Correlation Between Surface Area / Volume With Sensitivity

1083 WordsOct 18, 20155 Pages
Purpose The purpose of performing part I of this lab was to study the relationship between surface area/volume with regard to rate of diffusion. We used treated agar blocks to model artificial cells because their surface area and volume could be easily measured, and they visually show the amount of diffusion. By using blocks of different sizes (and with different SA: V ratios, we can compare the rate that diffusion occurred for each block. Background Information All molecules are constantly in motion and have kinetic energy. When these molecules are clustered together and have a high concentration in one area, they tend to collide frequently and spread out. Even though individual molecules may be moving in all directions, the net movement of molecules will go from areas of high concentration to areas of low concentration. This spreading out of molecules is called diffusion. Once the molecules have spread out and reached equal concentration in all areas of the system, there is a dynamic equilibrium where the molecules continue to move but there is no net movement. Diffusion also occurs because it increases entropy in the system; when the molecules spread out, they become more disordered, adhering to the 2nd Law of Thermodynamics (entropy increases for all spontaneous processes). The difference in concentration between two areas forms a concentration gradient; molecules will diffuse down their concentration gradient. This process is a type of passive transport and requires no
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