Disease and Immune System

• What are communicable diseases caused by bacteria?

  Ring rot, bacterial meningitis, TB
• Name a communicable disease caused by a virus.

  Influenza
• What is a communicable disease caused by protoctista?

  Malaria
• What is a communicable disease caused by fungi?

  Athlete’s foot
• What are the two types of disease transmission?

  • Direct transmission
  • Indirect transmission
• What is direct transmission of a disease?

  Transmission directly from one organism to another
• What are some factors that affect disease transmission?

  Overcrowding, climate, social factors
• What are the primary non-specific defences against pathogens in animals?

  • Skin
  • Blood clotting
  • Wound repair
  • Inflammation
  • Expulsive reflexes
  • Mucous membranes
• What is the role of skin in pathogen defence?

  Forms physical and chemical barriers
• How does blood clotting help defend against pathogens?

  Forms a clot to isolate pathogens
• What triggers inflammation in response to pathogens?

  Release of histamine from damaged tissues
• What is an antigen?

  A foreign protein triggering an immune response
• What is phagocytosis?

  Process where phagocytes engulf pathogens
• What is antigenic variability?

  Pathogens changing their surface antigens
• Why might people experience a disease more than once?

  Due to antigenic variability of pathogens
• What is the role of T helper cells in the immune response?

  Activate B cells and phagocytosis
• What do T killer cells do?

  Kill abnormal and infected body cells
• How do antibodies help clear infections?

  Bind to antigens and agglutinate pathogens
• What is the structure of an antibody?

  A protein with a specific primary structure

  
• Why are antibodies specific to antigens?

  Due to their unique tertiary structure
• What are the functions of antibodies?

  • Agglutinate pathogens
  • Neutralize toxins
  • Prevent pathogen binding to cells
• What do anti-toxins do?

  They bind to toxins, neutralizing them.
• How do anti-toxins prevent pathogen binding?

  By blocking cell surface receptors on host cells.
• What is an antibody?

  A protein specific to an antigen.
• Who secretes antibodies?

  Plasma cells secrete antibodies.
• Why are antibodies specific?

  They have a specific primary structure.

  
• How does the structure of antibodies relate to their function?

  Specific structure allows binding to specific antigens.

  
• What forms the antigen-binding sites on antibodies?

  The variable region forms antigen-binding sites.

  
• What is the role of the hinge region in antibodies?

  It allows flexibility in binding.

  
• What do disulphide bonds do in antibodies?

  They hold polypeptide chains together.

  
• What are opsonins?

  They increase the likelihood of phagocytosis.
• What do agglutinins do?

  They clump pathogens together for phagocytosis.
• Name two phagocytic white blood cells.

  Neutrophils and macrophages.
• What is an autoimmune disease?

  It results from an abnormal immune response.
• How are autoimmune diseases treated?

  With immunosuppressants.
• What role do T regulatory cells play in autoimmune diseases?

  They help prevent the immune system from attacking self cells.
• What are cytokines?

  Cell signaling molecules.
• What do cytokines stimulate?

  Cells involved in the specific immune response.
• What characterizes the primary immune response?

  It is slower due to clonal selection.
• What is produced during the primary immune response?

  Memory cells are produced.