BIOL110s05-41 - BIOL 110 Principles of Biology Spring 2005 Quiz#7(Last Quiz up ~Today Quiz(microbes plants animal Tissues& homeostasis

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Unformatted text preview: BIOL 110: Principles of Biology Spring 2005 Quiz #7 (Last Quiz!): up ~Today Quiz!): (microbes, plants, animal Tissues & homeostasis). http://smcwebtest.smccd.net/accounts/staplesn/index.tpx Lecture 41, W 5/11/05 http://www.smccd.net/accounts/staplesn/biol110/ Extra Credit: Stanford Talk, and 2nd Journal Article due TODAY, 5/11. NO Late E.C. will be accepted!!! Midterm 3 (if <70%), Rewrite/Extra Credit due by Fri., 5/13. WED. & MON. Field Trip: Edgewood Park (@ 280 & Edgewood Road) Trip: Grade for participation & Worksheet!!! (Replace 1 quiz!!!) Bring: Good shoes/boots, light-colored clothing/pants, notepad & worksheet, shoes/boots, lightworksheet, binoculars?, hat, sunblock, water, snack? hat, sunblock, Wed.: Meet at 8:10am, leave at 8:20am. DON'T BE LATE! DON' Next Mon.: Meet at Old Stage Camp entrance, 1:10pm. We leave up the Sylvan Sylvan Trail at 1:20pm. Maps, info: www.friendsofedgewood.org Next: Ch. 25, 23, 29 & 30, (31, 32). 30, 32). Meet Here!! 1 REVIEW: Ch. 23: Immunity Barriers tissue, fluid; Cells phagocytes, NK Nonspecific chemicals lysozyme, complement lysozyme, Immunity specific for each pathogen!! & Memory TODAY: Ch. 23: Immunity Immunity specificity & Memory! B cells humoral, antibody-antigen humoral, antibody Intra-cellular pathogens Intra- T cells cell-mediated immunity cell Extra-cellular pathogens Extra- Memory and Effector Cells When a B or T cell is stimulated to divide, it produces more than one cell type Memory cells are set aside for future use; they are the basis for immune memory Effector cells engage and destroy the current threat Macrophage 2 B. Key Components of Immune Response 1. MHC markers = "tags" that sound the "alarm" tags" alarm" 2. Antigen-presenting cells (APCs) = "scouts" Antigen(APCs) scouts" B cells Dendritic cells - executioners Macrophages marching soldiers & executioners ....many other cells of the body.... body... 3. Helper T cells (Th) = "buglers" rally the troops! (Th) buglers" 4. Effector cytoxic T cells (Tc) = "skilled swordsmen" (Tc) swordsmen" 5. Natural killer cells (NK) = "frontline swordsmen" swordsmen" 6. B cells = "archers and taggers" taggers" NK cells?? eosinophils neutrophils basophils T mast cells lymphocytes lymphocytes (mature in bone marrow) (mature in thymus) B forerunners of the white blood cells (leukocytes) ? stem cells that multiply and differentiate in bone marrow monocytes (immature phagocytes) red blood cells (erythrocytes) mature macrophages dendritic cells megakaryocytes platelets Ch. 22 3 Overview of Interactions Antibody - mediated response Cell - mediated response AntigenAntigenpresenting cell Naive B cell (APC) Naive helper T cell Effector B cell (plasma cell) interleukins interleukins Naive cytotoxic T cell Activated helper T cell Effector cytotoxic T cell Phagocytosis and Antigen Presentation Inside APC antigen framents MHC molecule antigen-MHC complex 4 C. B Cell Formation Derived from stem cells in bone marrow Acquire unique antigen-binding receptors in marrow Receptors interact with just one antigen Exposure to that antigen causes clonal selection Division of cells specific for that antigen Clonal Selection of a B Cell Only the B cell with antigen-receptor that matches antigen is stimulated to divide B1 B2 B3 antigen binds only to antibody specific to it on a nave B cell. na antigen Mitosis yields many cells with that receptor B2 B2 B2 B2 Clonal population of effector B cells Clonal effector B cells secrete the SAME SPECIFIC antibody 5 D. Immunological Memory Memory cells specific for an antigen are quickly activated to divide upon subsequent exposure to that antigen Primary Immune Response: naive T or B cell effector cells memory cells Secondary Immune Response: effector cells memory cells Figure 23.6 Page 394 E. Lymphocyte Battlegrounds Lymph nodes filter antigens from body fluids Macrophages, dendritic cells, B cell and T cells in nodes and spleen mount a defense 6 VI. Antibody-Mediated Response Carried out by B cells Targets are extracellular pathogens and toxins Antibodies bind and mark target for destruction by phagocytes and complement Also neutralize and agglutinate (corral) Antibody Structure Antibody consists of four polypeptide chains Linked by disulfide bonds antigen-binding site variable region of heavy chain antigen-binding site hinge region (flexible) Certain parts of each chain are variable; impart antigen specificity IgG, IgD, and IgE IgA variable region of light chain constant region of light chain IgM 7 antigen on surface of bacterial cell variable region of heavy chain antigen-binding site hinge region (flexible) antigen-binding site binding site on one kind of antibody molecule for this specific antigen variable region of light chain constant region of light chain constant region of heavy chain antigen on surface of a virus particle binding site on a different antibody molecule for this specific antigen Antibody- Mediated Response "Nave"/virgin B cell becomes antigen-presenting B cell Helper T cell binds to antigen-MHC complex on the B cell Interleukins stimulate B cell division and differentiation Effector cells secrete Antibodies, which: 1. 2. 3. 4. Neutralize antigens, Agglutinate antigens, Enhance phagocytosis, phagocytosis, Activate complement Naive B cell Antigenpresenting B cell Helper T cell Interleukins Effector B cell secretes antibodies Memory B cell 8 Click to view animation. animation VII. Cell-Mediated Response Carried out by T cells Stimulated by antigenpresenting macrophages Main target is antigenpresenting body cells (cells with intracellular pathogens) or tumor cells Infected One macrophage Ingested Another macrophage interleukins Cytotoxic interleukins T cell Helper T cell Infected body cell Intracellular pathogens Intracellular pathogens 9 Click to view animation. animation Organ Rejection Cytotoxic T cells can contribute to rejection of transplanted tissue They recognize a portion of the donor cell's MHC complex as self, view a portion as foreign Treat the combination as an antigen-MHC complex and attack donor cells 10 D. AIDS Combination of disorders that follows infection with HIV Human Immunodeficiency Virus Includes Yeast (Candida) infections Pneumocystis pneumonia Karposi's sarcoma HIV Replication RNA retrovirus A protein (gp120) at virus surface binds to host cells with CD4 and chemokine receptors These receptors occur on helper T cells Once bound, RNA and viral enzymes enter the host cell Viral RNA is reverse-transcribed to DNA HIV DNA is called provirus; it inserts into host DNA (integrates) The host cell makes copies of viral DNA and viral proteins that assemble to form new virus particles 11 lipid envelope (proteins span it, line its inner surface, spike out above it) strands of viral RNA (two) viral coat (proteins) viral genes are integrated into the host DNA viral RNA enters cell DNA is transcribed reverse a strand of viral RNA undergoes reverse transcription viral DNA viral RNA viral proteins budding integrase transcriptase STRUCTURE OF HIV host cell Fig. 35.21, p. 593 T Cell Decline 1. Release of new viral particles kills the host T cell new helper T cells! infect 2. The body is constantly making new T cells, but cannot outpace the rate of destruction 3. As infection proceeds, T cell numbers inevitably decline 4. EFFECTS of T cell Decline: 1. CD4 helper T cells play a vital role in immune function 2. They are required for both cell-mediated celland antibody-mediated immunity antibody3. Infected individual becomes vulnerable to other infections, which eventually result in death HIV-infected T-cell HIVT- 12 Transmission of HIV 1. HIV does not live long outside human body 2. Most often spread by exchange of bodily fluids with an infected person 3. In the U.S., anal intercourse and needle sharing are main modes of transmission 4. Less commonly transmitted by vaginal intercourse and oral sex 5. Can travel from mothers to offspring during pregnancy, birth, or breast-feeding 6. Not known to be transmitted by food, air, water, casual contact, or insect bites Treatment 1. No cure 2. Once HIV genes are incorporated, no way to get them out 3. AZT, and other drugs slow the course of the disease and increase life span 1. Inhibit Reverse Transcriptase (copies viral RNA genome) 2. Can't replicate makes defective DNA Can' (nucleotide analog can't be polymerized) can' 4. Researchers continue to develop drugs and to work toward an AIDS vaccine 13 ...
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This document was uploaded on 03/18/2010.

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