what are two distinguishing characteristics of prokaryotes?
http://en.wikipedia.org/wiki/Prokaryote
they range in size from 1 to 5 micrometers
Prokaryotes does not have well defined nucleus and does not have well defined cell membrane. Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA.
Two distinguishing characteristics of prokaryotes are the absence of a nucleus and the lack of membrane-bound organelles.
To understand why prokaryotes do not have a nucleus, we need to know the difference between prokaryotic and eukaryotic cells. Prokaryotes, which include bacteria and archaea, are simpler in structure compared to eukaryotes. They lack a true nucleus, which means their genetic material, usually in the form of a single circular molecule of DNA, is not enclosed within a membrane-bound organelle. In contrast, eukaryotic cells, found in organisms such as plants, animals, fungi, and protists, have a defined nucleus that houses their genetic material.
Another characteristic of prokaryotes is the absence of membrane-bound organelles. While eukaryotic cells contain many specialized compartments called organelles, including mitochondria, endoplasmic reticulum, and Golgi apparatus, prokaryotes lack these distinct structures. Instead, prokaryotic cells have a simpler internal organization with various functional components dispersed throughout the cytoplasm.
To summarize, the two distinctions of prokaryotes are the absence of a nucleus and the lack of membrane-bound organelles.