Compare three respiration equations
הוצג| English | משמעות |
|---|---|
| aerobic respiration/eəˈrəʊbɪk ˌrespɪˈreɪʃn/ | נשימה תאית אווקסילרית |
| fermentation/fɜːmənˈteɪʃn/ | תסיסה |
What would explain this observation?
- Muscle cells and yeast can both transfer energy without oxygen, but their products differ. Name the organism before selecting the anaerobic equation.
Build the model
- Cellular respiration is continuously occurring in living cells and is exothermic.
- It transfers energy needed for chemical reactions building larger molecules, movement and keeping warm.
- Aerobic respiration 有氧呼吸 uses oxygen: glucose + oxygen → carbon dioxide + water.
- Required symbols are C₆H₁₂O₆, O₂, CO₂ and H₂O.
- aerobic respiration: Cellular respiration using oxygen.
- fermentation 发酵: Anaerobic respiration in yeast producing ethanol and carbon dioxide.
Which products match anaerobic respiration in yeast?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Yeast respires anaerobically to ethanol and carbon dioxide - the basis of brewing and baking. Lactic acid is the product in animal muscle, and glucose with oxygen are reactants, not products.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Anaerobic respiration in muscle is glucose → lactic acid.
- Oxidation is incomplete, so much less energy is transferred than in aerobic respiration.
- In plant and yeast cells, anaerobic respiration is glucose → ethanol + carbon dioxide.
- Yeast fermentation is economically useful: carbon dioxide helps bread dough rise, and ethanol is used in alcoholic-drink manufacture.
In the lab: Build a comparison table with oxygen requirement, products and relative energy transfer. Use teacher-provided fermentation data or a supervised approved yeast practical; control temperature, substrate amount and observation time. Keep apparatus safely vented according to school instructions. Do not infer an energy yield from gas volume alone or introduce unrequired ATP counts.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: an approved yeast model produces 18 cm³ gas in 6 minutes, giving a mean rate of 3 cm³ per minute.
- A matched condition produces 12 cm³ in the same time, or 2 cm³ per minute.
- This compares carbon dioxide output under the stated conditions; it is not a direct comparison of muscle lactic-acid production.
Your turn: An approved yeast model produces 20 cm³ gas in 5 minutes. Calculate mean output rate.
An approved yeast model produces 20 cm³ gas in 5 minutes. Calculate mean output rate.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 4 cm³/min. Known: 20 cm^3 of gas in 5 minutes. Use mean rate = volume / time. Rate = 20/5 = 4 cm^3 per minute. This compares gas output under the stated conditions only.
Check the conclusion and its limits
- Respiration is a chemical process in cells, whereas breathing moves air.
- Plants also respire.
- Carbon dioxide is a product of the yeast anaerobic model but is not a product of the muscle equation here.
- Less energy transfer is not the same as no energy transfer.
Not true: Anaerobic respiration in muscles produces ethanol and carbon dioxide. In human muscle, anaerobic respiration produces lactic acid alone. Ethanol and carbon dioxide are the yeast pathway - the two equations must not be swapped.
- Cellular respiration is continuously occurring in living cells and is exothermic.
- Anaerobic respiration in muscle is glucose → lactic acid.
- Watch for: respiration is a chemical process in cells, whereas breathing moves air.
Anaerobic respiration in muscles produces ethanol and carbon dioxide.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
In human muscle, anaerobic respiration produces lactic acid alone. Ethanol and carbon dioxide are the yeast pathway - the two equations must not be swapped.
Cellular respiration using oxygen: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
aerobic respiration means Cellular respiration using oxygen.