Question 1Multiple choice · 1 mark
Where does aerobic respiration take place in a cell?
- A mitochondria
- B chloroplasts
- C nucleus
- D ribosomes
Show answer
Answer: A
Free Respiration questions for IGCSE Biology (0610), part of Disease, gas exchange & respiration. Each question has the answer and the marking points an examiner would look for.
Generate a full Respiration worksheet →All Disease, gas exchange & respiration questionsWhere does aerobic respiration take place in a cell?
Answer: A
Yeast can respire aerobically or anaerobically.
Write the word equation for anaerobic respiration in yeast.
Give one use of this reaction in industry.
Describe how you would investigate the effect of temperature on the rate of respiration of yeast.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | glucose → ethanol + carbon dioxide glucose → ethanol + carbon dioxide B2 | 2 |
| (b) | bread / alcohol production bread-making (CO₂ raises dough) or brewing (ethanol) B1 | 1 |
| (c) | water baths; count bubbles/measure gas; same conditions yeast and sugar solution in water baths at different temperatures B1 measure rate by counting bubbles / volume of CO₂ per minute B1 keep concentration and volume constant B1 | 3 |
A student investigates the effect of temperature on anaerobic respiration in yeast. The volume of carbon dioxide collected in 10 minutes is measured.
| temperature / °C | 20 | 25 | 30 | 35 | 40 |
|---|---|---|---|---|---|
| volume of CO2 / cm³ | 4 | 11 | 12 | 18 | 9 |
State the word equation for anaerobic respiration in yeast.
Calculate the mean rate of carbon dioxide production at 35 °C in cm³ per minute.
Explain the change in volume between 35 °C and 40 °C.
Suggest why a layer of oil is placed on the surface of the yeast suspension.
During vigorous exercise, human muscles also respire anaerobically. Explain why a person continues to breathe deeply after the exercise has stopped.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | glucose → ethanol + carbon dioxide glucose → B1 ethanol + carbon dioxide B1 | 2 |
| (b) | 1.8 cm³/min 1.8 B1 | 1 |
| (c) | Enzymes in yeast begin to denature above the optimum, so the rate of respiration decreases enzymes (in yeast) denatured above optimum B1 rate of respiration decreases B1 | 2 |
| (d) | Stops oxygen entering so respiration is anaerobic prevents oxygen entering / keeps conditions anaerobic B1 | 1 |
| (e) | Lactic acid has built up (oxygen debt); extra oxygen needed for aerobic respiration of lactic acid in the liver (to carbon dioxide and water); lactic acid carried in blood to liver lactic acid built up / oxygen debt B1 lactic acid transported to liver in blood B1 oxygen used to break down lactic acid (aerobic respiration) B1 | 3 |
A student counts the number of times a fish opens and closes its gill covers in 30 seconds, at different water temperatures. Table 4.1 shows the mean results.
| temperature / °C | 10 | 15 | 20 | 25 | 30 |
|---|---|---|---|---|---|
| gill movements in 30 s | 28 | 51 | 77 | 115 | 197 |
Calculate the rate of gill movements per minute at 20 °C.
Describe the relationship between temperature and the rate of gill movements.
Fish are ectotherms (their body temperature matches the water). Explain why the rate of gill movements increases with temperature.
Suggest one variable, other than temperature, that the student should keep constant, and explain why.
Suggest why the student recorded the movements for 30 s three times at each temperature.
State two features of gills that make them efficient gas exchange surfaces.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 154 per minute 77 × 2 = 154 B1 | 1 |
| (b) | rate increases as temperature increases; data quote as temperature increases the rate of gill movements increases B1 data quote, e.g. from 28 to 197 movements per 30 s between 10 °C and 30 °C / more than doubles for every 10 °C rise B1 | 2 |
| (c) | enzymes faster; more respiration; more O₂ needed enzymes in the fish’s cells are more active at higher temperatures B1 so the rate of respiration increases B1 more oxygen must be absorbed / more CO₂ removed, so ventilation increases B1 | 3 |
| (d) | size/species of fish; oxygen content; time acclimatised e.g. the same fish / size of fish, the oxygen concentration of the water, time left to adjust to each temperature B1 because it also affects the rate of respiration / ventilation B1 | 2 |
| (e) | calculate a mean / reliability to calculate a mean and reduce the effect of anomalous counts B1 | 1 |
| (f) | large surface area (filaments, lamellae); thin; good blood supply Any 2 of: large surface area (many filaments / lamellae); thin walls / short diffusion distance; good blood supply B2 | 2 |
Respiration releases energy in all living cells.
Write the word equation for aerobic respiration.
State three uses of the energy released by respiration in humans.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | glucose + oxygen → carbon dioxide + water glucose + oxygen B1 → carbon dioxide + water B1 | 2 |
| (b) | muscle contraction; protein synthesis; cell division; active transport; growth; nerve impulses; body temperature Any 3 of: any three: muscle contraction; protein synthesis; cell division; active transport; growth; passage of nerve impulses; maintenance of body temperature B3 | 3 |
A student investigates the effect of temperature on anaerobic respiration in yeast. Yeast in sugar solution is placed in a sealed flask, covered with a layer of oil, in a water bath at each temperature. The volume of carbon dioxide produced in 10 minutes is measured.
| temperature / °C | 15 | 25 | 35 | 45 | 55 |
|---|---|---|---|---|---|
| volume of CO₂ / cm³ | 4 | 16 | 20 | 12 | 1 |
Write the word equation for anaerobic respiration in yeast.
Define aerobic respiration.
Calculate the rate of carbon dioxide production at 35 °C in cm³ per minute.
Explain the results between 35 °C and 55 °C.
Explain why the yeast must be left in the water bath for several minutes before measurements start.
State two uses of anaerobic respiration in yeast.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | glucose → ethanol + carbon dioxide glucose → ethanol B1 + carbon dioxide B1 | 2 |
| (b) | chemical reactions in cells using oxygen to break down nutrient molecules to release energy chemical reactions in cells that use oxygen B1 to break down nutrient molecules to release energy B1 | 2 |
| (c) | 2.0 cm³/min 20/10 = 2.0 B1 | 1 |
| (d) | rate decreases; enzymes in yeast denatured; active site shape changes volume falls above 35 °C B1 respiration is controlled by enzymes B1 enzymes are denatured at high temperature so the active site changes shape B1 | 3 |
| (e) | to reach the temperature of the water bath so that the yeast mixture reaches the temperature of the water bath B1 | 1 |
| (f) | bread-making; ethanol / alcoholic drinks / biofuel making bread (CO₂ makes dough rise) B1 making ethanol for alcoholic drinks / biofuels B1 | 2 |
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