Cytoplasmic Structures
(a). Nucleoid - An area of concentrated DNA with no nuclear membrane.
The DNA is single circular, double stranded without proteins. (b). Ribosomes
- 30S and 50S to form a 70S complex. (c). Plasmids - Extrachromosomal
loops of DNA, some code for drug resistance, toxins and other factors.
Endospores
Under environmental stress (lack of water, nutrients etc.) some vegetative
cells produce endospores e.g. Clostridium and Bacillus. Spores
can be dormant for many years. They can survive extreme heat, desiccation,
radiation and toxic chemicals. However, when conditions become favorable
they revert to a vegetative state. Spore germination is activated by heat
in the presence of moistures but the endospore must degrade the layers
around the spore. |
