This free quiz has all 15 multiple choice questions from Section A of the OCR A Level Biology A Biological Processes paper (H420/01), June 2023. It marks itself, so you get your score as soon as you finish.
What the multiple choice section covers
Nucleotides, carbohydrates and proteins as polymers (2.1.2)
Lipids, amino acid structure and collagen (2.1.2)
How pH affects enzyme-controlled reactions (2.1.4)
Water movement through plants and the cardiac cycle (3.1.3, 3.1.2)
Photosynthetic pigments and products made in a leaf cell (5.2.1)
Neurones, sensory receptors and communication systems (5.1.3, 5.1.1)
Phototropism experiments on shoot tips (5.1.5)
Processing practical data and choosing a statistical test (1.1.3)
How to use it
Section A is worth 15 of the 100 marks in 2 hours 15 minutes, so aim to spend roughly 20 minutes on it. Examiners advise reading all four options carefully before answering, especially when a question asks which statement is not true. Paper 1 tests modules 1, 2, 3 and 5, so expect Year 12 and Year 13 content side by side.
Where students lost marks on this paper (from the OCR examiners' report and mark scheme)
These points cover the whole paper, not just the multiple choice section. Each is followed by wording that gained marks.
Cardiac output calculation and units: Some candidates divided stroke volume by heart rate instead of multiplying, and many gave units such as cm3/bpm.
✔ Gains credit: cardiac output = heart rate x stroke volume, with units of cm3 min-1 (or dm3 min-1), since beats are not a unit of cardiac output.
Valves open due to pressure: A common misconception was that the left atrioventricular valve opens because of atrial systole, and some candidates compared pressures between the two sides of the heart instead of within the left side.
✔ Gains credit: a logical sequence through the left side of the heart from the pulmonary vein, linking contraction to pressure changes and explaining that valves open and close because of pressure differences across them.
Fetal haemoglobin needs low pO2: Most candidates knew fetal haemoglobin has a higher affinity for oxygen, but few stated that the transfer happens at the low partial pressure of oxygen in the placenta.
✔ Gains credit: at the same pO2 fetal haemoglobin has a higher affinity, so at low pO2 in the placenta oxygen dissociates from maternal haemoglobin, diffuses into fetal blood and increases the saturation of fetal haemoglobin.
Control experiment, not control variable: Many candidates called the distilled water dish a control variable rather than a control experiment, and few went on to say what it was for.
✔ Gains credit: a control experiment that shows growth without IAA, so results with and without IAA can be compared or a percentage change calculated.
Vesicles do not cross the cleft: 'Synapse' alone was not precise enough for the gap between neurones, and some candidates said vesicles move across the cleft.
✔ Gains credit: naming the synaptic cleft precisely, and describing vesicles fusing with the presynaptic membrane to release neurotransmitter by exocytosis, which then crosses the cleft.
Name the ions and the limb: Weak answers referred to 'solutes' or 'salt', listed the wrong ions such as K+ or Ca2+, or did not say which limb of the loop of Henle they meant.
✔ Gains credit: sodium and chloride ions are actively transported out of the upper ascending limb, which is impermeable to water, while water leaves the descending limb by osmosis, as part of a countercurrent multiplier.
Water is lost as vapour: Many candidates described loss of 'water' without saying it leaves as water vapour, and some claimed no photosynthesis happens in the shade.
✔ Gains credit: higher light intensity increases the rate of photosynthesis, so stomata open wider for carbon dioxide entry and more water evaporates and is lost as water vapour by transpiration.
Keep practising
Try the multiple choice sections of the June 2023 AS paper and June 2023 Biological Diversity paper, or practise by topic with the Transport in Animals, Plant and Animal Responses, Photosynthesis, Enzymes quizzes. You can also browse all our OCR A Level Biology quizzes. Our OCR A masterclasses (Year 12 on Wednesdays at 5.15pm, Year 13 on Tuesdays at 6.30pm) work through real exam questions on one topic each week.
Practising recall is so important for retention and learning. Try this quiz without books first !