Hobbies And Interests
Etymology
The name "prokaryote" is derived from Greek. The prefix pro- means "before" while karyote is derived from karyon, which means "kernel" or "nut." The word "prokaryote" literally means "before the kernel" and refers to the absence of a true, membrane-bound nucleus in these organisms. On the other hand, the word "eukaryote" literally means true (eu-) kernel, and refers to the presence of a membrane-bound nucleus, and its associated genetic material, in eukaryotic cells.
Prokaryote characteristics
A prokaryotic cell is surrounded by a plasma membrane. Exterior to the plasma membrane there may be other structures, including a cell wall or an outer membrane, that determine whether the cell is Gram-positive or Gram-negative, respectively. The cell does not have a membrane-bound nucleus and its circular piece of DNA is found in the cytoplasm. The cytoplasm of a prokaryotic cell also contains ribosomes, which are involved in protein synthesis, dispersed throughout. A prokaryote might also possess a flagellum, which aids in its movement through the environment.
Eukaryote characteristics
Eukaryotic cells are surrounded by a plasma membrane and contain a membrane-enclosed nucleus, which contains the cell's DNA. Unlike prokaryotes, they also contain a number of other membrane-bound organelles. These organelles include mitochondria, which are involved in energy production, and the endoplasmic reticulum and Golgi apparatus, involved in vesicle transport and protein synthesis. Other structures found in the cell include lysosomes and peroxisomes, and various cytoskeletal proteins. Like prokaryotic cells, eukaryotes contains ribosomes, which are necessary for protein synthesis.
Morphology
Prokaryotic cells can be classified based on their shape and such classifications are frequently encountered when we talk about medically important bacterial organisms. A spherically shaped cell is a coccus and a common example of this would be bacteria from the genus Staphylococcus or Streptococcus. Rod-shaped cells are known as bacilli, and this includes E. coli and Salmonella. Spiral-shaped bacteria, or spirochaetes, include Borellia burgdorferi, which causes Lyme disease. The genus Vibrio, which contains cells that are rod-shaped and curved, includes the bacterium Vibrio cholerae, which causes cholera.