1.1: Bacteria are single-celled microorganisms with a simple cellular organization whose nucleus lacks a membrane. Viruses are DNA wrapped in a thin coat of protein that replicates only within the living hosts.
Fungi come in many different varieties and we eat quite a few. Mushrooms are fungi as is the mould that forms the blue or green veins in some types of cheese. Yeast is another type of fungi and is the necessary ingredient to make most types of bread.
Lastly, parasites may be protozoa, yeasts or multi-cellular organisms such as fungi or worms. They live in or on a host to obtain nourishment without providing any benefit to the host.
1.2: The common illnesses and infections caused by bacteria are Salmonella, E coli and MRSA. Viruses are Aids, Hepatitis A, B and C as well as the common cold. Fungi illnesses include Athletes’ foot. Illnesses caused by parasites are Scabies, Malaria and Lyme disease. 1.3: Infection begins when an organism enters the body, growing and multiplying. Most people are not easily infected. Those that are weak, ill, malnourished, have cancer or are diabetic are more prone to chronic or persistent infections.
Entrances to the host are mainly open wounds, nose, mouth, eyes, genital areas or the anus. Colonisation is where few organisms can grow at the original site of entry yet many migrate and cause systematic infection in different organs. 1.4: Systematic infections affect the whole body probably travelling in lymph or blood. A localised infection is where a local infection infects the area in which the infection enters the host. 1.5: Poor practices that may lead to the spread of infection are not washing hands, sharing personal items (e.g. towels, toothbrushes etc.), unsafe food practices (i.e. not keeping surfaces clean or tidy), reusing uncleaned equipment and failure to wear correct PPE.
2.1: Conditions needed for the growth of micro-organisms are: * nutrients – need food to survive
* warmth – organisms need warmth between 20°-40° in order to multiply * time – a single micro-organism becomes 2 every 20 minutes * moisture – this is needed to multiply
2.2: An infective agent might enter the body through:
* Sexual transmission
* Open wound(s)
* Insect/animal bites
2.3: A common source of infection is human-to-human which is more airborne like coughing and sneezing than fluid. Physical contact and infected food and drink are also common causes. 2.4: Infective agents can be transmitted to a person by droplet contact i.e. coughing over another person. Indirect physical contact usually by touching contaminated soil, animals and insects. 2.5: Key factors that will make it more likely that infection will occur are open wounds or sores and people who have a low immune system, young people, pregnant women, elderly and those with poor nutrition.