A2 1 2019-style muscle and respiration link · 6 marks
Describe how ATP is used in muscle contraction and explain what happens when ATP supply is limited during vigorous exercise.
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CCEA A2 Biology 2019 past paper and mark scheme
Summer 2019 is part of the current CCEA GCE Biology (2016) specification, so every question style in it is still examinable. The papers and mark schemes themselves are published by CCEA; BioCCEA is an independent study tool and is not endorsed by CCEA.
What you sit in A2 2019
A2 1: Physiology, Co-ordination and Control, and Ecosystems
A2 1 written paper (2 hours)
Homeostasis and the kidney, nervous transmission, muscle contraction, hormonal co-ordination, photosynthesis, respiration and ecosystems.
A2 1 topic list and exam focusA2 2: Biochemistry, Genetics and Evolutionary Trends
A2 2 written paper (2 hours)
Respiration and ATP, monohybrid and dihybrid inheritance, sex linkage, population genetics, natural selection, speciation and gene technology.
A2 2 topic list and exam focusA2 3: Practical Skills in A2 Biology
A2 3 practical booklet plus a written practical-skills paper (1 hour 15 minutes)
Designing valid investigations, precision and error, statistical treatment of biological data and evaluating limitations.
A2 3 topic list and exam focus
How to sit the 2019 paper properly
- 1Print the paper and sit it in one block, to time, with no notes. A paper done in pieces tells you nothing about your exam performance.
- 2Mark it with the official CCEA mark scheme in front of you and award a mark only where the scheme's point is actually made.
- 3Log every dropped mark by unit topic, not by question number, so patterns appear across papers.
- 4Rewrite the two worst answers in full, using mark-scheme wording, then re-mark them.
- 5Come back to the same paper three weeks later and redo only the questions you lost marks on.
Sit the A2 2019 style questions
Answer each one under exam conditions. Your wording is marked against every mark scheme point before the full-mark answer appears.
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These questions are written in the style of the CCEA GCE Biology (2016) papers and are not reproduced from any live paper. CCEA owns the copyright in its question papers and mark schemes — always download the official paper and mark scheme from CCEA and use these worked answers alongside them. BioCCEA is an independent study tool and is not endorsed by CCEA.
Worked A2 2019 questions with mark schemes
Question styles that carried the most marks in the Summer 2019 papers, each with the full list of creditworthy mark scheme points, a model answer at full marks, and the marking point candidates most often missed.
A2 1 2019-style muscle and respiration link · 6 marks
Describe how ATP is used in muscle contraction and explain what happens when ATP supply is limited during vigorous exercise.
Command word: Describe — how to answer itMark scheme — 6 creditworthy points
- ATP binds to the myosin head, causing it to detach from actin
- Hydrolysis of ATP by ATPase returns the myosin head to its cocked position
- ATP is also used to actively transport calcium ions back into the sarcoplasmic reticulum
- When ATP is limited, anaerobic respiration produces ATP by glycolysis only
- Lactate accumulates, lowering pH, which can denature enzymes and cause fatigue
- Creatine phosphate can regenerate ATP rapidly from ADP in the short term
Full-mark answer
ATP binds to the myosin head, causing the cross-bridge with actin to break, and hydrolysis of that ATP by ATPase returns the head to its cocked position ready to bind again further along the actin. ATP is also required for the active transport of calcium ions back into the sarcoplasmic reticulum so that the muscle can relax. During vigorous exercise oxygen supply becomes limiting, so ATP is produced mainly by glycolysis in anaerobic respiration, which yields only 2 ATP per glucose. Creatine phosphate can regenerate ATP from ADP very rapidly, but only for a few seconds. Lactate accumulates, lowering the pH of the sarcoplasm, which reduces enzyme activity and contributes to muscle fatigue.
Examiner insight: This question rewards linking two topics. Candidates who write only about the sliding filament theory and never reach respiration typically score 3.
A2 2 2019-style heart control question · 6 marks
Explain how the sinoatrial node coordinates the cardiac cycle, and explain how heart rate is increased during exercise.
Command word: Explain — how to answer itMark scheme — 7 creditworthy points
- The sinoatrial node in the right atrium initiates a wave of excitation - it is the pacemaker
- The wave spreads across both atria causing atrial systole
- Non-conducting tissue prevents the wave passing directly to the ventricles, so there is a delay at the atrioventricular node
- The wave passes down the bundle of His and Purkyne fibres to the apex, causing ventricular systole from the base upwards
- During exercise chemoreceptors detect a fall in blood pH (rise in CO2) and stretch receptors detect increased movement
- The cardiovascular centre in the medulla sends impulses along the sympathetic nerve, releasing noradrenaline at the SAN, which increases the rate of excitation
- Adrenaline in the blood has the same effect
Full-mark answer
The sinoatrial node in the wall of the right atrium acts as the pacemaker, initiating a wave of excitation that spreads across both atria and causes atrial systole. A band of non-conducting tissue prevents the wave from spreading directly to the ventricles, so it is delayed briefly at the atrioventricular node, allowing the atria to empty. The wave then travels down the bundle of His and the Purkyne fibres to the apex of the ventricles, so ventricular systole begins at the base and pushes blood upwards into the arteries. During exercise, chemoreceptors detect the fall in blood pH caused by rising carbon dioxide, and stretch receptors in the muscles detect increased movement. The cardiovascular centre in the medulla then sends more impulses along the sympathetic nerve to the sinoatrial node, where noradrenaline is released and increases the frequency of excitation. Adrenaline secreted into the blood has the same effect, so heart rate rises.
Examiner insight: The delay at the atrioventricular node must be linked to atrial emptying, and the apex-upwards detail is a separate mark. For the exercise half, name the receptor, the centre and the nerve - 'the brain speeds the heart up' scores nothing.
A2 1 2019-style Calvin cycle application · 5 marks
Explain how the products of the light-independent reaction are used to make other biological molecules, and explain why RuBP must be regenerated.
Command word: Explain — how to answer itMark scheme — 6 creditworthy points
- Triose phosphate (TP) is the immediate product and can be converted to glucose / hexose sugars
- Hexoses can be polymerised to starch for storage or cellulose for cell walls
- TP can be converted to glycerol and fatty acids to form lipids
- With a source of nitrogen, GP / TP can form amino acids and then proteins
- Most TP is used to regenerate RuBP, using ATP from the light-dependent reaction
- Without regeneration there would be no RuBP to accept carbon dioxide and the cycle would stop
Full-mark answer
Triose phosphate is the immediate product of the light-independent reaction. Two molecules can join to form a hexose sugar such as glucose, which can be polymerised into starch for storage or cellulose for cell walls. Triose phosphate can also be converted into glycerol and fatty acids to make lipids, and with a supply of nitrogen, GP and triose phosphate can be used to make amino acids and then proteins. However, five out of every six triose phosphate molecules are used to regenerate RuBP, a reaction that requires ATP from the light-dependent reaction. This regeneration is essential because RuBP is the carbon dioxide acceptor: without it no more carbon dioxide could be fixed and the cycle would stop.
Examiner insight: The 5-in-6 detail is not required, but the ATP requirement for regeneration is. Answers that list molecules without saying which precursor they come from lose the first two marks.
These questions are written in the style of the CCEA GCE Biology (2016) papers and are not reproduced from any live paper. CCEA owns the copyright in its question papers and mark schemes — always download the official paper and mark scheme from CCEA and use these worked answers alongside them. BioCCEA is an independent study tool and is not endorsed by CCEA.
Download the official CCEA paper and mark schemePractise the A2 2019 paper in the app
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Get your 2019 answers marked
Photograph a written answer from this paper and see it marked line by line in CCEA mark-scheme language, with the exact phrase you needed to earn each missing mark.