Osmosis and Diffusion

In: Science

Submitted By berad2424
Words 1110
Pages 5
Brad Sanford
Bio 1120 Section 6
September 17, 2013
Partners: Dominique & Carleigh
Lab #2: Osmosis & Diffusion

Introduction
Diffusion is the movement of molecules from a high concentration gradient to a low concentration gradient. This can occur in gases, liquids, and solids. Osmosis is a type of diffusion that allows water molecules to move through a semipermeable membrane freely by way of passive transport. During osmosis a semipermeable membrane will allow small water molecules to pass through freely without any help but larger molecules like proteins will not move through the semipermeable membrane without active transport. Active transport requires a chemical energy like ATP (adenosine triphosphate) to help the larger molecules move through the cell’s membrane.(Krane) When describing high and low concentrated solutions, it is useful to understand the terms hypertonic, hypotonic, and isotonic. A hypertonic solution has a higher concentration of solutes compared to a lower concentrated solution as water will move out of the solution (Dehydration). A hypotonic solution has a lower concentration of solutes compared to a solution with a higher concentration of solutes and water will move into the solution (Swelling). In a isotonic solution the solutes are at an equal concentration and there is no movement of the water.
In this lab, two experiments were performed. The first one uses a small plastic bag closed up and filled with cornstarch and distilled water sitting inside a beaker filled with water and a potassium iodide solution. The bag is the semipermeable membrane and the cornstarch is our molecule that will diffuse through the membrane and into the potassium iodide solution. The hypothesis of this experiment is the cornstarch will move across the membrane of the plastic bag and into the potassium iodide solution. The starch will turn a…...

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