Pathogens

Bacteria cause many diseases in humans.

Which term describes a pathogen?

In the UK, most children are immunised against serious infections such as measles.

Give two advantages of immunising children against measles.

Humans have physical barriers to prevent bacterial infections.

Name two of these physical barriers.

State the chemical in the stomach that destroys bacteria.

*(c) Many food crops are damaged by pests.

Some farmers use insects for the biological control of plant pests.

Figure 14 shows a ladybird which can be used for biological control.

Explain the advantages and disadvantages of biological control.

The pathogen Vibrio cholerae causes the disease cholera.

Figure 7 shows Vibrio cholerae bacteria.

Complete the table to show the function of structure P and structure Q.

On the original image, the length of one bacterial cell is 12 mm.

The actual length of this bacterial cell is 2.0 µ m.

Calculate the magnification.

State one symptom of the disease caused by Vibrio cholerae.

State how the disease caused by Vibrio cholerae is transmitted.

Describe the specific immune response when a pathogen infects the body.

Malaria is a disease that causes damage to the blood and liver.

Which type of pathogen causes malaria?

State how the pathogen that causes malaria is spread.

Measles is a disease caused by a virus.

Figure 4 shows the number of measles cases reported in England and Wales from 1985 to 2015.

Explain one conclusion that can be made about the change in the number of measles cases reported from 1985 to 2015.

Describe two ways the immune system will respond to an infection by a pathogen.

Beriberi is a disease caused by a lack of vitamin B1 in the diet.

Give one reason why beriberi is classed as a non‑communicable disease.

Figure 17 shows colonies of bacteria growing on an agar plate.

Each colony starts as one bacterium.

Every time bacteria reproduce, the number of bacteria in each colony doubles.

Calculate the number of bacteria in a colony after five hours, if each bacterium reproduces every 30 minutes.

Some bacteria are pathogens.

State the meaning of the term pathogen.

Explain why antibiotics can be used to treat bacterial infections.

A rod-shaped bacterium is 0.005 mm long.

A student draws the rod-shaped bacterium.

The bacterium in the drawing is 80 mm long.

Calculate the magnification of this drawing.

* (c) Figure 18 shows a bacterial cell and a plant cell.

Describe the similarities and differences of a bacterial cell and a plant cell.

Figure 4 shows colonies of bacteria growing on an agar plate.

Each colony starts as one bacterium.

Every time bacteria reproduce, the number of bacteria in each colony doubles.

Calculate the number of bacteria in a colony after five hours, if each bacterium reproduces every 30 minutes.

Some bacteria are pathogens.

State the meaning of the term pathogen.

Explain why antibiotics can be used to treat bacterial infections.

A rod-shaped bacterium is 0.005 mm long.

A student draws the rod-shaped bacterium.

The bacterium in the drawing is 80 mm long.

Calculate the magnification of this drawing.

Some bacteria cause disease.

Which word describes an organism that causes disease?

Draw one straight line from each disease to the main way that the disease is spread.

disease
main way the

A scientist investigated the effect of temperature on the growth of bacteria.

The bacteria were grown at 10 °C and 20 °C.

The number of bacteria grown at each temperature were counted every two hours.

Figure 1 shows the result.

Figure 2 shows a graph of the results at 20 °C.

Plot the points on the graph for the number of bacteria at 10 °C.

The first two points have been plotted for you.

Draw a line of best fit on the graph for 10 °C.

Describe how the growth of bacteria at 10 °C was different from the growth of bacteria at 20 °C.

Figure 2 shows the number of people diagnosed with sexually transmitted infections (STIs) in the UK during 2017.

State the sexually transmitted infection that has the median number of people diagnosed.

The population of the UK in 2017 was 66 million people.

Calculate the total number of people diagnosed with chlamydia in the UK in 2017.

State why chlamydia can be described as a communicable disease.

Give one way the transmission of chlamydia can be prevented.

Explain why chlamydia can be treated with antibiotics.

HIV is another sexually transmitted infection.

Explain how HIV can lead to the onset of AIDS.

Measles is a communicable disease caused by a virus.

What can a virus also be classified as?

Give one reason why measles is described as a communicable disease.

The human immunodeficiency virus (HIV) can cause AIDS.

Which type of cell is destroyed by the HIV virus?

Describe how the specific immune system defends the body against disease.

Figure 13 shows the number of people per million of the population in five European countries who were diagnosed with measles in one year.

The population of Belgium in that year was 11.18 million.

Calculate the number of people in Belgium diagnosed with measles.

Give your answer to three significant figures.

Countries do not report the total number of people diagnosed with measles. Countries report the number of people diagnosed with measles per million of the population.

Give one reason why this is better.

Give one reason why the number of people per million diagnosed with measles is different in these countries.

The human immunodeficiency virus (HIV) can cause AIDS.

Which type of cell is destroyed by the HIV virus?

Describe how the specific immune system defends the body against disease.

Figure 1 shows the number of people per million of the population in five European countries who were diagnosed with measles in one year.

The population of Belgium in that year was 11.18 million.

Calculate the number of people in Belgium diagnosed with measles.

Give your answer to three significant figures.

Countries do not report the total number of people diagnosed with measles. Countries report the number of people diagnosed with measles per million of the population.

Give one reason why this is better.

Give one reason why the number of people per million diagnosed with measles is different in these countries.

Pathogens cause disease.

Draw one straight line from each type of pathogen to the disease that is caused by that pathogen.

Antibiotics can be used to treat diseases.

Antibiotics kill

Figure 1 shows the number of white blood cells in blood samples from three patients.

Explain why the data suggests that Patient Z has a bacterial infection.

HIV is diagnosed by blood tests.

State two safety precautions that need to be taken when handling blood samples.