Disease (Edexcel GCSE Biology)

In 2012 there was an outbreak of whooping cough in the UK.

Figure 1 shows the number of new cases of whooping cough in the UK from April to December 2012.

Figure 1

(i) Describe the trend shown in the graph from April to December.

(1)

(ii) In September 2011 there were 168 cases of whooping cough in the UK.
Calculate the difference in numbers of cases of whooping cough between September 2011 and September 2012.

(2)

Dysentery is a bacterial disease which results in symptoms such as diarrhoea containing blood or mucus, sickness and stomach cramps. Houseflies, such as the one pictured in Figure 2, can be an animal vector for dysentery.

Figure 2

(i) Define what is meant by the term 'vector' in this scenario.

(1)

(ii) Describe a series of events by which a housefly causes a person to become infected with dysentery. (3)

Higher Tier only

Chalara Ash Dieback is a fungal disease affecting ash trees. 

Cases of Ash Dieback were reported in a region of Devon. The affected trees were cut down to avoid infection of nearby ash trees. It was also recommended that all trees within a 30 km radius of the infected trees were checked for infection.

(i) Describe the signs that would indicate that an ash tree has been infected with Chalara Ash Dieback.

(1)

(ii) Explain how Chalara Ash Dieback could infect trees as far as 30 km away from an infected tree. (2)

Figure 1 shows the structure of a virus particle.

Figure 1

(i) Complete the table below to identify the structures labelled in Figure 5.

(3)

(ii) Describe the function of component B.

(2)

Explain why a virus could be considered parasitic.

The Human Immunodeficiency Virus (HIV) is a virus which emerged during the  20th century and has since infected millions of people globally. 

Below are some facts about the Human Immunodeficiency Virus (HIV):

• It is a transmissible disease passed on through through bodily fluids

• HIV infects and destroys lymphocytes in the bloodstream

• HIV may eventually lead to the onset of Acquired Immunodeficiency Syndrome (AIDS)

(i) Describe two precautions which could reduce or prevent transmission of HIV.

(2)

(ii) Explain how infection with HIV can lead to the development of AIDS.

(4)

HIV is caused by a virus which infects lymphocytes in the blood.

(i) Complete the table to correctly order the statements about HIV infection.

(2)

(ii) Which viral pathway is represented in part (i)?

(1)

Streptococcus bacteria can cause a sore throat or skin infection.

An illness called scarlet fever can also develop during an infection with this bacterium.

(i) Give two precautions a doctor should take when treating a patient who is infected with Streptococcus.

(2)

(ii) From September 2013 to March 2014 there were 2 830 cases of scarlet fever in the UK.

From September 2014 to March 2015 there were 5 943 cases of scarlet fever.

Calculate the percentage increase of the number of cases of scarlet fever between the periods September 2014 to March 2015 and September 2013 to March 2014.

(2)

.......................................... %

(iii) Figure 1 shows some Streptococcus bacteria.

Figure 1

Some bacteria are motile, meaning they can move themselves.

Why is a Streptococcus bacterium not motile?

(1)

Infections can also be caused by viruses.

Describe the lytic pathway of a virus and how this causes the spread of infection through a population.

Measles is a disease caused by a virus.

Describe the lytic pathway for a virus.

Name the organisation which defines health as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.

Tuberculosis (TB) is a communicable disease.

(i) State two ways that communicable diseases are different from non-communicable diseases.

(2)

(ii) Explain one way that the spread of tuberculosis (TB) can be reduced or prevented.

(2)

(iii) A student researched the number of people with TB in some countries.

Figure 1 shows the student’s data.

Figure 1

Complete the table to show the student’s data.

(2)

Explain why people with AIDS are more susceptible to TB.

Chlamydia is caused by a pathogen.

(i) Chlamydia is transmitted by

(1)

(ii) The type of pathogen that causes chlamydia is a

(1)

Figure 1 shows the number of cases of chlamydia in the United Kingdom per 100000 people between 1996 and 2013.

Figure 1

(i) Describe the trend in the number of cases of chlamydia between 1996 and 2013.

(2)

(ii) State the number of cases of chlamydia per 100 000 in 2013.

(1)

(iii) The population of the United Kingdom in 2013 was 64 000 000.

Calculate the number of people with chlamydia in 2013.

(2)

One type of food poisoning is caused by Salmonella microorganisms. Raw chicken often contains Salmonella and so should be frozen within 1 or 2 days of purchase for up to 9 months. Raw chicken should be kept refrigerated for no longer than 2 days. To prevent food poisoning from frozen chicken, it should be thoroughly defrosted before cooking. The raw chicken should not be allowed to touch other food which is not going to be cooked. After cooking, the chicken should be cooled quickly and stored in a refrigerator at 4 °C for 3 to 4 days.

(i) Identify the type of pathogen which causes Salmonella food poisoning.

(1)

(ii) Suggest and explain why raw chicken can be preserved in a freezer for up to 9 months but only 1 to 2 days in the fridge.

(2)

Figure 1 shows the number of cases of tuberculosis (TB) per 100 000 in 3 regions of England between the years of 2000 and 2011.

Figure 1

(i) Compare the trend shown in Figure 1 in the data for the three regions of England.

(3)

(ii) Suggest why a higher number of cases of TB would be expected in a city compared to a rural region.

(2)

Gonorrhoea is a sexually transmitted bacterial infection.

Figure 1 shows the number of people diagnosed with gonorrhoea in the UK.

Figure 1

Explain how gonorrhoea is transmitted and how the number of people infected can be reduced.

Use data from the graph to justify why it is necessary to reduce the number of people infected.

This question is about a disease called cholera. Cholera is an acute diarrhoeal infection caused by ingestion of contaminated food or water.

(i) Cholera is caused by a pathogen.

Identify the type of pathogen that causes cholera. 

(1)

(ii) Cholera is a communicable disease. 

Describe the difference between a communicable and a non-communicable disease. 

(1)

Since the 19th century, there have been cholera outbreaks worldwide. The most affected countries are in East Africa and South-East Asia.

Figure 1 shows the number of reported cases in Addis Ababa, Ethiopia from 1990-2010.

Figure 1

(i) Calculate the percentage decrease in the number of cholera cases in Addis Ababa from 1996 to 2010. Give your answer to 1 decimal place

(2)

(ii) Suggest and explain two reasons why the number of cases might have decreased.

(4)

The graph in Figure 1 shows data about men in the UK who have died from throat cancer and cigarettes smoked from 1900 to 2000.

Figure 1

(i) Which statement about the graph is correct?

Put a cross (☒) in the box to indicate your answer.

(1)

(ii) Describe the changes in throat cancer deaths from 1950 to 2000.

Use data from the graph to support your answer.

(2)

(iii)     Suggest an explanation for the changes described in part (ii).

(2)

Vaping has become a popular alternative to smoking cigarettes in the last decade.

Figure 2 shows data on the effect of smoking tobacco cigarettes, vaping and abstinence (not smoking at all) on heart rate throughout a typical day.

Figure 2

One student concluded that vaping is good for your health.

Evaluate their statement. Use information from Figure 2 and your own knowledge. 

Norovirus is a highly contagious virus that causes vomiting and diarrhoea.

(i) A virus is an example of a pathogen.

State what is meant by the term ‘pathogen’.

(1)

(ii) Complete Table 1 below to compare viruses and bacteria.

Put a tick (✓) in the correct boxes.

(5)

Table 1

The image in Figure 1 shows a norovirus capsid, which shows the virus magnified 900,000x.

The cell has an image size of 36mm.

Figure 1

Calculate the actual size of the norovirus capsid in Figure 1. Give your answer in micrometres.

Viruses, such as noroviruses, have two stages in their lifecycle.

Compare and contrast the stages in the lysogenic pathway and the lytic pathway.