Investigating the Factors that Affect Osmosis in Living Tissue

Investigating the Factors that Affect Osmosis in Living Tissue

Aim:

To investigate the factors that effect osmosis in living tissue.

Planning:

Introduction

Essentially, osmosis is the diffusion of water across a selectively

permeably membrane. Osmosis is one of the ways by which substances

enter and exit cells. Other ways include diffusion, the Donnan effect[1],

solvent drag, filtration, endocytosis, exocytosis and active

transport. All of these methods are necessary to provide cells with

the conditions necessary for their survival. Osmosis helps cells

absorb the water that they need and also pass it on from one cell to

another. Osmosis occurs in the uptake of water in root hair cells, it

also occurs in the return of water from tissues to blood capillaries

and is constantly occurring during the opening and closing of the

stomata in plant leaves.

Factors that shall be tested:

Bearing in mind that we have limited time and shall be conducting our

experiments in a laboratory, measuring certain things may therefore be

impractical. We shall therefore limit our investigation to the effect

of three things: Cross-sectional area of plant cylinder, concentration

of solution and temperature of solution.

Variables

There are three main types of variable; Independent (input), control

and dependent variables.

An independent variable, otherwise known as an input variable, is the

variable that is to be tested by experiment and therefore deliberately

changed. The control variable is the variable that is kept constant in

order to test the independent variable fairly. The dependent variable

is the one that depends on the control and independent variables.

Since the control is to be kept constant, any effect on the control

variable will therefore be due to the independent variable.

Throughout our investigation the variables and there complexities

shall be as follows:

The constants or control variables for this experiment are going to

be:

· The vegetable used-We shall be using the common white potato.

Potatoes are produced by plants of the genus Solanum, of the family