Edexcel Biology Gcse - Treating, Curing and Preventing Diseases Part 2

The introduction of an inactive form of a disease into the human body that causes the immune system to produce antibodies against that disease.

When a person’s body is not prone to a disease because they have a resistance to it.

White blood cells which attack pathogens by producing antibodies.

Enzymes found in tears that destroy bacterial cells.

Slimy white protein, which lines the respiratory tract and alimentary canal

A random and spontaneous change in the structure of a gene, chromosome or number of chromosomes.

Microorganism that causes disease.

A clear glass or plastic dish, used to grow living cells from organisms so they can be studied.

Cells, such as white blood cells, that engulf and absorb waste material, harmful microorganisms, or other foreign bodies in the bloodstream and tissues.

The production of proteins from amino acids, which happens in the ribosomes of the cell.

A type of natural poison produced by an organism, often as a form of protection.

The windpipe, the tube that leads from the mouth towards the lungs.

Substances containing disabled antigens of a particular disease, usually administered via injection. Vaccines stimulate the body to produce antibodies to provide immunity against that disease.

A type of cell found in blood that defends against infection.

The area around an antibiotic or antiseptic on agar where bacterial growth is not visible. The size of the zone depends on how effective the antibiotic or antiseptic is.

The body is constantly defending against attacks from pathogens. The first line of defence against infection stops the pathogens from entering your body. These first lines are general defences, and are not specific to fight against certain types of pathogen. We call this non-specific, and they can be physical or chemical barriers.

• Skin

• Nose

• Mucus and ciliated cells

The skin covers almost all parts of your body to prevent infection from pathogens. If it is cut or grazed it immediately begins to heal itself, often by forming a scab, which prevents infection as the skin acts as a physical barrier. Parts of the body that do not have skin have developed other ways to prevent infection. For example, the eyes produce tears which contain enzymes. These enzymes are chemical barriers.

The nose has internal hairs, which act as a physical barrier to infection. Cells in the nose produce mucus. This traps pathogens before they can enter the lungs. When the nose is blown, mucus is removed and any pathogens are trapped within it.

The trachea runs from the nose towards the lungs. The cells that line the trachea also have hairs called cilia, which are much smaller than those in the nose. These are called ciliated cells. The ciliated cells waft their hairs in a motion like a Mexican wave at a football match and move mucus and pathogens upwards towards the throat where it is swallowed into your stomach. Other cells called goblet cells create the mucus in order to trap pathogens. The production of mucus in your airways is a physical barrier.