Explaination for dot point 3.2.4 (1 Viewer)

[pedro_0952]

Hi, can someone quickly explain why the processes of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes in some organisms

Thankyou

 

[alchetor]

-> Diffusion is too slow and non-selective of solutes(dissolved ions i.e ammonia,)
-> As osmosis is the movement of water from an area of high water concentration to low water concentration through a semi-permeable membrane, this would generally mean that metabollic wastes would remain within cells/body as water moves out.

Hope that helped

 

[sinophile]

-> As osmosis is the movement of water from an area of high water concentration to low water concentration through a semi-permeable membrane, this would generally mean that metabollic wastes would remain within cells/body as water moves out.

Allow me to explain why. Diffusion and osmosis wants to make the concentration of some substance equal on both sides. This means that ALL the waste inside the cell will never diffuse out unless you forcibly remove wastes from the other side.

 

[Spark_Coaching]

– Diffusion and osmosis are both examples of passive transport, relying on random movements of molecules.
– Diffusion is too slow for the normal functioning of the body and does not select for reabsorption of useful solutes.
– Osmosis only deals with the movement of water and thus would only allow water to move out of the body, not the nitrogenous wastes.
– Osmosis without active reabsorption of water would result in excess water loss