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Describe the advantage of the Bohr effect during intense exercise - AQA - A-Level Biology - Question 6 - 2020 - Paper 1
Question 6
Describe the advantage of the Bohr effect during intense exercise. VT can be identified as the first point when there is an increase in pO2 breathed out, without an... show full transcript
Worked Solution & Example Answer:Describe the advantage of the Bohr effect during intense exercise - AQA - A-Level Biology - Question 6 - 2020 - Paper 1
Step 1
Describe the advantage of the Bohr effect during intense exercise.
Answer
The Bohr effect enhances oxygen delivery to muscles during intense exercise. As the intensity of exercise increases, the production of carbon dioxide (CO2) rises, resulting in increased acidity (lower pH) in the blood. This shift causes hemoglobin to release oxygen more readily in areas where it is most needed, such as the active muscles, thereby improving aerobic performance.
Step 2
Use Figure 3 to determine the time after the exercise started when the cyclist reached VT.
Answer
Referring to Figure 3, the cyclist reached VT at 10 minutes into the exercise. This is identified by the point where the increase in pO2 breathed out occurs without a corresponding rise in pCO2.
Step 3
Step 4
Suggest one physiological change that could cause this result. Explain how the physiological change would allow for the removal of the increase in the volume of carbon dioxide produced.
Answer
One physiological change is an increase in breathing rate. As exercise intensity increases, the body requires more oxygen and needs to expel more CO2. An increased breathing rate enhances gas exchange, enabling more efficient removal of CO2 from the bloodstream, thus preventing a significant rise in pCO2 levels during heightened activity.
Step 5
Use Figure 4 to suggest one reason why ATP can only be made for a limited time.
Answer
According to Figure 4, muscle fibres have a limited amount of phosphocreatine available to rapidly regenerate ATP. Once the phosphocreatine stores are depleted, ATP production becomes limited, restricting sustained high-intensity efforts.
Step 6
Use Figure 4 to justify why professional athletes are not allowed to take GW1516.
Answer
Figure 4 indicates that GW1516 promotes the development of slow muscle fibres at rest, which could enhance endurance at the cost of overall muscle power and performance. Such alteration would provide athletes with an unfair advantage, leading to its prohibition in competitive sports to maintain fairness.
Step 7
Suggest how overuse of EPO can increase the risk of a heart attack.
Answer
Overuse of EPO can lead to an excessively high haematocrit level, making the blood more viscous. This increased viscosity can strain the heart, block coronary arteries, and also lead to clot formation, significantly raising the risk of a heart attack.