OCR A Level Biology A
OCR A Level Biology A Exchange Surfaces Exam Questions
Free OCR A Level Biology A exam questions on Exchange Surfaces, with mark schemes. Covers surface area to volume ratio, the mammalian gas exchange system, ventilation and gas exchange in fish and insects.
Exchange Surfaces exam questions
1 question pack of real past exam questions with its mark scheme. Answer every question without notes, then mark your answers line by line against the mark scheme.
StemUp mark scheme flashcards
OCR A Level Biology A H420 Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About OCR A Level Biology A Exchange Surfaces
This topic covers how organisms exchange gases.
What you need to know
- SA:V Larger organisms need specialised exchange surfaces.
- Mammals Alveoli, cartilage, ciliated epithelium and goblet cells.
- Ventilation Breathing mechanism, spirometry, tidal volume and vital capacity.
- Fish and insects Countercurrent flow in gills; tracheal system in insects.
Common mistakes in Exchange Surfaces
- Saying alveoli walls are one cell thick blood vessels.
- Mixing tidal volume and vital capacity.
- Forgetting countercurrent maintains a gradient throughout.
Try three Exchange Surfaces exam-style questions
1. Explain why countercurrent flow is efficient. (2 marks)
Show the mark scheme answer
Blood and water flow in opposite directions (1), keeping a concentration gradient along the whole gill (1).
2. State the function of goblet cells. (1 mark)
Show the mark scheme answer
Secrete mucus to trap particles.
3. Define vital capacity. (1 mark)
Show the mark scheme answer
The maximum volume of air breathed out after a maximum breath in.
Exchange Surfaces FAQs
What does Exchange Surfaces cover?
Gas exchange in mammals, fish and insects.
Which practical links here?
Dissection of gas exchange systems and using a spirometer.
Why do small organisms not need lungs?
Their SA:V ratio is large enough for diffusion.
Revise this topic with flashcards: OCR A Level Biology A H420 Flashcards, with mark scheme answers for Anki and Quizlet.
