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.
haploid - (genetics) an organism or cell having only one complete set of chromosomes. heteroploid - (genetics) an organism or cell having a chromosome number that is not an even multiple of the haploid chromosome number for that species. polyploid - (genetics) an organism or cell having more than twice the haploid number of chromosomes.