chapter 2

• Pathogen


  Infectious agents and organisms that cause harm and disease to the host
• Pathogens

  • Bacteria, virus, fungi, parasite
• How pathogens enter the body

  1. Eyes, ears, the mouth and the nose

  2. Intravenous (injections)

  3. Through open wounds or cuts

  4. Through sexual intercourse (sexually transmitted)
• Parasite


  An organism that lives and feeds on or in another which also causes harm to the host
• Budding


  A type of asexual reproduction that often occurs in bacteria and yeast, where the parent organism creates a bud from its own cells which form the basis of the offspring
• Bacteria


  Live microscopic organisms that have the capability to reproduce rapidly by binary fission
• Bacteria are bigger than viruses, however, they can be infected by viruses as the virus reproduces within the bacteria
• How bacteria make you feel ill

  1. Bacteria releases poisons/toxins that are carried around the body through the bloodstream

  2. Toxins come from the waste products of the bacteria
• Antibiotics


  Treatments for bacterial infections, meaning 'anti-living'
• There are antibiotic resistant bacteria known as 'superbugs' due to many factors such as mutations
• Diseases caused by bacteria

  • Cholera
  • Typhoid
  • Salmonella
• Not all bacteria have harmful effects, some are probiotics
• Probiotics


  Living bacteria or other microorganisms which are beneficial for health when consumed, promoting a healthy digestive tract and immune system
• Probiotic drink


  • Yakult
• Industrial uses of bacteria

  Making of yoghurt and cheese
• Virus


  Among the smallest organisms known, consisting of a fragment of genetic material that lies inside a protective protein coat
• How viruses reproduce


  Viruses can only reproduce inside a host cell through two different cycles (either the lytic cycle or the lysogenic cycle) ultimately destroying the host
• Diseases caused by viruses cannot be treated by antibiotics as viruses are not considered to be 'living'