Question
Tue May 31, 2011 By: Manaswini Mullagiri

Sumeet mam,i want to know how the unicellular organisms respire?-M.Manaswini,anantapur.

Expert Reply
Thu June 02, 2011
Single-celled organisms exchange gases directly across their cell membrane through diffusion. Diffusion works quickly enough to meet the metabolic demands for oxygen in unicellular orgnisms. However, the slow diffusion rate of oxygen relative to carbon dioxide limits the size of single-celled organisms. 
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