-cellular structures. (6 marks)
A student photographs a cell using a light microscope. In the image, one chloroplast measures 6 mm across. The student is told that the real (actual) width of the chloroplast is 4 μm.
(Remember: 1 mm = 1000 μm.)
(a) Calculate the magnification of the image. Show your working. (3 marks)
(b) Using a higher-power objective lens, the magnification is now ×1500. In this new image a mitochondrion appears 3 mm long. Calculate the real length of the mitochondrion, in micrometres (μm). (1 mark)
The diagram describes the cell cycle, which includes interphase followed by mitosis and then division of the cytoplasm.
(a) State two things that happen to a cell during interphase. (2 marks)
(b) Mitosis produces two new cells. State how the chromosome content of each new cell compares with that of the original parent cell. (1 mark)
A student investigated osmosis using cylinders cut from a potato. Five cylinders of equal starting mass were each placed in a different sucrose concentration for 40 minutes, then reweighed. The percentage change in mass was calculated for each.
| Sucrose concentration / mol dm⁻³ | Percentage change in mass / % |
|---|---|
| 0.0 | +14 |
| 0.2 | +6 |
| 0.3 | 0 |
| 0.5 | −9 |
| 0.7 | −18 |
(a) One cylinder had a starting mass of 5.0 g and a final mass of 5.7 g. Show that the percentage change in mass was +14 %. (2 marks)
(b) State the concentration of sucrose solution that has the same water concentration as the potato cells, and explain how the data show this. (1 mark)
Stem cells from a human embryo can be used to treat some medical conditions.
(a) Explain why an embryonic stem cell can be used to make many different types of body cell, whereas a stem cell from adult bone marrow cannot. (1 mark)
(b) Suggest one reason some people object to using embryonic stem cells in medical treatments. (1 mark)
A root hair cell absorbs mineral ions from the soil even when the concentration of those ions is higher inside the cell than in the soil water.
Name the process by which the root hair cell absorbs the mineral ions in this situation. (1 mark)