Respiration

Explain why a person’s heart rate increases when they are running compared with when they are at rest.

Figure 16 shows a diagram of mucus‑producing goblet cells and ciliated epithelial cells in the airways of the lungs.

(Source: © K.K.T Madhusanka/Shutterstock)

Figure 16

Describe how pathogens are removed from the airways by ciliated epithelial cells.

During a race, athletes respire aerobically and anaerobically.

Figure 17 shows an athlete after a race.

Explain how aerobic respiration provides energy for running.

The rate of respiration of maggots was investigated using the equipment shown in Figure 18.

State the reason why the soda lime is placed in the test tube.

The drop of liquid in Figure 18 is at 20 mm.

The drop of coloured liquid moved at a mean rate of 2 mm per minute.

Draw, on Figure 19, the new position of the bubble after the five minutes.

The investigation was repeated with two maggots.

Explain how the movement of the drop of coloured liquid would be affected if the investigation was repeated using fewer maggots.

State one way this investigation can be improved to obtain more reliable results.

Figure 2 shows a diagram of mucus‑producing goblet cells and ciliated epithelial cells in the airways of the lungs.

(Source: © K.K.T Madhusanka/Shutterstock)

Figure 2

Describe how pathogens are removed from the airways by ciliated epithelial cells.

During a race, athletes respire aerobically and anaerobically.

Figure 3 shows an athlete after a race.

Explain how aerobic respiration provides energy for running.

The rate of respiration of maggots was investigated using the equipment shown in Figure 4.

State the reason why the soda lime is placed in the test tube.

The drop of liquid in Figure 4 is at 20 mm.

The drop of coloured liquid moved at a mean rate of 2 mm per minute.

Draw, on Figure 5, the new position of the bubble after the five minutes.

The investigation was repeated with two maggots.

Explain how the movement of the drop of coloured liquid would be affected if the investigation was repeated using fewer maggots.

State one way this investigation can be improved to obtain more reliable results.

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

(a) 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.

(i) Describe how to set up a control for this investigation.

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

(b) The results of this investigation are shown in Figure 7.

Figure 7

(i) The student thought one of the results was anomalous. Explain which of these results is anomalous.

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

8 (a) Figure 9 shows a human heart.

(i) Draw arrows on Figure 9 to show the direction of blood flow through the left side of the heart.

(ii) Name the main blood vessel that carries deoxygenated blood into the heart.

(b) Figure 10 shows the heart rate and stroke volume of a person when at rest and when doing exercise.

Figure 10

(i) Calculate the difference in cardiac output when at rest and when doing exercise. Give your answer to 3 significant figures and include units in your answer.

(ii) Explain why the cardiac output needs to increase during exercise.

9 Respiration occurs in cells.

(a) Why do cells respire?

(b) An athlete runs every day as part of their training.

(i) Explain why the breathing rate of the athlete increases when running.

(ii) When the athlete is running, their muscle cells use both aerobic respiration and anaerobic respiration. State two differences between aerobic respiration and anaerobic respiration.

(c) Bromothymol blue (BTB) solution is an indicator of pH. Figure 16 shows the colour of BTB at different pH levels.

Figure 16

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.

(i) 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 5 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 6 shows these test tubes at the start of the investigation.

Figure 7 shows the colour of the BTB solution after 5 hours.

Explain the results for tube A and tube B shown in Figure 7.

3 (a) Figure 3 shows a section through the skin.

(Source: © mariyaermolaeva/Shutterstock)

The skin helps to keep body temperature constant.

(i) Which is the correct term for maintaining a constant internal environment?

(ii) Explain how structures X and Y help to regulate body temperature when the body is too cold.

(iii) Explain how shivering can help a person regulate their body temperature.

(b) Figure 4 shows a person’s body temperature during 24 hours. midnight midday midnight

0 2 4 6 8 10 12 14 16 18 20 22 24 time in hours

Figure 4

(i) State this person’s highest body temperature.

(ii) Explain the change in body temperature from 0 hours to 4 hours.

3 (a) Figure 4 shows a cross-section of an artery and a vein.

(Source: © The University of Kansas Medical Center)

Figure 4

(i) Explain one difference between the artery wall and the vein wall shown in Figure 4.

(ii) Name one structure that is found in veins but not found in arteries.

(b) A human body has 5 dm³ of blood. At rest 20% of the blood travels to the muscles. During exercise 60% of the blood travels to the muscles.

(i) Calculate the volume of blood travelling to the muscles during exercise.

(ii) Explain one reason why there is an increase in blood flow to muscles during exercise.

7 (a) A gardener read information on a gardening society website about how to use a compost bin. Figure 11 shows the compost bin and some of the instructions.

Figure 11

(i) Give one reason why the gardener thought the gardening society website was a good source of information.

(ii) Give reasons why soil is added to the compost bin and why the contents are turned to add air.

(iii) The gardener noticed the compost bin became warm a few days after vegetation was added. Why did the contents of the compost bin become warm?

(iv) The mass of the contents of the compost bin at the start was 40 kg. After 60 days the mass of the contents was 32 kg. Which is the rate of decay?

*(b) Explain the uses of auxins, gibberellins and ethene in the commercial production of plants and fruits.

8 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 12. This measurement was used to calculate the heart rate.

(Source: © dityazemli/Shutterstock)

Figure 12

The athlete exercised for 20 minutes. The heart rate was recorded every 5 minutes during each type of exercise.

(a) (i) State how the heart rate was calculated using this method.

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

Figure 13 shows the results of this investigation.

Figure 13

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

(b) Exercise increases adrenalin levels.

(i) State which endocrine gland secretes adrenalin.

(ii) Explain the effect of adrenalin on liver cells during exercise.

(c) After high intensity exercise, the pH of muscles can decrease from pH 7.0 to pH 6.3. Explain this change in pH.

In Ireland during the 19th century, a mould caused potato plants to rot.

Explain how this mould affected food security in Ireland.

A group of pupils investigated the effect of temperature on mould growth on bread.

Figure 8 shows the bread after being kept at different temperatures for seven days.

Which is the best estimate of the percentage cover of mould on the bread at 40C?

State two conclusions that can be made about the growth of mould on the bread from 0C to 40C shown in Figure 8.

Explain why there was no mould growing on the bread kept at 60C.

Figure 9 shows some part-baked bread in a sealed bag.

The gas in the bag is nitrogen, which prevents the bread from going mouldy.

If the bag is opened, the bread goes mouldy within days.

State why the bread goes mouldy.

Explain why keeping food in a fridge slows down the growth of mould.

Figure 10 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 11 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.

Figure 18 shows ciliated epithelial cells from the airways of a human as seen using a light microscope.

Draw the cell labelled A in the box below.

Label three parts of this cell on your diagram.

State the function of the ciliated epithelial cells in the airways of the human breathing system.

Figure 19 shows equipment used to investigate the rate of respiration in maggots.

As the maggots respire, the drop of coloured liquid moves towards the test tube.

Figure 20 shows the position of the drop of coloured liquid after ten minutes.

Use information from Figures 19 and 20 to calculate the mean rate of respiration of the maggots in mm per minute.

*(c) Explain how alveoli in human lungs are adapted for gas exchange.

Include the names of the gases that are being exchanged.

Figure 4 shows ciliated epithelial cells from the airways of a human as seen using a light microscope.

Draw the cell labelled A in the box below.

Label three parts of this cell on your diagram.

State the function of the ciliated epithelial cells in the airways of the human breathing system.

Figure 5 shows equipment used to investigate the rate of respiration in maggots.

As the maggots respire, the drop of coloured liquid moves towards the test tube.

Figure 6 shows the position of the drop of coloured liquid after ten minutes.

Use information from Figures 5 and 6 to calculate the mean rate of respiration of the maggots in mm per minute.

Describe a control for this investigation.

A hospital patient was tested for diabetes.

A nurse recorded his mass and height.

Figure 10 shows these measurements.

Calculate the BMI of this patient using the information in Figure 10.

Blood samples were taken from this patient every four hours.

The glucose concentrations were recorded in Figure 11.

Describe the trends shown in this data.

This patient was diagnosed as being type 2 diabetic.

Explain why the blood glucose concentration of this patient remained high from 4 hours to 8 hours.

This patient did some exercise during these 24 hours.

Explain how the data in Figure 11 shows that this exercise occurred after 8 hours but before 12 hours.

Exercise causes changes in the circulation of the blood.

In an investigation, the change in blood flow to different parts of the body during exercise was measured.

All the volunteers used in the study were healthy females of the same age.

Figure 13 shows the results of this investigation.

During exercise, the blood flow to the stomach changes.

Calculate the percentage change in blood flow to the stomach in response to exercise.

Give your answer to the nearest whole number

Suggest two other variables that should be controlled in this investigation.

*(iii) Explain the changes in blood flow, shown in Figure 13, that are caused by exercise.

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 11 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 12 shows the results.

Explain the trend shown in Figure 12.

A slide of potato cells was viewed using a light microscope.

Figure 20 is a drawing of the slide showing starch grains in the potato cells.

Calculate the mean number of starch grains in potato cells P, Q and R.

Which structures are found in plant cells but are not found in animal cells?

A scientist investigated how the length of starch grains in potatoes changed when the potatoes were stored in the dark.

Figure 21 shows a potato after being stored in the dark.

Three potatoes were used in the investigation.

The length of starch grains in potato 1 were measured at the start.

The length of starch grains were measured in potato 2 after 5 weeks in the dark.

The length of starch grains were measured in potato 3 after 10 weeks in the dark.

Figure 22 shows the results.

Calculate the percentage difference in the mean length of starch grains in potato 2 at 5 weeks and in potato 3 at 10 weeks.

State two variables the scientist should have controlled to improve this investigation.

The starch grains in the potatoes became smaller as the starch was converted into glucose.

State why the potatoes need glucose.

*(c) Figure 23 shows a diagram of some equipment that can be used to investigate the rate of photosynthesis.

Devise a plan to investigate the effect of light intensity on the rate of photosynthesis.

Include variables you would need to control.

A slide of potato cells was viewed using a light microscope.

Figure 4 is a drawing of the slide showing starch grains in the potato cells.

Calculate the mean number of starch grains in potato cells P, Q and R.

Which structures are found in plant cells but are not found in animal cells?

A scientist investigated how the length of starch grains in potatoes changed when the potatoes were stored in the dark.

Figure 5 shows a potato after being stored in the dark.

Figure 5

Three potatoes were used in the investigation.

The length of starch grains in potato 1 were measured at the start.

The length of starch grains in potato 2 were measured after 5 weeks in the dark.

The length of starch grains in potato 3 were measured after 10 weeks in the dark.

Figure 6 shows the results.

Calculate the percentage difference in the mean length of starch grains in potato 2 at 5 weeks and in potato 3 at 10 weeks.

State two variables the scientist should have controlled to improve this investigation.

The starch grains in the potatoes became smaller as the starch was converted into glucose.

State why the potatoes need glucose.

Describe how starch is broken down into glucose.

(a) A student investigated respiration in three different organisms.

Red hydrogencarbonate indicator was placed in each of three test tubes.

Gauze was placed in each test tube to hold the organisms.

In test tube 1 the student placed four germinating peas.

In test tube 2 the student placed four dried peas.

In test tube 3 the student placed four mealworms.

Bungs were added to each of the test tubes.

The three test tubes were left for one hour.

The equipment used is shown in Figure 16.

test tube 1 test tube 2 test tube 3

Figure 16

State two ways this method could be improved to make the results for these three organisms more comparable.

Describe a suitable control for this investigation.

Hydrogencarbonate indicator changes from red to yellow when more carbon dioxide is present.

The results for this investigation are shown in Figure 17.

Explain why the result for the germinating peas is different from the result for the dried peas.

How was the carbon dioxide produced in this investigation?

*(c) Carbon dioxide is carried in blood plasma.

Human blood also contains red blood cells and white blood cells.

Explain how the structure of red blood cells and white blood cells is related to their function.

(a) A student investigated respiration in three different organisms.

Red hydrogencarbonate indicator was placed in each of three test tubes.

Gauze was placed in each test tube to hold the organisms.

In test tube 1 the student placed four germinating peas.

In test tube 2 the student placed four dried peas.

In test tube 3 the student placed four mealworms.

Bungs were added to each of the test tubes.

The three test tubes were left for one hour.

The equipment used is shown in Figure 3.

test tube 1 test tube 2 test tube 3

Figure 3

State two ways this method could be improved to make the results for these three organisms more comparable.

Describe a suitable control for this investigation.

Hydrogencarbonate indicator changes from red to yellow when more carbon dioxide is present.

The results for this investigation are shown in Figure 4.

Explain why the result for the germinating peas is different from the result for the dried peas.

How was the carbon dioxide produced in this investigation?

Explain why cellular respiration is essential for living organisms.

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

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.

(a) Iguanas are lizards.

Some species of iguana live on hot islands in the Pacific Ocean and use the environment to regulate their body temperature.

Figure 11 shows an iguana on a rock in the sunshine.

A marine biologist measured the oxygen consumption of an iguana at different temperatures.

Figure 12 shows the results.

Describe how the body temperature of the iguana affects its oxygen consumption.

Explain why the body temperature of the iguana affects its oxygen consumption.

Iguanas do not have sweat glands.

When an iguana is too hot, it pants by opening its mouth to cool down.

Explain how this behaviour helps to cool the iguana down.

Where in the human brain is the thermoregulatory centre?

Explain the role of vasodilation in thermoregulation.