AQA GCSE Biology

Topic Questions

3.1 Communicable Diseases

1a3 marks

Diseases can be caused by a variety of different types of pathogens. 

Draw one line from each disease to the type of pathogen that causes it. 

connect-the-disease-to-the-pathogen

1b2 marks

Rose black spot is a disease caused by a fungi. 

One of the symptoms of rose black spot is that the leaves of the plant get purple or black spots on them. 

Why would this reduce the growth of the plant? 

1c1 mark

The black spots in the leaves are caused by the cells of the plant being digested by the fungi.

Which chemical do fungi make that cause the cells to be digested?

  • Antibodies

  • Acid

  • Enzymes

  • Antibiotics

1d2 marks

How is rose black spot treated? 

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2a1 mark

Which of the following options is not a non-specific defence against pathogens?

  • Skin

  • White blood cell

  • Trachea

  • Stomach

2b3 marks

Figure 1 shows the process of phagocytosis. 

Figure 1

phagocytosis-1

Describe the stages of phagocytosis shown in the image. 

2c
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2 marks

Table 1 shows how the number of white blood cells in the blood changes before and during an infection with a pathogen. 

Table 1
  Before infection During infection
Number of white blood cells per dm3 of blood 9 x 109 7 x 1010

Calculate the difference in the number of white blood cells per dm3 of blood before and during an infection. 

2d2 marks

After the person has recovered from the infection, the number of white blood cells reduces but is slightly higher than the pre-infection levels. 

Explain why. 

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3a2 marks

What is a communicable disease? 

3b2 marks

HIV is an example of a communicable disease. 

State one method that allows HIV to spread and state one strategy that can be used to prevent its spread. 

3c2 marks

Currently HIV has no cure, unlike many other diseases which can be treated using antibiotics. 

Why can HIV not be treated using antibiotics?

3d1 mark

Select a word from the options below to complete the sentence. 

When a pathogen enters the body, white blood cells respond by releasing _____________ .

  • Acid

  • Antigens

  • Toxins

  • Antibodies

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4a3 marks

When scientists need to discover a new drug, such as a new type of antibiotic, they often turn to plants and microorganisms for ideas. 

Complete the table to match up the species of plant or microorganism with the drug that is extracted from them.

Species of plant or microorganism Drug that is extracted from them 
Penicillium  
  Heart drug digitalis
Willow  
4b2 marks

Before new drugs can be used by the public they must first go though preclinical and clinical trials. 

What are some of the steps involved in preclinical trials?

4c3 marks

Some drugs trials make use of a placebo. 

Describe the type of trial that uses a placebo and explain why it is useful.

4d2 marks

At the end of the trial, the findings from the research undergo a process called peer review. 

Why is peer review an important stage of this process? 

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5a4 marks

People can become immune to a disease by being vaccinated against it. 

How do vaccines work? 

5b2 marks

An example of a type of vaccine is the MMR vaccine. 

It provides protection against three different diseases.

One of them is measles.

What are the other two?

5c
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2 marks

The World Health Organisation (WHO) has set a target that 95% of all children should have received the first dose of the MMR vaccine by the date of their fifth birthday. 

England has consistently not met that target. 

In the year 2020 there were 693 928 children in England that celebrated their fifth birthday. 

654 197 of these children had received their first MMR dose. 

Calculate the percentage of five-year-old children that had received their first MMR vaccine.

5d2 marks

The WHO believe that by vaccinating at least 95% of all communities they can effectively 'eliminate' cases of measles.

Explain why they believe this. 

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1a1 mark

Ignaz Semmelweis was a doctor in Vienna in 1846.

It was his job to oversee the treatment of women during childbirth in two maternity clinics at the Vienna General Hospital. 

It was very common in those days for women to die shortly after childbirth from a condition known as 'puerperal fever', which we now know to have frequently been caused by infection with the pathogenic bacteria Streptococcus pyogenes.

How do pathogenic bacteria negatively affect the body after the first infection?

1b
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2 marks

Table 1 shows the number of births and deaths in the two clinics between 1841 and 1846. 

Table 1

semmelweis-data-1841-1846

Calculate the percentage death rate in the first clinic during the year 1843. 

1c3 marks

In the middle of the 19th century, Ignaz Semmelweis, a doctor in Hungary, noticed that the first clinic had a much higher average death rate in comparison to the second clinic. 

He did some investigations and found that, in the first clinic, the doctors were learning anatomy through the dissection of dead bodies, often moving straight onto delivering babies immediately after. He hypothesised that there were "particles" on their hands that were being transferred to the patients from the dissection. 

He asked the doctors to wash their hands before delivering babies in the maternity unit to see if it made a difference to the number of mothers dying from 'puerperal fever'.

Figure 1 shows the death rate in the first clinic during the years 1846-1848.

Figure 1

handwashing

Describe how introducing the handwashing policy affected the death rate from 'puerperal fever'.

1d2 marks

At the time of Semmelweis' research, bacteria had not yet been discovered.

Given our modern-day knowledge of pathogens and their methods of spread, suggest two other strategies doctors should carry out in order to avoid infecting their patients. 

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2a2 marks

In order to feed the growing human population, farming practice has changed in recent years to be much more intensive. 

Animals are often kept in small barns with hundreds of other animals in close proximity. 

This has led to a rise in the number of farm animals suffering from diseases caused by pathogens. 

Explain why. 

2b3 marks

To prevent the spread of these pathogens, some farmers have been giving antibiotics to their animals even when they are not sick. 

This has lead to the problem of increasing the amount of antibiotic resistance held by animal pathogens. 

Explain how this has occurred.

2c
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3 marks

In order to counteract this issue an organisation called "Responsible Use of Medicines in Agriculture" (RUMA) was set up in 1997. 

In 2019 RUMA made the announcement that the sale of veterinary antibiotics for use in food-producing animals was down 53% between 2014 and 2018.

In 2014 62.5 mg/kg veterinary antibiotics were sold for use in food-producing animals.

Calculate the mass of antibiotics that were sold in 2018.

Give your answer in mg/kg.

2d2 marks

In 2022 there was a large outbreak of avian influenza in the UK, which is sometimes referred to a bird flu. 

Explain why the overuse of antibiotics was not related to this recent outbreak. 

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3a
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5 marks

Table 2 shows information about the number of deaths from malaria in a particular area of Africa. 

Table 2

Year Number of deaths from malaria per 100 000 people
2005 159
2007 136
2009 114
2011 97
2013 94
2015 92

Complete Figure 2 using data from Table 2.

Figure 2

malaria-death-graph-axes-1

3b1 mark

Malaria is a disease that is spread through the bite of female Anopheles mosquitoes. 

What is the name used to describe the role of the mosquito in this process? 

3c5 marks

The mosquito is effective at infecting humans with the malaria pathogen because it is able to bypass the non-specific defence of the skin. 

Describe the how the skin acts as a non-specific defence against pathogens. 

3d5 marks

Describe how the human body defends itself against pathogens in the blood. 

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4a2 marks

When someone is suffering from an infection it is possible for them to take painkillers and antibiotics at the same time.

Compare the mechanism of action of painkillers and antibiotics.

4b1 mark

A trial was carried out to test the efficacy of a new type of painkiller drug. 

This is the method used.

  1. Participants were asked to take a drug.
  2. Half an hour later they were poked with a blunt needle.
  3. They were asked to rate their pain on a scale of 0 - 5, with 0 being no pain at all and 5 being extreme pain.

It was a double-blind trial.

Of the 40 participants, 20 took the painkiller and 20 took a placebo. 

Table 3 shows the findings from the trial. 

Table 3

  Painkiller drug Placebo
Average pain rating (scale from 0 - 5) 2.4 4.1

The researcher concluded:

"The painkiller stops people feeling pain". 

Give one piece of evidence that supports their statement. 

4c2 marks

The researcher concluded:

"The painkiller stops people feeling pain". 

Suggest two reasons why the statement may not be valid. 

4d2 marks

As well as efficacy, what else needs to be established before a new drug can be approved for use?

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5a1 mark

Pathogens such as measles and Covid-19 are spread through sneezes and coughs which travel through the air. 

Give the correct term for this method of spreading an infection.

5b2 marks

The chance of dying from measles and Covid-19 can be reduced by getting vaccinated. 

When a vaccine enters the body, the body responds by producing antibodies. 

Explain why. 

5c2 marks

Complete the graph in Figure 3 to show how the number of antibodies changes when a vaccinated person becomes infected with a live pathogen. 

Figure 3
antibody-graph-1

5d3 marks

After a lot of people were vaccinated against Covid-19, a new variant of the virus emerged that had different shaped antigens to the first version of the virus. 

This caused the vaccine to be less effective against the virus.

Why would having different shaped antigens cause the vaccine to be less effective against the virus?

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1a1 mark

Read the following information about lungworm:

Foxes can be infected by a parasitic lungworm.

The life cycle of the lungworm includes an adult stage, during which the lungworm reproduces in the fox and infects its lungs.

The larvae (young stages of the worm) end up in the digestive system of infected foxes. Lungworm is spread through the faeces of infected foxes.

Slugs can pick up these larvae.

If a fox comes into contact with a slug that carries lungworm larvae, it can become infected. 

What type of organism is the slug in the life cycle of the lungworm?

1b1 mark

Give one way in which the spread of lungworm can be prevented.

1c2 marks

Explain why it is not possible to use antibiotics to treat a fox infected with lungworm. 

1d2 marks

Malaria is a disease characterised by a recurrent fever.

Female mosquitoes are responsible for spreading the pathogen that causes malaria as they feed on blood, whereas males do not. 

Mosquitos also feed on flowers from crop plants, pollinating them in the process.

Describe two ways in which the spread of malaria can be reduced. 

1e4 marks

A biotechnology company has created male, genetically modified (GM) mosquitoes that carry a bacterial gene.

The bacterial gene affects the growth of mosquito larvae.

Larvae with this gene die before they reach adulthood.

Evaluate whether the scientists should release these GM mosquitoes into the wild. 

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2a1 mark

The immune system aims to destroy pathogens such as bacteria and viruses if they manage to enter the body and infect organs and tissues.

Pathogens make us feel unwell.

Give one reason why this is the case.

2b3 marks

Outline the possible responses of white blood cells to infection caused by pathogens.

2c3 marks

The measles virus can cause serious illness in humans. 

Vaccination can protect individuals and populations from diseases such as measles.

Explain how the measles vaccine works to prevent disease.

2d2 marks

The measles vaccine will not give a child immunity against the influenza virus.

Explain why.

2e2 marks

Parents are encouraged strongly by healthcare professionals to vaccinate their children.

In recent years, there has been a growing movement of parents who are not having their children vaccinated for diseases such as measles. These parents cite concerns about the side effects of vaccines. 

What might be a consequence of a reduction in the number of children who are vaccinated for measles?

Explain your answer. 

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3a2 marks

Many diseases can be cured with antibiotics and others can be prevented with vaccinations.

Explain why antibiotics should not be prescribed by doctors to individuals with a known viral disease. 

3b3 marks

Immunisation against a particular disease is possible when a person is injected with a weakened or inactive form of the pathogen. 

Explain how this confers immunity to a disease. 

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4a1 mark

Scientists are continually developing new drugs and medicines. These must be trialled before they can be prescribed to patients.

Before clinical trials can begin, drugs are tested in the laboratory.

The laboratory trials are not trials on people. 

What are drugs tested on before they are tested on patients?

4b3 marks

Drugs must be tested extensively before they can be prescribed routinely to patients.

Explain why.

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5a6 marks

Between 2013 and 2016, the Ebola virus was responsible for around 12 000 deaths.

Almost all of the victims were in Western Africa.

There is currently no clinically approved medicine available to treat individuals infected with the Ebola virus. 

Drug companies have developed a new drug to treat Ebola.

Describe the stages of testing this new drug must go through before it can be used on patients. 

5b1 mark

How are new drug compounds discovered?

5c2 marks

A potential vaccine for Ebola began development in 2003.

In 2014, the World Health Organisation ruled that it would approve the vaccine for use on individuals recently infected with Ebola.

At that time the vaccine had not yet been tested on humans.

Suggest two reasons reason why the World Health Organisation deemed it ethical to use the vaccine on infected individuals despite it not having been tested on humans.

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6a1 mark

Influenza viruses are responsible for causing 'the 'flu' in many different vertebrate species, including humans.

How do viruses cause illness?

6b3 marks

An American TV crew visited a remote tribe in the Brazilian rainforest to make a documentary. 

Two weeks after the crew's visit, six members of the tribe died and many more were seriously ill.

The members of the TV crew did not show symptoms of influenza during their visit, but members of the remote tribe died from the disease.

Suggest an explanation for this. 

6c2 marks

The Center for Disease Control and Prevention estimated that 3.55 × 107 individuals were infected with influenza in the United States during the 2018-19 'flu season. 

Of those individuals affected, an estimated 3.42 × 104 died, sadly.

Based on these estimated figures, what percentage of people infected with influenza died from the disease during the 2018-19 'flu season?

Show your answer to 2 decimal places and show your working.

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