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.

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.

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.

Figure 1 shows the structure of a virus particle.

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)

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

Streptococcus bacteria can cause a sore throat or skin infection.

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

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Figure 1 shows some Streptococcus bacteria.

Figure 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.

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.

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

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.

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.

(1)

(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

(2)

(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

(1)

(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.

(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.