Chap. 23 : BacteriaChap. 23 : Bacteria

I.I. Characteristics of BacteriaCharacteristics of Bacteria 1. Unicellular – live in 1. Unicellular – live in

coloniescolonies 2. Prokaryotes2. Prokaryotes 3. A sample is called a 3. A sample is called a

cultureculture 4. Grown in lab on 4. Grown in lab on mediamedia

called called agaragar (algae) (algae) 5. Domain Archae or 5. Domain Archae or

BacteriaBacteria

A. ArcheabacteriaA. Archeabacteria

PeptidoglycanPeptidoglycan - sugar/protein found - sugar/protein found in cell walls but only in Eubacteria.in cell walls but only in Eubacteria.

3 Groups :3 Groups : --- Methanogens – convert H and CO2 --- Methanogens – convert H and CO2

into methane gas. Forms marsh into methane gas. Forms marsh gas.Found in cows intestinesgas.Found in cows intestines

--- Halophiles – salt-loving--- Halophiles – salt-loving--- Thermoacidophiles – acid and hot --- Thermoacidophiles – acid and hot

places. Volcanos and ocean vents.places. Volcanos and ocean vents.

B. Eubacteria :Gram B. Eubacteria :Gram StainingStaining

Gram Positive – stain purple, have Gram Positive – stain purple, have more peptidoglycan so first stain more peptidoglycan so first stain (which is purple) sticks. Usually more (which is purple) sticks. Usually more harmful. (botulism, strep, staph, harmful. (botulism, strep, staph, syphilis, anthrax)syphilis, anthrax)

Gram Negative – stains red, have Gram Negative – stains red, have less peptidoglycan so first stain less peptidoglycan so first stain washes out and the 2washes out and the 2ndnd stain (which stain (which is red) remains. is red) remains.

C. Eubacteria :Classified by their shapeC. Eubacteria :Classified by their shape

1. 1. CoccusCoccus ( cocci ) – round shape ( cocci ) – round shape

a. a. diplodiplococus – cocus – pairspairs of cocci of cocci

b. b. staphylostaphylococcus – (boils) – coccus – (boils) – clustersclusters of cocci. of cocci.

c. c. streptostreptococcus – (strept throat) – coccus – (strept throat) – chains chains of cocciof cocci

2. 2. Bacillus Bacillus (bacilli)- rod-shaped(bacilli)- rod-shaped ex. ex. E. coliE. coli – found in our intestines and – found in our intestines and

used for digestion.used for digestion. ex. ex. BotulismBotulism – type of deadly food – type of deadly food

poisoning (can goods and oysters)poisoning (can goods and oysters)3. Spirillium (spirilla) – spiral-shaped ~~3. Spirillium (spirilla) – spiral-shaped ~~ ex. Syphyllis – STDex. Syphyllis – STD-- Gram staining – process used to identify -- Gram staining – process used to identify

eubacteriaeubacteria a. gram negative – red/pink. Little a. gram negative – red/pink. Little

peptidoglycan.peptidoglycan. b. gram positive – purple. More b. gram positive – purple. More

peptidoglycanpeptidoglycan

II. Bacterial StructureII. Bacterial Structure

III. RespirationIII. Respiration 1. 1. Obligate aerobesObligate aerobes – requires – requires

oxygen to live. Ex. Diptheria oxygen to live. Ex. Diptheria ( trachae) and TB (lungs)( trachae) and TB (lungs)

2. 2. Obligate anaerobesObligate anaerobes – cannot live – cannot live in presence of oxygen.in presence of oxygen.

Ex. Tetanus, Syphillis, Halotosis, Ex. Tetanus, Syphillis, Halotosis, and Botulismand Botulism

3. 3. Facultative BacteriaFacultative Bacteria –can live with –can live with or without oxygen. Ex. or without oxygen. Ex. E.coliE.coli

IV. Adaptations for survivalIV. Adaptations for survival

Endospores – hard outer covering Endospores – hard outer covering around some bacteria used to survive around some bacteria used to survive harsh conditions. Some can survive harsh conditions. Some can survive up to a thousand years. Ex. Botulism up to a thousand years. Ex. Botulism and tetanusand tetanus

V.ReproductionV.Reproduction 1. Binary fission – one cell pinching 1. Binary fission – one cell pinching

into two. Asexual ( occurs about every into two. Asexual ( occurs about every 20 min.) Reason you should take 20 min.) Reason you should take antibiotic until completely gone.antibiotic until completely gone.

2. Conjugation – sexual – two 2. Conjugation – sexual – two bacteria exchange their genetic bacteria exchange their genetic information through their piliinformation through their pili

VI.Benefits of BacteriaVI.Benefits of Bacteria

1. Make products like Swiss cheese, 1. Make products like Swiss cheese, pickle, yogurt, butter, sauerkraut, pickle, yogurt, butter, sauerkraut, coffee, cocoacoffee, cocoa

2. Breakdown our food2. Breakdown our food 3. Breakdown waste and return 3. Breakdown waste and return

nutrients back to soilnutrients back to soil 4. Fix nitrogen (change N to a form we 4. Fix nitrogen (change N to a form we

can use)can use) 5. Used as medicines (antibiotics)5. Used as medicines (antibiotics)

VII.Controlling BacteriaVII.Controlling Bacteria

Need warm, wet, dark environment to Need warm, wet, dark environment to growgrow

1. Canning – heat food, seal 1. Canning – heat food, seal containers while hot, no aircontainers while hot, no air

2. Pasteurization – heating milk to kill 2. Pasteurization – heating milk to kill bacteriabacteria

3. Refrigeration and freezing – slows 3. Refrigeration and freezing – slows bacterial growthbacterial growth

4 Dehydration – getting rid of water 4 Dehydration – getting rid of water in foods – kills bacteria – ex. pastain foods – kills bacteria – ex. pasta

5. Antiseptics – chemicals that kill 5. Antiseptics – chemicals that kill bacteria on living things. Ex. Iodine, bacteria on living things. Ex. Iodine, alcoholalcohol

6. Disinfectant – chemicals that kill 6. Disinfectant – chemicals that kill bacteria on non-living things. bacteria on non-living things. Stronger than antiseptic. Ex. bleach, Stronger than antiseptic. Ex. bleach, ammonia, chlorineammonia, chlorine

7. Antibiotics (kill bacteria once in 7. Antibiotics (kill bacteria once in body) and Vaccines ( prevent body) and Vaccines ( prevent bacteria from occurring)bacteria from occurring)

VIII. Blue-green Bacteria: VIII. Blue-green Bacteria: CyanobacteriaCyanobacteria

Once considered a plant because Once considered a plant because they can photosynthesize. Has cell they can photosynthesize. Has cell structure like bacteriastructure like bacteria

Help produce oxygen and fix Help produce oxygen and fix nitrogennitrogen