refer to the following: An art student decides to hand-paint coasters and sell sets at a ea market. She decides to make two types of coaster sets: an ocean watercolor and black-and-white geometric shapes. The cost, prot, and time it takes her to paint each set are summarized in the following table.Prot. If her costs cannot exceed $100 and she can spend only 90 hours total painting the coasters, determine the number of each type she should make to maximize her prot.
HUMAN BIOLOGY STUDY GUIDE EXAM THREE VOCAB WORD RELEVANCE VIRUS Genetic material (DNA or RNA) surrounded by a protein capsule. Cannot reproduce or do anything life-like without a host cell. However, when applied to a host cell they take over the host organelles and use it to reproduce. Virus enters either by endocytosis, combining it’s membranes, or injection-like to insert its DNA to the host and then the host starts reproducing tons of viruses instead of its normal function. HIV Human Immunodeficiency Virus, a virus that attacks the immune system. 2/3 of infected humans live in sub-Saharan Africa. RNA Ribonucleic acid. Single strand. Uses AUCG DNA Deoxyribonucleic acid, double stranded nucleotides in helix. Organized and arranged by chromosomes in nucleus. Uses ATCG bases. PATHOGEN Definition: a disease-causing agent that comes from outside of the body, including bacteria, viruses, parasites. LYMPH Lymphatic system maintains blood volume in cardiovascular, transports fat soluble vitamins and fat from dig to cardiovascular, defends bod against infection. Lymphatic system consists of lymph vessels, nodes, spleen, thymus gland, tonsils, adenoids. Lymphatic capillaries take up substances that are too large to enter the blood capillaries. Lymph is a milky body fluid containing WBC, proteins, fats, occasional bacterium and virus. Lymphatic vessels have three thin layers and have one-way valves so there isn’t backflow. Aided by skeletal muscle contraction/pressure changes from respiration. Vessels merge to create two ducts: right lymphatic duct and the thoracic duct. Two ducts join veins near shoulders and returns lymph to cardiovascular system. LYMPH NODE CLEANS LYMPH Small organs that remove (microorganisms, cellular debris, abnormal cells) from lymph. Clustered in digestive tract, neck, armpits, groin. Inside, macrophages and lymphocytes identify and remove microorganisms. SPLEEN CLEANS BLOOD Soft, size of fist in upper left abdominal cavity. Inside, two tissue types are red pulp and white pulp. Functions: controls quality of circulating RBC (removes damaged/old) and fights infection. Red pulp has microphages that look for/break down microorganisms and old/damaged RBCs/cells/platelets. Clean blood stored in red pulp (reserved for blood loss or fall in blood pressure). White pulp has lymphocytes searching for foreign pathogens, does not store blood. Enlarged with mononucleosis and leukemia. If ruptured, severe internal bleeding to cause fatal hemorrhaging. Functions shared by lymph glands, liver, red bone marrow so can live without. However, more vulnerable to infections. THYMUS GLAND Located in lower neck. Contains lymphocytes and epithelial cells. Secretes thymosin and thymopoietin hormones that cause lymphocytes called T cells to mature and specify defense. May disappear in old age as other defense mechanisms become more specialized. PHAGOCYTE Engulf foreign cells, they’re WBC that destroy by phagocytosis (captures bacterium w/ cytoplasmic extensions, engulfs w/ endocytosis, encloses in vesicle and fuses to lysosomes. WBC can go through blood vessel wall to tissue space because substances released by injured cells at infection sites. Some only stay in connective tissues of lymph nodes, spleen, liver, lungs, brain. 2 Neutrophils: WBC, first to respond to infection. Digest/destroy bacteria in blood and tissue fluid. Monocytes: other WBC, leaves vascular and enters tissue fluid and develops into macrophages Macrophages engulf and digest large amounts foreign, especially virus and bacteria parasites. Serve as cleanup function, scavenges old blood cells/dead tissue fragments/cellular debris. Also releases chemicals into the bloodstream to stimulate more WBC production. No longer “WBC: because no longer in blood. Eosinophils: other WBC that work on invaders too big for phagocytosis. Cluster around large parasites and bombard digestive enzymes, can engulf and digest certain foreign proteins. Pus (dead phagocytes and microorganisms, tissue fluid, cell debris that accumulate at the infection site) accumulates to abscess if cannot drain. LSYOSOME When vesicle fuses to lysosome from above situation, enzymes from lysosomes dissolve the membranes of bacteria. Then digests and phagocyte releases via exocytosis. NATURAL KILLER CELLS A group of WBC (lymphocytes) destroy tumor cells and body cells infected by viruses. Recognizes changes in plasma membranes. Nonspecific killers. Not phagocytes. Release chemicals to break down target cell membrane, after attack membrane develops holes and nucleus disintegrates. Secrete substances that enhance inflammatory response. INFLAMMATION Redness, warmth, swelling, pain. Triggered by any type of tissue injury (infection, burns, chemicals, physical trauma). The symptoms prevent damage from spreading, disposes cellular debris and pathogens, sets stage for repair. 3 1. Release of chemicals from damaged cells stimulate mast cells (connective tissue cells specialized to release histamines) 2. Histamine promotes vasodilation (WBC called basophils can secrete histamines too) 3. as vessels dilate, become more permeable, allows phagocytes out to attack foreign organisms/damaged cells. After destroying, phagocytes go to lymphatic system and presence stimulates initiation of other defense mechanisms. 4. Vasodilation = more blood = more red and warm, rising temperature increases phagocyte activity. Increases leakiness of capillary walls, more fluid in tissue, = swelling. More fluid dilutes pathogen/toxin and brings in clotting protein to wall of damaged from healthy. Fluid has extra O2 and nutrients to promote healing; carries away dead cells, microorganisms, etc. 5. Swollen tissue presses nerves, making pain. Discomfort hinders movement and forces injured to rest, facilitating healing. COMPLEMENT PROTEIN Complement system assists other defense mechanisms. At least 20 plasma proteins circulate blood and assist other defense. Normally inactive. Activated by infection, one protein activates next and so on = domino effect. Activated complement proteins join to form protein complexes for creating holes in bacterial cell walls, bacterium swells/bursts. OR bind to bacteria membrane that flags down phagocytes. OR stimulates mast cell’s release of histamines. INTERFERON Early warning, cells infected by viruses secrete proteins called interferons. Diffuse to nearby heathy cells to produce proteins that interfere with synthesis of viral proteins, so virus can’t infect nearby protected cells. Some produced in labs, shown to help against viral diseases like genital warts, HEP B, leukemia. 4 FEVER Raises body temperature. Pyrogens (chemicals released by macrophages when detect/attacking foreign) cause brain to reset thermostat to higher temperature. Modest fever may be beneficial to make internal environment less hospitable to pathogen. May help body fight infection. Increases metabolic rate. When infection is gone, macrophages stop releasing pyrogens, thermostat setting returns to normal. Fever breaks. High fevers dangerous. May break chemical bonds that give protein shape. If shape changes, may not function normally. MACROPHAGE As lymph flows through nodes, macrophages destroy foreign cells by phagocytosis while lymphocytes activate other defense mechanisms. HISTAMINE Secreted by mast cells (connective tissue) or basophils (WBC). Dilates blood vessels. ANTIHISTAMINE Drugs that block the effect of a histamine. Often are used as relief for allergies. ANTIGEN A substance that mobilizes immune system to provoke immune response. Large proteins or polysaccharide molecules. Each antigen has a unique shape, every bact/virus has a different one. Immune system responds to each antigen by producing specific antibodies to attack and inactivate antigen (and cell carrying it). Located in outer surface of cell or virus. Immune system cannot detect once inside host cell. Human cells have surface proteins that act as antigens. = proteins (below) MHC PROTEINS Our human cells have unique proteins on surfaces that immune system uses to recognize own cells. Self parkers called major histocompatibility complex proteins. Unique to each person by genetics. Normally, signal immune system to bypass own cells. In another person, your own MHC proteins would = an antigen. Abnormal and cancer cells in own body have MHC that are not recognized as “self”. Immune system targets all antigens, including pathogens and 5 foreign, and damaged human cells for destruction. B CELL Lymphocyte that matures in bone marrow. Recognizes and targets antigen-bearing cells. Responsible for antibody-mediated immunity. Produce antibodies. Releases them into lymph, bloodstream, tissue fluid. Inactive in bloodstream until encounters foreign cell with particular antigen. Then, surface receptor binds to antigen and activates B cell to grow and multiply to produce exact copies of B cell (exact cell descending from one cell all with same receptors are called clones) When antibodies encounter matching antigens, bind to them and create antigen- antibody complex. Antibodies recognize certain proteins. Formation of complex marks for destruction by activated complement proteins or phagocytes. Some antibodies inactivate pathogens by causing the cells to agglutinate (clump together) to prevent them to enter human cells and cause disease. T CELL Lymphocyte that matures in thymus gland. Recognizes and targets antigen-bearing cells. Responsible for cell-mediated immunity. Do NOT produce antibodies. Directly attack foreign cells carrying antigens. OR release proteins that help coordinate other aspects (actions of T cells, B cells, macrophages). Identifies and kills human cells before having a chance to release new bacteria or viruses into blood. Antigen-presenting cells have to engulf foreigns, digest, display fragments of antigens on surfaces. Partially degrades antigen inside vesicle. Vesicle with antigen fragments joins with another vesicle with MHC = markers. MHC binds to antigen and moves to cell surface to display as an antigen- MHC complex. Cell presents a fragment of the antigen for T cells to recognize, along with own marker. Develop from stem cells, migrate to thymus gland, mature but remain inactive. 6 Maturation develops either surface protein called CD4 or CD8. Protein determines the type of T cell. CD4 T cells are helter and memory, CD8 t cells are cytoxic and suppressor cells. ANTIBODY Proteins that bind with and neutralize specific antigens. Belong to the class of blood plasma protein called gamma globulins. 5 classes of antibodies, covered in “Immunoglobulins” structure enables them to bind to specific antigens. All antibodies have same basic shape: 4 polypeptide chains arranged in a Y shape. Two larger are called heavy chains, 2 smaller are called light chains. Each of four has a region that represents the antigen binding site. Because of the unique amino acid sequence, each variable region has a unique shape for only one specific antigen. Constant regions differ between classes. ANTIBODY-MEDIATED IMMUNITY Works best against viruses, bacteria, foreign molecules that are soluble in blood and lymph. CELL-MEDIATED IMMUNITY Depends on actions of several types of T cells. Protection against parasites, bacteria, viruses, fungi, cancerous cells, cells as foreign (happens with transplants). IMMUNE RESPONSE Immune system is comprised of cells, proteins, lymphatic system to kill pathogens and abnormal body cells. Immune response = the collective activities of immune system. = specific defense mechanisms. Three important characteristics 1. Recognizes and targets specific pathogens and foreign substances 2. Has a memory: stores info from past exposures to respond quicker to later invasions by same pathogens 3. Protects entire body, resulting immunity not limited to site of infection. 7 Specific defenses are able to tell own cells and foreign invaders apart. In own cells, has to distinguish healthy vs. abnormal vs. dead and dying. MEMORY CELL Some clone cells from the B cell become memory cells- long living inactive states until same antigen reappears. Stores information about pathogen. Upon 2 ndexposure, immune response is faster than 1 time. When re exposed, become plasma cells and start to secrete antibodies. Basis for long term immunity. Memory t cells reactive during later exposures. Some activated t cells become memory cells, retain receptors for antigen. If antigen presented again = reactivation. Some make new helter t cells to trigger immune response and some form more cytotoxic t cells to distinguish specific defenses from non. PLASMA OR EFFECTOR CELL Plasma cells are cloned b cells that secrete their antibodies into the lymph fluid and blood plasma. Super fast production for only few days. IMMUNOGLOBULIN Blood plasma proteins called gamma globulins of antibodies, crucial role in immunity so term immunoglobulin (Ig) is used. Five classes, each w/ different letter. Each has a different size, location in body, function. Five classes of antibodies 1. IgG (75% of immunoglobulins) most common. Blood, lymph, intestine, tissue fluid. Long lived antibodies activate complement system and neutralize toxins. Only antibodies that cross placenta during pregnancy to transfer immunity to fetus. 2. IgM (5-10%) first to be released in immune response. Blood and lymph, activate complement system. Cause foreign cells to agglutinate. ABO blood cell antibodies belong to this class. 3. IgA (15%) 8 enter areas covered by mucous membranes like digestive, respiratory, and reproductive tracts. Neutralize infectious pathogens. Present in breast milk and transmitted to child in feeding. 4. IgD (less than 1%) in blood, lymph, and B cells. Unclear function, may activate B cells. 5. IgE (about .1%) rarest immunoglobulins. In B cells, mast cells, basophils. Activate inflammatory response by triggering histamine release. Troublemakers behind allergic response. HELPER T CELL CD4 surface proteins. Helper t cells stimulate other immune cells. When a t cell with CD4 receptors encounters antigen-presenting fragment, differentiates into a HELPER T CELL and undergoes mitosis= clone (can recognize same antigen) Secretes signaling molecules called cytokines. Role (plus role of their cytokines) = directs activities of other immune cells. Crucial to effective immune response. w/o, would be impaired or nonexistent. CYTOTOXIC T CELL Kills abnormal and foreign cells. When a mature t cell with CD8 receptors meets an antigen producing cell displaying antigen fragment, t cell produces a clone of cytotoxic t cells (= killer t cells). These are only t cells that can attack and destroy other cells. When activated, roam throughout body. Blood, lymph, lymphatic tissue searching for cells with antigens they recognize. May migrate to tumor or site of infection to release chemicals toxic to abnormal cells. Locates and binds to a target cell, secretory vesicles release protein = perforin into space between cells. Perforin molecules make a pore, allowing water and salt to enter. Eventually kills cell kind of like activated complement protein. 9 Releases granzyme (toxic enzyme that is small enough to pass through the pore). Cytotoxic t cell detaches from target cell and goes off in search of other prey. Treatments try to harness defensive capability of cytokines, especially interferons. Genetically engineered gamma interferon used to treat HEP C (chronic viral disease). Some used for multiple sclerosis, one for cancer treatment. CYTOKINE A class of signaling molecules secreted by helper t cell clones. Have proteins that stimulate actions of T cells and macrophages AND promotes development of other immune cells. Those released by helper t cells stimulate other immune cells like phagocytes, natural killer cells, t cells with CD8 receptors. Attract other types of WBCs to area, enhances nonspecific defenses. Activates B cells, creates link between antibody-mediated and cell-mediated immunity. ALLERGY 10% north americans suffer from allergies. Range from minor to severe (hay fever to poison ivy) definition: an inappropriate response of the immune system to an allergen. Inappropriate: allergen is not a dangerous pathogen, but body reacts like it is. Culprits of allergies are the IgE group of immunoglobulins. Exposure to allergen triggers primary immune response, causes B cells to produce specific IgE antibodies. They bind to mast cells and circulating basophils. When entering the body the second time, binds to the IgE antibodies on mast cells and basophils, causing them to release histamine. Results in allergic reaction (includes inflammatory response that includes warmth, redness, swelling, pain). Histamine increases secretion of mucus in the region. Every time body is exposed to this allergen, body reacts as if injury or infection even though it 10 doesn’t. Symptoms of severe systemic allergic reaction: difficult breathing (constricted airways), stomach cramps (muscle contraction), swelling throughout the body (increased capillary permeability), circulatory collapse because of fall in blood pressure because of dilated arterioles. Relief: antihistamines or allergy shots (shots cause body to produce more IgG antibodies to combine with allergen and block attachment to IgE) To reduce risk of anaphylactic shock (above) = kit with hypodermic syringe of epinephrine (hormone that dilate airways and constricts peripheral blood vessels to prevent shock) ALLERGEN Any substance that causes an allergic reaction. Some only affect area expose, some are absorbed or injected into the bloodstream. Once in bloodstream, allergens reach circ/respit/cardiovasc/dig systems and cause a systemic response (affecting many systems of organs). Includes constriction of smooth muscle in lungs, digestive system, and dilation of blood vessels. AUTOIMMUNE DISORDER = defective recognition of itself. Immune system may produce antibodies and cytotoxic t cells to target own cells. Antibodies produced against a foreign antigen may cross-react with the person’s own tissues. Basically no cures. Treatments are therapies that depress body’s defense mechanisms to relieve symptoms. Examples: MS (progressive disorder of nervous system), type one diabetes mellitus (targets pancreatic cells), lupus erythematosus and rheumatoid arthritis. AIDS Acquired Immune Deficiency Syndrome 11 Caused by HIV. It’s so devastating because HIV destroys helper t cells and weakens the body’s cell-mediated immunity ability. READ BELOW CHART REPLICATION DNA to DNA. Uncoils helices, produces an exact copy of DNA. Uses old uncoiled/unzipped as a template to create a new complementary strand. New base pair nature ensures exact replication. New nucleotides positioned by DNA polymerases, an enzyme type. Not linear, multiple locations in replication bubbles. TRANSCRIPTION Converts DNA to mRNA. Only segment of DNA representing single gene unwinds, not entire molecule. RNA is single stranded, only one of the two strands of DNA actually carries the code specified for the synthesis of RNA. In RNA, uracil replaces thymine. Sugar groups of RNA is ribose, not deoxyribose. When transcribed, RNA is released from DNA and two DNA strands go back. TRANSLATION Uses mRNA to convert into amino acid sequence. Three steps 1. Initiation: initiator tRNA binds to smaller subunit and to mRNA. Move along mRNA until finding a start codon. Then joined by larger unit. 2. Elongation: lengthens one amino acid at time. 3. Termination: no tRNA anticodon corresponding to a stop codon on mRNA. So, ribosomal subunits and new peptide chain detaches from mRNA. MRNA VS TRNA VS RRNA RNA formed from the primary transcript is the mRNA bc it’s the message/template that can be translated into a specific sequence of amino acids to make a protein. Transfer and Ribosomal take place in protein synthesis Transfer RNA are small that carry code for just one amino acid. Carry an anticodon, a base triplet complementary to codon of mRNA. Captures single amino acids and brings to appropriate spot on mRNA chain. 12 Ribosomal RNA brings together into one long chain to become a protein. Ribosome has two subunits of rRNA and proteins. Ribosome has binding sites for mRNA and tRNA. Contains enzymes to connect amino acids. Ribosome holds mRNA and tRNA together while joining amino acids. MUTATION Could cause cancer within the body. Definition: an alteration in DNA. May result from mistakes made during replication. Chemicals/physical force could damage segment before replication. Unless detected and corrected, may be passed on to future cells or prevent replication. DNA POLYMERASE Enzymes that add new nucleotides to each of the original strands, producing two complete molecules of DNA from one. CODON Three successive bases of mRNA, each code for one of 20 amino acids. Several codons may specify same amino acids. Codon AUG is only start and there are three stop codes. Start and Stop are needed to know when to end and begin protein. GENE EXPRESSION A gene is expressed when it’s called into action and the protein for which it codes is produced. This is done by transcription. RNA POLYMERASE Attaches to promoter, starts DNA unwinding process, assists in attaching appropriate RNA nucleotides to chain. Ends by base sequences identifying end of gene. BASE PAIR ATCG is DNA, paired AT CG or in RNA AU CG NUCLEOTIDE Consists of a five carbon sugar, a single or double ringed structure containing nitrogen called a base, and one or more phosphate groups. 8 exist: four in DNA and four in RNA. GENETIC CODE DNA represents the genetic code for life while RNA is responsible for carrying out these instructions. PROMOTER A unique base sequence marking the beginning of every gene. Immunity includes: A. Barriers, methods to expel, methods to neutralize pathogens. examples: skin layer, vomiting/defecation, stomach acid B. Nonspecific defense response to general damaged tissue and common/obvious viruses 13 C. Specific defense body’s ability to recognize and neutralize specific viruses Lymphocytes have a huge role in specific defense mechanisms. WBCs originated from stem cells in bone marrow. Small, single nucleus fills nearly entire cell. 30% or all WBCs. Found in bloodstream, tonsils, spleen, lymph node, thymus gland. Two types: B lymphocytes and T lymphocytes (B cells and T cells) B VS T CELLS: B cells produce circulating antibodies, t cells release chemicals to stimulate other cells of the immune system or directly attack foreign cell and kill it. AND t cell receptors cant recognize whole antigens, only react to small fragments of antigens. So, antigen processing has to happen before T cell can do its job. Antigen must be present in recognizable form. T cells: mature in thymus, responsible for cell mediated immunity. Helper t cells: produce cytokines. Enhances immune response by stimulating other immune cells Cytotoxic t cells: attack and destroy abnormal cells Memory t cells: store info, when re exposed become helper and cytotoxic t cells. Cytokines: a class of signaling molecules that stimulate various immune system activities B cells: mature in bone marrow, antibody-mediated immunity. Plasma cells: produce and secrete specific antibodies Memory b cells: store info, re exposure makes them become plasma cells and secrete antibodies Immunoglobulins: five classes of antibodies. Every one has a unique shape, fitting one specific Antigen Lupus erythematosus is inflamed connective tissue. Discoid lupus erythematosus affects areas of skin exposed to sunlight. Systemic LE affects tissues and organs including heart, blood vessels, lungs, kidneys, joints, brain. Starts with a red rash on face/head. Or, fever fatigue joint pain, weight loss. Spread of inflammation leads to osteoarthritis and pericarditis or pleurisy (inflammation of lining in lungs). Affects women 9x more than men. Occurs during childbearing age, more common in African americans, west Indians, Chinese. Medications reduce inflammation/alleviate symptoms Rheumatoid arthritis is inflammation of synovial membrane lining certain joints. B cells make antibodies against protein in the cartilage of synovial membranes. Immune response it triggers 14 releases inflammatory chemicals that cause more tissue damage (Fingers/wrists/toes/etc = pain, stiff). Eventually inflammation destroys joint cartilage and nearby bone. Then, bony tissue breaks and fuses = deformities reducing motion. Pain relief from medication may help (so can mild exercise and physical therapy to increase motion range). Drugs neutralizing chemicals in inflammatory response can prevent joint deformity. Surgery could replace damaged joints with artificial ones, may restore movement, may prevent painful disability. ON AIDS: IMMUNE DEFICIENCY: GENERAL TERM FOR IMMUNE SYSTEM NOT FUNCTIONING PROPERLY. SEVERE COMBINED IMMUNODEFICIENCY DISEASE (SCID): INHERITABLE, EVEN MINOR INFECTION IS LIFE THREATING. PEOPLE WITH SCID DO NOT HAVE ENOUGH FUNCTIONING LYMPHOCYTES TO DEFEND BODY AGAINST INFECTION. MOST COMMON AND BEST KNOWN SEVERE IMMUNE DEFICIENCY CONDITION SYNDROME: MEDICAL FOR A GROUP OF SYMPTOMS THAT OCCUR TOGETHER ACQUIRED: ONE CATCHES IT, IN AIDS CATCHES BY INFECTION OF VIRUS CALLED HIV HIV TARGETS HELPER T CELLS OF IMMUNE SYSTEM. o HIV IS A VIRUS WITH A SINGLE STRANDED RNA AND ENZYMES WRAPPED IN TWO PROTEIN COATS + PHOSPHOLIPID MEMBRANE W/ PROTEIN SPIKES. NO NUCLEUS/ORGANELLES. o INFECTS BY ENTERING CELL AND USING CELL TO REPRODUCE. TARGETS HELPER T CELLS, GAINS ENTRY BY ATTACHING TO CD4 RECEPTORS. o BELONGS TO VIRUS CLASS= RETROVIRUSES BC OF UNIQUE WAY OF REPLICATION. THEY ATTACT TO CD4 RECEPTOR OF HELPER T CELL. THEN, FUSES ENVELOPE WITH CELL’S MEMBRANE. RELEASES VIRAL RNA AND ENZYMES INTO CELL. THEN, HOST CELL IS FORCED TO MAKE A SINGLE STRAND OF DNA COMPLEMENTARY TO THE FIRST. THE NEW X2 STRANDED DNA FRAGMENT IS THEN INSERTED INTO CELL’S DNA. CELL DOES NOT RECOGNIZE DNA AS FOREIGN SO USES IT TO PRODUCE MORE VIRAL RNA AND PROTEINS, THEN ASSEMBLED INTO THOUSANDS OF NEW VIRUSES WITHING THE CELL. THE MAGNITUDE OF VIRAL REPRODUCTION TAKES T CELLS ENERGY (DIES AND RUPTURES TO RELEASE VIRAL COPIES). NEW COPIES MOVE TO INFECT MORE T CELLS. TRANSMITTED BY BODILY FLUIDS. CANNOT SURVIVE IN DRY CONDITIONS. BLOOD, SEMEN, BREAST MILK, VAGINAL SECRETIONS. NOT BY URINE, FECES, SALIVA, PERSPIRATION, TEARS, NASAL SECRETION UNLESS CONTAINING BLOOD. TRANSMITTED MOST COMMONLY VIA SEX OR HYPODERMIC NEEDLES. OR, PASSED IN PRENANCY/LABOR/DELIVERY/BREAST FEEDING. VERSUS FLU: HIV IS NOT TRANSMITTED THROUGH AIR OR EASILY LIKE FLU. HOWEVER, SUPER VIRULENT UNLESS AGGRESSIVE TREATMENT APPLIED, UNLIKE FLU. +90% US CITIZENS DIAGNOSED W AIDS BEFORE 1988 ARE NOW DEAD. 15 DEVELOPS SLOWLY. SYMPTOMS OF HIV INFECTION AND DEVELOPMENT OF FULLBLOWN AIDS PROGRESS SLOWLY. THREE DISTINCT PHASES o PHASE ONE FEW WEEKS-FEW YEARS AFTER INITIAL EXPOSURE TO VIRUS. BRIEF SPIKE OF HIV IN BLOOD, THEN FLULIKE SYMPTOMS (SWOLLEN LYMPH NODES, CHILLS AND FEVER, FATIGUE, BODYACHE) T CELL COUNT MAY DECLINE BUT REBOUND BC BODY PRODUCES MORE CELLS/ANTIBODIES AGAINST CIRUS. PRESENSE OF ANTIBODIES AGAINST HIV = “HIV POSITIVE” PERSON DOES NOT YET HAVE AIDS THOUGH. MOST PPL DON’T SUSPECT HIV, SO DON’T GET TESTED. ANTIBODIES DO NOT DESTROY ENTIRE VIRUS BC MANY VIRUS PARTS ARE INSIDE CELL WHERE ANTIBODIES AND IMMUNE SYSTEM CAN’T REACH OR DETECT o PHASE TWO VIRUS BEGINS TO DAMAGE: WIPES OUT MORE AND MORE T CELLS, MAKES PERSON VULNERABLE TO OPPROTUNISTIC INFECTIONS (ONES THAT TAKE ADVANTAGE OF WEAK IMMUNE SYSTEM TO ESTABLISH SELVES IN BODY) MAY HAVE PERSISTENT OR RECURRENT FLULIKE SYMPOTOMS, OR MAY NOT W/O OPPROTUNISTIC INFECTION. MAY STILL NOT KNOW THEY HAVE HIV IF HAVENT BEEN TESTED. .66-.75 OF PPL DON’T HAVE SYMPTOMS ASSOCIATED WITH AIDS WHEN POSTIVE FOR HIV. PHASE TWO CAN OCCUR WITHIN SIX MONTHS, AVERAGE TAKES ABOUT TEN YEARS TO PROGRESS TO PHASE THREE. LEFT UNTREATED, 95% OF PHASE TWO PATIENTS PROGRESS TO PHASE 3. o PHASE THREE WHEN HELPER T CELL IN HIV POSITIVE FALLS BELOW 200 HELPER T CELLS/ML^3 BLOOD AND PERSON HAS AN OPPROTUNISTIC INFECTION OR CANCER ASSOCIATED WITH HIV = AIDS INFECTIONS/CANCERS ASSOCIATED WITH HIV INCLUDE PNEUMONIA, MENINGITIS, TUBERCULOSIS, ENCEPHALITIS, KAPOSI’S SARCOMA, NON- HODGKIN’S LYMPHOMA, ETC AIDS MAY NOT APPEAR UNTIL MANY YEARS AFTER HIV INFECTION. UNTREATED AIDS = FATAL. HIV MAY HAVE FIRST INFECTED HUMANS FROM PRIMATES IN 1960S. HIV SUPRESSIVE DRUG TREATMENT IS ABOUT 14-20K PER YEAR. NO CURE FOR AIDS, RESEARCH INVESTIGATING +100 DRUGS TO TREAT. AIDS DRUGS WORK BY INTERFERING WITH HIV REPLICATION AT ONE OF THE MANY STEPS OF VIRUS LIFE CYCLE. 16 o INTERFERES WITH VIRAL ENTRY TO CELL IF CANT ENTER CELL, CAN’T TAKE OVER AND REPLICATE. DRUGS = ENTRY INHIBITORS. WORK BY BLOCKING ABILITY TO LOCK ONTO RECEPTORS OF HOST SURFACE. o INHIBITION OF ENZYMES REQUIRED FOR REPLICATION OF VIRAL RNA REVERSE TRANSCRIPTASE INHIITORS ARE DRUGS THAT PREVENT PATHS TO REPLICATION AFTER VIRUS GAINS ENTRY TO CELL o PREVENTION OF INTERTION OF VIRAL GENOME INTO CELLS DNA INTEGRASE INHIBITOR DRUGS BLOCK VIRAL ENZYME THAT INSERTS RNA INTO HOST CELL DNA o INHIBITION OF ENZYMES REQUIRED TO ASSEMBLE VIRAL PROTEINS PROTEASE INHIBITOR DRUGS PREVENT VIRUS ASSEMBLY WITHIN IN CELL, EVEN IF VIRUS FORCED TO REPLICATE ITS RNA AND PROTEINS. Most effectives are combinations. No proven vaccinations because HIV can mutate quickly. With each strain, new vaccination would be needed. And HIV is too dangerous to make a vaccine: need weakened virus to introduce to immune system, instead of introduction it could just contaminate a person with HIV AIDS. 17