Bio paper 1

• Communicable diseases


  Diseases that can be spread from person to person (e.g. measles)
• Non-communicable diseases


  Diseases that cannot be passed from person to person (e.g. coronary heart disease)
• Communicable diseases are spread by pathogens such as bacteria or viruses
• Ill health can be caused by both communicable and non-communicable diseases, poor diet, high levels of stress, and other life situations
• People with a defective immune system (e.g. HIV)

  Are much more likely to suffer from infectious diseases (e.g. TB)
• Infection with HPV


  Can cause cervical cancer
• Infection with a pathogen


  Can trigger an allergy (e.g. asthma, dermatitis)
• Physical illness (e.g. arthritis)

  Can trigger a mental illness (e.g. depression)
• Health is defined as the state of physical and mental well-being
• the nucleus is the control centre of the cell
• the cytoplasm contains organelles, ribosomes and enzymes
• ribosomes are made up of proteins and rna
• The cytoplasm contains organelles that carry out specific functions
• Cell membrane controls what enters or leaves the cell
• Mitochondria produce energy through respiration
• enzymes catalyse reactions within cells
• mitochondria produce energy through respiration
• organelles have specific functions e.g. mitochondria produce energy
• vacuoles store water and waste products
• chloroplasts contain chlorophyll which absorbs light to make glucose during photosynthesis
• Pathogen


  Microorganisms that cause infectious disease
• Types of pathogens


  • Bacteria
  • Viruses
  • Protists
  • Fungi
• Bacteria


  • Reproduce very rapidly under ideal conditions
  • Can release harmful chemicals called toxins that damage tissues and make us feel ill
• Viruses


  • Cannot be produced by themselves, can only reproduce inside a host cell
  • Invade host cell, reproduce inside, can cause cell to burst open and die
• Ways pathogens are spread

  • Airborne (e.g. influenza)
  • Waterborne (e.g. cholera)
  • Direct contact (e.g. HIV)
• Reducing the spread of pathogens

  1. Practicing basic hygiene (e.g. handwashing)

  2. Providing clean drinking water

  3. Reducing direct contact (e.g. using condoms)

  4. Isolation of highly infectious patients

  5. Vaccination
• Around 300,000 people in the UK get food poisoning from a type of bacteria every year
• Many bacterial diseases can kill us
• Viruses are very different to bacteria as they cannot be produced by themselves, they can only reproduce inside a host cell
• When a virus leaves a host cell, it can cause the cell to burst open and die
• Viruses


  Pathogens that cannot be killed by antibiotics
• Viruses are microorganisms that cause infectious disease
• Measles


  • Highly infectious disease
  • First symptom is fever
  • After 3 days, develops red skin rash
  • Virus spread through coughing/sneezing droplets
  • Can cause complications and be fatal
• HIV


  • First symptom is flu-like illness
  • Virus attacks immune system cells
  • Immune system becomes severely damaged
  • Patient can contract other infections and develop cancer
  • Late stage is AIDS, often fatal
  • Treated with antiretroviral drugs that stop virus multiplying
  • Transmitted through exchange of bodily fluids
• Vaccination can protect against measles
• Antiretroviral drugs do not cure HIV/AIDS, but allow patients to live a normal life expectancy
• Communicable disease


  A disease that is passed from person to person by a pathogen
• Pathogen


  A microorganism that causes an infectious disease
• Unlike viruses, bacteria can be killed by antibiotics
• Salmonella food poisoning


  A bacterial disease caused by ingesting infected food