Gas Exchange (Edexcel IGCSE Biology)

The diagram shows the human thorax.

(i) Name structures Q and R.

(1)

(ii) Explain how structure S helps a person to exhale.

(3)

The graph shows how the volume of air exhaled varies with time during one breath.

This is shown for a person with lung disease and a person with healthy lungs.

Explain why a person with lung disease is often breathless and unable to exercise.

The diagram shows apparatus a student uses to compare inhaled and exhaled air.

The student breathes into and out of the mouthpiece for one minute.

(i) Explain which flask exhaled air passes through.

(2)

(ii) Explain the changes that will happen in the limewater in flask A and in flask B.

(2)

(iii) The student uses limewater to compare the composition of exhaled and inhaled air. 

Suggest an alternative substance that they could use.

(1)

Describe the role of the diaphragm and the intercostal muscles in inhalation.

The diagram shows the location of the lungs in a horse.

(i) Identify the part labelled X.

(1)

(ii) Identify which blood vessel transports blood to the horse’s lungs.

(1)

(iii) Identify which row of the table describes what happens when the horse breathes in.

(1)

The table shows the percentage of total blood flow in different body parts of a horse at rest and when running.

Comment on the changes in the percentage of total blood flow in these body parts.

The horse breathes faster and deeper when running.

Explain why the horse continues to breathe faster and deeper for a period of time after it has stopped running.

The data in the table were collected in Japan during a seven-year study.

Scientists collected data on the age of mothers and whether they smoked during pregnancy.

They also recorded the percentage of the babies that had a low birth mass.

(i) Calculate the percentage of mothers aged 19 years and under who smoked during pregnancy.

(2)

(ii) Determine the ratio of non-smokers to smokers used in the study.

Give the ratio as the nearest whole number (n) in the form n:1

(2)

A student examines this data and concludes that smoking is the main factor that causes low birth mass.

Use the data and your own biological knowledge to comment on this conclusion.

An electronic cigarette (e‐cigarette) has been invented.

E‐cigarettes are held in the hand like normal cigarettes. Instead of burning tobacco, e‐cigarettes heat a liquid that contains nicotine and flavourings to produce a vapour that is inhaled.

Scientists carried out an investigation to see how the smoking habits of students changed between 2011 and 2016.

Each year they determined the percentage of students who used e‐cigarettes and the percentage of students who smoked normal cigarettes during the year.

The results are shown in the table.

Plot a line graph to show how the percentage of students who used e‐cigarettes and the percentage of students who smoked normal cigarettes changed between 2011 and 2016.

Join the points with straight lines.

Describe the changes in the percentages of students smoking cigarettes and using e‐cigarettes between 2011 and 2016.

The scientists interviewed 60 000 students each year during the period of the investigation.

Calculate the change in the number of students who were smoking normal cigarettes from 2011 to 2016.

Some people are promoting e‐cigarettes as a healthier alternative to smoking normal cigarettes.

(i) Suggest why using e‐cigarettes may be thought to be less harmful than smoking normal cigarettes.

(4)

(ii) Suggest why many doctors are concerned about promoting the use of e‐cigarettes to young people.

(2)

The scientist Richard Doll collected data about deaths from cancer in the 1950s.

The table shows data for four groups.

(i) Plot a bar chart to show the number of deaths from lung cancer and from other cancers for each of the four groups.

(5)

(ii) Calculate the difference in the percentage of all deaths caused by lung cancer in heavy smokers compared to the percentage of all deaths caused by lung cancer in light smokers.

(3)

This table gives no information about the age of the people who died.

Suggest why age may affect the likelihood of dying from lung cancer.

Explain one effect, other than lung cancer, that smoking has on health.