White blood cells help to defend the body against pathogens.
.1
What are the molecules on the surface of a pathogen that white blood cells recognise as foreign?
[1 mark]
.2
Describe three ways white blood cells defend the body against pathogens.
[3 marks]
.3
A person has antibodies against the measles virus. These antibodies do not protect the person against the mumps virus.
Explain why.
[2 marks]
3 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Peat bogs are areas of partly decayed plant material that has built up over thousands of years. Peat is dug up to make garden compost.
.1
Explain why destroying peat bogs increases the amount of carbon dioxide in the atmosphere.
[2 marks]
.2
Give one other reason why destroying peat bogs is harmful.
[1 mark]
5 marksFoundation
Spec and skills
Original practice question
Answer and supported method checks
A student estimated the number of daisies in a field 50 m long and 40 m wide. She placed a 0.25 m² quadrat at five random positions and counted the daisies in each.
Daisies in five quadrats: 4, 7, 0, 5, 9.
Quadrat
1
2
3
4
5
Number of daisies
4
7
0
5
9
.1
Calculate the mean number of daisies per quadrat.
[2 marks]
.2
Estimate the number of daisies in the whole field.
[3 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Some strains of bacteria are resistant to antibiotics. MRSA is resistant to several antibiotics.
.1
Explain how a population of bacteria becomes resistant to an antibiotic.
[4 marks]
.2
Give two ways to reduce the rate at which antibiotic-resistant strains develop.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Scientists studied the risk of lung cancer in adults who smoked different numbers of cigarettes each day. The graph shows how many times greater the risk was than for non-smokers.
051015202530510152025Cigarettes smoked per dayRisk compared with non-smokers1481522
.1
Describe the pattern shown in the graph.
[1 mark]
.2
Calculate how many times as great the risk is for a person smoking 20 cigarettes a day as for a person smoking 5 a day.
[1 mark]
.3
A correlation does not always mean that one factor causes another.
Explain what other evidence scientists needed before concluding that smoking causes lung cancer.
