International A Level Biology / Practical Skills in Biology II
The Unit 5 pre-release article revision notes
Edexcel International A Level Biology (YBI11), chapter 26: Practical Skills in Biology II, specification point U5. Free lesson.
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The Unit 5 pre-release article question is worth 20 of the paper’s 90 marks, so preparing the article carefully can make a real difference. Use its facts to answer the exact question in your own words, with the biology linked to the article’s example.
How to prepare the article
Most marks are won before the exam. Work through the article in stages so you understand its story first, then build the knowledge you will need to answer questions about it.
What the question parts ask
The 20 marks are divided into several short parts. Most ask you to define a term, explain a process, describe a study or use data. Follow the command word because it tells you what kind of answer is needed. Define: give a precise meaning. For example, ischaemia means an inadequate blood supply to a tissue or organ. Explain: use specification biology and apply it to the article’s example. Describe a study: give a fair design that could test the idea. For example, a study of dementia could compare people with and without dementia. Use data: give exactly the form asked for.…
Use the article without copying it
Copying a sentence or a chunk from the article does not show that you can apply biology. Use the article’s facts, but put them in your own words and connect them to what the question asks. A quotation only earns credit when you put it in the context of the question. Avoid repeating information already given in the stem. Add what follows from it instead. Make your answer specific: name the article’s gene, cell or organism rather than giving a generic answer such as “use bioinformatics”. Give the direction of change. Say whether something increases or decreases, rather than only saying that…
Start a pathway at its real beginning
If a question says that a drug is taken by mouth but acts in the brain, include the steps between swallowing it and its action. Starting at the brain misses early stages that can earn marks.
Explain how myelin affects impulse speed
For a question about multiple sclerosis damaging myelin, explain what myelin normally does and then state how the speed changes. Myelin insulates the axon, so depolarisation normally happens only at the nodes of Ranvier. The impulse jumps between nodes, which is called saltatory conduction. Without myelin, depolarisation is no longer limited to the nodes. Impulses are conducted more slowly.