Microorganisms, Defence against Disease, Medicines and Drugs Flashcards
What is pasteurisation?
Pasteurisation is a process that kills the growth of most microbes in milk (or other products). It involves heating the milk to a high temperature (but below the boiling point) for a short period of time, followed by rapid chilling to a low temperature. This kills most bacteria present.
Why does pasteurisation not heat the milk to boiling point?
Heating the milk to boiling point would affect the quality and taste of the milk.
What are organisms that cause disease called?
Organisms that cause disease are called pathogens.
Name the three main types of disease causing microorganisms?
Bacteria, viruses and fungi.
What is the name given to the unique proteins that are find on the cells of the body?
These proteins are called antigens.
What is the body’s initial line of defence against foreign microorganisms?
The initial protection is provided by the skin. This acts as a barrier to prevent the entry of microorganisms.
Describe two ways in which the immune system works.
Lymphocytes produces antibodies. These stick to the antigen of the pathogen meaning they are unable to spread or reproduce.
Phagocytes engulf and digest the pathogens.
Name five ways in which diseases can be spread and give an example for each.
Direct contact - athlete’s foot
In the air - colds and flu
Through body fluids - HIV/AIDS, chlamydia and gonorrhoea
Through food and water - salmonella, polio
Insects and other animals - malaria
What causes food to become contaminated?
Contamination of food is caused by microorganisms in the air.
How are measles, mumps and rubella spread and how can this be prevented?
Measles mumps and rubella are spread by airborne droplet infection three coughing and sneezing. They can be prevented by the MMR vaccination.
How are you salmonella spread and how can be prevented?
Salmonella food poisoning is spread by contaminated food. It can be prevented by always cooking food thoroughly and making sure that raw and cooked foods are not mixed.
How is HIV spread and how can it be prevented?
HIV is a virus and it is spread through the exchange of bodily fluid during sex or through infected blood. It can be prevented by using a condom or ensuring needles are not shared.
How is athlete’s foot spread and how can it be prevented?
Athlete’s foot is a fungus and it is spread through direct contact. It can be prevented by avoiding direct contact in the areas where spores are likely to be present. For example, wearing flip-flops in changing areas and swimming pools.
How do you phagocytes fight infection?
The cells carry out phagocytosis in which they surround and engulf pathogens, placing them in a vacuole and using their enzymes to digest and destroy it.
How do lymphocytes fight infection?
Lymphocytes fight infection by producing chemicals called antibodies. These antibodies stick to the antigens, causing clumping of the microorganisms in an antibody-antigen reaction. This makes them unable to move or reproduce and also makes them an easier target for the phagocytes.
