Biology- Infectious diseases

• Cytoplasm - The fluid substance inside the cell where most chemical reactions occur.
• Cell membrane - A thin layer surrounding the cytoplasm that regulates what enters or exits the cell.
• The nucleus is the control center of the cell, containing genetic material (DNA) that determines an organism's characteristics.
• Nucleus - A membrane-bound organelle that contains genetic material (DNA) and controls cellular activities.
• Mitochondria - Organelles responsible for producing energy through cellular respiration.
• Nucleus - Contains genetic material (DNA) and controls cell activities.
• Chromosomes are thread-like structures made up of DNA and proteins found within the nucleus.
• Ribosomes - Small structures involved in protein synthesis, found both free floating or attached to the endoplasmic reticulum.
• Ribosomes - Sites of protein synthesis.
• Mitochondria - Site of aerobic respiration, producing energy-rich molecules like ATP.
• Mitochondria are responsible for producing energy through cellular respiration.
• Ribosomes synthesize proteins using instructions from DNA.
• Chloroplasts - Found only in plant cells, they contain chlorophyll and are responsible for photosynthesis.
• Chloroplasts - Organelles found only in plant cells that contain chlorophyll and are responsible for photosynthesis.
• Types of immunity

  Immunity is active or passive depending on the origin of the immune response. It can develop naturally through purposeful introduction of antigens or antibodies into the body (such as vaccinations). Both active and passive immunity can arise naturally or artificially.
• Active immunity


  Active immunity is protection provided by an individual’s own adaptive immune response. This type of immunity takes time to develop but the memory B and T lymphocytes that result can provide immunological memory that can last for many years, and for some diseases a lifetime
• Natural active immunity


  Results from an organism's own immune system reacting to an infection
• If exposed to the same antigen in the future


  The immune system will recognise it immediately and a secondary immune response will occur
• Secondary immune responses


  • Much faster and stronger than primary immune responses
  • More likely to protect you against the disease
• Artificial active immunity


  Artificially administering antigens to induce an adaptive immune response
• Vaccination


  The process of administering a vaccine to induce artificial active immunity
• Vaccine


  The material used to induce artificial active immunity
• Inducing artificial active immunity


  1. Administering a specific vaccine

  2. Made of altered, weakened or killed microorganisms such as bacteria or viruses

  3. Or inactivated forms of toxins or proteins
• As with natural active immunity


  The primary response to vaccination takes time to develop
• Booster vaccines


  Needed to stimulate the stronger secondary immune response that provides longer-lasting immunity
• Passive immunity


  Passive immunity is protection provided to an individual by the transfer of antibodies produced by another organism. This type of immunity is immediate, but will only protect the recipient for a limited time because it does not result in immunological memory and the transferred antibodies degrade over time and are removed from the body.
• Natural passive immunity


  Natural passive immunity involves the passive transfer of antibodies from mother to foetus through the placenta prior to birth and from mother to baby through breastfeeding. These maternal antibodies provide protection to the baby for weeks or months while its own immune system is developing.
• Artificial passive


  Artificial passive immunisation can a be useful way to treat an infection by a pathogen, or a bite or sting by a venomous animal, when death or injury is likely to occur before the primary immune response has developed or an immune suppressed individual.
• Artificial passive immunity 


  Artificial passive immunity involves an individual receiving, usually by injection of antiserum, antibodies produced by another organism. Antiserum contains specific antibodies that can act against a current infection. However, introducing antibodies to contain the threat provides only temporary immunity as no immunological memory is formed.
• Public health campaigns

  Public health campaigns assist in protecting people from disease. These are government researched and run programs to increase public awareness and reduce the incidence of diseases that can seriously impact people’s health and longevity. They are often partnered with public health programs such as:

  1.   Childhood immunisation

  2.   Free flu vaccinations for the elderly

  3.   Slip, slop, slap

  4.   Breast cancer screening

  5.   Bowel cancer screening
• Pesticides


  Chemicals used to kill the pests of plants and animals, including pathogens and the vectors that transmit pathogens between organisms including humans
• Purpose of pesticides


  • Killing pests and vectors reduces the occurrence of disease or controls the spread of disease through the population
• Types of pesticides


  • Insecticides - kill insects
  • Fungicides - kill fungal pathogens
  • Herbicides - kill weeds
• DDT


  An insecticide used to control the spread of typhus by killing the lice that transmitted the pathogen (bacteria)
• Anopheles mosquito


  Carries the plasmodium that causes malaria
• DDT used to kill Anopheles mosquito


  Controlled the spread of malaria by preventing transmission of the pathogen
• The effectiveness of DDT was reduced as mosquitoes developed resistance to it due to natural selection
• Many countries have since banned the use of DDT because of its harmful effects on the environment
• Some malaria-infested countries still use DDT to control mosquito numbers, even though it is not as effective
• Pyrethrum


  An insecticide that is less harmful to the environment and more effective in controlling mosquito numbers compared to DDT