OCR GCSE Combined Science
Topic questions Evolution and biodiversity Selective breeding
7 questions · 43 marks · about 50 minutes
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.
Which is an example of selective breeding?
A Bacteria developing antibiotic resistance.
B Farmers developing food plants resistant to disease.
C Gardeners adding nitrogen to the soil to help plants grow.
D Scientists changing the genes of an organism.
The diagram shows some crops that have been developed from a wild mustard plant.
The cauliflower crops grown today have taken many years to develop.
Name the process used by humans to develop cauliflower plants from wild mustard plants.
Put a tick (✓) next to the correct answer.
Some bacteria have genes which mean that they can produce a natural insecticide. Scientists have produced cauliflowers that contain these genes. This means the cauliflowers can now make their own natural insecticide.
What is modified inside the cauliflower so that it has the genes?
Suggest one reason for and one reason against producing cauliflowers with these genes.
Scientists can now treat blood disorders using gene therapy. To do this they need to obtain blood stem cells.
The blood stem cells are then modified before being placed into the patient.
Complete these sentences to explain the benefits of using modified stem cells.
The stem cells can be modified to stop the........ blood cells of the immune system detecting the stem cells.
This will reduce the chance of........
Selective breeding in cattle can have risks.
Which outcome of selective breeding will have the greatest risk for the cattle?
A Greater muscle mass.
B Increased chance of genetic defect.
C Increased milk yield.
D Loss of horns.
Water is cycled in nature.
Name one abiotic factor that affects water uptake by a plant.
Look at the diagram of the carbon cycle.
Which process is shown by arrow X in the diagram above?
Tick (✓) one box.
Which process releases carbon when organisms die ?
Tick (✓) one box.
The graph shows how carbon dioxide levels in the atmosphere have changed during the last 160 000 years.
Read this statement:
Carbon dioxide levels in the atmosphere are rising out of control.
What evidence is there in the graph for and against this statement?
Look at the section of the graph for the last 20 000 years.
What conclusions can be made about the release of carbon dioxide into the atmosphere and also its removal from the atmosphere during the last 20 000 years?
Describe how human activity has contributed to the trends in the graph and suggest how this activity could affect biodiversity.
The information in the box is part of a scientific journal report.
Growing crops with shiny leaves could cause an annual global cooling of over 0.1 °C.
This is almost 20% of the total global temperature increase since the Industrial Revolution.
Most crop plants have non-shiny leaves.
A few varieties of crop plants do have shiny leaves but they do not all produce high yields.
Explain how scientists could use selective breeding to help reduce global temperatures.
Water is cycled in nature.
Name one abiotic factor that affects water uptake by a plant.
Look at the diagram of the carbon cycle.
Which process is shown by arrow X in the diagram?
Tick (✓) one box.
Which process releases carbon when organisms die ?
Tick (✓) one box.
The graph shows how carbon dioxide levels in the atmosphere have changed during the last 160 000 years.
Read this statement:
Carbon dioxide levels in the atmosphere are rising out of control.
What evidence is there in the graph for and against this statement?
Look at the section of the graph for the last 20 000 years.
What conclusion can be made about the release of carbon dioxide into the atmosphere and also its removal from the atmosphere during the last 20 000 years?
Describe how human activity has contributed to the trends in the graph and suggest how this activity could affect biodiversity.
The information in the box is part of a scientific journal report.
Growing crops with shiny leaves could cause an annual global cooling of over 0.1 °C.
This is almost 20% of the total global temperature increase since the Industrial Revolution.
Most crop plants have non-shiny leaves.
A few varieties of crop plants do have shiny leaves but they do not all produce high yields.
Explain how scientists could use selective breeding to help reduce global temperatures.
A Environmental selection
B Genetic engineering
C Natural selection
D Selective breeding
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Combined Science starter pack