Investigating the Concentration of Sucrose in Cells of Carrots and Potatoes

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Investigating the Concentration of Sucrose in Cells of Carrots and Potatoes

Plan

Introduction

Osmosis is defined as 'the net movement of water molecules from a

region of high water concentration to a region of lower water

concentration through a partially permeable membrane'. In my

experiment the process of osmosis will be due to the concentration of

sucrose inside the cell compared to outside. Therefore if there is a

higher concentration of sucrose molecules outside the cell then the

net movement of water molecules will be out of the cell and similarly

if there is a higher concentration of sucrose molecules inside the

cell then the net movement of water molecules will be into the cell.

This movement of water molecules causes the cells to become either

turgid, which is when the cells are filled with water, or flaccid,

which is when the cells are 'limp' with little water.

Aim

To find the concentration of sucrose in cells of carrot and potato.

Osmosis

When a substance such as sugar dissolves in water, the sugar molecules

attract some of the water molecules and they stick to the sugar

molecules. This means that there are fewer free water molecules in the

solution. When two different sugar solutions come into contact with

each other through a partially permeable membrane the free molecules

can go through the membrane easily but the sugar molecules are too

big. If one of the solutions has more free molecules than the other

then more of those free molecules will pass through the membrane than

the other way round, hence the definition. The following diagram

illustrates this

Low Water High Water

Concentration Concentration

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