BacteriaBacteria

I. ProkaryotesI. Prokaryotes

A.A. Prokaryotes: single-celled organisms that Prokaryotes: single-celled organisms that lack a nucleuslack a nucleus

1. Eubacteria – walls contain 1. Eubacteria – walls contain peptidoglycan (a carbohydrate)peptidoglycan (a carbohydrate)

2. Archaebacteria – lack peptidoglycan, 2. Archaebacteria – lack peptidoglycan, DNA similar to eukarotes DNA similar to eukarotes

B.B. Identifying ProkaryotesIdentifying Prokaryotes

1. Shapes1. Shapes

a. Bacilli (rod shaped)a. Bacilli (rod shaped)

b. Cocci (spherical)b. Cocci (spherical)

c. Spirilla (spiral)c. Spirilla (spiral)

2. Cell Walls2. Cell Walls

a. Gram-positive (w/peptidoglycan) a. Gram-positive (w/peptidoglycan) – purple– purple

b. Gram-negative (w/o peptidoglycan b. Gram-negative (w/o peptidoglycan – red– red

3. Arrangement3. Arrangement

a.a. Staphyl: Clumps or clusters Staphyl: Clumps or clusters

b. Strepto: long chainsb. Strepto: long chains

4. Movement 4. Movement

a.a. Propelled by tail-like structure called Propelled by tail-like structure called flagella flagella

b. Glide along a slime secretionb. Glide along a slime secretion

c. Move along like snakes c. Move along like snakes

d. Some dond. Some don’’t move t move

C.C. Obtaining EnergyObtaining Energy

1. Autotrophs1. Autotrophs

a. a. Photoautotrophs: obtain Photoautotrophs: obtain energy energy from photosynthesisfrom photosynthesis

b. b. Chemoautotrophs: obtain Chemoautotrophs: obtain energy energy from inorganic moleculesfrom inorganic molecules

2. Heterotrophs2. Heterotrophs

a. Can cause food poisoninga. Can cause food poisoning

b. Photoheterotrophs: b. Photoheterotrophs: photosynthetic, photosynthetic, but also need but also need organic compounds organic compounds for nutrition for nutrition

D.D. Releasing EnergyReleasing Energy

1. Obligate aerobes: require oxygen1. Obligate aerobes: require oxygen

2. Obligate anaerobes: cannot live in 2. Obligate anaerobes: cannot live in presence of oxygenpresence of oxygen

3. Facultative anaerobes: do not need 3. Facultative anaerobes: do not need oxygen, but can live in the presence oxygen, but can live in the presence of itof it

E.E. Growth and ReproductionGrowth and Reproduction

1. Binary fission: cell divides, asexual1. Binary fission: cell divides, asexual

2. Conjugation: transfer of genetic 2. Conjugation: transfer of genetic information from one cell to another, information from one cell to another, sexualsexual

3. In unfavorable conditions, many 3. In unfavorable conditions, many bacteria can form endospores – can bacteria can form endospores – can remain dormant for months or years remain dormant for months or years

II. Bacteria in NatureII. Bacteria in Nature

A.A. DecomposersDecomposers

1. Help recycle nutrients – break down 1. Help recycle nutrients – break down dead organismsdead organisms

2. Used in sewage treatment2. Used in sewage treatment

B.B. Nitrogen FixersNitrogen Fixers

1. Nitrogen fixation: converting nitrogen 1. Nitrogen fixation: converting nitrogen into a form plants can useinto a form plants can use

2. 2. RhizobiumRhizobium grow on roots of grow on roots of soybeans and other legumes soybeans and other legumes

– – converts nitrogen to ammonia converts nitrogen to ammonia for for the plant the plant

C.C. Bacteria and DiseaseBacteria and Disease

1. Pathogen: disease-causing agents1. Pathogen: disease-causing agents

2. 2 ways bacteria cause disease2. 2 ways bacteria cause disease

a. Break down tissues for fooda. Break down tissues for food

b. Release toxins b. Release toxins

3. Many can be treated with 3. Many can be treated with antibioticsantibiotics

D.D. Human Uses of BacteriaHuman Uses of Bacteria

1. Food – cheese, yogurt, buttermilk, 1. Food – cheese, yogurt, buttermilk, sour cream, pickles, sauerkrautsour cream, pickles, sauerkraut

2. Industry – cleaning up oil spills, 2. Industry – cleaning up oil spills, mining minerals, synthesizing drugsmining minerals, synthesizing drugs

3. Bacteria live in our digestive tract to help 3. Bacteria live in our digestive tract to help in digestion (called normal flora) in digestion (called normal flora)

E.E. Controlling BacteriaControlling Bacteria1. Sterilization: destroy bacteria by 1. Sterilization: destroy bacteria by

subjecting them to great heat or subjecting them to great heat or chemicals chemicals

a. Boiling, frying, steaming a. Boiling, frying, steaming can all can all kill bacteria kill bacteria

b. Disinfectant chemical b. Disinfectant chemical solutions solutions can be used in homes can be used in homes and and hospitals hospitals2. Refrigeration – bacteria grow slowly 2. Refrigeration – bacteria grow slowly at low temperaturesat low temperatures

Antibiotics•Fighting Bacteria Bacterial disease can be fought with soap, chemicals, and antibiotics.

•Antibiotic-Resistant Bacteria Mutations that confer resistance to antibiotics are strongly favored in bacterial populations being treated with an antibiotic.

III. VirusesIII. Viruses

A.A. Viruses: particles of nucleic acid and Viruses: particles of nucleic acid and proteinprotein

1. Nucleic acid = DNA or RNA that 1. Nucleic acid = DNA or RNA that contains instructions for making contains instructions for making new new copies of the virus copies of the virus

2. Capsid: outer protein coat2. Capsid: outer protein coat

B.B. Viral InfectionViral Infection

1. Infect cells and replicate inside host 1. Infect cells and replicate inside host cellcell

2. Bacteriophage: viruses that infect 2. Bacteriophage: viruses that infect bacteria bacteria

3. 2 types of viral infections3. 2 types of viral infections

a. Lytic infection: virus enters cell, a. Lytic infection: virus enters cell, make copies of itself and causes make copies of itself and causes

the the cell to burst cell to burst

b. Lysogenic infection: virus embeds b. Lysogenic infection: virus embeds its DNA into DNA of host and is its DNA into DNA of host and is replicated with host cell replicated with host cell’’s DNAs DNA

C.C. Viruses and DiseaseViruses and Disease

1. Many viruses can be prevented 1. Many viruses can be prevented through the use of vaccines (polio, through the use of vaccines (polio,

measles, influenza)measles, influenza)

2. Oncogenic viruses cause cancer2. Oncogenic viruses cause cancer

3. Retroviruses contain RNA3. Retroviruses contain RNA

4. Prions contain no DNA or RNA, only 4. Prions contain no DNA or RNA, only proteinprotein