Exchange and Transport in Protozoa :: Biology

Exchange and Transport in ProtozoaThe central of gases mingled with the environment and cells occurs via theprocess of distribution. Diffusion depends on The amount of emerge range available for diffusion. The larger the surface orbit the greater the rate of diffusion. The concent balancen gradient. An organism which respires very quickly will ache a a good deal lower concentration of oxygen in the cells and a higher than design concentration of Carbon Dioxide. So the greater the concentration gradient crosswise the respiratory surface the quicker the rate of diffusion. The thickness or distance of the diffusion path. The greater the thickness of the path the slower the rate of diffusion because the gases will have to travel a larger distance. So the respiratory surface must be as thin as possible.The affinity of the three points above can be summed up by Ficks LawHowever, the amount of gas which an organism needs to exchange isgreatly proportional to its volume, nevertheless, the amount ofgaseous exchange which takes place is proportional to the surface areaover which the exchange happens.For single celled/unicellular organisms the surface area to volumeratio is large, however, for larger organisms the surface area tovolume ratio decreases. The larger the object gets the morecomplicated it gets.The smaller the object the larger thesurface area to volume ratio. This is where single celled organismhave an advantage. Organisms like Amoeba can exchange gases withenvironment quickly and easily. However exchange surfaces need toattain certain properties to maximise gaseous exchange. They are shoot to have a good blood supply- high concentration gradient Moist- Dissolve gases Large Surface Area Thin walls PermeableAs single celled organisms are small so they do not have to havespecialised systems like much larger organisms like mammals. wizcelled organisms like amoeba do not have to have send off systems orspecialised systems because they are so small so IMAGEsubstances donot have to travel far to get to their desired destination.The contractile vacuole in this amoeba is used for water regulation.