communicable diseases/disease prevention/immune system

• What are the main disease-causing pathogens in humans?

  Bacteria and viruses
• How do bacteria and viruses differ in terms of cellular structure?

  Bacteria are prokaryotic cells with no membrane-bound organelles, while viruses consist of nucleic acid enclosed in a protein coat.
• What form does bacterial genetic information take?

  A circular strand of DNA
• Why do bacteria not require a host to survive?

  Bacteria can survive independently, while viruses are entirely dependent on their hosts.
• How do the sizes of bacteria and viruses compare?

  Viruses are significantly smaller than bacteria.
• What structures do bacteria possess that viruses do not?

  Bacteria have a cell membrane, cell wall, cytoplasm, ribosomes, plasmids, flagellum, and pili.
• What bacterium causes tuberculosis (TB)?

  Mycobacterium tuberculosis
• What happens during the first infection of TB?

  The first infection is symptomless as infected phagocytes are sealed in tubercles.
• Why do bacteria lie dormant inside tubercles in TB?

  They are not destroyed by the immune system due to the thick waxy coat of tubercles.
• What symptoms arise when TB bacteria become active again?

  Breathing problems, coughing, weight loss, and fever.
• What is meningitis caused by?

  Bacterial infection of the meninges.
• What virus causes AIDS?

  Human Immunodeficiency Virus (HIV)
• What are the first symptoms of HIV?

  Fevers, tiredness, and headaches.
• What happens after several weeks of HIV infection?

  HIV antibodies appear in the blood, making a person HIV positive.
• What is the relationship between HIV and AIDS?

  After the immune system weakens, HIV leads to AIDS.
• What virus infects the ciliated epithelial cells of the gas exchange system?

  Influenza virus
• How is Athlete's foot transmitted?

  By direct contact with spores on the skin surface or other surfaces.
• What is the vector for malaria?

  A female Anopheles mosquito.
• What virus infects tobacco plants?

  Tobacco mosaic virus
• What are the physical barriers of pathogen entry in plants?

  Cellulose cell walls, lignin layer, and waxy cuticles.
• What happens when a pathogen is detected in plants?

  Various mechanisms are activated to prevent the spread of infection.
• What is necrosis in plants?

  It is when cells near the site of infection are killed to prevent the spread of pathogens.
• What are menthols produced by mint classified as?

  Terpenoids
• What role do lysozymes play in animal defenses?

  They kill bacterial cells by damaging their cell walls.
• What is the function of interferons in the immune response?

  They prevent viruses from spreading to uninfected cells.
• What is phagocytosis?

  A process where white blood cells engulf and destroy pathogens.
• What happens after a pathogen is engulfed by a phagocyte?

  The phagocyte presents the pathogen's antigens on its surface.
• What are memory cells in the immune response?

  Cells that replicate when exposed to an invading pathogen, leading to a faster immune response.
• What type of immunity results from the production of antibodies by the immune system?

  Active immunity
• What is the difference between natural active immunity and natural passive immunity?

  Natural active immunity arises from exposure to an antigen, while natural passive immunity comes from maternal antibodies.
• How is active artificial immunity acquired?

  Through vaccinations that stimulate the immune system.
• What are bactericidal antibiotics?

  Antibiotics that kill bacteria by destroying their cell walls.
• What is antibiotic resistance?

  When bacteria survive and reproduce despite the presence of antibiotics.
• How can hospitals control the spread of antibiotic-resistant infections?

  By screening new patients, isolating infected individuals, and following strict hygiene protocols.
• What are the key differences between bacteria and viruses?

  • Bacteria are prokaryotic cells; viruses are not cells.
  • Bacteria have a cell wall and organelles; viruses do not.
  • Bacteria can survive independently; viruses require a host.
  • Bacteria have circular DNA; viruses have either DNA or RNA.
• What are the primary non-specific defenses in animals?

  • Skin: tough barrier made of keratin.
  • Stomach acid: kills bacteria.
  • Gut and skin flora: compete with pathogens.
  • Inflammation: increases blood flow and permeability.
  • Lysozyme action: kills bacteria in secretions.
  • Interferon: prevents virus spread.
  • Phagocytosis: white blood cells engulf pathogens.
  • Blood clotting: seals wounds to prevent pathogen entry.
• What are the components of the specific immune response?

  • B cells: mature in bone marrow, involved in humoral response.
  • T cells: mature in thymus, involved in cell-mediated response.
  • Memory cells: replicate upon re-exposure to pathogens.
  • B effector/plasma cells: produce antibodies.
  • T helper cells: stimulate B and T killer cells.
  • T killer cells: destroy infected cells.
• What are the mechanisms of antibody action?

  • Neutralization: antibodies inhibit pathogen action.
  • Agglutination: antibodies bind pathogens together.
  • Facilitation of phagocytosis: antibodies help phagocytes bind to pathogens.
• What are the types of immunity and their subtypes?

  • Active immunity: produced by the immune system.
  • Natural: from disease exposure.
  • Artificial: from vaccinations.
  • Passive immunity: introduced from another source.
  • Natural: from mother’s antibodies.
  • Artificial: from antibody injections.
• What are the types of antibiotics and their functions?

  • Bactericidal: kill bacteria by destroying cell walls.
  • Bacteriostatic: inhibit bacterial growth by stopping protein synthesis.