686
edits
Changes
Jump to navigation
Jump to search
Line 7:
Line 7: − +
no edit summary
#Few membrane-bound organelles, no double-membrane bound organelles.
#Few membrane-bound organelles, no double-membrane bound organelles.
#They are 'small' because diffusion limits the rate of transport across the cell - 1 μm.
#They are 'small' because diffusion limits the rate of transport across the cell - 1 μm.
[[Image:Bacterial_cell.png|center|thumb|Prokaryotes are characterised by the lack of a nucleus and membranes bound organelles.]]
[[Image:Bacterial_cell.png|center||Prokaryotes are characterised by the lack of a nucleus and membranes bound organelles.]]
The cytosol contains oil droplets, food reserves and the 70S ribosomes, and is surrounded by a plasmalemma. In Gram negative bacteria, a further outer membrane surrounds the plasmalemma, with a thin cell wall and periplasmic space trapped between them. In Gram positive bacteria, there is no outer membrane, and the cell wall is thicker. The cell wall is composed of peptidoglycan and various organic acids in Eubacteria. Bacteria have flagella, but they are simple proteinaceous strands attached to a rotary motor, completely dissimilar to the complex eukaryotic undulipodium. Membranes may be present in the cell, as in the thylakoids of the Cyanobacteria. The cytosol may also contain various episomes (small circular chromosomes), some called plasmids, and others called (bacterio)phages, which are bacterial viruses.
The cytosol contains oil droplets, food reserves and the 70S ribosomes, and is surrounded by a plasmalemma. In Gram negative bacteria, a further outer membrane surrounds the plasmalemma, with a thin cell wall and periplasmic space trapped between them. In Gram positive bacteria, there is no outer membrane, and the cell wall is thicker. The cell wall is composed of peptidoglycan and various organic acids in Eubacteria. Bacteria have flagella, but they are simple proteinaceous strands attached to a rotary motor, completely dissimilar to the complex eukaryotic undulipodium. Membranes may be present in the cell, as in the thylakoids of the Cyanobacteria. The cytosol may also contain various episomes (small circular chromosomes), some called plasmids, and others called (bacterio)phages, which are bacterial viruses.