Anaerobic respiration

A student investigated the effect of glucose concentration on the rate of anaerobic respiration in yeast.

The student used five concentrations of glucose: 5 %, 10 %, 15 %, 20 % and 25 %.

A teaspoon of dried yeast was added to 20 cm³ of the 5 % glucose concentration in a measuring cylinder.

A drop of washing up liquid was added and the mixture was stirred.

A reaction occurred and bubbles collected as foam on the surface of the mixture.

The height of the foam was measured after five minutes.

This method was repeated for each concentration of glucose.

Describe how to set up a control for this investigation.

State how the scientist could improve this investigation to increase the rate of the reaction.

The results of this investigation are shown in Figure 5.

The student thought one of the results was anomalous.

Explain which of these results is anomalous.

Explain why the height of the foam was greatest for the 25 % glucose concentration.

Respiration occurs in cells.

Why do cells respire?

An athlete runs every day as part of their training.

Explain why the breathing rate of the athlete increases when running.

When the athlete is running, their muscle cells use both aerobic respiration and anaerobic respiration.

State two differences between aerobic respiration and anaerobic respiration.

Bromothymol blue (BTB) solution is an indicator of pH.

Figure 10 shows the colour of BTB at different pH levels.

When air is passed through green BTB, for one minute, the solution stays green.

When a person breathes out through a straw into BTB for one minute the solution turns yellow.

Explain why the air breathed out turns the BTB solution yellow.

*(ii) Devise a plan, using green BTB solution, to investigate the amount of carbon dioxide in the air athletes breathe out after they have been running at different speeds.

Include:

• how you would use green BTB solution.

• how you would control at least two variables.

Respiration occurs in cells.

Why do cells respire?

An athlete runs every day as part of their training.

Explain why the breathing rate of the athlete increases when running.

When the athlete is running, their muscle cells use both aerobic respiration and anaerobic respiration.

State two differences between aerobic respiration and anaerobic respiration.

Bromothymol blue (BTB) solution is an indicator of pH.

Figure 2 shows the colour of BTB at different pH levels.

When air is passed through green BTB, for one minute, the solution stays green.

When a person breathes out through a straw into BTB for one minute the solution turns yellow.

Explain why the air breathed out turns the BTB solution yellow.

A scientist placed pondweed into two sealed test tubes containing green BTB solution.

Test tube A was kept in the dark. Test tube B was kept in the light. All other conditions were kept the same. Figure 3 shows these test tubes at the start of the investigation.

Figure 4 shows the colour of the BTB solution after 5 hours.

Explain the results for tube A and tube B shown in Figure 4.

The effect of different types of exercise on the heart rate of an athlete was investigated.

The athlete counted the number of beats in 10 seconds at the carotid artery pulse point, as shown in Figure 7.

This measurement was used to calculate the heart rate.

The athlete exercised for 20 minutes.

The heart rate was recorded every 5 minutes during each type of exercise.

State how the heart rate was calculated using this method.

Give two ways of improving the method used to obtain the data needed to calculate the heart rate.

Figure 8 shows the results of this investigation.

Comment on the difference in the heart rates during these types of exercise.

Exercise increases adrenalin levels.

State which endocrine gland secretes adrenalin.

Explain the effect of adrenalin on liver cells during exercise.

After high intensity exercise, the pH of muscles can decrease from pH 7.0 to pH 6.3.

Explain this change in pH.

Figure 7 shows a single-celled pond organism (Amoeba proteus).

Which row of the table allows the net diffusion of oxygen into Amoeba proteus ?

Amoeba proteus uses oxygen for aerobic respiration.

Complete the equation for aerobic respiration.

glucose + oxygen _........ +_........ (+ energy is released)

Humans breathe faster when they exercise.

Which two changes allow the rate of respiration in the muscle to increase?

Figure 8 shows breathing data for a human at rest and when running at 5 metres per second on a running machine.

Calculate the mean volume of air breathed per minute when running at 5 metres per second.

Give your answer to one decimal place.

_........ dm³ per minute

Devise an investigation to compare the mean number of breaths per minute for men, with the mean number of breaths per minute for women, when running at 5 metres per second on a running machine.

Whilst running, the leg muscles of an athlete tightened up, causing cramp.

Name the product of anaerobic respiration that can cause cramp.

Which row of the table shows the endocrine gland and hormone involved in the control of blood glucose concentration?

State a target organ for the hormone that controls blood glucose concentration.

People with a high BMI are more likely to develop type 2 diabetes. Figure 8 shows the mass, height and BMI for two people.

Use the formula to calculate the BMI for person A

Person B develops type 2 diabetes.

Describe two lifestyle changes person B should make to help to control their blood glucose concentration.

Which row of the table shows the type or types of respiration that use glucose?

A scientist measured the rate of respiration in a person when sleeping and then running at different speeds.

Figure 9 shows the results.

Explain the trend shown in Figure 9.

Figure 2 shows alveoli from a healthy lung.

Smoking can cause a condition called emphysema.

Figure 3 shows alveoli from a person with emphysema.

Use words from the box to complete the following sentences.

breathing diffusion larger

osmosis smaller thicker

The alveoli from the person with emphysema have a_........

surface area than the alveoli from a healthy lung.

The surface area of the alveoli will affect how much oxygen moves into the blood

by the process of_........ .

The graph in Figure 4 shows the volume of oxygen an athlete absorbs at different running speeds.

Describe the trend shown in Figure 4.

Which uses more oxygen when the running speed of the athlete changes from 4 to 6 km per hour?

Explain why the athlete produces lactic acid when running at 14 km per hour.