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1. Describe the advantage of the Bohr effect during intense exercise - AQA - A-Level Biology - Question 6 - 2020 - Paper 1
Question 6
1. Describe the advantage of the Bohr effect during intense exercise. 2. VT can be identified as the first point when there is an increase in pO2 breathed out, with... show full transcript
Worked Solution & Example Answer:1. 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 working muscles during intense exercise. When exercising, the production of carbon dioxide (CO2) and lactic acid increases in the muscles, leading to a lower pH (more acidic conditions). This change causes hemoglobin to release oxygen more readily. Consequently, more oxygen is available for consumption by the muscles, which is crucial for sustaining high-intensity exercise.
Step 2
VT can be identified as the first point when there is an increase in pO2 breathed out, without an equivalent increase in pCO2 breathed out. Use Figure 3 to determine the time after the exercise started when the cyclist reached VT.
Answer
The time when the cyclist reached VT is identified as 10 minutes after the exercise began.
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 potential physiological change is an increase in breathing rate. During intense exercise, as CO2 levels rise, the respiratory system compensates by increasing the rate of breathing. This enhanced ventilation helps to expel more CO2, thus preventing its accumulation in the bloodstream and maintaining acid-base balance.
Step 5
Step 6
GW1516 is a performance-enhancing drug. Use Figure 4 to justify why professional athletes are not allowed to take GW1516.
Answer
GW1516 activates AMPK, which enhances the aerobic capacity and endurance of muscle fibres. This leads to unfair advantages in performance due to an improved ability to utilize fat as an energy source, allowing athletes to perform at higher intensities for longer durations without fatigue.
Step 7
Suggest how the overuse of EPO can increase the risk of a heart attack.
Answer
The overuse of EPO leads to increased red blood cell production, which thickens the blood. This increased viscosity can cause blockages in the coronary arteries, restricting blood flow to the heart muscle. As a result, the heart may receive insufficient oxygen and glucose, increasing the risk of a heart attack.