Infectious disease

Mel Hughes
Flashcards by Mel Hughes , updated more than 1 year ago
Mel Hughes
Created by Mel Hughes about 5 years ago


GCSE Biology (B1.1 Healthy eating) Flashcards on Infectious disease, created by Mel Hughes on 03/18/2016.

Resource summary

Question Answer
Pathogens Microorganisms that cause infectious disease
Bacteria - Bacteria are very small single-celled organisms. - Not all cause disease. - Pathogenic bacteria reproduce rapidly inside the body and may produce poisons (toxins) which make us feel ill.
Viruses - Viruses are much smaller than bacteria. - All viruses are pathogens. - Viruses produce toxins and they damage the cells in which they reproduce, leading to illness.
How do viruses work? What does this cause? Example? - Viruses replicate by invading cells, reproducing inside them and bursting them. - This causes damage to tissues, leading to illness. - Example: HIV virus damages white blood cells, reducing immunity and leading to AIDS.
When does disease occur? Disease occurs when large numbers of pathogenic micro-organisms enter the body.
Disease transmission Give 3 examples Diseases are transmitted through: 1) Unhygienic conditions 2) Direct contact with infected people 3) Inhaling droplets from coughs or sneezes.
Preventing transmission -Ignaz Emmelweiss -In the 1850s, Ignaz Emmelweiss insisted that medical students washed their hands before delivering babies. - This idea was not accepted – people were not aware of microorganisms. - people now have to wash hands after treating patients, to prevent disease being transmitted to other patients.
Medicines What are they used for? Give examples - Some medicines, including painkillers, help to relieve the symptoms of infectious disease, but DO NOT kill the pathogens. - E.g. painkillers, hayfever drugs, asthma inhalers.
Antibiotics -Antibiotics are substances that are used to cure bacterial infections by killing pathogenic bacteria inside the body. -Antibiotics cannot be used to kill viral pathogens This is because viruses live and reproduce inside cells.
Give example of an antibiotic - Penicillin is one example of an antibiotic. Other antibiotics include tetracycline and ampicillin.
Antibiotics are only useful if they... ... attack the bacteria and not the human body.
Immunisation Where people can be immunised against a disease by introducing small quantities of dead or inactive forms of the pathogen into the body (vaccination).
How do vaccines work? Vaccines stimulate the white blood cells to produce antibodies that destroy the pathogens. This makes the person immune to future infections by the microorganism.
Example of vaccine An example is the MMR vaccine used to protect children against measles, mumps and rubella:
LEARN THIS Bacteria and viruses may reproduce rapidly inside the body and may produce poisons (toxins) which make us feel ill. Viruses damage cells in which they reproduce.
What can white blood cells do (Give three points) -Ingest pathogens and destroy them - Produce antibodies to destroy particular pathogens -Produce antitoxins that counteract the toxins released by pathogens.
Key points about white blood cells - The pathogens are not the disease - they cause the disease - White blood cells do not eat the pathogens - they ingest them -Antibodies and antitoxins are not living things - they are specialised proteins.
Vaccination Vaccination involves putting a small amount of an inactive form of a pathogen, or dead pathogen, into the body.
What can vaccines contain? -Live pathogens treated to make them harmless - Harmless fragments of the pathogen dead pathogens.
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