Higher Tier: lactic acid and recovery
| English | 中文 | Pinyin |
|---|---|---|
| lactic acid/ˈlæktɪk ˈæsɪd/ | 乳酸 | rǔ suān |
| oxygen debt/ˈɒksɪdʒn det/ | 氧债 | yǎng zhài |
What would explain this observation?
- Higher Tier: Stopping an activity does not immediately return oxygen demand to its resting level. Recovery includes handling substances accumulated during anaerobic respiration.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- When oxygen supply cannot meet vigorous muscle demand, incomplete glucose oxidation produces lactic acid 乳酸. In the specified Higher Tier model, blood flowing through muscles transports lactic acid to the liver, where it is converted back into glucose. Oxygen debt 氧债 is the extra oxygen the body needs after exercise to react with accumulated lactic acid and remove it from the cells.
- oxygen debt: Extra oxygen needed after exercise to handle accumulated lactic acid in the specified model; lactic acid: The product of anaerobic respiration in muscles in this course model.
Where is transported lactic acid converted back into glucose in the specified model?
Explain the sequence using location and transport: muscle production, blood movement, liver processing and continued oxygen demand. The examination model supports explaining raised breathing during recovery. It does not imply that all oxygen consumed during exercise was absent or that every recovery process is the same chemical reaction.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Explain the sequence using location and transport: muscle production, blood movement, liver processing and continued oxygen demand. The examination model supports explaining raised breathing during recovery. It does not imply that all oxygen consumed during exercise was absent or that every recovery process is the same chemical reaction.
- Interpret supplied recovery oxygen-use data against a stated resting baseline. For equal observation intervals, subtract the resting requirement from each interval and total the extra volumes. This is an evidence model, not an invitation to provoke oxygen debt or fatigue experimentally. Human observations stay voluntary, low-risk and supervised.
Which two habits make the investigation or model in this case more defensible?
Interpret supplied recovery oxygen-use data against a stated resting baseline. For equal observation intervals, subtract the resting requirement from each interval and total the extra volumes. This is an evidence model, not an invitation to provoke oxygen debt or fatigue experimentally. Human observations stay voluntary, low-risk and supervised.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: resting oxygen use in a fictional model is 0.30 L per minute. Recovery use over three one-minute intervals is 0.90, 0.60 and 0.45 L. Extra oxygen = (0.90−0.30)+(0.60−0.30)+(0.45−0.30) = 1.05 L. Adding total use without subtracting baseline would overestimate the extra amount.
Two one-minute intervals use 0.80 and 0.50 L oxygen; baseline is 0.20 L per minute. Calculate total extra oxygen. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Two one-minute intervals use 0.80 and 0.50 L oxygen; baseline is 0.20 L per minute. Calculate total extra oxygen.
The result is 0.9 L. Known: resting oxygen use in a fictional model is 0.30 L per minute. Recovery use over three one-minute intervals is 0.90, 0.60 and 0.45 L. Extra oxygen = (0.90−0.30)+(0.60−0.30)+(0.45−0.30) = 1.05 L. Adding total use without subtracting baseline would overestimate the extra amount.
Check the conclusion and its limits
- An oxygen debt is a quantity of extra oxygen, not a financial cost or simply the time taken to rest. Blood transports lactic acid; it does not mean the heart converts it into glucose. This finite supplied record estimates only the extra oxygen included in its stated intervals.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Oxygen debt is calculated by adding all recovery oxygen without allowing for the resting requirement. This claim is false: An oxygen debt is a quantity of extra oxygen, not a financial cost or simply the time taken to rest. Blood transports lactic acid; it does not mean the heart converts it into glucose. This finite supplied record estimates only the extra oxygen included in its stated intervals.
Higher Tier: lactic acid and recovery: Explain the sequence using location and transport: muscle production, blood movement, liver processing and continued oxygen demand. The examination model supports explaining raised breathing during recovery. It does not imply that all oxygen consumed during exercise was absent or that every recovery process is the same chemical reaction.
Oxygen debt is calculated by adding all recovery oxygen without allowing for the resting requirement.
An oxygen debt is a quantity of extra oxygen, not a financial cost or simply the time taken to rest. Blood transports lactic acid; it does not mean the heart converts it into glucose. This finite supplied record estimates only the extra oxygen included in its stated intervals.
Extra oxygen needed after exercise to handle accumulated lactic acid in the specified model: write the technical term.
oxygen debt means Extra oxygen needed after exercise to handle accumulated lactic acid in the specified model.