OCR GCSE Combined Science
Topic questions Health and disease Spread of disease
13 questions · 101 marks · about 2 hours
The picture shows the plant pathogen that causes powdery mildew.
Why is powdery mildew called a communicable disease ?
Describe how selective breeding is used to make plants resistant to powdery mildew.
Why does a plant scientist use antibodies specific to a type of antigen?
A To develop new plants using selective breeding
B To find new species of plants growing around the world
C To identify communicable diseases in plants
D To study the evolution of plants
The picture shows the plant pathogen that causes powdery mildew.
Describe how powdery mildew is spread from one plant to another.
Powdery mildew reduces the efficiency of chloroplasts.
Explain how this might reduce the rate of respiration in a plant.
Plants resistant to powdery mildew are developed by genetic engineering.
Complete the sentences about genetic engineering.
The gene for resistance is cut out of DNA using a........ enzyme.
The gene is then joined to bacterial DNA using a........ enzyme.
To find out if the bacteria contain the gene, scientists use........
Explain why the process of cutting the DNA is prevented by high temperatures.
Use your knowledge of enzymes.
Powdery mildew can be controlled using chemicals.
Producing plants resistant to powdery mildew is better for biodiversity compared to using chemicals.
Suggest two reasons why.
Which type of pathogens cause crown gall disease in plants?
A Bacteria
B Fungi
C Protists
D Viruses
The diagram shows the four main components of the blood.
Draw lines to connect each letter to the component that they are labelling. Then draw lines from each component to their correct function.
Two lines have been drawn for you.
Letter Component Function
White blood cells are adapted to their function.
Explain two adaptations of white blood cells.
Read the information in the text box.
Prevent the spread of HIV
• Use protection during sexual intercourse
• Don’t share needles to inject drugs
• Avoid contact with blood from an infected person
• Get tested
Use your knowledge of HIV as a communicable disease to answer these questions.
Why can HIV be spread by sharing needles?
Suggest how testing will help prevent the spread of HIV.
The microorganism that causes Cowpea mosaic disease can pass through a filter that blocks anything larger than 100 nm.
Which type of microorganism causes Cowpea mosaic disease?
| Microorganisms | Smallest size of microorganism | |
| A | bacteria | 120 nm |
| B | fungi | 2  m |
| C | protist | 8  m |
| D | virus | 15 nm |
HIV and TB (tuberculosis) are infectious diseases.
HIV is spread between humans during sexual intercourse when body fluids come into contact.
TB is a disease caused by bacteria. It affects the lungs.
Explain how TB is spread between humans.
Describe how the lungs defend the body against infection from TB bacteria.
The lungs can also be affected by cancer.
Complete these sentences to describe what cancer is.
Use the words in the list.
differentiated meiosis mitosis multiple undifferentiated
Cancer is the result of uncontrolled growth when cells divide by........
This may lead to millions of........ cells that are unable to become specialised.
The deaths in one country from different diseases were measured over a 40-year period.
Lifestyle and living conditions in this country changed during the 40 years of the study.
The graph shows the number of deaths per 100 000 of the population for each disease.
The diseases can be grouped into communicable and non-communicable diseases. The graph shows the trends of these two different types of disease over the 40-year period.
Complete the sentences explaining these trends shown in the graph.
Communicable diseases have........
Non-communicable diseases have........
Suggest how lifestyle and living conditions in this country might have changed to cause the trends shown in the graph.
To calculate the death rate in a given year, the following formula is used:
In 1972, the population was 55 million. The death rate from coronary heart disease was 28 deaths per 100 000 people.
Calculate the number of deaths from coronary heart disease in 1972.
The immune system provides a defence against bacterial diseases like TB (tuberculosis).
Part of this defence involves the production of antibodies.
Describe how antibodies help defend the body. Use ideas about antigens in your answer.
What does a vaccination contain and why does it protect the body from infection?
Vaccinations contain........
Vaccinations protect the body because........
This question is about diseases.
Complete the table to compare some different diseases.
Tick (✓) five boxes.
Tuberculosis has been done for you.
TB is a disease of the lungs. TB is transmitted by breathing in when an infected person near you coughs or sneezes.
One way to prevent the spread of TB is vaccination.
Describe two other ways you could prevent the spread of TB.
There are many diseases and disorders of the circulatory system.
Some blood cell disorders can affect the function of white blood cells or red blood cells.
Suggest two effects on the body if either white blood cells or red blood cells are prevented from working efficiently.
Cardiovascular diseases affect the heart.
Which lifestyle factor can increase a person’s chance of developing cardiovascular disease?
Tick (✓) one box.
*(c) The cornea is the front part of the eye that allows in light. The layers of cells in the cornea are similar to the cells in skin layers, the difference is that they have become transparent to allow the light through.
Scientists are now using stem cell technology for treating damage to the cornea to restore vision.
Describe how stem cells could be used in the treatment of damage to the cornea and any possible risks involved in this type of treatment.
Chalara ash dieback is a fatal disease affecting ash trees. It is caused by a fungus growing on the leaves.
When the leaves fall to the ground the fungus releases spores spreading the disease.
Which of these would help prevent the spread of Chalara ash dieback?
A Collecting the fallen leaves to make compost that is then added to the soil.
B Cutting off infected leaves and branches, and leaving them on the ground to decay.
C Stopping the import of ash seeds, plants and trees from countries with infected trees.
D Replanting young ash trees to replace those that have died.
HIV is a virus that causes AIDS.
HIV infects human cells by inserting genes into the cells. The human cells then copy the genes.
In which part of a human cell are HIV genes copied?
chloroplast cytoplasm mitochondria nucleus
In the laboratory, scientists have used gene technology to completely remove HIV genes from infected cells.
Explain how removing HIV genes could affect the spread of HIV.
Suggest why some people are concerned about the use of gene technology in HIV treatment.
The Human Genome Project mapped the human genome.
Write down what is meant by the term genome.
Knowledge of the human genome could identify the genes affected by HIV.
Write down two ways knowledge of the human genome could help with the treatment of HIV.
*(d) Some countries have set up centres where a person is counselled and tested for HIV.
The aim is to reduce new infections by 50%.
Describe how HIV is transmitted and how these centres can contribute to reducing the spread of HIV.
HIV invades white blood cells stopping them working.
Describe the role of white blood cells in the defence against disease.
HIV is a virus that causes AIDS.
Some countries have set up centres where a person is counselled and tested for HIV.
The aim is to reduce new infections by 50%.
Write down two types of testing that can be done to identify someone with HIV.
Humans who contract HIV do not die from the virus. Instead they die from AIDS-related diseases such as tuberculosis (TB).
HIV infects human cells by inserting genes into the cells. The human cells then copy the genes.
TB is caused by bacteria that infect the lungs.
Explain why a person with HIV is more likely to die from TB than a person without HIV.
Use ideas about the immune system in your answer.
HIV can be transmitted during unprotected sexual intercourse.
Name one method of contraception and explain why it prevents the transmission of HIV.
Name of method of contraception........
Why it prevents the transmission of HIV........
Scientists are trying to develop a vaccine against HIV.
Explain how a vaccine could protect people against HIV.
Which type of medication can be used to treat people who already have HIV?
The bacteria, Agrobacterium tumefaciens, causes crown gall disease that affects walnut trees.
Galls form on the parts of the plant growing above ground (crown) or on the roots.
Describe how the galls form and cause damage to the walnut tree.
Explain one reason why the scientists thought this would happen.
To what extent does the evidence support their hypothesis?
Explain your answer.
Write down two other conclusions that can be made from the data.
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