IB Biology: Defence and Immunity

14 flashcards · Other · by Gabrielle Wong

1. Defence: skin layer Epidermal layer: dead cells that act as a physical barrier to pathogens Sebaceous glands that secrete sebum, olily substance that aids in retaining mositure and lowering pH so bacteria cannot survive

   In openings, mucuous (sticky glycoproteins) trap pathogens an dparticels, plus cilia move in a wave to trap pathogens

2. Macrophage white blood cells (phagocytes): squeeze out from capillaries large numbers form pus at the site of an infection identify the pathogen - able to recognize what is "self" and "not self" engulfs "not self" materials with endocytosis often have many lysosomes to digest these materials

   This is non-specific immunity because it isn't specific to a pathogen; it just recognizes something as not being part of the body

3. Process of blood clotting

   Damaged blood vessels platelets detect injury and caccumulate at the wound forms a temporary soft clot release of clotting factors (this ensures clotting doesn't occur without this process) prothrombin is converted into thrombin thrombin catalyzes reaction that turns fibrinogen into fibrin fibrin and platelets form a mesh that catches red blood cells this becomes a scab when dried

4. Antigens: antibody producing substances ex. a pathogen

   Antibodies will bind to a specific antigen to destroy it

5. Antibodies: protein responsible for a specific immune response lymphoctyes snese presence of antigen, produce antibody in response binding occurs at the hypervariable region antigens stimiulate division of lymphocytes - plasma cells occurs until there are enough to control the pathogen

   Longer term immunity is created because some lymphocytes are stored as memory cells, remain long lived and inactive until needed again

6. Specific immune response:

   Immune responses for a particular antigen (marker on a pathogen)

7. Passive immunity

   Occurs when antiboides are recieved, leading to a rapid response, ex. a baby recieving antibodies from breastmilk

8. Active immunity

   Occurs when antibodies are produced, leading to a slower, but more long-term response, such as using a vaccine to stimulate antibody production

9. Antibiotics: (natural) substance that prevents micro-organism growth by targetting biochemical pathways of prokaryotic cells ex. by preventing DNA replication

   This explains why antibiotics will not work against viruses, as they insert genetic material into the host eukaryotic cell

10. Antibiotic resistance: when a bacteria is immune to the effects of antibiotics, may lead to superbugs ex. MRSA, a type of staph infection

    Can be caused by mutations and genetic variation natural seelction overuse of antibiotics

11. Coronary thrombosis: a blood clot in a major vessel of the heart

    Causes: cholestoerol and plaque buildup Consequences: Restriction of blood flow to the heart, leading to increased pressure increased risk of myocardial infarction because heart tissue dies, resulting scar tissue prevents normal function

12. HIV/AIDS: human immunodeficiency virus / acquired immunodeficiency syndrome Occurs because the virus attacks lymphotcyte cell necessary for specific immune response, leading to lowered production of antibodies Inability to combat secondary illness is often what kills infected

    Methods of transmission include: unprotected sex with infected using hypodermic material infected individual used HIV positive mother could infect child

13. Blood types

    Placeholder

14. Pathogens

    Virus or organism capable of causing disease