The Rate Of Diffusion Process

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As an organism increases in its size the surface region to volume ratio decreases over a pobtainable eriod of time. This implies that the living being has a moderately less surface area which allows substances to diffuse through the organism, so the rate of diffusion might not be as fast to meet the prerequisites of a living being. Large multicellular organisms for that reason cannot definitely depend on the diffusion process alone in order for it to source their cells with such substances for example, sustenance and oxygen and to remove waste products. Large multicellular organisms require particualr transport systems as they are certain in its function. The smaller the organism the larger the surface area volume ratio, this provides…show more content…
However, unicellular organism is single celled organisms that can only be dependent on diffusion to move substances in and out of the cells. Whereas its surface area is fairly large compared to the volume of the organism, this means that the nutrients and other substances can easily go through the cell membrane and around its ‘body’. Smaller cells have a substantial surface area compared to cell volume, while larger cells have a diminished proportionof surface area to volume. This is the reason why bacterial cells are so small is that they need a large surface area to cell volume to take in nutrients. Microbes collect nutrients from the environment by diffusion. Single celled organisms such as Euglena, does not need a specialised area to carry out gaseous exchange because they have large surface area to volume ratio (SA:Vol), so the demand for the gases such as O2 and CO2 is low and the body surface area SA enough to meet needs by diffusion. In a large organism diffusion is a net movement of particles from an area of higher concentration to an area of lower concentration. It is a passive process and it doesn’t require energy, whereas Osmosis is the movement of water molecules across a partially permeable membrane from an area of higher water potential to an area of lower water potential. It is a passive process and it doesn’t require energy. Large, active organisms have higher demand for oxygen and removal of waste products such as CO2. They also have small surface area
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