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Taxonomy SBI 3C Definition: ________________________ is the science of classifying organisms (both living & extinct). Taxonomic System developed by Carl Linnaeus (1707-1778) in ___________________ based his classification on ____________________ and ______________________ features the ____________ features organisms have in common, the __________________ their relationship Binomial Nomenclature (common worldwide language) The ________________________ Name: note: both parts of the scientific name first part of name – called the __________________ first letter is always _____________________ are italicized this part __________ be written ____________ (e.x. Acer meaning all maple trees, Ursus = all bears) second part of name – called the ________________ is __________ capitalized (lowercase) is ______________ written ___________________ (e.x. Acer rubrum, referring to a red maple, Ursus americanus = North American Black Bears) Species species: a _____________ of organisms with similar features that can interbreed and produce fertile offspring horse + donkey = Binomial Nomenclature Genus Homo Castor Escherichia Species sapiens canadensis coli 7 Levels of Classification ______________________ ______________________ ______________________ ______________________ ______________________ ______________________ ______________________ Abbreviated H. sapiens C. Canadensis E. coli Common Name human beaver E. coli Largest / General Smallest / Specific mule Taxonomic Classifications Man Gorilla Chimpanzee Orangutan Baboon Kingdom Animalia Animalia Animalia Animalia Animalia Phyllum Chordata Chordata Chordata Chordata Chordata Class Mammalia Mammalia Mammalia Mammalia Mammalia Order Primates Primates Primates Primates Primates Family Hominidae Hominidae Hominidae Hominidae Hominidae Subfamily Homininae Homininae Homininae Ponginae Cercopithecidae Genus Homo Gorilla Pan Pongo Papio Species sapiens gorilla troglodytes pygmaeus ursinus Gorillas & Chimps have __________% same DNA as us. Dichotomous Key _________-part key used to identify ______________ things a series of ___________________ must be made each choice leads to a new __________________ of the key end result is the _________________ of the organism being identified Complete Activity 2.2 on page 102. We will also look at a few other classification keys. Homework: Text Page 101 # 1 – 7 Microbiology Microbiology is the field of biology that studies microorganisms such as: • viruses • archaea • eubacteria • protists • fungi Microorganisms are either: 1. prokaryotic – cells which have no nucleus and no membrane-bound organelles (archaea and eubacteria, the two types of bacteria) 1. eukaryotic – cells which have numerous membrane-bound organelles including a nucleus (protists, fungi, plants, animals) Microorganisms usually require magnification to be observed. Many are unicellular (made of a single cell) and others form multicellular groups of associated cells. 6 Kingdom Classification System 1. 2. 3. 4. 5. 6. The 5 Kingdoms Archaebacteria / Eubacteria Viruses Questions 1. Where do viruses fit into the model of the 6 Kingdom classification system? 2. Are viruses considered living organisms? Viruses What are the characteristics of living organisms? Living things… are made of cells grow and develop reproduce respond to their environment adapt to their environment obtain and use energy produce wastes … unless they are reproducing Answer viruses are not considered to be living organisms because: 1. not made up of cells 2. only capable of 1 life function i.e. reproduction & only within a living cell outside cells, viruses are lifeless chemicals Typical Viral Stucture Viral Capsids Viruses come in many shapes. Examples Viral Classification Viruses are generally classified by: 1. the organisms they infect host range (types of cells that the virus can infect) examples: a) cold virus b) rabies c) HIV d) bacteriophage 2. structure a. size and shape of the capsid b. type genetic material (DNA or RNA) Viral Size very small, measured in units called nanometres (nm) 1nm = 1X10-9 m (billionth of a metre) size ranges from 20 - 400 nm Homework Questions page 107 # 1, 2, 5 – 8 SBI 3C Viruses and Human Health Most viral infections are difficult to _____________, they are not ______________________ by antibiotics. antibiotics - inhibits the _______________ of or __________________ bacteria Some viruses can remain ____________________ for years before symptoms appear. Certain viruses cause ______________ by adding specific _______________ to an infected cell. vaccine - liquid preparation of __________ or weakened _______________ or bacterial cells that stimulate the body’s ______________________ system to fight back. Influenza (FLU) Usually considered to be more ___________________ than dangerous Spread by ________________ contact and can live for ___________ in dry _______________. First host: cells in the ____________ _____________________ tract Sore ______________, congested _______________, chills, ______________, pain, sweating… Contagious ___ day before symptoms appear, up to _______________ days after. Incubation ____________ days Last up to ____ weeks Influenza vaccine can be ______% effective Viral Reproduction Viruses can reproduce only within a host cell because: a) lack specific __________________ and ribosomes (necessary to make new cores & capsids) b) have no __________________ of their own (needed to synthesize their parts) There are 2 modes of viral reproduction 1. Lytic Cycle: all ________ viruses reproduce this way 2. Lysogenic Cycle: mostly ___________ viruses use this cycle Difference between RNA and DNA viruses RNA viruses DNA viruses e.x. common cold e.x. chickenpox Unstable they change their _______________ coat and “fool” the immune system Stable and are the ____________ throughout infection Why do we need a Flu shot once a year? The Lytic Cycle The Lytic Cycle • All DNA viruses reproduce with the ____________ cycle and are called _______________ (capable of causing ________________ & extremely _______________________) The Lysogenic Cycle RNA viruses cannot ___________ over the host cell machinery directly They must first _______________ their RNA to DNA. To do this they have a special ______________ called __________________ ____________________. Because this is a reverse process RNA viruses are called _____________________. Retroviruses are especially _______________ to their hosts because the viral _______ produced by this enzyme can ____________ into (join with) the host chromosome and stay _________________ or latent for months or years. When each host cell ________________, it also copies the viral DNA '_________________' within its own chromosome. During this dormant period, the host's _________________ system does not 'see' the viral DNA and produces no _____________________ against it. The host feels _____ symptoms, but carries the disease and may _______________ others. Examples of diseases caused by retroviruses are ______________, genital _____________ and cold sores. Some unknown stimulus will '______________' the viral genes to become active, take over the cell's protein ________________ and continue as in the lytic cycle. Steps Of The Lysogenic Cycle Viruses & Human Health Viral diseases are difficult to treat because: 1. No drug is available to _________ viruses in the body 2. Some viruses are ____________________ can remain dormant for years (hide inside cells) ex. a) Herpes Simplex Virus I (HSV I) (___________ _____________) b) HIV (____________) 3. some viruses are _____________________ • cause cells to become ____________________ onco = tumour (genital warts) (cervical cancer) ex. Human Papiloma Virus (_______) Protection Against Viral Diseases vaccines: only true protection against viral diseases people are given a dead or weakened form of the virus builds up an army of WBC’s & antibodies to kill the living virus immediately before it can reproduce ex. polio vaccine, hepatitis B vaccine antiviral agents: drugs given after infection to slow the reproduction of the virus ex. Valtrex – helps heal and decrease pain (herpes) Viral Uses In Medicine Viral Vectors Viruses can be used for gene therapy as “carriers” Viral core is removed & desired human gene is added Virus is mixed with living cells Virus attaches to human host cell & injects the human gene i.e. acts like a microscopic hypodermic needle AIDS - HIV (Human Immunodeficiency Virus) virus that causes AIDS RNA core (retrovirus) can only infect helper T cells (type of white blood cell) cannot survive outside the body because glycoprotein membrane around its capsid dries out (membrane picked up as it buds off white blood cell) can only be transmitted from 1 bodily fluid to another ex. 1. blood to blood: needles, transfusions, toothbrushes 2. semen & vaginal secretions 1. breast milk HIV positive: virus is in its lysogenic cycle (dormant) patient is not sick, but is a carrier of the virus can infect others AIDS (Acquired Immunodeficiency Syndrome) patient has symptoms of the disease (begins when HIV enters the lytic cycle) WBC’s are being destroyed Early symptoms: night sweats, diarrhea, cold symptoms AIDS Associated Disease Late Symptoms • Gastrointestinal: Cause most of illness and death of late AIDS • Symptoms: Wasting (extreme weight loss) Abdominal pain Infections of the mouth and esophagus • Respiratory: 70% of AIDS patients develop serious respiratory problems Bronchitis Pneumonia Tuberculosis Lung cancer More Associated AIDS Disease • Skin Disorders: 90% of AIDS patients develop skin or mucous membrane disorders • Herpes • Thrush • Eye Infections: 50-75% patients develop eye conditions. • Dry eye syndrome The ultimate fate of a patient with AIDS • patient dies from other infections due to a lack of immune response ex. pneumonia, cancer Drug Therapy • • • • • Reverse Transcriptase Inhibitors: Competitive enzyme inhibitors. Example: AZT, ddI, ddC Protease Inhibitors: Inhibit the viral proteases. Prevent viral maturation Problem with individual drug treatments: Resistance Drug Cocktails: A combination of: • One or two reverse transcriptase inhibitors • One or two protease inhibitors Drug cocktails have been very effective in suppressing HIV replication and prolonging the life of HIV infected individuals, but are not considered to be a cure Viral Uses In Medicine 1. Oncolytic viruses used in targeted cancer treatment Choose a nonpathogenic virus that can infect human cells is chosen ex. Vaccinia (cowpox) Allow this virus to attack human tumour cells After reproducing, viruses released kill host cancer cell i.e. lytic cycle New viruses infect neighbouring tumour cells Also stimulate immune system, bringing WBC’s in to help kill cancer cells Note: cancer is caused by a mutated ‘stop’ gene results in uncontrollable cell division