is composed of prokaryotic organisms, and consists of unicellular bacteria and blue algae (cyanobacteria) are more primitive than eukaryotes. They all have ribosomes and a circular chain of DNA associated with a small amount of RNA and nonhistone proteins, which is not enclosed within a membrane. FEATURES
lack of membrane-bound organelles (mitochondria, lysosomes, endoplasmic reticulum, etc.). Divide by binary fission and budding or fragmentation, but may have genetic recombination.
The size is usually smaller than that of eukaryotes. The cell membrane of prokaryotes lack of cholesterol and other steroids.
In photosynthetic bacteria, the sites of photosynthesis, are in the cell membrane.
possess rigid walls, are hypertonic in relation to their environment, if they lack walls, burst. EXAMPLES
bacilli: straight lines on the pole.
coconuts: a spherical shape.
spirilla: corkscrew long sticks.
vibrios: incomplete spirals.
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