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:

first part of name – called the ______

first letter is always ______

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, Ursusamericanus = North American Black Bears)

Species

species: a______of organisms with similar features that can interbreed and produce fertile offspring

horse + donkey = mule

Binomial Nomenclature

Genus / Species / Abbreviated / Common Name
Homo / sapiens / H. sapiens / human
Castor / canadensis / C. Canadensis / beaver
Escherichia / coli / E. coli / E. coli

7 Levels of Classification

______
______
______
______
______
______
______/ Largest / General
Smallest / Specific

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

  1. size and shape of the capsid
  2. 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
  • Unstable they change their ______coat and “fool” the immune system
/
  • e.x. chickenpox
  • 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

VirusesHuman 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

(genitalwarts)

(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 microscopichypodermic 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 patientsdevelop 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
  2. Choose a nonpathogenic virus that can infect human cells is chosen ex. Vaccinia(cowpox)
  3. Allow this virus to attack human tumour cells
  • After reproducing, viruses released kill host cancercell i.e. lytic cycle
  • New viruses infect neighbouringtumour cells
  • Also stimulate immune system, bringing WBC’s in tohelp kill cancer cells

Note: cancer is caused by a mutated ‘stop’ gene

results in uncontrollable cell division