Gas Exchange in Mammals and Plants | OCR A-Level Biology B (Advancing Biology) (H422)
Gas Exchange in Mammals and Plants
- 76 questions
- 5 subtopics
- Further biology content, examined on all three papers
- Component 01, Component 02 and Component 03
Gas Exchange in Mammals and Plants is examined in all three written papers — the specification states that Components 01, 02 and 03 can each assess content from any of the five modules, so nothing is confined to one paper.
It covers tissues of the mammalian gas exchange system, gas exchange in the alveoli, pulmonary ventilation and lung volumes, expired air resuscitation and gas exchange and stomata in terrestrial plants.
Sample questions from Gas Exchange in Mammals and Plants
Answer each one closed book first, then open the answer.
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Tissues of the mammalian gas exchange system
What is the role of the goblet cells in the airway lining?
Show the answer
They secrete mucus, which traps dust particles, pollen and pathogens in the incoming air. -
Tissues of the mammalian gas exchange system
Explain why the smallest bronchioles contain no cartilage.
Show the answer
They are held open by the surrounding lung tissue and must be able to change diameter, which rigid cartilage would prevent. -
Gas exchange in the alveoli
Explain how ventilation helps to maintain the concentration gradients at the alveoli.
Show the answer
Breathing brings in fresh air with a high oxygen and low carbon dioxide concentration and removes air that has equilibrated with the blood, so the gradients are kept steep. -
Gas exchange in the alveoli
Describe the contribution of smooth muscle to gas exchange in the alveoli.
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By contracting or relaxing it changes the diameter of the bronchioles, adjusting how much air reaches the alveoli. -
Pulmonary ventilation and lung volumes
Define vital capacity and give a typical value for a healthy adult.
Show the answer
It is the largest volume of air that can be breathed out after taking the deepest possible breath in, typically about 4.5 dm³. -
Pulmonary ventilation and lung volumes
What does FEV1 measure?
Show the answer
It is the forced expiratory volume in one second, the volume of air a person can breathe out in the first second of a maximal forced exhalation. -
Expired air resuscitation
How can a rescuer tell that a rescue breath has been effective?
Show the answer
The casualty's chest is seen to rise as the breath is given and to fall again afterwards. -
Expired air resuscitation
State the ratio of chest compressions to rescue breaths used in adult CPR.
Show the answer
Thirty chest compressions to two rescue breaths.
The 5 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Tissues of the mammalian gas exchange system | Recall questions on the path of air to the alveoli, squamous alveolar epithelium, ciliated epithelium and goblet cells, C-shaped cartilage rings in the trachea, smooth muscle and elastic fibres in the airways and lungs, and recognising these tissues in stained sections. | 15 |
| Gas exchange in the alveoli | Recall questions on the thin barrier and large surface area of the alveoli, the factors setting the rate of diffusion, how ventilation and blood flow keep gradients steep, surfactant and premature babies, elastic fibres, smooth muscle and cilia, the moist surface, and emphysema. | 14 |
| Pulmonary ventilation and lung volumes | Recall questions on tidal volume and breathing rate, calculating pulmonary ventilation rate, vital capacity and residual volume, peak expiratory flow rate in asthma, FEV1 and airway obstruction, and how ventilation changes during exercise and with body size. | 14 |
| Expired air resuscitation | Recall questions on why exhaled breath supplies oxygen, opening an airway, giving an effective breath, how the technique differs for a baby, and the devices used instead of mouth-to-mouth. | 13 |
| Gas exchange and stomata in terrestrial plants | Recall questions on gas exchange by leaves by day and night, air spaces in the spongy mesophyll, lenticels, the structure of stomata and guard cells and how they open and close, the cost of closing stomata in drought, nail varnish impressions, and estimating stomatal density. | 20 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
OCR A-Level Biology B (Advancing Biology) Active Recall Guide
Every topic, not just this one. 2,895 questions with their answers.