Respiration Banker

1. (a) What are the products of anaerobic respiration in yeast?A lactic acid onlyB carbon dioxide and waterC ethanol and carbon dioxideD lactic acid and carbon dioxide [1]

1. (a) Write the word equation for anaerobic respiration in human muscle cells. [1]
2. (b) State one way in which anaerobic respiration in yeast differs from anaerobic respiration in muscle. [1]

1. (a) State two differences between aerobic and anaerobic respiration in humans. [2]

1. (a) For each type of respiration, state whether each substance is used or produced, or is not involved.Type: aerobic (human); anaerobic (human muscle); anaerobic (yeast).Substances: oxygen; carbon dioxide; lactic acid; ethanol. [4]

A student puts 50 cm³ of warm sugar solution and 5 g of dried yeast into a conical flask and stretches a balloon over its neck. The circumference of the balloon is measured every 10 minutes.time / min | 0 | 10 | 20 | 30 | 40circumference / cm | 8.0 | 9.5 | 13.0 | 17.5 | 21.0

1. (a) Calculate the increase in circumference between 0 and 40 minutes. [1]
2. (b) Name the gas that inflates the balloon and the process that produces it. [2]
3. (c) State one variable that should be kept constant if the experiment is repeated with different sugars. [1]

1. (a) After vigorous exercise, what happens to the lactic acid that has built up in the muscles?A It is converted to glucose in the muscles and stored.B It is carried in the blood to the liver and broken down by aerobic respiration.C It is excreted unchanged by the kidneys.D It is converted to ethanol in the liver. [1]

1. (a) Which statement correctly compares anaerobic respiration with aerobic respiration?A Anaerobic respiration releases much less energy per glucose molecule.B Anaerobic respiration takes place only in mitochondria.C Anaerobic respiration releases more energy per glucose molecule.D Anaerobic respiration uses oxygen but produces no carbon dioxide. [1]

1. (a) After running up four flights of stairs, a student continues to breathe deeply and quickly for several minutes. Explain why. [4]

A student investigates the effect of glucose concentration on anaerobic respiration in yeast. Yeast suspension and glucose solution are placed in a test-tube with a delivery tube dipping into water, and the number of gas bubbles released in 2 minutes is counted. Each concentration is tested three times.glucose concentration / % | bubbles: trial 1 | trial 2 | trial 30 | 0 | 0 | 02 | 8 | 10 | 94 | 17 | 16 | 316 | 24 | 25 | 268 | 26 | 25 | 27

1. (a) Identify the anomalous result and calculate the mean number of bubbles for 4 % glucose, ignoring the anomalous result. [2]
2. (b) Name the gas in the bubbles. [1]
3. (c) Describe and explain the effect of glucose concentration on the rate of respiration shown by these results. [3]

A student boils some glucose solution, cools it and then adds yeast. The mixture is put in a test-tube and covered with a layer of vegetable oil. A delivery tube leads from the test-tube into a second tube containing limewater.

1. (a) Explain why the glucose solution was boiled and then cooled before the yeast was added. [2]
2. (b) State the purpose of the layer of oil. [1]
3. (c) Describe and explain the change seen in the limewater. [2]

1. (a) A baker in Lahore mixes yeast, sugar and flour with warm water to make naan dough and leaves it in a warm place. The dough doubles in size. Explain why. [3]
2. (b) Explain why the ethanol made by the yeast is not present in the cooked naan. [1]

1. (a) A sprinter in a 100 m race relies largely on anaerobic respiration in the leg muscles, while a marathon runner relies mainly on aerobic respiration. Explain why. [3]
2. (b) Suggest why a sprinter cannot keep running at top speed for 10 minutes. [2]

1. (a) During 5 minutes of hard exercise, a cyclist's muscles needed 3.0 dm³ of oxygen per minute, but her lungs and heart supplied only 2.4 dm³ per minute. Calculate the total oxygen shortfall during the exercise. [2]
2. (b) Explain how the shortfall is repaid after the exercise. [3]

1. (a) When a field of maize is flooded for several days, the soil becomes waterlogged and the roots run short of oxygen. State the products of anaerobic respiration in the root cells. [1]
2. (b) Explain why the plants absorb fewer mineral ions from waterlogged soil. [3]

1. (a) Which is the balanced chemical equation for anaerobic respiration in yeast?A C₆H₁₂O₆ → C₂H₅OH + CO₂B C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂C C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂OD C₆H₁₂O₆ → 2C₃H₆O₃ [1]

The concentration of lactic acid in the blood of an athlete was measured before, during and after a 400 m race.time / min | 0 (start) | 1 (end of race) | 5 | 15 | 30 | 45lactic acid / mmol per dm³ | 1.2 | 12.6 | 11.0 | 6.4 | 2.9 | 1.3

1. (a) Calculate the percentage increase in lactic acid concentration from the start to the end of the race. [2]
2. (b) Describe the changes in lactic acid concentration after the race. [2]
3. (c) Explain why lactic acid concentration rose during the race. [2]

Yeast and sugar-cane juice were kept at 30 °C in a sealed fermentation vessel. The total volume of carbon dioxide released was measured every hour.time / h | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7total CO₂ / dm³ | 0 | 12 | 30 | 52 | 70 | 80 | 84 | 85

1. (a) Calculate the mean rate of carbon dioxide production between 1 h and 3 h, in dm³ per hour. [2]
2. (b) Suggest two reasons why the rate of carbon dioxide production falls after 4 hours. [2]
3. (c) Name the useful product, other than carbon dioxide, that a sugar mill distillery obtains from this process. [1]

Equal masses of bread dough containing yeast were placed in 100 cm³ measuring cylinders at different temperatures. The increase in volume of the dough after 20 minutes was recorded.temperature / °C | 20 | 30 | 40 | 50 | 60increase in volume / cm³ | 8 | 22 | 40 | 26 | 2

1. (a) Calculate the rate of increase in volume at 40 °C in cm³ per minute. [2]
2. (b) Explain the result at 60 °C. [2]
3. (c) Suggest how the student could find the optimum temperature more precisely. [1]

1. (a) The ethanol produced when yeast respires anaerobically can be burned as a fuel, releasing a large amount of energy. Use this fact to explain why anaerobic respiration releases much less energy per glucose molecule than aerobic respiration. [3]
2. (b) Suggest why human muscle cells can respire anaerobically for only a short time. [2]

Two students ran on a treadmill for 6 minutes. Their heart rates (beats per minute) were then recorded every minute until they returned to resting values.time after exercise / min | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8student P (trained athlete) | 150 | 120 | 98 | 80 | 66 | 64 | 64 | 64 | 64student Q (untrained) | 172 | 158 | 140 | 122 | 108 | 96 | 88 | 80 | 74Resting heart rate: P 64, Q 74.

1. (a) State how long each student took to return to their resting heart rate. [2]
2. (b) Calculate the percentage fall in Q's heart rate during the first 4 minutes after exercise. Give your answer to two significant figures. [2]
3. (c) Suggest why heart rate remains above resting level for several minutes after exercise and why it falls faster in the trained athlete. [3]

1. (a) Which is the word equation for aerobic respiration?A glucose + oxygen → carbon dioxide + waterB carbon dioxide + water → glucose + oxygenC glucose → lactic acidD glucose + oxygen → ethanol + carbon dioxide [1]

1. (a) Define aerobic respiration. [2]
2. (b) Name the cell structure where most aerobic respiration takes place. [1]

1. (a) State three uses of the energy released by respiration in the human body. [3]

1. (a) Which process in the human body does NOT need energy from respiration?A contraction of musclesB synthesis of proteinsC diffusion of oxygen from alveoli into the bloodD uptake of ions by active transport [1]

A simple respirometer contains 10 germinating mung (moong) beans on a gauze above soda lime in a boiling tube. The tube is connected to a horizontal capillary tube containing a drop of coloured liquid. The tube is kept in a water-bath at 25 °C. After 12 minutes the drop has moved 36 mm towards the boiling tube. The internal cross-sectional area of the capillary is 0.8 mm².

1. (a) State the function of the soda lime. [1]
2. (b) Explain why the coloured drop moves towards the beans. [2]
3. (c) Calculate the rate of oxygen uptake in mm³ per minute. [2]
4. (d) Describe a suitable control for this experiment. [1]

1. (a) Name the two substances that the blood must deliver to leg muscle cells for aerobic respiration. [2]
2. (b) Explain why the rate of aerobic respiration in leg muscle increases when a person starts running. [2]

Hydrogencarbonate indicator is red-orange in air, turns yellow when carbon dioxide concentration rises and purple when it falls. Five woodlice were placed on a gauze above the indicator in a sealed tube. The time taken for the indicator to turn yellow was recorded at three temperatures.temperature / °C | 10 | 20 | 30time to turn yellow / min | 24 | 12 | 7

1. (a) Explain why the indicator turns yellow. [2]
2. (b) Calculate the rate as 100 ÷ time at 10 °C and at 30 °C. Give each to one decimal place. [2]
3. (c) Explain the effect of temperature on the rate of respiration shown. [2]

1. (a) Which is the balanced chemical equation for aerobic respiration?A C₆H₁₂O₆ + O₂ → CO₂ + H₂OB C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂OC 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂D C₆H₁₂O₆ + 6O₂ → 6CO₂ + 12H₂O [1]

Germinating moong beans were placed in vacuum flask A. Flask B contained the same mass of beans that had been boiled, cooled and rinsed in disinfectant. A thermometer was put into each flask, and the mouth plugged with cotton wool. Temperatures were read every day.day | 0 | 1 | 2 | 3 | 4flask A / °C | 21.0 | 23.5 | 26.0 | 28.0 | 29.0flask B / °C | 21.0 | 21.0 | 21.0 | 21.5 | 21.0

1. (a) Calculate the temperature rise in flask A over the 4 days. [1]
2. (b) Explain why the temperature in flask A rises. [2]
3. (c) Explain why the beans in flask B were rinsed in disinfectant. [2]
4. (d) Suggest why the flask was plugged with cotton wool rather than a rubber bung. [1]

1. (a) Climbers who travel quickly from Islamabad to a base camp at 5000 m in the Karakoram often feel tired after very little effort. At this altitude each breath contains about half as much oxygen as at sea level. Explain why the climbers tire easily. [4]