Viruses

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Viruses Bacteria

• Chapter 19
• Pages 471 - 490

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Compare/Contrast

• Prokaryotes (Bacteria) Eukaryotes
• Smaller Larger
• Simpler Complex
• Has genetic material Has genetic material
• No nucleus Nucleus
• Grow, reproduce, Grow, reproduce,
• respond to environment respond to
  environment
• Some move by gliding All move
• or swimming
• Some have internal Have internal membranes
• membranes
• Unicellular Unicellular multicellular
• Has organelles cytoplasm

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Bacteria

• Prokaryotes
• Smallest, most common microorganism
• Single-celled
• Lack nucleus
• Has DNA

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Bacteria

• 2 Kingdoms
• Archaebacteria
• Look similar.
• Live in harsh environments.
• Lack peptidoglycan in the cell wall.
• Have different membrane lipids.
• DNA sequences of key genes are more like those of
  eukaryotes than eubacteria.
• Are thought to be ancestors of eukaryotes.
• Ex. Methangones- produce methane gas.

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Bacteria

• 2 Kingdoms
• Eubacteria (pg. 472)
• live almost everywhere, larger of the two.
• Usually surrounded by a cell wall made up of
  carbohydrate peptidoglycan.
• Cell membrane inside cell wall.
• Cytoplasm.
• Ex. E coli

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Bacteria

• How we Identify Prokaryotes (cont.)
• How they release energy by cellular respiration
  and fermentation
• Obligate aerobes require constant supply of
  oxygen. Ex. Tuberculosis.
• Obligate anaerobes do not require oxygen.
  Oxygen could kill it. Ex. Botulism is found in
  canned food thats not properly sterilized.
• Facultative anaerobes can survive with or
  without oxygen. Can live anywhere. Ex. E coli
  which is found in the large intestines or in
  sewage or contaminated water.

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• Bacteria contain
• one circular piece of DNA
• tiny circular pieces of DNA called plasmids
• ribosomes

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Bacteria have cell walls made of

• peptidoglycan (a sugar linked to chains of amino
  acids).
• this may be covered with an outer membrane of
  lipopolysaccharide (chain of sugar with a fat
  attached).

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Some bacteria

• have a gelatinous layer called a capsule
  surrounding the cell wall.

• form thick-walled endospores around chromosomes
  when they are exposed to harsh conditions
  (drought, high temperatures) - these types
  cause botulism

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Some bacteria have

• flagella for locomotion.
• pili (short, thicker outgrowths that help cell
  to attach to surfaces)

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1. Rod shaped are called bacillus
2. Sphere shaped are called coccus
3. Spiral shaped are called spirillum

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Bacteria

• How we Identify Prokaryotes
• Shape bacilli, cocci, spirilla.
• By the way they move.
• By the way they obtain energy.
• Most are Heterotrophes which obtain energy by
  consuming food.
• Chemoheterotroph- Ex. Botulism (food poisoning).
• Photoheterotroph- uses photosynthesis.
• Autotrophs make their own food.
• Chemoautotroph- found in deep ocean floors.
• Photoautotroph- found near surface in lakes
  oceans streams.
• The chemical nature of their cell walls.
• A method of Gram Staining is used to determine
  nature. Gram () violet, Gram (-) pink.

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Bacteria

• Reproduction
• Binary fission DNA replicates divides
  producing 2 daughter cells. Asexual reproduction.
• Conjugation process where genetic information
  is exchanged.
• Spore formation an endospore may form when
  growth conditions become unfavorable.

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Bacteria reproduce asexually using binary
fission.
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Bacteria reproduce sexually using conjugation.
Bacteria exchange plasmid DNA. This is how
bacteria become antibiotic resistant.
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• Most are heterotrophs

• Decomposers feed on and recycle organic
  material

• Pathogens parasitic, disease-causing bacteria
• Either attack cells or secrete toxins

• Nitrogen-fixing bacteria (Rhizobium)
• Found in nodules of soybeans, peanuts, alfalfa,
  and clover
• Convert atmospheric nitrogen (N2) into ammonia,
  called nitrogen fixation.
• Used in crop rotation

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Nitrogen fixing bacteria in the nodules of roots
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• 2. Some are photosynthetic.
• These are autotrophs that use the suns energy to
  make food.

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3. Chemoautotrophs

• Obtain energy from molecules like ammonia and
  methane to make food.

• Examples Nitrobacter and Nitrosomonas
• - live in soil
• - have a crucial role in nitrification (turn
  ammonia into nitrates, the form of
  nitrogen commonly used by plants).

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There are three types of bacteria based on how
they obtain energy heterotrophs, photosynthetic,
and chemoautotrophs.
This is the anthrax bacterium.
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Antibiotics

• work by preventing cell wall formation,
  breaking up cell membranes, or disrupting
  chemical processes.

• cannot treat viral infections.

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Strep throat
Streptococcus
Staphylococcus
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Gonorrhea-Passed from Mother to Baby
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Syphilis
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Helpful Bacteria

• Decomposers break down dead organic material
• Biotechnology - inserting helpful genes into a
  plasmid
• Bioremediation - bacteria eat up oil spills
• Food production cheese and yogurt
• Put nitrogen back into the soil
• Aid in digestion

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Interdependence
Viruses and organisms relyon their
environmentand other species for survival.
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Viruses

• Viruses are NOT cells. A virus is an infectious
  agent made up of
• a core of nucleic acid (RNA or DNA)
• a protein coat

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Alive or not?
Even scientists disagree as to whether or not
viruses are alive. What do you think? Look at the
chart on the next page to help you decide.
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Characteristic of life
CELL VIRUS
Made of cells YES NO
Obtain use energy YES NO
Grow develop YES Only inside a living cell
Reproduce YES Only inside a living cell
Respond adapt YES YES
Contain RNA or DNA YES YES
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Viruses

• Viruses are particles of
• Nucleic acid
• Protein
• Lipids (only in some)
• They vary in size and structure.
• They enter living cels use the machinery of the
  infected cell to produce more viruses.
• Composed of
• A core DNA or RNA (which has the instructions for
  making copies)
• This is surrounded by a protein coat called a
  capsid which binds the virus to the surface of
  the host cell.

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Structureof a virus
ENVELOPE

• Envelope (part of the protein coat)
• Capsid (part of the protein coat)
• Nucleic acid (either DNA or RNA)

NUCLEIC ACID
CAPSID
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Viruses

• Bacteriophages-
• Viruses that infect bacteria.
• Ex. Bacteriophage T4

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Bacteriophage

• A virus that only infects bacteria

CAPSID
HEAD
DNA
CAPSID
TAIL FIBER
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Ticking time bombs . . .
Viruses do not reproduce, EXCEPT inside a living
cell. They invade a living cell and let the cell
do the work for them.
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Lytic Cycle
The viral infection that rapidly kills the host
cell is the lytic cycle.
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Cycle Illustration
1
2
3
4
5
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Lysogenic Cycle
The viral infection that enters a cell, remains
harmless for a period of time (sometimes years),
and then becomes harmful later is called the
lysogenic cycle.
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Viruses

• Once inside a host cell pg. 481
• Lytic infection
• Virus inters cell and makes copies of itself.
• Causes cell to burst, releasing new virus
  particales that can attack other cells.
• It then uses materials of host cell to make
  copies of its own DNA molecule.
• Host cell is destroyed.
• Lysogenic infection
• Virus integrates its DNA into the DNA of host
  cell.
• The viral genetic info. replicates along with the
  host cells DNA.
• Viral DNA thats embedded in hosts DNA is called
  prophage.
• Unlike lytic, it does not lyse the host cell
  right away so it may remain a part of DNA of host
  for many generations.

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Viruses

• Retroviruses
• contain RNA as their genetic information.
• Genetic information is copied backwards.
• It may remain dormant for any length of time
  before becomes active and it can cause death of
  the host cell.
• Ex. AIDS, some cancers.

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Retrovirus
CAPSID

• A virus that contains RNA instead of DNA
• Human Immunodeficiency Virus (HIV) is a
  retrovirus
• HIV causes AIDS

ENVELOPE
RNA
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Viruses

• Must infect living cells in order to reproduce.
• Are Parasites.
• Are not considered to be living things because
  they are not made up of cells cannot live
  independently.
• See Chart on pg. 483

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Obj. 15 Jenner and Pasteur (p. 931)

• Edward Jenner, English Doctor.
• Invented vaccine
• Infected own son with cow pox (a mild form of
  small pox)
• Son didnt contract small pox
• Cow pox triggered immune system to create an
  immunity against small pox

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Obj. 15, cont.

• Louis Pasteur
• Pasteurization
• Disproved spontaneous generation
• Said life came from life
• Boiled broth to kill microorganisms

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Obj. 16 What is an epidemiologist? (p. 457)

• A scientist who studies the causes and controls
  of disease outbreaks.
• Involved in preventing disease outbreaks and in
  stopping outbreaks that do occur spreading.
• Work for CDC, FBI, etc.

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Obj. 17 Inoculation Incubation of culture
medium

• Culture medium either a broth or an agar with
  nutrients added to it to aid in the growth of
  microorganisms.
• Inoculation referred to as a streak or stab
  (putting microorganisms in a nutrient agar or
  broth so they can grow)
• Incubation usually 24 48 hours at a
  temperature of 20º C or 37º C.

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Inoculation Technique
Heat loop
Inoculation
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Inoculation Broth
Inoculation Slant
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Agar Plate
Agar Deep
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Streak Plates
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Finished Product
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Pathogen disease causing organisms

• Virus
• Bacteria
• Fungi
• Protozoans

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Bacterial Diseases

• Louis Pasteur the first to show that bacteria
  caused diseases and established the germ theory
  of disease.
• Diseases
• Tuberculosis- bacteria is inhaled into lungs
  which destroys tissue and gets into the blood to
  travel to other places throughout the body.
• Strep Throat- bacteria releases toxins. This
  bacteria also causes scarlet fever.
• Diphtheria- infects tissues of the throat which
  leads to breathing problems, heart failure,
  paralysis death.
• Lyme Disease
• Tooth Decay

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Obj. 18 Kochs Postulates (p. 930)

1. The pathogen must be found in an animal with the
   disease and not in a healthy animal.
2. The pathogen must be isolated from the sick
   animal and grown in a laboratory culture.
3. When the isolated pathogen is injected into a
   healthy animal, the animal must develop the
   disease.
4. The pathogen should be taken from the second
   animal and grown in a laboratory culture. The
   cultured pathogen should be the same as the
   original pathogen.

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Obj. 6 Infectious v. Noninfectious diseases (p.
924)

• Infectious disease - Any disease caused by the
  presence of pathogens in the body
• Easily spread from one person to another or from
  one body part to another
• Non-Infectious disease - One that does not spread
• Rheumatoid arthritis

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Obj. 7 - How is disease spread?

• People Direct contact
• Touching
• Kissing
• Sexual contact
• Object food poisoning
• Air, Soil and Water
• Vectors insects malaria

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Bacteria produce disease in 2 ways

• Bacteria damage the cells tissues of the
  infected organism directly by breaking down the
  cells for food.
• Bacteria release toxins (poisons) that travel
  throughout the body interfering with the normal
  activity of the host.

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Prevention Control

• Vaccine a preparation of weakend or killed
  pathogens. It can prompt the body to produce
  immunity to the disease.
• Immunity the bodys natural way of killing
  pathogens.
• Antibodies compounds that block the growth
  reproduction of bacteria.
• When a bacterial infection occurs, antibiotics
  can be used to fight the disease.
• Animals can suffer from bacterial diseases as
  well. Ex. Anthrax sheep to farmers wool
  workers which can lead to death. (biological
  warfare)

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Obj.11 Active v. Passive immunity (p. 930 932)

• Immunity resistance to a particular disease
• Active immunity - immunity that you get because
  you have been exposed to a disease
• Passive immunity immunity that you get because
  of a vaccine

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Obj. 8 T cells and B cells (p. 927 929)

• Both are white blood cells
• Regulated by helper T cells
• B cell response defense that aids the removal
  of extracellular pathogens
• B cells
• Stay in lymph nodes organs
• Mature in bone marrow
• T cell response destruction of intracellular
  pathogen by cytotoxic T cells
• Both lymph, organs circulation
• Occur in thymus gland (located in lower neck
  thorax)
• Act directly against certain pathogens

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Obj. 9 Specific v. Nonspecific (p. 924-929)

• Nonspecific always present, fights off anything
  foreign to the body.
• 2 lines of defense (1 outside, 1 inside)
• Specific body has been exposed to disease
  before (immunity to chicken pox once you have
  already had the disease)

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Obj. 9, cont.

• 1st line of nonspecific defense
• Mucous membranes traps it before it can enter
  the body
• Skin acts as a physical barrier
• Sweat contains lysozyme (which digest bacterial
  walls)
• 2nd line of nonspecific defense
• Inflammatory response
• Temperature response
• Proteins
• White blood cells

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Obj. 9, cont.

• Temperature response
• Disease causing bacteria dont grow well at high
  temperatures
• Normal body temperature 37º C (98.6º F)
• gt 39º C (103º F) dangerous
• gt41º C (105º F) - fatal

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Obj. 9, cont.

• Inflammatory response

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Obj. 9, cont.

• Protein complement system
• About 20 different proteins circulate in the
  blood and became active when they encounter
  certain pathogens by attaching to the surface of
  proteins and damaging plasma membrane.
• Interferons
• Protein is released by cells infected with virus
  which causes nearby cells to produce an enzyme
  that prevents viruses

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White blood cells patrol the bloodstream-wait
to attack the pathogen

• Neutrophils engulf bacteria, then release
  chemicals that kill bacteria, can also squeeze
  between cells in the walls of capillaries to
  attack pathogens.
• Macrophage ingest kill bacteria and clear
  dead cells other debris, travel through the
  body in lymphatic systems and between cells,
  concentrated in particular organ (spleen and
  lungs)
• Natural killer cells attack cells infected with
  pathogens, puncture cell membrane, water rushes
  into infected cell which swells burst (bodys
  defense against cancer)

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Obj. 9, cont.

• SPECIFIC RESPONSE
• White Blood Cells produced in bone marrow and
  circulate in the blood and lymph nodes
• Macrophage consume pathogens and infected cells
• Cytotoxic (killer) T cells attack kill
  infected cells
• B cells label invaders for later destruction by
  macrophages
• Helper T cells activate cytotoxic T cells B
  cells

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Obj. 9, cont.

• Infected cell has an antigen (substance that
  triggers an immune response) of an invader on its
  surface
• White blood cells are covered with receptor
  proteins that respond to infection by binding to
  specific antigens on the surfaces of the
  infecting microbes
• They recognize and bind to antigens that match
  their particular shape.

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Viral diseases

• usually cannot be cured, but many can be
  prevented by
• Good hygiene

• Immunization

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VIRAL DISEASES
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BACTERIAL DISEASES
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Viral Diseases

• Viruses disrupt the bodys normal equilibrium.
• Viruses attack destroy certain body cells
  causing the symptoms of the disease.
• Diseases Chart pg. 489
• Common cold
• Influenza
• AIDS
• Chickenpox
• Measles
• Can produce other serious diseases in both
  animals plants.
• Plant viruses have a difficult time entering
  cells they infect partly because plant cells have
  though cell walls.

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Viral Diseases

• 2 Virus like particles can cause disease
• Viroids single-stranded RNA molecules that have
  no surrounding capsoid. (cause disease in
  plants).
• Ex. Tobacco mosaic virus.
• Prions particles that contain only protein
  which have no DNA or RNA. (cause disease in
  animals humans).
• Ex. Foot mouth disease in livestock.

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MEASLES
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SMALLPOX
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HERPES
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Prevention Control

• Methods of controlling bacterial growth
• Sterilization heat most cant survive high
  temperatures for long period on time.(kills
  bacteria)
• Disinfectants soaps cleaning solutions
  sterilizes hospitals overuse may cause bacteria
  to evolve.(kills bacteria)
• Food storage refrigeration (bacteria takes
  longer to multiply at low temperatures) boiling
  frying steaming.
• Food processing canning (heated to high
  temperature, placed into sterile jars sealed)
  chemical treatments such as salt, vinegar,sugar.
  (kills bacteria)

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Protection Against

• Vaccines prevention.
• Antibiotics viruses do not respond to
  antibiotics but sometime the symptoms can be
  treated.

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Obj. 12 HIV (p. 934 935)

• HIV is transmitted when the body fluids of an
  infected individual are passed on to an
  uninfected individual by direct contact or
  contaminated objects.
• Breaks down immune system, so can no longer fight
  off disease
• Hides in Helper T cells
• People w/HIV, then AIDS suffer from two rare
  problems.
• Pneumosystis carinii protozoan infections of
  lungs
• Kaposis sarcoma - cancer

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Obj. 13 Allergies (p. 926)

• Occur when antigens bind to mast cells.
• Activate mast cells which release histamines.
• Histamines produce sneezing, runny eyes nose

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Common Antigens that cause allergies

• Foods
• Dust
• Milk, eggs
• Antibiotics
• Penicillin
• Cosmetics
• Pollen
• Molds
• Microbes
• Chemicals in plants poison ivy

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Obj. 14 Autoimmune diseases (p. 933)

• A disease in which the immune system starts
  attacking body cells as if they were pathogens.
• Affect organs and tissues in different parts of
  the body.
• Graves disease, Multiple sclerosis (MS),
  Rheumatoid arthritis, Systemic lupus
  erythematosus (SLE), Type I diabetes

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Some Autoimmune Diseases

• Rheumatoid Arthritis exact cause is unknown,
  but clear the immune system is involved.
• Involves inflammation of joint, swelling, pain
  loss of function.
• Rheumatic Fever happens when streptococcus
  bacteria causes a disease known as strep throat.
• If left untreated, the immune system produces
  antibodies that destroy bacteria.
• Multiple sclerosis result of destruction by
  immune system of special cells that surround
  nerve fibers and permit rapid impulse
  transmission.

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Autoimmune diseases, cont.

• Lupus exact cause unknown, although it is
  certain that both environment genetic factors
  are involved.
• Believed a genetic pre-disposition to the disease
• Symptoms include
• Achy joints, 100F fever, Arthritis, Prolonged
  or extreme fatigue, Skin rashes, Anemia, Kidney
  disorders
• Factors that trigger Lupus
• Infections, Antibiotics, Ultra-violet lights,
  Extreme stress, Hormones

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AUTOIMMUNE DISEASES
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Chapter 20 40 Vocabulary Quiz

• An agent that causes a disease is a __________.
• The process in which two organisms exchange
  genetic material is __________.
• The four step guide for identifying specific
  pathogens is called __________ __________.
• A non living, infectious particle composed of a
  nucleic acid and a protein coat is a __________.
• A __________ is a protein that reacts to a
  specific antigen or that inactivates or destroys
  toxins.
• A protective response of tissues affected by
  disease or injury, characterized by redness,
  swelling, and pain is an _____ _____.

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Chapter 20 40 Vocabulary Quiz

• In bacterial viruses, the cycle of viral
  infection, replication, and cell destruction is
  called the __________ cycle.
• A substance that can inhibit the growth of or
  kill some microorganisms is called a __________.
• A virus that infects a bacteria is a __________.
• An __________ is a substance that stimulates an
  immune response.

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Chapter 20 40 Vocabulary Quiz

• An agent that causes a disease is a pathogen.
• The process in which two organisms exchange
  genetic material is conjugation.
• The four step guide for identifying specific
  pathogens is called Kochs Postulate.
• A non living, infectious particle composed of a
  nucleic acid and a protein coat is a virus.
• An antibody is a protein that reacts to a
  specific antigen or that inactivates or destroys
  toxins.
• A protective response of tissues affected by
  disease or injury, characterized by redness,
  swelling, and pain is an inflammatory response.

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Chapter 20 40 Vocabulary Quiz

• In bacterial viruses, the cycle of viral
  infection, replication, and cell destruction is
  called the lytic cycle.
• A substance that can inhibit the growth of or
  kill some microorganisms is called an antibiotic.
• A virus that infects a bacteria is a
  bacteriophage.
• An antigen is a substance that stimulates an
  immune response.