BACTERIABACTERIA Prokaryotes are single-celled organisms that do not have a Prokaryotes are single-celled organisms that do not have a

membrane-bound nucleus. membrane-bound nucleus. Prokaryotes are the MOST NUMEROUS ORGANISMS ON EARTH. Prokaryotes are the MOST NUMEROUS ORGANISMS ON EARTH. Prokaryotes have evolved into many different forms, and they are Prokaryotes have evolved into many different forms, and they are

now part of nearly every environment on Earth.  They have been now part of nearly every environment on Earth.  They have been found at the bottom of the oceanic trenches 9.6 km (6 mi) below the found at the bottom of the oceanic trenches 9.6 km (6 mi) below the water's surface and in Arctic and Antarctic Regions. water's surface and in Arctic and Antarctic Regions.

Evidence in the fossil record indicates that Prokaryotes are about Evidence in the fossil record indicates that Prokaryotes are about 2.5 Billion Years Old and Modern Humans arose about 100,000 2.5 Billion Years Old and Modern Humans arose about 100,000 years ago. years ago.

It wasn't until the late 1600s that scientists discovered bacteria.  In It wasn't until the late 1600s that scientists discovered bacteria.  In fact, bacteria were discovered by accident. fact, bacteria were discovered by accident.

Anton van Leeuwenhoek accidentally noticed them while looking at Anton van Leeuwenhoek accidentally noticed them while looking at scrapings from his teeth through a very simple microscope.  He did scrapings from his teeth through a very simple microscope.  He did not know what they were, but he was essentially the first person to not know what they were, but he was essentially the first person to see bacteria. see bacteria.

Organisms are classified as Prokaryotes by Organisms are classified as Prokaryotes by ONE ONE CHARACTERISTIC: THE LACK OF A CELL NUCLEUSCHARACTERISTIC: THE LACK OF A CELL NUCLEUS. .

Contains two kingdoms. Contains two kingdoms.

Kingdom ArchaebacteriaKingdom Archaebacteria

1 THE 1 THE ARCHAEBACTERIARCHAEBACTERIAA ARE A GROUP OF Prokaryotes THAT LIVE IN ARE A GROUP OF Prokaryotes THAT LIVE IN UNUSUALLY UNUSUALLY HARSH ENVIRONMENTSHARSH ENVIRONMENTS.. 2. Scientists treat Archaebacteria as a separate Kingdom because these 2. Scientists treat Archaebacteria as a separate Kingdom because these organisms are So Different from other Prokaryotes. organisms are So Different from other Prokaryotes. 3. Archaebacteria are CHEMICALLY DISTINCT from other Prokaryotes in 3. Archaebacteria are CHEMICALLY DISTINCT from other Prokaryotes in several ways: several ways: A.  The Cell Walls, Cell Membranes, and Ribosomal RNA are different A.  The Cell Walls, Cell Membranes, and Ribosomal RNA are different from those of other BACTERIA. The Absence of PEPTIDOGLYCAN, a from those of other BACTERIA. The Absence of PEPTIDOGLYCAN, a protein-carbohydrate found in the cell walls of Eubacteria. protein-carbohydrate found in the cell walls of Eubacteria.       B. They can live where no other organism can survive.  They live in B. They can live where no other organism can survive.  They live in extreme environments, such as acidic hot springs, near undersea extreme environments, such as acidic hot springs, near undersea volcanic vents, and highly salty water. volcanic vents, and highly salty water. 4. The PREFIX "4. The PREFIX "ARCHEAARCHEA" means " means ANCIENTANCIENT.  They are considered ancient .  They are considered ancient because they probably resemble the FIRST FORMS of LIFE on Earth. because they probably resemble the FIRST FORMS of LIFE on Earth. 5. Scientist think that the harsh environments in which Archaebacteria now live 5. Scientist think that the harsh environments in which Archaebacteria now live are like conditions on the Earth when life first appeared and began to evolve. are like conditions on the Earth when life first appeared and began to evolve.

Kingdom ArcheabacteriaKingdom Archeabacteria Archaebacteria can be divided into THREE Groups, based on the Archaebacteria can be divided into THREE Groups, based on the

Environment in which they live: Environment in which they live:         A.  A.  METHANOGENSMETHANOGENS - Live in oxygen-free environments (anaerobic - Live in oxygen-free environments (anaerobic

conditions) and produce Methane Gas.   They are named for their unique conditions) and produce Methane Gas.   They are named for their unique method of harvesting Energy by converting H2 and CO2 into Methane Gas. method of harvesting Energy by converting H2 and CO2 into Methane Gas. Because Oxygen is a Poison To Them, Methanogens can Live Only in Because Oxygen is a Poison To Them, Methanogens can Live Only in ANAEROBIC Conditions, such as the Bottom of Swamps and in Sewage.  ANAEROBIC Conditions, such as the Bottom of Swamps and in Sewage.  The methane produced by methanogens living in the waters of SWAMPS, The methane produced by methanogens living in the waters of SWAMPS, SEWAGE, or MARSHES is called SWAMP GAS.  Methane produced in the SEWAGE, or MARSHES is called SWAMP GAS.  Methane produced in the DIGESTIVE TRACTS of many animals including humans is called DIGESTIVE TRACTS of many animals including humans is called INTESTINAL GAS.  In the digestive track of cows they break down INTESTINAL GAS.  In the digestive track of cows they break down CELLULOSE, enabling cows to use nutrients in grass and plants.  They are CELLULOSE, enabling cows to use nutrients in grass and plants.  They are used in INDUSTRY to treat SEWAGE and to help PURIFY WATER. used in INDUSTRY to treat SEWAGE and to help PURIFY WATER.

        B.  B.  THERMOACIDOPHILESTHERMOACIDOPHILES - Can live in Water that is Extremely HOT - Can live in Water that is Extremely HOT (230 degrees F.) and ACIDIC (pH less than 2), two conditions that would kill (230 degrees F.) and ACIDIC (pH less than 2), two conditions that would kill other organisms.  Can be found around HOT SPRINGS like those at other organisms.  Can be found around HOT SPRINGS like those at Yellowstone National Park, No other organism can live in these waters!  Yellowstone National Park, No other organism can live in these waters!  Thermoacidophiles live near volcanic vents on land or near hydrothermal Thermoacidophiles live near volcanic vents on land or near hydrothermal vents, cracks in the ocean floor miles below the surface that leak scalding vents, cracks in the ocean floor miles below the surface that leak scalding acidic water. acidic water.

        C.  C.  EXTREME HALOPHILESEXTREME HALOPHILES - Live in Extremely SALTY Conditions.  - Live in Extremely SALTY Conditions.  Found in the Great Salt Lake in Utah and the Dead Sea.  Can grow in water Found in the Great Salt Lake in Utah and the Dead Sea.  Can grow in water that is up to ten times saltier than seawater. High salt concentrations would that is up to ten times saltier than seawater. High salt concentrations would kill most bacteria, but this high concentration is beneficial to the growth of kill most bacteria, but this high concentration is beneficial to the growth of Extreme Halophiles, and these organisms use Salt to Generate ATP. Extreme Halophiles, and these organisms use Salt to Generate ATP.

Kingdom EubacteriaKingdom Eubacteria

1. 1. EubacteriaEubacteria account for most bacteria; they occur account for most bacteria; they occur in many shapes and sizes and have distinct in many shapes and sizes and have distinct Biochemical and Genetic Characteristics. Biochemical and Genetic Characteristics.

2. The PREFIX "2. The PREFIX "EUEU" means " means TRUETRUE.  The so-called true .  The so-called true bacteria are all the organisms traditionally known as bacteria are all the organisms traditionally known as BACTERIABACTERIA OR AS MOM WOULD SAY " OR AS MOM WOULD SAY "GERMSGERMS". ".

3. Bacteria can be one of 3. Bacteria can be one of THREE Different shapes; THREE Different shapes; round, rod, and spiral shaped. round, rod, and spiral shaped.

4. We will be studying many different types of 4. We will be studying many different types of these kinds of bacteria. these kinds of bacteria.

General Structure of BacteriaGeneral Structure of Bacteria

General Structure of BacteriaGeneral Structure of Bacteria1. 1. Nucleoid:Nucleoid: The nucleoid is a region of cytoplasm where the chromosomal DNA is located. It The nucleoid is a region of cytoplasm where the chromosomal DNA is located. It

is not a membrane bound nucleus, but simply an area of the cytoplasm where is not a membrane bound nucleus, but simply an area of the cytoplasm where the strands of DNA are found. Most bacteria have a single, circular the strands of DNA are found. Most bacteria have a single, circular chromosome that is responsible for replication, although a few species do have chromosome that is responsible for replication, although a few species do have two or more. Smaller circular auxiliary DNA strands, called plasmids, are also two or more. Smaller circular auxiliary DNA strands, called plasmids, are also found in the cytoplasm found in the cytoplasm

2. 2. CytoplasmCytoplasm - The cytoplasm, or protoplasm, of bacterial cells is where the - The cytoplasm, or protoplasm, of bacterial cells is where the functions for cell growth, metabolism, and replication are carried outfunctions for cell growth, metabolism, and replication are carried out

3. 3. CapsuleCapsule - Some species of bacteria have a third protective covering, a capsule - Some species of bacteria have a third protective covering, a capsule made up of polysaccharides (complex carbohydrates). Capsules play a number made up of polysaccharides (complex carbohydrates). Capsules play a number of roles, but the most important are to keep the bacterium from drying out and of roles, but the most important are to keep the bacterium from drying out and to protect it from phagocytosis (engulfing) by larger microorganisms. The to protect it from phagocytosis (engulfing) by larger microorganisms. The capsule is a major virulence factor in the major disease-causing bacteria, such capsule is a major virulence factor in the major disease-causing bacteria, such as as Escherichia coliEscherichia coli and and Streptococcus pneumoniaeStreptococcus pneumoniae. Nonencapsulated . Nonencapsulated mutants of these organisms are avirulent, i.e. they don't cause disease. mutants of these organisms are avirulent, i.e. they don't cause disease.

4. 4. FlagellaFlagella - Flagella (singular, flagellum) are hairlike structures that provide a - Flagella (singular, flagellum) are hairlike structures that provide a means of locomotion for those bacteria that have them. means of locomotion for those bacteria that have them.

General Structure of BacteriaGeneral Structure of Bacteria5. Pili5. Pili - Many species of bacteria have pili (singular, pilus), small hairlike projections - Many species of bacteria have pili (singular, pilus), small hairlike projections

emerging from the outside cell surface. These outgrowths assist the bacteria in emerging from the outside cell surface. These outgrowths assist the bacteria in attaching to other cells and surfaces, such as teeth, intestines, and rocks. Without attaching to other cells and surfaces, such as teeth, intestines, and rocks. Without pili, many disease-causing bacteria lose their ability to infect because they're pili, many disease-causing bacteria lose their ability to infect because they're unable to attach to host tissue. unable to attach to host tissue.

6. 6. Ribosomes- Ribosomes- the building blocks of proteins. Proteins are the molecules that the building blocks of proteins. Proteins are the molecules that perform all the functions of cells and living organisms perform all the functions of cells and living organisms

7. 7. Cell WallCell Wall - Each bacterium is enclosed by a rigid cell wall composed of - Each bacterium is enclosed by a rigid cell wall composed of peptidoglycan, a protein-sugar (polysaccharide) molecule. The wall gives peptidoglycan, a protein-sugar (polysaccharide) molecule. The wall gives the cell its shape and surrounds the cytoplasmic membrane, protecting the cell its shape and surrounds the cytoplasmic membrane, protecting it from its environment. it from its environment.

8. 8. Cytoplasmic MembraneCytoplasmic Membrane - A layer of phospholipids and proteins, called the - A layer of phospholipids and proteins, called the cytoplasmic membrane, encloses the interior of the bacterium, cytoplasmic membrane, encloses the interior of the bacterium, regulating the flow of materials in and out of the cell. This is a structural regulating the flow of materials in and out of the cell. This is a structural trait bacteria share with all other living cells; a barrier that allows them trait bacteria share with all other living cells; a barrier that allows them to selectively interact with their environment. (this is also called cell to selectively interact with their environment. (this is also called cell membrane)membrane)

Shapes of Bacteria (Eubacteria only)Shapes of Bacteria (Eubacteria only)

Three Shapes:Three Shapes:

1. 1. Spirochetea/Spirochetea/Spirilla: Spiral ShapedSpirilla: Spiral Shaped- - This type of bacteria is generally responsible for diseases This type of bacteria is generally responsible for diseases

such as cholera (such as cholera ( Vibrio cholerae Vibrio cholerae ), and are generally found in ), and are generally found in stagnant water, and water which has been contaminated with stagnant water, and water which has been contaminated with sewage (this actually looks like a curved rod). sewage (this actually looks like a curved rod).

- Basically a corkscrew shaped bacterium. It causes - Basically a corkscrew shaped bacterium. It causes diseases such as lyme disease (diseases such as lyme disease ( Borrelia burgdorferi Borrelia burgdorferi ). ).

Shapes of Bacteria (Eubacteria)Shapes of Bacteria (Eubacteria)2. Bacillus or Rod-shaped2. Bacillus or Rod-shaped

- - The second and slightly more complex type of bacteria are the The second and slightly more complex type of bacteria are the genus genus BacillusBacillus. These bacteria are rod shaped, and can be very . These bacteria are rod shaped, and can be very short or very long. Most bacilli are capable of forming spores, short or very long. Most bacilli are capable of forming spores, which can protect the bacteria from harsh conditions such as which can protect the bacteria from harsh conditions such as dryness etc, and the bacteria within can remain viable for up to dryness etc, and the bacteria within can remain viable for up to 100 years.100 years. - - Bacilli are also capable of causing many diseases, such as Bacilli are also capable of causing many diseases, such as Yersinia pestisYersinia pestis, which causes bubonic, pneumonic and , which causes bubonic, pneumonic and sceptacaemic plague, and sceptacaemic plague, and Bacillus anthracisBacillus anthracis, which causes the, , which causes the, by now probably very famous disease, due to the post 9/11 by now probably very famous disease, due to the post 9/11 attacks, anthrax. Common types of bacillus are attacks, anthrax. Common types of bacillus are LactobacillusLactobacillus spp which generally cause milk to spoil, and a number of spp which generally cause milk to spoil, and a number of various soil dwelling species. various soil dwelling species.

Salmonella typhi

Shapes of Bacteria (Eubacteria)Shapes of Bacteria (Eubacteria)3. Cocci or round shaped:3. Cocci or round shaped:

- - These bacteria are generally some of the smallest, and These bacteria are generally some of the smallest, and simplest, being small and spherical, hence simplest, being small and spherical, hence CocciCocci (berry shaped). (berry shaped).

- There are a number of bacteria in this category which are - There are a number of bacteria in this category which are pathogenic (disease causing) such as pathogenic (disease causing) such as Staphlycoccus aureusStaphlycoccus aureus , , which causes a type of food poisoning, and is rapidly becoming which causes a type of food poisoning, and is rapidly becoming known as the hospital superbug, a variant of this species called known as the hospital superbug, a variant of this species called MRSA (Methicillin Resistant MRSA (Methicillin Resistant Staphylococcus aureusStaphylococcus aureus ), ), N. N. meningitidismeningitidis, which causes the often deadly diseases, , which causes the often deadly diseases, meningitis, meningitis, Staphylococcus epidermisStaphylococcus epidermis which inhabits the skin which inhabits the skin and can cause spots and boils, and finally and can cause spots and boils, and finally Moraxella catarrhalisMoraxella catarrhalis, , which generally tends to cause infections in the lower which generally tends to cause infections in the lower respiratory tract in humans.respiratory tract in humans.

pair of Cocci

Staphylococcus aureus

Bacteria exists in groups and Bacteria exists in groups and

coloniescolonies A. A. Strepto:Strepto: chains of bacteria chains of bacteria

Streptococcus

Groups of BacteriaGroups of Bacteria

B. Staphylo: Clusters B. Staphylo: Clusters

Staphylococcus

Groupings of bacteriaGroupings of bacteria

C. C. Diplo: twoDiplo: two

Diplococcus

Bacterial groupsBacterial groups

D. Tetra: FourD. Tetra: Four

A tetrad appears as a square of four cocci (arrows).

Tetracoccus

Gram Staining Gram Staining Most species of bacteria can be grouped into TWO Categories Most species of bacteria can be grouped into TWO Categories based on their response to a laboratory technique called based on their response to a laboratory technique called GRAM STAINING.GRAM STAINING. (Figure 23-4) (Figure 23-4)

1. TAXONOMISTS divide bacteria into various subgroups 1. TAXONOMISTS divide bacteria into various subgroups including GRAM-POSITIVE AND GRAM-NEGATIVE including GRAM-POSITIVE AND GRAM-NEGATIVE BACTERIA. BACTERIA.

2. Hans Christian Gram, a Danish Microbiologist, developed 2. Hans Christian Gram, a Danish Microbiologist, developed the Gram-stain technique in 1884 the Gram-stain technique in 1884

3. The technique involves STAINING Bacteria with a PURPLE 3. The technique involves STAINING Bacteria with a PURPLE DYE (Crystal Violet), AND IODINE,   AND RINSED WITH DYE (Crystal Violet), AND IODINE,   AND RINSED WITH ALCOHOL.  Then Restained with A PINK DYE (Safarinin). ALCOHOL.  Then Restained with A PINK DYE (Safarinin). (Figure 24-3) (Figure 24-3)

4. Depending on Structure of their CELL WALLS, THE 4. Depending on Structure of their CELL WALLS, THE BACTERIA ABSORB EITHER THE PURPLE DYE OR THE PINK BACTERIA ABSORB EITHER THE PURPLE DYE OR THE PINK DYE. DYE.

    5.  5.  Gram-Positive Bacteria will retain the PURPLE DYE Gram-Positive Bacteria will retain the PURPLE DYE and appear Purple.and appear Purple.

6.  6.  Gram-Negative Bacteria will appear PINK from the Gram-Negative Bacteria will appear PINK from the

PINK DYEPINK DYE..

Gram Positive Bacteria: antibiotics can workGram Positive Bacteria: antibiotics can work 1. 1. GRAM-POSITIVE BACTERIAGRAM-POSITIVE BACTERIA HAVE A THICKER LAYER OF HAVE A THICKER LAYER OF

PEPTIDOGLYCANPEPTIDOGLYCAN IN THEIR CELL WALLS, MADE OF A PROTEIN- IN THEIR CELL WALLS, MADE OF A PROTEIN-SUGAR COMPLEX THAT TAKES ON THE PURPLE COLOR DURING SUGAR COMPLEX THAT TAKES ON THE PURPLE COLOR DURING GRAM STAININGGRAM STAINING

2. Gram-positive bacteria include organisms that produce BENEFICAL 2. Gram-positive bacteria include organisms that produce BENEFICAL Substances and organisms that cause important DISEASE. Substances and organisms that cause important DISEASE.

3. They are used to make yogurt, pickles and buttermilk. 3. They are used to make yogurt, pickles and buttermilk. 4. Another group of Gram-positive bacteria, are used to make 4. Another group of Gram-positive bacteria, are used to make

ANTIBIOTICSANTIBIOTICS, INCLUDING TETRACYCLINE AND STREPTOMYCIN.  , INCLUDING TETRACYCLINE AND STREPTOMYCIN.  THESE BACTERIA ARE CALLED THESE BACTERIA ARE CALLED ACTINOMYCETESACTINOMYCETES. .

5. Antibiotics kill other Gram-positive bacteria by preventing them from 5. Antibiotics kill other Gram-positive bacteria by preventing them from making proteins.  They affect only the GROWTH of bacteria without making proteins.  They affect only the GROWTH of bacteria without harming the body cells of humans. harming the body cells of humans.

6. Gram-positive bacteria cause many HUMAN DISEASES, INCLUDING 6. Gram-positive bacteria cause many HUMAN DISEASES, INCLUDING SCARLET FEVER, TOXIC SHOCK SYNDROME, AND PNEUMONIA. SCARLET FEVER, TOXIC SHOCK SYNDROME, AND PNEUMONIA.

7. Many of these bacteria produce 7. Many of these bacteria produce TOXINSTOXINS, which are poisons to our , which are poisons to our bodies. bodies.

8. Toxins can be deadly; a single gram of the toxin produced by 8. Toxins can be deadly; a single gram of the toxin produced by Clostridium botulinum Clostridium botulinum  ( (BotulismBotulism) could kill more than one million ) could kill more than one million people. people.

Gram-negative bacteria: antibiotics Gram-negative bacteria: antibiotics cannot workcannot work

1. 1. GRAM-NEGATIVE BACTERIAGRAM-NEGATIVE BACTERIA HAVE AN EXTRA HAVE AN EXTRA LAYER OF LIPID ON THE OUTSIDE OF THE CELL WALL LAYER OF LIPID ON THE OUTSIDE OF THE CELL WALL AND APPEAR PINK AFTER GRAM STAINING. AND APPEAR PINK AFTER GRAM STAINING.

2. The extra lipid layer stops the PURPLE Stain from 2. The extra lipid layer stops the PURPLE Stain from entering the CELL WALL.  They do absorb the PINK Stain, entering the CELL WALL.  They do absorb the PINK Stain, so they are easily distinguished with a microscope. so they are easily distinguished with a microscope.

3. The extra lipid layer also stops many 3. The extra lipid layer also stops many ANTIBIOTICSANTIBIOTICS from entering the bacteria.  Treatment for these requires a from entering the bacteria.  Treatment for these requires a different ANTIBIOTIC than those used for infections different ANTIBIOTIC than those used for infections caused by Gram-positive bacteria. caused by Gram-positive bacteria.

Bacterial ReproductionBacterial Reproduction Bacteria can reproduce at tremendous speeds.  Some bacteria Bacteria can reproduce at tremendous speeds.  Some bacteria

can reproduce as often as once every 20 minutes!  However, can reproduce as often as once every 20 minutes!  However, bacteria have to have certain conditions in which to bacteria have to have certain conditions in which to reproduce.  These conditions are not often met, and that is reproduce.  These conditions are not often met, and that is one thing that keeps bacteria from growing out of control. one thing that keeps bacteria from growing out of control.

Bacteria reproduce using two basic methods:  Bacteria reproduce using two basic methods:  asexual asexual reproductionreproduction and and sexual reproductionsexual reproduction. .

Asexual reproduction involves only one individual or parent.  Asexual reproduction involves only one individual or parent.  The offspring generated by asexual reproduction are exact The offspring generated by asexual reproduction are exact duplicates of the parent.  duplicates of the parent.  Binary fissionBinary fission is the process by is the process by which a bacteria splits into two cells.  Each cell gets an exact which a bacteria splits into two cells.  Each cell gets an exact copy of the parent cell's genetic material.copy of the parent cell's genetic material.

Binary Fission

ReproductionReproduction

Sexual reproduction involves the joining of two parent cells and the exchanging of genetic materials.  In sexual reproduction, the offspring will have a mixture of the parent cells' traits.  Conjugation is the process by which bacteria join and exchange genetic materials.  Once genetic materials are exchanged, each bacteria cell will go through binary fission to produce an offspring with a new genetic makeup.

Additional Vocabulary

1. Aerobic: needs oxygen2. Anaerobic: without oxygen3. Faculatice Anaerobic: with or without oxygen4. Autotrophs: Make own food

a. Photoautotroph: Use sunlight to make food b. Chemoautotrophs: Use energy of chemical reactions

for food5. Heterotrophs: Get food from another source

a. Saprophyte: feeds on dead decaying matter