Gases are constantly consumed and produced by cellular and metabolic reactions in most living things, so an efficient system for gas exchange between, ultimately, the interior of the cell(s) and the external environment is required. Small, particularly unicellular organisms, such as bacteria and protozoa, have a high surface-area to volume ratio.
Polyploid. (genetics) an organism or cell having more than twice the haploid number of chromosomes.Of a cell or organism having more than twice the haploid number of chromosomes; a polyploid cell; a polyploid species .Organisms that possess two sets of each chromosome.
Mycoplasmas are very small bacteria lacking cell walls that belong to various genera within the class Mollicutes. These flexible, pleomorphic organisms can be as small as 0.2 to 0.3 Âµm in diameter Figure 1a-A common feature is the variability in cell morphology related to the absence of a cell wall.SEM of mycoplasma filaments-Image courtesy of Dr. Michael Gabridge (Figure 1a).hey are considered to be the smallest free-living organisms capable of self replication with a genome in the range of only 600-2200 kb. They have become one of the most prevalent and serious microbial contaminants within cell culture systems used in research and industry today.