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.
Polyploidy is used in genetics and is defined as an organism or cell having more than twice the haploid number of chromosomes. Rarely is this seen in animals but it is common in plants. It is seen in some animal tissues such as muscle and red marrow. Most organisms are diploid. If an organism is polyploidy, it is due to an abnormal division of the cell. It is seen in salmon or goldfish but mostly in plants. It can occur in about 2â3 of all human pregnancies and ~15% of miscarriages. 85% never get beyond the first few cell divisions. Most wheat types are polyploidy.