Revision

1. Revision
Biology

2. What is a Pathogen?
• A bacterium, virus, or other microorganism that can cause disease.

3. Explain how vaccination work?
• Vaccines work by stimulating our immune system to produce
antibodies without actually infecting us with the disease. They trigger
the immune system to produce its own antibodies, as though the
body has been infected with a disease. This is called "active
immunity".

4. How can the following drugs be used to treat
disease?
• Painkillers:
Painkillers helps to relieve the symptoms of an infectious disease, but they do not kill the
pathogens involved. For example, paracetamol, aspirin and morphine block nerve
impulses from the painful part of the body, or block nerve impulses travelling to the part
of the brain responsible for perceiving pain.
• Antibiotics
Some antibiotics stop the bacteria reproducing and others kill the bacteria
directly. Antibiotics are helpful to treat diseases caused by bacteria, such as tuberculosis
and food poisoning. They do not harm viruses, so antibiotics cannot treat diseases such
as colds and flu, which are caused by viruses.

5. Explain how bacteria will make you ill?
• Bacteria are living cells and, in favourable conditions, can multiply
rapidly. Once inside the body, they release poisons or toxins
that make us feel ill. Diseases caused by bacteria include: food
poisoning.