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		1.3.7— More Examples of Scaling Relationships

		1— Scaling Relationships in Space

		We have already seen that there is a scaling relationship that tells us how the amount of membrane area measured in a cell depends on the resolution in space used to measure it.

		Additional examples of scaling relationships in space include how the diameter of the tubes that bring air into the lung, the width of the spaces between the cells that line the capillaries in the lung, and the surface areas of proteins each depend on the spatial resolution used to measure them.

		2— Scaling Relationships in Time

		We have already seen that there is a scaling relationship that tells us how the rate of switching between the open and closed states of an ion channel protein depends on the resolution in time used to measure it.

		Another example of scaling relationships in time is the rate of chemical reactions that are limited by the time it takes for the molecules to reach each other. The reaction slows down with time because the nearby molecules have reacted and it takes ever longer for the unreacted molecules to reach each other. The scaling relationship describes how the kinetic rate constant of the reaction depends on the time measured since the reaction began.

		A scaling relationship in time is also present in the washout kinetics of how the concentration of substances in the blood decay with the time measured since the substances were first injected into the blood.

 

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