| Line 12: |
Line 12: |
| | Prokaryotes are extraordinarily diverse: | | Prokaryotes are extraordinarily diverse: |
| | | | |
| − | Archaea.
| |
| | | | |
| − | (Eu)bacteria:
| + | Proteobacteria - Gram-negative, two cell membranes, hugely diverse, Escherichia coli. |
| − | :Cyanobacteria - photosynthetic, oxygenic.
| + | Firmicutes and Actinobacteria - Gram-positive, thick peptidoglycan cell wall. |
| − | :Proteobacteria - Gram-negative, two cell membranes, hugely diverse, Escherichia coli.
| + | Spirochaetes - helical bacteria. |
| − | :Firmicutes and Actinobacteria - Gram-positive, thick peptidoglycan cell wall.
| |
| − | :Spirochaetes - helical bacteria.
| |
| | | | |
| − | Prokaryotic DNA lacks histones (packaging proteins) and molecules have direct access to DNA. They have a junk-free genome, transcribed by just one RNA polymerase. Transcription leads to translation with no intermediate processing, which allows several genes to be encoded in a single transcriptional unit (a polycistron). They have small (70S) ribosomes. | + | Prokaryotic DNA lacks histones (packaging proteins), although other packaging proteins are present, and molecules have direct access to DNA. They have a junk-free genome, transcribed by just one RNA polymerase. Transcription leads to translation with no intermediate processing, which allows several genes to be encoded in a single transcriptional unit (a polycistron). They have small (70S) ribosomes. |
| | | | |
| | [[Category:biology]] | | [[Category:biology]] |
| | [[Category:microbiology]] | | [[Category:microbiology]] |