Prokaryotes

Carissa Fletcher

Inter Community School Zurich

Background

The prokaryotes are a group of organisms whose cells lack a cell nucleus(karyon).

The organisms whose cells do have a nucleus are called eukaryotes. Most prokaryotes are unicellular organisms

Prokaryotes do not have a nucleus, mitochondria, or any other membrane-bound organelles.

In prokaryotes the intracellular water-soluble components (proteins, DNA and metabolites) are located together in the same area enclosed by cell membrane, rather than separated in different cellular compartments.

The division to prokaryotes and eukaryotes reflects two distinct levels of cellular organization rather than biological classification of species.

Prokaryotes include two major classification domains: the bacteria and the archaea.

Archaea were recognized as a domain of life in 1990. These organisms were originally thought to live only in inhospitable conditions such as extremes of temperature, pH, and radiation but have since been found in all types of habitats.

Background

• E. coli is a Gram-negative, facultative anaerobic rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms).

• Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans

• The harmless strains are part of the normal flora of the gut, and can benefit their hosts by producing vitamin K2, and by preventing the establishment of pathogenic bacteria within the intestine.

• E. coli and related bacteria constitute about 0.1% of gut flora and fecal–oral transmission is the major route through which pathogenic strains of the bacterium cause disease.

• In 1997 strain MG 1655 was found to be a circular DNA molecule 4.6 million base pairs in length, containing 4288 annotated protein-coding genes

• Major role in Biotechnology and genetic engineering and is also a model organism for microbiology.

http://abcnews.go.com/topics/lifestyle/health/e-coli-infection.htm?mediatype=Image

2.2.1- 3 Draw and label a diagram of the ultrastructure of Escherichia coli (E. coli) as an example of a prokaryote.

2.2.4 State that prokaryotic cells divide by binary fission.

2.3.4 Compare prokaryotic and eukaryotic cells.

Feature Prokaryotes Eukaryotes