3.2.1 The Causes of Disease: Pathogens, Lifestyle & Disease Flashcards Preview

A-level Biology Oxford AQA > 3.2.1 The Causes of Disease: Pathogens, Lifestyle & Disease > Flashcards

Flashcards in 3.2.1 The Causes of Disease: Pathogens, Lifestyle & Disease Deck (17)
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Define Pathogen

Microorganisms that cause disease


Define Infection 

When a pathogen enters a host cell and colonises tissues


Define Disease

Description of symptoms 


Define Transmission

When pathogens are transferred from one individual to another


Define Interface

Surface or boundary linking the internal environment and the external environment


Name the 4 factors that must be present for a microorganism to be considered a pathogen

  1. Gain entry to a host
  2. Colonise tissues in host
  3. Resist defences of host
  4. Cause damage to host tissues


Name 3 natural defences the body has to prevent the entry of pathogens

  •  Mucous layer 
    • Covers exchange surfaces and forms a sticky barrier that’s difficult to penetrate
  • Produce enzymes
    • Breaks down pathogens
  • Produce stomach acid
    • Kills microorganisms 


Name ways pathogens gain entry to a host

  1. Penetrate one of organism’s interfaces e.g. through a cut/abrasion/bite in the skin
  2. Gas exchange system 
  3. Digestive system 
  4. Reproductive system 


Name the 2 main ways pathogens affect the body 

  • Damaging host tissues
  • By producing toxins


What is a correlation?

When change in one of 2 variables is reflected by change in other variable


What do you need to prove something causes something else (e.g. smoking is the cause of lung cancer)?

causal relationship


What is a risk?

Measure of probability that damage to healthy will occur as a result of given hazard


Name the 2 elements of a risk

  • Probability hazardous event will occur
  • Consequences of hazardous event


Name a genetic factor that increases the risk of cancer

Specific inherited alleles  


Name 2 environmental factors that increases the risk of cancer

  • Exposure to radiation 
  • Lifestyle


Name 5 lifstyle choices that increases the risk of cancer

  • Smoking 
  • Diet 
  • Obesity 
  • Physical activity 
  • Sunlight 


Suggest why people with a family history of cancer are at greater risk of cancer than those with no family history of cancer (1)

Gene which gives predisposition to cause cancer

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