Some white blood cells

and digest

cells, this process is called

Pathogens have a unique layer of molecules on it their surface called

White blood cells produce specific

if it is a new, foreign pathogen which

the pathogen. When antibodies have been produced successfully, it means that the person is

to the pathogen.

Vaccinations involve

pathogens that are dead or

so that the white blood cells can produce

to attack them. Then, if in the future a

pathogen infected the body, you would be

to it.

Vaccinations have helped control many

disease and

can be prevented if most of the population are vaccinated.

However, vaccines don't always work and some people can have

to them, even though it is rare.

Painkiller, are drugs used to

pain. They don't tackle the

of the disease, but just reduces the

Antibiotics

the bacteria causing the disease without

They don't kill

a they use your body cells to

and so it is difficult to develop a drug to kill it without damaging they cell.

Bacteria can

to become

to antibiotics, and so won't be killed by them.

When this bacteria reproduces, the population of

bacteria is

The placebo effect is when a patient

a treatment to work, and so feels

even though the treatment did

Antibodies are produced by white blood cells called

are produced from lots of clones of B-lymphocytes and so they are all

and target a

B-lymphocytes are fused to a

to create a

These cells are then

and the antibodies are collected. It is possible to create an antigen for

Plants need

from soil, otherwise they suffer

Monoclonal antibodies can be used to treat

An anti-cancer drug can be attached to the monoclonal antibody, which will then

speific cells and kill the

but not the

Monoclonal antibodies can be used to bind to

and other chemicals in

to measure levels, test blood samples for

and locate specific molecules on a cell or a

Plants can be infected by bacterial, fungal and

diseases and can also be infested by

It is easy to tell if a plant has been infected as it can have stunted or abnormal

spots on the

patches of discolouration and

as well as malformed leaves and