Ch 23.2 Biology of Prokaryotes

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I) Structure – composed of cell walls, cell membrane, and cytoplasm

A) Cell wall – eubacteria cell walls are made of peptidogycan

B) The cell membrane is composed of a lipid bilayer, and there is no organelles in the cytoplasm

C) Capsules – are an outer covering used for protectionD) Endospores – thick outer covering that surrounds the

DNA, used for protection

DNA- most bacteria contained in a singlecircular molecule, called the bacterialchromosome.

Plasmid- small circular DNA molecules.~An origin of replication~A selectable marker gene (e.g. resistance

to ampicillin)~A cloning site (a place to insert foreignDNAs)

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Flagella

• Bacteria that can move have protein appendages flagella

• Whiplikestructures used for movement

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Pili• Short protein appendagesWhich adhere bacteria to surfaces

• Used in conjugation for Exchange of genetic information

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II) Nutrition and MetabolismA) Bacteria can live in all type of environments, some

get their energy from the sun (Autotrophs), others from dead animals , they can live with or with out oxygen and many other ways

III) Prokaryotic HabitatsA) Obligate Anaerobes – organisms that cannot live where oxygen is presentB) Faculatative anaerobes – can live with or without oxygenC) Obligate aerobes – need oxygen to live

• Most grow best at pH of 6.5 to 7.0

• Many act as decomposers recycling nutrients

• Some cause disease (Pathogens)

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Reproduction• Bacteria reproduce asexually by binary fission

• Single chromosome replicates & then cell divides

• Rapid

• All new cells identical (clones)8

IV) Genetic recombinationA) Transformation – occurs when bacteria takes in DNA from its environmentB) Transduction – a virus obtains a small part of DNA from a host prokaryoteC) Conjugation – two bacteria bind together and transfers genetic material. Held together by pili. New cells NOT identical

Ch 23.3 Bacteria and Humans

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I) Bacteria and Health A) Pathology – is the scientific study of diseaseB) Toxins – poisons produced by bacteriaC) Exotoxins – toxins made of proteinsD) Endotoxins – toxins made of lipids and carbohydratesE) Antibiotics – drugs that combat bacteria by interfering with the bacteria

1. Broad-spectrum antibiotics – are antibiotics that affect many types of bacteria. Other antibiotics include Penicillin, Tetracycline, and Sulfa drugs

F) Antibiotic Resistance – bacteria can change so the antibiotics will not kill them

II) Emerging Infectious Diseases Caused by BacteriaA) Zoonosis – diseases that are past from wild

animals to humans (lyme disease), as people continue to move to new areas new diseases arise

III) Food Hygiene and Bacteria – the improper preparation, handling, or storage of food may cause foodborne illnessesIV) Bacteria in Industry

A) Useful bacteria – bacteria can be used to process food (Cheese, Yogurt, sour cream), produce chemical fuels, and even break down human waste

B) Bioremediation – bacteria is used to break down pollutants (ingesting petroleum, synthesis of drugs)

Controlling Bacteria

• Sterilization- by heat or chemical

• Refrigeration- bacteria cause food to spoil

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How do bacteria cause

diseases?

• 1.Damage the

tissue of the

infected

organism by

directly

breaking them

down for food

• *Tuberculosis

– break down

lung tissue

•2. Release poisons that

harm the body

•*Food poisoning –

meat or eggs

•*Streptococcus –

step throat or

scarlet fever

(reddish rash all

over the body)

Can you get rid of a bacterial

infection?

•*Yes !

•*Antibiotics –block

growth and

reproduction of

bacteria

• penicillin and

tetracycline