2.1 distinguish between infectious and non-infectious disease

An infectious disease is one that is caused by and organism and that can be transferred from one person to another. The transfer maybe direct, where the disease-causing organisms, such as viruses or bacteria, pass directly from person to person for example. “Chicken pox”
Non-infectious diseases are diseases that are not due to disease-causing organisms E.G down syndrome
2.1 identify the conditions under which an organism is described as a pathogen
* A pathogen is any organism that can produce a disease. Pathogens range from viruses so small that thousands will fit side by side in one millimetre to tapeworms that can be several meters long. They are all infectious

2.5 describe ways in which drinking water can be treated and use available evidence to explain how these methods reduce the risk of infection from pathogens
Examples of water treatments are:
Filtrations – water filtrations is a general term that refers to any type of filtration system or process that is used to filter out particles and / or pollutants from water
Chlorination – water chlorination is the process of adding chlorine or hypochlorite to water as a method of water purification to make it fit for human consumption
Ozone filtration – is the process of using ozone to purify that is removing the harmful microorganisms that can make you sick.

Pathogen
Description
Examples of diseases it causes
Fungi
Heterotrophic organisms. Some are unicellular, others consist of long branching threads
Tinea
Macro-organisms
Organisms that are visible to the naked eye, also called parasites
Fleas
Viruses
Contains DNA or RNA enclosed in proteins. They are small that they cannot be seen with a light microscope
Herpes
Prions
Proteins that has been changed from its normal structure and cab then change others proteins to develop more prions.
Creutzfeldt-Jakob (CJD) disease in humans
Bacteria
Very simple cells with no internal membranes tuberculosis Protozoans
Microscopic single-celled organisms with internal membranes malaria 4.1 identify defence barriers to prevent entry of pathogens in humans: skin, mucous membrane, cilia, chemical barriers and other body secretion

Line of defence
Description
What it does
Cilia
Hair-like projection from cells lining the air passages
Moves to push pathogens from the lungs up to the throat
Skin
Skin always grows by new cells being produced. cells fit together to form a protective layer covered by dead cells
When unbroken, skin prevents the entry of pathogens. Pores in the skin secrete substances that kill bacteria
Chemical barriers
Acid in the stomach; alkali in the small intestine, the enzymes, lysozyme , in tears
Stomach acid destroys pathogens, lysozyme dissolves the cell membranes of bacteria
Mucous membrane
Cells lining the respiratory tract and openings of the urinary and reproductive