B3: Infection & Response

• The immune system is made up of cells, tissues, organs, and proteins that work together to defend the body against pathogens.
• Four ways in disease caused by pathogens can spread: through air, through water, direct contact, and through vectors
• A pathogen is a microorganism that causes disease
• A vaccine contains a small quantity of dead or innactive pathogen
• Antibiotics kill bacteria but not viruses
• New drugs are tested in clinical trials to see if they are safe and effective.
• New drugs are tested to check if they are safe and effective
• Antibodies recognise and bind to antigens on the surface of pathogens
• Painkillers are used to treat the symptom, not the cause of the pain.
• It is difficult to treat viral diseases as antibiotics cannot cure them
• The body's immune system can be boosted by vaccination
• The four main types of pathogens are: Bacteria, Viruses, Fungi and Protists
• A vector is an organism that can spread a disease
• The two types of white blood cells are: Phagocytes (cells that engulf and destroy foreign particles) Lymphocytes (cells that produce antibodies)
• An antigen is any substance that causes an immune reaction
• Monoclonal antibodies are identical antibodies produced by B lymphocytes
• Monoclonal antibodies are used for pregnancy testing and anti-cancer drugs
• A problem of using monoclonal antibodies is that they have more side effects than expected
• Antigens are injected into a small animal to fuse a B lymphocyte with a tumour cell to create a hyrbidoma, that then produces monoclonal antibodies
• Phagocytosis is when white blood cells engluf pathogens and then digest them
• White blood cells perfom phagocytosis, produce antitoxins and antibodies.
• Antibodies, produced by the white blood cells, lock onto the antigen on the outside of the pathogen
• Placebo is a substance that is like the drug, but does not do anything
• The skin acts like a barrier to pathogens
• Hair and mucus trap particles
• The stomac contains hydrochloric acid to kill any pathogens that enter the body, via the mouth
• Viruses live inside your cells, where they replicate. They then burst out of the cell and infect other cells.
• Bacteria produce toxins that make you feel ill, damaging your cells and tissue
• Viral diseases include: Measles, HIV, and Tobacco Mosiac Virus (TMV)
• Measles is spread by droplets of liquid, from sneezes, coughs, etc
• Symptoms of measles include: fever, cough, red skin rash, and red eyes
• HIV is spread by sexual contact or exchanging bodily fluids
• HIV attacks the immune system, and can be controlled by antiviral drugs
• TMV affects plants. It causes yellowing of leaves and stunted growth.
• TMV stops the plant from carrying out photosynthesis
• Malaria is caused by a protis. It is spread by the bite of an infected mosquito
• Rose black spot is caused by a fungus and spread by the wind or water
• Bacterial diseases include: Samonella and Gonorhhoea
• Salmonella causes food poising.
• Symptoms of samonella include: diarrhoea, vomiting, fever, stomach cramps