kingdom bacteria, kingdom archaea, and viruses. outline cellular detail and reproduction of bacteria...

Kingdom Bacteria, Kingdom Archaea, and Viruses

Outline

• Cellular Detail and Reproduction of Bacteria• Classification of Bacteria• Kingdom Bacteria

Phylum Bacteriophyta- Class Bacteriae- Class Cyanobacteriae- Class Prochlorobacteriae

• Kingdom Archaea• Viruses

Features of Kingdoms Bacteria and Archaea

• All have prokaryotic cells.• Nutrition is primarily by the absorption of food in

solution through the cell wall.• Reproduction is predominately asexual, by means

of fission.• More than 90% are either harmless or beneficial to

humans.• Motility

Most are nonmotile Some posses bacterial flagella Others move by gliding motion

Cellular Detail and Reproduction of Bacteria

• Plasma folds and other membranes apparently perform some of the functions of the organelles of eukaryotic cells.

• Plasmids may be present. Replicate independently of large DNA

molecule.• Mitosis does not occur.

Internal reorganization of material during which two DNA molecules migrate to opposite ends of the cell.

Fig. 17.1

Fig. 17.2

Cellular Detail and Reproduction of Bacteria

• Three Forms of Genetic Recombination Conjugation

- DNA transferred from donor cell to recipient cell.

Transformation- Living cell acquires DNA fragments

released by dead cells. Transduction

- DNA fragments carried from one cell to another by viruses.

Fig. 17.3

Classification of Bacteria

• Most bacteria are less than 2 or 3 micrometers in diameter, the smallest being 0.15 micrometers.

• Occur primarily in three forms: Cocci - Spherical or Elliptical Bacilli - Rod shaped or Cylindrical Spirilla - Helix or Spiral

Bacteria are classified based on a reaction to a dye into:

Gram positive

Gram negative

Kingdom Bacteria - The True Bacteria

• Phylum Bacteriophyta Class Bacteriae Have muramic acid in their cell walls and have different

RNA bases, metabolism, and lipids than archaebacteria- Unpigmented, Purple, and Green Sulfur Bacteria.

Most are heterotrophic (cannot synthesize their own food and therefore depend on other organisms for it).

Majority of heterotrophic bacteria are saprobes (living organisms that obtain their food from non-living organic matter).

Some are parasites (depend on living organisms for their food).


Some are Autotrophic (like higher plants, can synthesize organic compounds from simple inorganic compounds by photosynthesis) e.g. cyanobacteria (blue green bacteria) and chloroxybacteria produce oxygen.

Some autotrophic bacteria such as purple sulfur, purple non-sulfur and green sulfur bacteria photosynthesize without producing oxygen. They appear purplish or red to brown because the presence of a mixture of greenish, yellow, and red pigments. Their greenish pigment is called bacteriochlorophyll and is very similar to chloropyll a of higher plants. No plastids in bacteria and their pigments are located in the plasma membrane.

Purple sulfur bacteria use H2S instead of H2O in photosynthesis:

CO2 + 2H2S -------------------------- (CH2O) + H2O + 2S

Purple non-sulfur bacteria use organic molecules instead of H2S.

Green sulfur bacteria used H2S but their green pigment is chlorobium chlorophyll which differs significantly from chlorophyll a of higher plants.

Some are Chemautotrophic i.e. get their energy by oxidation or reduction of various compounds such as NH3, H2S, and Fe++

- Examples: Iron, Sulfur, and Hydrogen Bacteria- Iron bacteria convert soluble compounds of iron to insoluble

substances that accumulate as deposits (e.g. in water pipes).- Sulfur bacteria convert H2S to elemental sulfur and sulfur to

sulfate. - Hydrogen bacteria (in soils) use molecular hydrogen produced

from anaerobic bacteria and nitrogen-fixing bacteria.


• Human Relevance of Class Bacteriae Composting

- Allow bacteria to decompose organic waste. Diseases

- Plant diseases caused by bacterial pathogens cause American farmers losses of more than $4 billion per year.

- Many human and animal diseases are cause by bacteria. Several modes of transmission of bacteria have been identified.


• Modes of Access Contamination of Food and Drink

- Salmonella- Legionnaire Disease- Botulism

Direct Contact- Syphilis and Gonorrhea- Anthrax


• Modes of Access Wounds

- Tetanus and Gangrene Insect Bites and Other Organisms

- Bubonic Plague- Tularemia- Rickettsias- Mycoplasmas- Lyme Disease

Koch’s Postulates

• Rules for proving a particular microorganism is the cause of a particular disease. Microorganism must be present in all

cases of the disease. Microorganism must be isolated from the

victim in pure culture.

Koch’s Postulates

Microorganisms from the pure culture must be able to infect hosts.

Microorganism must be isolated from the experimentally-infected host and grown in pure culture for comparison with the original culture.

True Bacteria Useful to Humans

• Insecticide Bacillus thuringiensis and Bacillus popilliae

• Bioremediation Explosives Petroleum

• Vision Rhodopsin production

Fig. 17.9

True Bacteria Useful to Humans

• Dairy Products Cheese, yogurt

• Human Health Lactobacillus acidophilus aid in digestion When used with antibiotics Lactobacillus

acidophilus are used to control female yeast infections

• Industrial Uses Photographic film Acetone

Class Cyanobacteria

• The Blue Green Algae Distinctions between traditional bacteria and

cyanobacteria.- Cyanobacteria have chlorophyll a (which is

found in higher plants) and oxygen is produced when they undergo photosynthesis.

- Cyanobacteria contain blue phycocyanin and red phycoerythrin pigments known as phycobilins.

- Cyanobacteria can both fix nitrogen and produce oxygen.

Class Cyanobacteria

• Form, Metabolism, and Reproduction Cells in about half of the approximately 1,500

species are blue-green in color. Produce a nitrogenous food reserve called

cyanophycin. In the common genera Nostoc and Anabaena,

nitrogen-fixing cells are called heterocysts. Also, thick-walled cells are produced and are known as called akinetes (resist freezing and other adverse conditions).

Do not produce gametes or zygotes and do not undergo meiosis.

Fig. 17.11

Class Cyanobacteria

• Human Relevance Included among the many aquatic and

photosynthetic organisms at the bottom of various food chains.

Often become abundant in bodies of fresh water in warmer months.

- Algal Blooms Swimmers Itch cause by a toxin produced by

Lyngbya, a cyanobacteria. Same toxin has been demonstrated to supress leukemia and other types of cancer.

Nitrogen Fixation

Class Prochlorobacteriae

• The Prochlorobacteria Have chlorophyll a and b of higher plants,

but no trace of the phycobilin accessory pigments of cyanobacteria.

- Adds to theory that chloroplasts may have originated from cells living within the cells of other organisms.

Fig. 17.13

Kingdom Archaea

• One of two distinct lines of most primitive organisms. Metabolism is fundamentally different from

other lines of bacteria.• Methane Bacteria

Killed by oxygen and active only under anaerobic conditions.

- Energy derived from the generation of methane gas from carbon dioxide and hydrogen.

Kingdom Archaea

• Salt Bacteria Metabolism enables these bacteria to

thrive under extreme salinity.- Carry on simple photosynthesis with the

aid of bacterial rhodopsin.• Sulfolobus Bacteria

Metabolism allows these species to thrive at very high temperatures.

- Also found in acidic hot springs.

Human Relevance of Archaebacteria

• Methane has a high octane level. Given off by bacteria as they digest

organic wastes in the absence of oxygen.- In a methane digester, sludge makes an

excellent fertilizer.

Viruses

• Consist of a nucleic acid core surrounded by a protein coat. Separated first according to the DNA or

RNA.- Next grouped according to size and

shape, nature of protein coats, and number of identical structural units in their cores.

Bacteriophages - Viruses that attack bacteria.

Phage Virus

Viral Reproduction

• Viruses can only replicate at the expense of their host cells. Attach to susceptible cell.

- Penetrate to cell interior. DNA or RNA dictates synthesis of new

molecules. New viruses released from host cell.

Some can mutate very rapidly.- Immunity becomes more difficult.

Human Relevance of Viruses

• Annual loss in work time due to common cold and influenza viruses alone amount to millions of hours. Immunizations have dramatically

decreased incidence of many viruses such as German Measles, Mumps, and Chicken Pox.

• AIDS Retrovirus

- Evolves extremely quickly.

Viroids and Prions

• Viroids - Circular strands of RNA that occur in the nuclei of infected plant cells. Transmitted from plant to plant via pollen,

ovules, or machinery.- Cause more than a dozen plant

diseases.• Prions - Appear to be particles of protein that

cause diseases of animals and humans. No nucleic acids yet detected.

Review

• Cellular Detail and Reproduction of Bacteria• Classification of Bacteria• Kingdom Bacteria

Phylum Bacteriophyta- Class Bacteriae- Class Cyanobacteriae- Class Prochlorobacteriae

• Kingdom Archaea

kingdom bacteria, kingdom archaea, and viruses. outline cellular detail and reproduction of bacteria...

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