B2-1 How do our bodies resist infection? Flashcards
How is damage done to cells?
Damage is done to cells by either the micro-organisms directly, or the toxins that are produced by the micro-organisms.
How and why do bacterium reproduce so quickly?
They reproduce by making copies of themselves - to do this they need a source of nutrients for energy, and warm/moist conditions. The human body has lots of these places, meaning they can easily multiply.
What do you need to know in order to calculate the population growth of micro-organisms?
You need to know:
• The number of MO’s before reproduction.
• How long it takes for on MO to reproduce.
• How long they are left to reproduce for.
Then use simple maths - I ain’t writing that here :) its easy!
What is the role of the immune system?
To deal with any infection diseases that enter the body.
What type of cells do the ‘fighting’?
Each immune response always involves white blood cells.
What are the two ways in which white blood cells fight?
They either:
• Engulf and digest the micro-organism
• OR they produce antibodies
Why are the WBC able to recognise the MO’s?
This is because they have receptors that detect anything foreign to the body. The WBC are non-specific, so they will kill anything that’s not meant to be there.
6 Mark Question: Explain the process by which the immune system protects the body from harmful microbes.
Firstly the receptors on the white blood cell recognise antigens on the microbes. This triggers an immune response. Antibodies are specific to antigens, meaning all microbes have different antigen markers. The antibodies are produced, and they then latch onto the microbes, which marks it. The WBC now produces lots and lots of those antibodies as it has been identified as the correct one. This allows the WBC to come and engulf and digest the microbe.
Explain how we could become immune to an illness.
Memory cells - these are WBC that stay around after the infection has been fought off. These act when the same microbe enters the body once again. The memory cell will instantly recognise and start producing heaps of antibodies. This means that the infection will be fought off before you feel ill. This is known as IMMUNITY.
