Biology pathogens and disease
- Created by: katiebrocklehurst251
- Created on: 29-10-14 16:14
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- Biology: Pathogens and Disease
- Pathogens
- Bacteria
- Living cells that multiply rapidly
- Release toxins into the body
- e.g. food poisoning, cholera, typhoid and whooping cough
- Viruses
- Consist of genetic material in a protective protein coat.
- Reproduce inside host cells
- The virus expands until it splits the host cell so it is passed into the bloodstream
- e.g. influenza, measles, mumps, chicken pox and AIDs
- A pathogen is a disease causing pathogen
- Pathogens spread by: air droplets, physical contact, food and drink, broken skin
- Bacteria
- Defence mechanisms
- First line of defence
- Skin and scabs provide a barrier
- mucus traps pathogens
- Stomach acid kills pathogens
- Second line of defence
- White blood cells ingest and destroy pathogens
- Third line of defence
- White blood cells release antibodies specific to antigens on the pathogen
- Lymphocytes produce a specific antibody
- when a lymphocyte meets the right antigen it reproduces quickly
- They also release antitoxins to neutralise toxins
- White blood cells release antibodies specific to antigens on the pathogen
- First line of defence
- Vaccinations
- inactive (weakened or dead) pathogen injected into the body
- These stimulate white blood cells to produce antibodies
- The right antibody is remembered so the body in future will know how to fight the disease
- These stimulate white blood cells to produce antibodies
- Protects a whole society from a disease
- E.g. MMR
- Mumps, measles and rubella
- E.g. MMR
- inactive (weakened or dead) pathogen injected into the body
- Antibiotics and medicine
- Medicine relives symptoms
- e.g. paracetamol, asprin and morphine
- Antibiotics kill bacteria
- Specific bacteria need specific antibiotics
- Penicillin was fund by Alexander Fleming in 1928
- Antibiotic resistance
- Bacteria can develop resistance to antibiotics
- Due to natural selection
- Bacteria can develop resistance to antibiotics
- Hygiene
- Ignaz Semmelweiss insisted doctors washed their hands
- It reduced the numbers of deaths from diseases in hospitals
- Ignaz Semmelweiss insisted doctors washed their hands
- Medicine relives symptoms
- Growing and investigating bacteria
- Equipment: agar jelly, petri dish, inoculating loop, temperature of 25 degrees for safety
- Sterilise the loop. Dip the loop into bacteria and zig-zag across the agar surface. Seal lid leaving space for air flow
- sterilising is boiling solutions and heat treating apparatus to kill bacteria already on them
- Epidemic and pandemic
- Epidemic
- rapid spread of infectious disease in one country
- Pandemic
- rapid spread of an infectious disease across many countries
- Epidemic
- Pathogens
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