MicroorganismsMicroorganisms

Chapter 24Chapter 24

BacteriaBacteria

Microorganisms DefinedMicroorganisms Defined

Microorganisms can be defined as those Microorganisms can be defined as those unicellular and multi-cellular organisms too unicellular and multi-cellular organisms too small to be seen with the naked eye.small to be seen with the naked eye.

Microorganisms are thought to be the Microorganisms are thought to be the descendants of the first living organisms on descendants of the first living organisms on earth.earth.

Microorganisms are thought to have started Microorganisms are thought to have started life as ocean dwellers that utilized organic life as ocean dwellers that utilized organic nutrients gathered from the ocean for their nutrients gathered from the ocean for their existence.existence.

Microorganisms DefinedMicroorganisms Defined

Evidence suggests that these first Evidence suggests that these first organisms were small, organisms were small, uncomplicated, lacked membrane uncomplicated, lacked membrane bound organelles and did not have a bound organelles and did not have a nucleus. nucleus.

Classification of Classification of MicroorganismsMicroorganisms

In the 6 kingdom system the In the 6 kingdom system the prokaryotes called bacteria are prokaryotes called bacteria are grouped in 2 kingdomsgrouped in 2 kingdoms Eubacteria and ArchaebacteriaEubacteria and Archaebacteria

The kingdom Protista are composed of The kingdom Protista are composed of two major types of organismstwo major types of organisms Monerans and AlgaeMonerans and Algae

The kingdom Fungi are made up of The kingdom Fungi are made up of Molds, Yeasts and LichensMolds, Yeasts and Lichens

Science of MicrobiologyScience of Microbiology

Dedicated to the study of the Dedicated to the study of the organisms, their relationship to other organisms, their relationship to other organisms and the environment and organisms and the environment and the impact microbes have on the the impact microbes have on the health and well being of the human health and well being of the human population.population.

MicrobiologistsMicrobiologists

Scientists who study ‘Microbes” and Scientists who study ‘Microbes” and enable us to develop an enable us to develop an understanding of how microbes understanding of how microbes effect our world.effect our world.

Specialized by the type of microbe Specialized by the type of microbe they studythey study Bacteriologist-BacteriaBacteriologist-Bacteria Virologist-VirusesVirologist-Viruses Mycologists-FungiMycologists-Fungi

Tools of the MicrobiologistTools of the Microbiologist

The main tools of the microbiologist The main tools of the microbiologist areare The light microscopeThe light microscope Electron microscopeElectron microscope Instruments used to grow microorganisms Instruments used to grow microorganisms

for studyfor study IncubatorsIncubators Petri DishesPetri Dishes Nutrient AgarNutrient Agar Stains to locate and identify microorganismsStains to locate and identify microorganisms

Kingdom ArchaebacteriaKingdom Archaebacteria

Make up group of bacteria called Make up group of bacteria called “Extremeophiles. Archaebacteria lack “Extremeophiles. Archaebacteria lack peptidoglycan in their cell walls and peptidoglycan in their cell walls and posses unusual lipids in their cell walls.posses unusual lipids in their cell walls. Methanogens-acquire energy from the Methanogens-acquire energy from the

conversion of H2 and CO2 into methane gas.conversion of H2 and CO2 into methane gas. Halophiles-salt loving bacteria, use salt to Halophiles-salt loving bacteria, use salt to

generate ATP.generate ATP. Thermoacidophiles-live in extreme acidic/hot Thermoacidophiles-live in extreme acidic/hot

environments. (temperatures up to 230 F)environments. (temperatures up to 230 F)

Kingdom EubacteriaKingdom Eubacteria

3 Basic Shapes3 Basic Shapes Bacilli-bacteria that have Bacilli-bacteria that have

rod shapesrod shapes Cocci-Bacteria that are Cocci-Bacteria that are

spherical in shapespherical in shape Spirilla-Bacteria that are Spirilla-Bacteria that are

spiral in shapespiral in shape Cocci that occur in Cocci that occur in

chains are called chains are called Streptococci and those Streptococci and those that occur in bunches that occur in bunches are called are called StaphylococciStaphylococci

Kingdom EubacteriaKingdom Eubacteria

Divided into 2 groups Divided into 2 groups based on their response to based on their response to a technique called the a technique called the Gram Stain.Gram Stain.

Bacteria that stain purple Bacteria that stain purple are called Gram Positive.are called Gram Positive.

Bacteria that do not take Bacteria that do not take up the stain and appear up the stain and appear pink are called Gram pink are called Gram Negative.Negative.

These bacteria can also be These bacteria can also be differentiated by how they differentiated by how they respond to antibiotics.respond to antibiotics.

Bacteria Groups -4 PhylumBacteria Groups -4 Phylum

Cyanobacteria-Cyanobacteria use photosynthesis Cyanobacteria-Cyanobacteria use photosynthesis to produce the energy that they need the by to produce the energy that they need the by product is oxygen.product is oxygen.

Spirochetes-Spiral Shaped bacterium Spirochetes-Spiral Shaped bacterium Treponema Treponema pallidum pallidum responsible for the sexually transmitted responsible for the sexually transmitted disease Syphilisdisease Syphilis

Gram Positive Bacteria-Actinomycetes grow in soil Gram Positive Bacteria-Actinomycetes grow in soil and produce antibiotics that inhibit or kill other and produce antibiotics that inhibit or kill other organismsorganisms

Proteobacteria-Enteric (Proteobacteria-Enteric (Escherichia coliEscherichia coli)) Chemoautotroph-extract energy from minerals and gasesChemoautotroph-extract energy from minerals and gases Example Rhizobium-Nitrogen fixing bacteria, get energy Example Rhizobium-Nitrogen fixing bacteria, get energy

from nitrogen gas in the atmosphere.from nitrogen gas in the atmosphere.

Bacterial StructureBacterial Structure

1. Cell Wall-made up of peptidoglycan1. Cell Wall-made up of peptidoglycan Cell Membrane and CytoplasmCell Membrane and Cytoplasm Capsules and PiliCapsules and Pili

Capsule- outer covering that protect it from Capsule- outer covering that protect it from drying and harsh chemicalsdrying and harsh chemicals

Pili-hair like surface structure that help the Pili-hair like surface structure that help the bacterium adhere to the cells of the host. Also bacterium adhere to the cells of the host. Also use to transfer genetic information from one use to transfer genetic information from one bacterium to another.bacterium to another.

Endospore-thick outer covering that Endospore-thick outer covering that protects the bacteria when exposed to protects the bacteria when exposed to harsh environmental conditions. harsh environmental conditions.

MovementMovement

Flagella are use to Flagella are use to move bacteria.move bacteria.

Bacteria may have 1 Bacteria may have 1 or a tuft of flagellaor a tuft of flagella

Spiral shaped bacteria Spiral shaped bacteria use corkscrew use corkscrew movementsmovements

Some bacteria secrete Some bacteria secrete a slime coat to glide a slime coat to glide throughthrough

Nutrition and GrowthNutrition and Growth

Bacteria may be heterotrophic or Bacteria may be heterotrophic or autotrophic.autotrophic. Autotrophs-Photoautotrophs obtain Autotrophs-Photoautotrophs obtain

energy from the sun.energy from the sun. Chemoautotroph-obtain energy from Chemoautotroph-obtain energy from

minerals in the environment.minerals in the environment. HeterotrophsHeterotrophs

Saprophytes-obtain energy from dead Saprophytes-obtain energy from dead and decaying material.and decaying material.

Oxygen RequirementsOxygen Requirements

Obligate Anaerobes-cannot live in Obligate Anaerobes-cannot live in the presence of oxygen-Ex. the presence of oxygen-Ex. Clostridium tetaniClostridium tetani

Facultative anaerobes-can live with Facultative anaerobes-can live with or without oxygen.or without oxygen.

Obligate Aerobes-cannot survive Obligate Aerobes-cannot survive without oxygen. Ex. without oxygen. Ex. Mycobacterium Mycobacterium tuberculosistuberculosis

Genetic RecombinationGenetic Recombination

A. Transformation-DNA taken in from A. Transformation-DNA taken in from the external environment.the external environment.

B. Conjugation-Pilus connects two B. Conjugation-Pilus connects two bacterium forming Conjugation bacterium forming Conjugation bridge for the exchange of genetic bridge for the exchange of genetic material.material.

C. Transduction-Replication of DNA C. Transduction-Replication of DNA fragments within a virus inside a fragments within a virus inside a bacterium.bacterium.

Bacteria and DiseaseBacteria and Disease

The study of diseases is called The study of diseases is called PathologyPathology

Bacteria cause disease by the Bacteria cause disease by the release of poisons called Toxins.release of poisons called Toxins.

Bacterial Toxins-2 kindsBacterial Toxins-2 kinds

Exotoxins-bacterial excretions into Exotoxins-bacterial excretions into the surrounding environment-the surrounding environment-TetanusTetanus

Endotoxins-toxins released as result Endotoxins-toxins released as result of the death and disintegration of of the death and disintegration of bacteria. Cause of body ache, bacteria. Cause of body ache, weakness and fever.weakness and fever.

AntibioticsAntibiotics

Antibiotics are drugs Antibiotics are drugs that destroy bacteria that destroy bacteria by interfering with by interfering with either the structure or either the structure or function of the function of the bacteriumbacterium

Two common Two common antibiotics are antibiotics are Penicillin-bacterial cell Penicillin-bacterial cell

wall synthesiswall synthesis Tetracycline-bacterial Tetracycline-bacterial

protein synthesisprotein synthesis

Useful BacteriaUseful Bacteria

Bacteria are used beneficially inBacteria are used beneficially in Sewage treatmentSewage treatment The recycling of dead organismsThe recycling of dead organisms Processing foodsProcessing foods

Yogurt, Cheeses, Sour Cream, Alcoholic Yogurt, Cheeses, Sour Cream, Alcoholic BeveragesBeverages

PesticidesPesticides Clean up of environmental disastersClean up of environmental disasters