When you tutor Biology 12, one topic that comes up is cell efficiency.\u00a0 It’s a bit tricky for some people, because it involves some math.<\/p>\n
Putting it simply, imagine a cell is a sphere.\u00a0 Its volume is what it needs to maintain, whereas its surface area is where it gets its supplies.\u00a0 You can quickly realize that it’s best to have a big surface area compared to volume (or surface area to volume ratio), so the cell can easily get enough supplies to feed its volume.\u00a0 Efficiency, in this context, refers to the cell’s surface area to volume ratio:<\/p>\n
Eff.=SA\/V<\/p>\n
As the radius of a cell grows, its surface area grows, but its volume grows more quickly.\u00a0 Therefore, its surface area to volume ratio decreases:\u00a0 its efficiency<\/span> decreases.<\/p>\n Therefore, cells are better off being small – which is why most cannot be seen with the naked eye.\u00a0 Ultimately, this same principle (of efficiency) is why a rat can run up the side of a building with ease, but a human cannot.\u00a0 The human’s muscles, since they have such greater volume than the rat’s, are much less efficient.<\/p>\n