Physical & chemical barriers

The symptoms of a measles infection include: a fever

a red skin rash.

Why do antibiotics not treat measles?

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Antibiotics cause the measles pathogen to release toxins.

Antibiotics do not kill viruses.

Antibiotics increase body temperature.

Cilia are small hair-like structures in the trachea and bronchi.

Describe how mucus and cilia defend against the entry of pathogens into the lungs.

How does stomach acid defend the body against pathogens?

People can be vaccinated against measles.

What does the measles vaccine contain?

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Hormones

Two types of blood cell

Weakened pathogen

Which part of the blood produces antibodies after receiving the measles vaccination?

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Platelets

Red blood cells

White blood cells

Figure 5 shows how the concentration of measles antibodies in the blood changes after vaccination.

Complete Figure 5 to show how the concentration of measles antibodies will change after the exposure to measles pathogens.

In one group of people: 25 people have been vaccinated against measles

5 people have not been vaccinated against measles.

What is the simplest ratio of people who have been vaccinated to people who have not been vaccinated?

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30: 1

25: 1

5: 1

Scientists recommend that over 95% of the population should be vaccinated against measles.

What is the advantage of a large percentage of the population being vaccinated against measles?

The symptoms of a measles infection are: a fever

a red skin rash.

Why can measles not be treated with antibiotics?

Describe two ways the human body defends against the entry of the measles pathogen into the lungs.

A person is given a measles vaccination by injection.

There is a small amount of bleeding from the wound.

What is the role of platelets after the person receives the injection?

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To begin phagocytosis

To cause the blood to clot

To release antitoxins

How do white blood cells respond to a vaccination against measles?

In the UK, most people have been vaccinated against measles.

In a sample population, the ratio of vaccinated people to unvaccinated people is 594 000: 99 000

Give 594 000: 99 000 as the simplest whole number ratio.

Simplest whole number ratio = __________: __________

Explain why it is important that the ratio of vaccinated people to unvaccinated people is high.

The human body protects itself from pathogens.

Describe how the skin and the stomach protect the human body from pathogens.

Earwax is produced by specialised cells in the ear.

Earwax can trap and kill bacteria.

People either have wet earwax or dry earwax.

The type of earwax people have is controlled by one gene.

Name the part of a human cell where genes are found.

Name the chemical that genes are made of.

Each person has two alleles for earwax.

Why does a person have two alleles for earwax?

The allele for wet earwax is dominant.

E = allele for wet earwax e = allele for dry earwax

Which word describes a person with the alleles Ee?

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Heterozygous

Phenotype

Recessive

A person with the genotype Ee and a person with the genotype ee plan to have a child.

Complete Figure 9 to determine the probability that the child will have dry earwax.

You should identify any offspring genotype that would have dry earwax.

Figure 9

Type of earwax is only affected by a gene.

Height is a characteristic that is affected by genes and environmental factors.

Give one other human characteristic that is affected by genes and the environment.

Do not refer to height in your answer.

Give one environmental cause for the variation in the characteristic you named in Question 06.7.

Pollutants in the atmosphere can be harmful to the environment and to human health.

Four pollutants in the atmosphere are:

Describe how carbon monoxide is produced from hydrocarbon fuels.

Describe one harmful effect of oxides of nitrogen.

Figure 7 shows the emissions of three atmospheric pollutants from 1970 to 2019.

Determine the percentage change in emission of oxides of nitrogen from 1970 to 2019.

Give your answer to 2 significant figures.

Compare the changes in the emission of atmospheric pollutants from 1970 to 2019.

You should refer to:

Use Figure 7.

Suggest one reason for the change in the emission of atmospheric pollutants shown in Figure 7.

Particulates are classified into different groups depending on diameter of the particulate.

Table 4 shows information about the different groups.

A soot particle was viewed using a microscope.

The magnification used was × 5000.

The diameter of the image of the soot particle was 7.5 mm.

Determine the particulate group of the soot particle.

1 mm = 1000 micrometres

Use Table 4.

Real diameter of soot particle = ____________________ micrometres

Particulate group.

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PM PM PM 10 2.5 0.1

Particulates in the air can be breathed in.

The body’s defences prevent particulates larger than 10 micrometres getting into the lungs.

Describe how the body prevents the particulates reaching the lungs and removes the particulates from the airways.

The human immune system responds to pathogens entering the body.

Which part of the blood is responsible for an immune response?

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Platelets

Red blood cells

White blood cells

Some pathogens release toxins in the body.

Name the type of substance produced in the body that destroys the toxins.

Cells in the immune system engulf pathogens.

What is the name of this process?

Plants release pollen.

The human breathing system has defences against the entry of pollen and pathogens.

Draw one line from each adaptation of the breathing system to the description of that adaptation.

The immune response to pollen is an example of an allergy.

Suggest two symptoms of an allergy to pollen.

An allergy to pollen cannot be treated using antibiotics.

Suggest why.

Explain one problem caused by the overuse of antibiotics.

This question is about health.

Some pathogens cause food poisoning.

Explain how the stomach is adapted to prevent food poisoning.

Different types of disease may interact.

Suggest one type of disease that may be triggered by infection with human papillomavirus (HPV).

Chlamydia, HIV and HPV are sexually transmitted diseases (STDs).

Chlamydia is caused by the same type of microorganism as gonorrhoea.

Suggest how chlamydia infections are treated.

One symptom of chlamydia infection is damage of the uterus lining.

Which two hormones are involved in maintaining the uterus lining?

Students were asked to estimate the percentage risk of a person becoming infected with different STDs.

` The estimate was compared to the actual percentage risk of infection.

Figure 8 shows the results.

Figure 8

Why is the data in Figure 8 plotted as a bar chart and not as a line graph?

The difference between the estimated risk and the actual risk is not the same for each STD.

Suggest two reasons why.

Explain how only some types of contraception reduce the spread of STDs.

Explain why patients with late-stage HIV infection or AIDS are likely to become very ill from other infections.

A nose spray has been produced.

The nose spray puts a thin layer of gel in the airways between the nose and the lungs.

The manufacturer of the nose spray claims that:

‘The nose spray defends against diseases such as the common cold.’

Why is the manufacturer’s claim difficult to test?

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A symptom of the common cold is a cough.

The common cold does not spread through drinking water.

We do not know who will get the common cold.

The nose spray was tested as a new medical drug.

In the drug trial some patients were given a nose spray with no drug.

What is the word used to describe the nose spray with no drug?

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Painkiller

Placebo

Statin

Most medicines contain a mixture of ingredients.

Why do some tablets contain sugar as well as the drug?

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So that the tablet is more difficult to swallow

To decrease the size of the tablet

To improve the taste of the tablet

Figure 9 shows some of the ways that the body defends itself against infectious diseases.

Describe how the skin, airways and stomach defend against diseases.

On aeroplanes, pathogens can easily spread from one person to another person.

Suggest one way pathogens can spread from one person to another person on an aeroplane.

The manufacturer of a nose spray claims that:

‘The nose spray defends against diseases such as the common cold.’

The nose spray puts a thin layer of gel in the airways between the nose and the lungs.

Describe how the nose spray and the body’s natural defences in the airways work in similar ways to defend against pathogens.

The nose spray was tested as a new medical drug.

The manufacturer of the nose spray claims:

‘The nose spray can decrease the number of days that a person has symptoms of the common cold.’

Suggest one reason why this claim is difficult to test.

The nose spray contains a mixture of ingredients.

Suggest two reasons why the nose spray is a mixture of ingredients.

Late-stage HIV (AIDS) affects the immune system.

A person with AIDS is more likely to suffer from another infectious disease.

Give one other example of how having one disease can affect the development of a different disease.

Do not refer to HIV or AIDS.

Figure 4 shows a mosquito on human skin.

Malaria is a communicable disease.

Mosquitos can transmit malaria when they bite.

What is a communicable disease?

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Humans have adaptations to defend the body against pathogens.

Draw one line from each body part to the adaptation that defends against pathogens.

What type of chemical is used to kill mosquitos?

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Scientists are trying to reduce the number of people developing malaria by using genetically modified (GM) mosquitos.

Mosquitos have 6 chromosomes in each normal body cell.

How many chromosomes are in each egg cell from a mosquito?

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Which statement describes genetic modification?

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GM mosquitos can be produced in large numbers in laboratories.

These GM mosquitos can be released to reduce the population of wild mosquitos.

What is one advantage of using GM technology to reduce the population of wild mosquitos?

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Cystic fibrosis is an inherited condition.

The allele for having cystic fibrosis is recessive, r.

The dominant allele is R.

A person who has the genotype Rr is a ‘carrier’ of cystic fibrosis.

Carriers do not have symptoms of cystic fibrosis.

What scientific term describes the carrier’s genotype, Rr ?

Figure 5 shows the inheritance of cystic fibrosis in one family.

Person 6 and person 7 plan to have another child.

Draw a Punnett square diagram to show the probability of the child having cystic fibrosis.

Identify the genotypes of any offspring with cystic fibrosis.

Use Figure 5.

Mucus is produced in the breathing system.

In people with cystic fibrosis the mucus is thicker than the mucus produced in an unaffected person.

Explain why a person with cystic fibrosis has an increased risk of lung infections.

Some medical products are produced by genetically modified (GM) organisms.

Hamsters are small mammals.

GM hamster cells are used to produce drugs to treat some human genetic disorders.

Describe how a human allele can be transferred into the genome of a hamster cell.

Name a medical product that can be produced by GM bacteria.

Give the name of the disorder the product is used to treat.