Infection and Response

• Describe the life cycle of a pathogen

  Infect host, reproduce themselves, spread from host, infect other organisms.
• Define pathogen

  A pathogen is a microorganism that causes a disease.
• How are viruses transmitted?

  Vector, water, unhygienic food preparation, direct contact
• Virus definition

  An ultramicroscopic infectious non-cellular organism that can replicate inside the cells of living hosts, with negative consequences.
• What are the human defence systems?

  Skin (physical barrier), stomach (acid kills microbes), lungs (cilia and mucus trap microbes), nose (hair and mucus trap microbes)
• What are the ways that white blood cells defend against disease?

  Phagocytosis (white blood cells engulf pathogen), antibodies (antibodies attach onto antigens on the pathogens surface, which help to kill the pathogen), antitoxins (white blood cells produce toxins which counteract toxins)
• How do vaccines work?

  The vaccine inserts dead or weakened pathogen to stimulate the production of antibodies. Memory cells are made so once the body is re-exposed to the pathogen, antibodies are made very quickly.
• What are antibiotics used to treat?

  Bacterial infections (are not effective for viral infections)
• What is the difference between antibiotics and painkillers?

  Antibiotics kill the bacteria, whereas painkillers relieve the symptoms.
• Describe the formation of monoclonal antibodies

  Mouse is injected with antigen.

  Mouse produces lymphocytes, which produce antibodies.

  Spleen cells are removed.

  Spleen cells fused with myeloma cells to form hybridoma cells which continuously divide.

  Hybridoma cells divide and produce millions of monoclonal antibodies specific to original antibody.
• Describe two uses of monoclonal antibodies.

  To locate blood clots.

  To diagnose some cancers.
• What is the name given to an organism that transmits disease?

  Vector
• Give an example of a fungal disease in a plant.

  Rose black spot
• How do pathogenic bacteria negatively affect the body after first infection?

  Pathogens produce toxins that damage cells/tissues.
• Describe 2 ways the spread of malaria can be reduced.

  Stop mosquitoes from breeding and use mosquito nets.