11

Viruses and Viruses and BacteriaBacteria

22

COVER YOUR MOUTH!!!COVER YOUR MOUTH!!!

33

COVER YOUR MOUTHCOVER YOUR MOUTH

44

I. VirusesI. Viruses

A. Is a virus a living organism?A. Is a virus a living organism?  

1. All living things are made of cells, able 1. All living things are made of cells, able to grow and reproduce.to grow and reproduce.

  2. A virus IS able to do these things but 2. A virus IS able to do these things but ONLY inside a host cell.ONLY inside a host cell.

  3. Viruses cause diseases in many 3. Viruses cause diseases in many organisms. organisms.

55

B. B. Discovery of virusesDiscovery of viruses

1. At the end of the 191. At the end of the 19thth century century scientists were trying to find the scientists were trying to find the cause of tobacco mosaic disease cause of tobacco mosaic disease (TMV).(TMV).

  2. In 1935 Wendell Stanley isolated 2. In 1935 Wendell Stanley isolated this virus.this virus.

66

77

  C. A virus’s Shape is determined by its C. A virus’s Shape is determined by its partsparts

  

1. The virus protein coat, or capsid, may 1. The virus protein coat, or capsid, may contain either RNA or DNA but NOT both.contain either RNA or DNA but NOT both.

  

2. RNA viruses include HIV, which causes 2. RNA viruses include HIV, which causes AIDS, influenza viruses and rabies virus.AIDS, influenza viruses and rabies virus.

88

99

3. DNA viruses include those viruses that 3. DNA viruses include those viruses that cause warts, chickenpox and cause warts, chickenpox and mononucleosis.mononucleosis.

  

4. Many viruses have a membrane or an 4. Many viruses have a membrane or an envelope that surrounds the capsid.envelope that surrounds the capsid.

  

5. The envelope helps the virus enter 5. The envelope helps the virus enter cells.cells.

1010

6. It consists of proteins, lipids, and 6. It consists of proteins, lipids, and glycoproteins.glycoproteins.

7. Viruses that infect bacteria, called 7. Viruses that infect bacteria, called bacteriophages, have a complicated bacteriophages, have a complicated structure. structure.

  

8. A bacteriophage has capsid and a tail.8. A bacteriophage has capsid and a tail.

1111

9. Viruses replicate inside living cells9. Viruses replicate inside living cells

  

10. Viruses cause damage when the 10. Viruses cause damage when the viruses replicate inside the cells.viruses replicate inside the cells.

  

11. Any agent that causes disease is 11. Any agent that causes disease is called a pathogen.called a pathogen.

1212

D. Lytic cycleD. Lytic cycle  

1. 1. Virus attaches to a cell and injects DNA.Virus attaches to a cell and injects DNA.  

2. Viral DNA enters the Lytic cycle.2. Viral DNA enters the Lytic cycle.  

3. New Viruses are made.3. New Viruses are made.  

4. Cell breaks open and releases viruses. 4. Cell breaks open and releases viruses. (destroying the host cells.)(destroying the host cells.)

1313

1414

E. Lysogenic cycleE. Lysogenic cycle  

1. Virus attaches to a cell and inject DNA.1. Virus attaches to a cell and inject DNA.  

2. Viral DNA enters the Lysogenic cycle.2. Viral DNA enters the Lysogenic cycle.  

3. Viral DNA integrates with host DNA.3. Viral DNA integrates with host DNA.

   4. The host cell divides normally4. The host cell divides normally

1515

5. Many cell divisions.5. Many cell divisions.  

6. The provirus may enter the Lytic cycle, or 6. The provirus may enter the Lytic cycle, or stay dominant.stay dominant.

  7. Then the DNA enters the Lytic cycle.7. Then the DNA enters the Lytic cycle.

  8. New viruses are made.8. New viruses are made.

  9. Cell breaks open and releases viruses9. Cell breaks open and releases viruses

1616

4. Viruses have a major impact on 4. Viruses have a major impact on the living world.the living world.

1717

1818

F. Viruses are host cell specificF. Viruses are host cell specific

  

1. Viruses are often restricted to 1. Viruses are often restricted to certain kinds of cells. certain kinds of cells.

  

2. Some will affect plants and some 2. Some will affect plants and some will affect animals. will affect animals.

1919

G. HIV can replicate in your cellsG. HIV can replicate in your cells  

1. Acquired immunodeficiency 1. Acquired immunodeficiency syndrome (AIDS) is a disease in syndrome (AIDS) is a disease in which an individual is unable to which an individual is unable to defend his or her own body against defend his or her own body against infections. infections.

  2. The HIV causes AIDS.2. The HIV causes AIDS.

2020

3. HIV – infected people do not develop 3. HIV – infected people do not develop AIDS symptoms until years after infection.AIDS symptoms until years after infection.

  

4. HIV infected individuals can feel healthy 4. HIV infected individuals can feel healthy and still spread the virus to others.and still spread the virus to others.

  

5. It is transmitted in body fluids, such as 5. It is transmitted in body fluids, such as semen and vaginal fluid.semen and vaginal fluid.

2121

H. H. Viruses cause many diseasesViruses cause many diseases  11 1. Diseases caused by viruses have been 1. Diseases caused by viruses have been

known and feared for thousands of years. known and feared for thousands of years.   

2. 22 million people died of the flu during 1918-2. 22 million people died of the flu during 1918-1919.1919.

  3. Viruses that evolve are called emerging 3. Viruses that evolve are called emerging viruses. viruses.

  

2222

4. These new pathogens are dangerous 4. These new pathogens are dangerous to public health.to public health.

  

5. 5. Prions are particles that are Prions are particles that are composed of proteins and have no composed of proteins and have no nucleic acids.nucleic acids.

  

6. Prions are infectious even though they 6. Prions are infectious even though they contain no genes. contain no genes.

2323

7. 7. Prions were first linked to a sheep Prions were first linked to a sheep disease called scrapie. disease called scrapie.

  8. This also causes mad cow disease.8. This also causes mad cow disease.

  9. 9. A viroid is a single strand of RNA that A viroid is a single strand of RNA that has no capsid. has no capsid.

  10. They affect plants like cucumbers, 10. They affect plants like cucumbers, potatoes, avocados, and oranges.potatoes, avocados, and oranges.

2424

II. BacteriaII. Bacteria

A. Bacteria have a simpler structure than A. Bacteria have a simpler structure than Eukaryotes.Eukaryotes.

  1. 1. Bacteria are prokaryotes they do not have a Bacteria are prokaryotes they do not have a nucleus.nucleus.

  2. Bacteria are small!- 2. Bacteria are small!-

  3. 3. Bacteria have only one cell.Bacteria have only one cell.

  4. Bacteria have one single circular DNA.4. Bacteria have one single circular DNA.

2525

5. Bacteria reproduce by binary 5. Bacteria reproduce by binary fission.fission.

  

6. Bacteria have flagella that move 6. Bacteria have flagella that move them around.them around.

  

7. Bacteria have many different 7. Bacteria have many different types of metabolic activities.types of metabolic activities.

2626

A. The structure A. The structure

  

1. A bacterial cell has three shapes.1. A bacterial cell has three shapes.

   Bacillus- rod shapedBacillus- rod shaped   

Coccus- round shaped  Coccus- round shaped  

Spirillum- spiral shaped Spirillum- spiral shaped

2727

2828

2. Bacteria can have two types of cell walls, 2. Bacteria can have two types of cell walls, you can tell this by gram staining.you can tell this by gram staining.

  3. Gram staining is important in medicine 3. Gram staining is important in medicine because the two groups of bacteria differ in because the two groups of bacteria differ in how they respond to antibiotics.how they respond to antibiotics.

  4. Some bacteria form thick walled 4. Some bacteria form thick walled endospores around their chromosomes and a endospores around their chromosomes and a small bit of cytoplasm when they are exposed small bit of cytoplasm when they are exposed to harsh conditions.to harsh conditions.

2929

5. Pili enable bacteria to stick to 5. Pili enable bacteria to stick to stuff like your skin.stuff like your skin.

  

6. Conjugation is a process in which 6. Conjugation is a process in which tow organisms exchange genetic tow organisms exchange genetic material.material.

3030

C. Bacteria are grouped according C. Bacteria are grouped according to how they obtain energyto how they obtain energy

  

1. 1. Photosynthetic bacteria- bacteria Photosynthetic bacteria- bacteria that is able to make food from the that is able to make food from the sunlight. They must live in an sunlight. They must live in an anaerobic (oxygen free) anaerobic (oxygen free) environments.environments.

3131

2. Chemoautotrophic bacteria- they 2. Chemoautotrophic bacteria- they obtain energy by chemically obtain energy by chemically removing electrons from material.removing electrons from material.

  

3. Heterotrophic bacteria- feed on 3. Heterotrophic bacteria- feed on organic material and other organic material and other organisms. They are aerobic, they organisms. They are aerobic, they need oxygen.need oxygen.

3232

D. Bacteria cause disease in two basic D. Bacteria cause disease in two basic waysways

  

1. Bacteria can metabolize their host. 1. Bacteria can metabolize their host. They take all the nutrients from the host. They take all the nutrients from the host. Example- TBExample- TB

  

2. Bacteria can cause toxins. Example 2. Bacteria can cause toxins. Example botulismbotulism

3333

3. Bacterial disease can be fought3. Bacterial disease can be fought

  

4. 4. Antibiotics- fight bacterial Antibiotics- fight bacterial infection.infection.

  

3434

E. Bacteria are importantE. Bacteria are important  

1. Food and chemical production- many 1. Food and chemical production- many foods we eat are processed by specific kinds foods we eat are processed by specific kinds of bacteria examples- pickles, buttermilk, of bacteria examples- pickles, buttermilk, cheese, sauerkraut, olives, vinegar, cheese, sauerkraut, olives, vinegar, sourdough bread and some sausages.sourdough bread and some sausages.

  2.2. Mining and environmental uses of Mining and environmental uses of bacteriabacteria

3535

THE ENDTHE END