White Blood Cells, Gcse Science

Front 1

What is an anti-biotic? What does it do?

Back 1

Antibiotics are substances that kill bacteria or stop their growth. They do not work against viruses: it is difficult to develop drugs that kill viruses without also damaging the body’s tissues

Front 2

What is a pathogen?

Back 2

Microorganisms that cause infectious disease.

Front 3

What are the features of bacteria?

Back 3

Cell wall, cell membrane, cytoplasm, chromosome

Front 4

What are the features of virus'?

Back 4

Chemical hooks and drills, DNA strand and Protein coat.

Front 5

What is the first way your body protects itself from pathogens? How?

Back 5

Passive immunity, stopping the pathogen getting into the body in the first place. The body’s passive immunity system includes the skin, mucus and cilia in the respiratory system, acid in the stomach, and enzymes in tears.

Front 6

What is the second defence called?

Back 6

Active Immunity

Front 7

What do white blood cells do?

Back 7

They can ingest pathogens and destroy them
produce antibodies to destroy pathogens
produce antitoxins that neutralise the toxins released by pathogens.

Front 8

What do phagocytes do?

Back 8

Phagocytes can easily pass through blood vessel walls into the surrounding tissue and move towards pathogens or toxins. They then either:

ingest and absorb the pathogens or toxins, or
release an enzyme to destroy them.
Having absorbed a pathogen, the phagocytes may also send out chemical messages that help nearby lymphocytes to identify the type of antibody needed to neutralise them.

Front 9

What do lymphocytes do?

Back 9

Phagocytes can easily pass through blood vessel walls into the surrounding tissue and move towards pathogens or toxins. They then either:

ingest and absorb the pathogens or toxins, or
release an enzyme to destroy them.
Having absorbed a pathogen, the phagocytes may also send out chemical messages that help nearby lymphocytes to identify the type of antibody needed to neutralise them.

Front 10

How do antibodies neutralise antigens?

Back 10

They bind to pathogens and damage or destroy them.
They coat pathogens, clumping them together so that they are easily ingested by phagocytes.
They bind to the pathogens and release chemical signals to attract more phagocytes.
Lymphocytes may also release antitoxins that stick to the appropriate toxin and stop it damaging the body.

Front 11

What does vaccination involve?

Back 11

A weak/ dead form of a pathogen being injected into the body and acting as a pathogen.
The white blood cells respond to the presence of the pathogen and identify the antibody to destroy the pathogen. Then it leaves memory cells around so that next time a real pathogen of that disease enters the body, the body is ready.

Front 12

Name a common antibiotic

Back 12

Penecillin

Front 13

What do bacteria do to become resistant to antibiotics?

Back 13

Bacterial strains can develop resistance to antibiotics. This happens because of natural selection. In a large population of bacteria, there may be some cells that are not affected by the antibiotic. These cells survive and reproduce, producing even more bacteria that are not affected by the antibiotic.

Front 14

Why is it important that we don't overuse antibiotics?

Back 14

Because then we can slow down, or stop, the development of other strains of resistant bacteria.

Front 15

Why didn't people believe Semmelweiss?

Back 15

Because they didn't know pathogens could be killed.