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Life Processes at the Cellular Level · Part 1 of 5
12 exam-style questions with model answers, plus 16 quick multi-choice questions — every question on this part of the standard, grouped by the 4 pages of notes they come from.
Write a full answer before you reveal the model one. That comparison is where the learning happens.
Name the organelle in which aerobic respiration takes place, and name the organelle in which photosynthesis takes place. State one structure found in a plant cell but not an animal cell, other than the chloroplast.
Explain why a plant cell needs both chloroplasts and mitochondria, when an animal cell needs only mitochondria.
A student examines two cells from the same plant under a microscope. Cell A is from a leaf and is packed with chloroplasts. Cell B is from a root and contains none, but has far more mitochondria than Cell A. Both cells contain identical DNA. Discuss how these differences arise and how they relate to the overall functioning of the plant.
A cube-shaped cell has sides of 10 μm. Calculate its surface area to volume ratio, and state what happens to this ratio as a cell grows larger.
Explain why a cell with a low surface area to volume ratio has difficulty supplying its centre with oxygen.
Cells in a growing tissue divide repeatedly rather than continuing to enlarge. Discuss why division, rather than continued growth, is the more effective strategy, and explain how cell shape offers an alternative solution to the same problem.
Define diffusion and define osmosis. State whether each requires energy from the cell.
Explain why oxygen can diffuse straight through the cell membrane but glucose requires a protein to cross it.
A plant cell and an animal cell are both placed in distilled water. The plant cell becomes firm; the animal cell bursts. Discuss the reasons for this difference, and explain why the difference matters for the organisms concerned.
Define active transport, and state where the energy for it comes from.
Explain why a root hair cell contains a large number of mitochondria.
A cell membrane can move glucose by both facilitated diffusion and active transport. Evaluate the effectiveness of each process for a cell lining the small intestine as digestion proceeds and the glucose concentration in the gut falls.