# Cell Membranes and Transport

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Cell Membranes and Transport
Cell Membranes and Transport
Hands-On Labs, Inc. Version 42-0033-00-01

Exercise 1: Diffusion

Observations

Data Table 1: Rate of diffusion in different temperatures | | ºC | Minutes | Temperature | InitialTemp. | InitialColor | 5 | 10 | 15 | 20 | 25 | 30 | 60 | Cold | 10°celsius | clear | clear | clear | clear | clear | clear | light purple | light purple | Ambient | 25°celsius | clear | clear | clear | clear | light purple | light purple | med purple | med purple | Hot | 75°celsius | clear | purple | purple | purple | purple | dark purple | dark purple | dark purple |

Questions

A. Write a one-paragraph analysis of the results for the procedure. Provide reasons for the difference in the rate of diffusion at the different temperatures.

- In this experiment three zip-loc bags were filled with a solution of starch. Each bag was placed in different beakers filled with IKI indicator and placed at different temperatures. When Iodine reacts with starch, it turns purple. The rate that a solution diffuses along a grain or membrane Is related to the concentration, the type of membrane and the temperature. Because the concentration of the solutions and type of membrane is the same, the only factor to determine the rate of diffusion in this experiment is the temperature. When molecules are placed in a hot temperature they become excited; And the higher the temperature the higher the rate of diffusion.That is why in this experiment, the zip-loc placed in the hot water bath achieved the fastest rate of diffusion when compared to the solutions placed in the refrigerator and in ambient room air.

B. Did the sizes of the molecules affect their movement?

-Yes sizes of molecules affect their movement during diffusion. In this experiment, the size of the iodine molecules were small enough to pass through the semi-permeable membrane

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