Osmosis and Diffusion

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Joshua Annan

Biology Section-04

Diffusion and Osmosis

December 14,2012

Alexis, Adiba, Elliot and Joey

Purpose:

The purpose of this lab is to get a better understanding of osmosis and diffusion in molecules. We will do this by studying different solutions and how they move through the permeable membrane.

Hypothesis:

The three different possible predictions were the lab were that the mass would stay the same, the mass will increase, or the mass will decrease. I predicted that for Section 1 the mass will stay the same, System 11 will decrease, System 111 will increase, and System 1V will decrease.

Prelab:

Diffusion and Osmosis are processes that deal with the movement of atoms and molecules from a higher concentration to a lower concentration. Osmosis deals specifically with the movement of water across the permeable membrane. Diffusion does not need a membrane and is not specific to any element. Diffusion happens in both short and long distances while osmosis takes place over short distances. Molecules are in a state of equilibrium across a selectively permeable membrane during osmosis. Water is the smallest with 3 atoms, then glucose with 24 atoms, than sucrose with about 48 atoms, and then finally starch.

Materials:

Refer to lab book

Procedure:ia

Refer to lab book

Data:

Refer to lab book

Analysis:

The purpose of the dialysis bag containing only water in a cup of water was to display an isotonic system. It was also to display osmosis in the water and it was used as a selectively permeable membrane to model the cell membrane. . This first system could be considered the control group out of the four other systems. The flow of water in and out of the cup was almost the same, this is because the percent change between the initial mass and final mass was 0.6%. This shows that the bag got heavier even though it is considered an isotonic system. The net flow of the second system was...
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