Microorganisms and Disease: Protecting Ourselves Against Infection Worksheet

In this worksheet, you will look at how we protect ourselves against diseases, both naturally and by using medicines.

You will look at how the body stops micro-organisms getting in and what the body can do if the micro-organisms do get in!

Sometimes the body needs extra help in the form of medicines. You will look at how they work and whether there are any problems associated with using medicines.

Finally the worksheet will also cover immunity and immunisations.

What is the body's main barrier against pathogens?

hair

skin

blood

Unfortunately our body is not entirely covered with skin, we have openings such as the nose, mouth, ears etc... These openings give pathogens a way into the body.

What extra defences do we have to stop the pathogens entering our bodies?

hydrochloric acid

sweat

tears

saliva

mucus

hairs

If we cut or damage our skin we create an opening into our body therefore giving pathogens an opportunity to get in.

What other natural defence do we have to prevent this from happening?

blood plasma

bone marrow

blood clotting

Sometimes microbes manage to avoid all these barriers. If this happens, and the microbes get inside your body, which type of cells is your next line of defence?

white blood cells

red blood cells

nerve cells

There are two main groups of white blood cells, phagocytes and lymphocytes.

Phagocytes kill pathogens that enter the body by________________.

engulfing and 'eating' them

damaging them

sending them to the wrong part of the body

Lymphocytes kill pathogens that enter the body by making important chemicals called...

antibiotics

antibodies

antiseptics

Antibiotics are important medicines. But they can only treat illnesses that have been caused by what pathogen?

viruses

bacteria

fungi

Both the NHS and health organisations across the world are trying to reduce the use of antibiotics, especially for conditions that are not serious. This is to try to combat the problem of antibiotic resistance.

What does antibiotic resistance mean?

countries refusing to use antibiotics.

the antibiotic is in short supply.

when a strain of bacteria no longer responds to treatment.

Once you have been infected with a particular pathogen and produced antibodies against it, some of the white blood cells remain. If you become infected again with the same pathogen, these white blood cells reproduce very rapidly and the pathogen is destroyed. This is active immunity.

Sometimes you may get antibodies from someone else. This is known as what type of immunity?

false

passive

artifical

People can be immunised against a pathogen through vaccination. Different vaccines are needed for different pathogens.

What do vaccines contain?

live but weakened pathogens

dead pathogens

toxins produced by pathogens

harmless pieces of pathogens

ANSWERS

Question 1

What is the body's main barrier against pathogens?

CORRECT ANSWER

skin

EDDIE SAYS

The human skin is the outer covering of the body. In humans, it is the largest organ in the body. Skin acts as a barrier to the environment and so plays a key role in protecting the body against pathogens.

ANSWERS

Question 2

Unfortunately our body is not entirely covered with skin, we have openings such as the nose, mouth, ears etc... These openings give pathogens a way into the body.

What extra defences do we have to stop the pathogens entering our bodies?

EDDIE SAYS

These are all produced by the body to help protect ourselves from pathogens.

Sweat, saliva and tears contain lysozyme - a chemical which kills bacteria.
Mucus produced in the nose and other parts of the respiratory system catches suspended micro-organisms from the air that you breathe in. Tiny hairs called cilia waft the mucus up the throat where it can be swallowed.
Hydrochloric acid - This is found in the stomach. It kills micro-organisms.

ANSWERS

Question 3

If we cut or damage our skin we create an opening into our body therefore giving pathogens an opportunity to get in.

What other natural defence do we have to prevent this from happening?

CORRECT ANSWER

blood clotting

EDDIE SAYS

Blood clotting - If the skin is broken the blood clot stops entry of pathogens.

ANSWERS

Question 4

Sometimes microbes manage to avoid all these barriers. If this happens, and the microbes get inside your body, which type of cells is your next line of defence?

CORRECT ANSWER

white blood cells

EDDIE SAYS

If pathogens do get past the physical barriers our second line of defence are our white blood cells.

ANSWERS

Question 5

There are two main groups of white blood cells, phagocytes and lymphocytes.

Phagocytes kill pathogens that enter the body by________________.

CORRECT ANSWER

engulfing and 'eating' them

EDDIE SAYS

Phagocytes - These are white blood cells that engulf pathogens. They ingest the pathogen in the same way as the Amoeba eats.

ANSWERS

Question 6

Lymphocytes kill pathogens that enter the body by making important chemicals called...

CORRECT ANSWER

antibodies

EDDIE SAYS

Antibodies recognise a unique part of the pathogen, called an antigen. They lock onto the pathogen or an infected cell and signal to the phagocytes that it needs to be destroyed. They can also destroy the pathogen directly (for example, by blocking a part of the pathogen that is essential for its invasion and survival).

ANSWERS

Question 7

Antibiotics are important medicines. But they can only treat illnesses that have been caused by what pathogen?

CORRECT ANSWER

bacteria

EDDIE SAYS

Antibiotics are medications used to treat, and in some cases prevent, bacterial infections.
Antibiotics work in one of two ways:
• they kill bacteria by disrupting one of the processes that they need to survive, such as respiration.
• they prevent bacteria from reproducing and spreading, for example by disrupting the processes bacteria use to produce new cells, such as making new proteins.

ANSWERS

Question 8

Both the NHS and health organisations across the world are trying to reduce the use of antibiotics, especially for conditions that are not serious. This is to try to combat the problem of antibiotic resistance.

What does antibiotic resistance mean?

CORRECT ANSWER

when a strain of bacteria no longer responds to treatment.

EDDIE SAYS

Antibiotic resistance is when a strain of bacteria no longer responds to treatment with one or more types of antibiotics. It has led to the emergence of so-called ‘superbugs’. These are strains of bacteria that have developed resistance to many different types of antibiotics. Including, meticillin-resistant Staphylococcus aureus (MRSA)

ANSWERS

Question 9

Once you have been infected with a particular pathogen and produced antibodies against it, some of the white blood cells remain. If you become infected again with the same pathogen, these white blood cells reproduce very rapidly and the pathogen is destroyed. This is active immunity.

Sometimes you may get antibodies from someone else. This is known as what type of immunity?

CORRECT ANSWER

passive

EDDIE SAYS

Babies have passive immunity. Antibodies are passed from the mother to the baby in her breast milk.

ANSWERS

Question 10

People can be immunised against a pathogen through vaccination. Different vaccines are needed for different pathogens.

What do vaccines contain?

CORRECT ANSWER

live but weakened pathogens
dead pathogens
toxins produced by pathogens
harmless pieces of pathogens

EDDIE SAYS

These all act as antigens. When injected into the body, they stimulate white blood cells to produce antibodies against the pathogen. Because the vaccine contains only a weakened or harmless version of a pathogen, the vaccinated person is not in danger of developing disease - although some people may suffer a mild reaction. If the person does get infected by the pathogen later, the required lymphocytes are able to reproduce rapidly and destroy it