Dialysis Lab and Nature of Science

Dialysis Lab

Take out your lab notebook!

If you have not finished your Cell Observations Lab conclusion, leave some space for your conclusion and skip to the next page

Title: Dialysis Lab

Purpose: To make observations of a dialysis apparatus in order to determine how dialysis tubing functions

Dialysis Lab – Materials and Method

Materials and Methods:

- Corn Syrup

- Dialysis Tubing

- 500 mL beaker

- 2 rubber bands

- 10mL pipette

- Water

- Clamp and Ring Stand

Dialysis Lab - Materials and Method

Dialysis Lab - Materials and Method

Dialysis Lab - Materials and Method

Dialysis Lab - Results

Write down any observations you see

Then write down any questions you have about the apparatus. For Example: Why does ______________ happen?

From one question you can come up with a hypothesis Maybe __________ happens because the pipette has a cotton

in it.

Dialysis Lab - Results

Then you can make an experiment around your hypothesis using an if … then statement If the cotton ball in the pipette causes the liquid in the pipette change

and we take out the cotton ball then, there will be no change in the amount of liquid in the pipette.

Here are the materials available for your experiment…

After writing your hypothesis, have an instructor check it and you can write method for this experiment Be sure to include

How you will be recording your data Only have 1 variable – change only 1 thing A control

Gallery Walk

When everyone is done with their method, we will walk around and annotate each group’s method Write one thing that you like about the method and one thing

they can do to make it better Things to look for

Does the method make sense to you? In other words, is it clear? Do they have a way to record their data qualitatively and quantitatively? Do they only have one variable?

Make any adjustments necessary and start your new lab.

What was happening?

Dialysis is a process that takes out waste and extra water from blood.

It is an artificial replacement for kidneys.

The dialysis tube is made of a permeable membrane that works by simple diffusion or passive diffusion.

Passive Diffusion: Molecules move from an area of high concentration to low concentration until it fills the space evenly (equilibrium)

Passive Diffusion: Molecules move from an area of high concentration to low concentration until it fills the space evenly

Ex: Farts, Purfume, Food coloring in water

Cell Membrane

The cell membrane is also semi-permeable and wants to balance with the water from the environment outside.

Lipid Bilayer

Lipid Bilayer: A thin membrane made of 2 layers of phospholipids.

Phospholipids: lipids with polar head (hydrophilic) and non-polar tail (hydrophobic) that make up the cell membrane.

But Wait!

If the fatty acid tails on the phospholipid are non-polar, how do the water molecules go through?

Aquaporins! Proteins in the cell membrane that have a tunnel for water to pass through.

Aquaporins! Proteins in the cell membrane that have a tunnel for water to pass through using passive transport

Types of Transport Proteins

Passive Transport: Moving molecules in and out of a membrane without using energy. Can only move from high to low concentration

Active Transport: Moving molecules in and out of a membrane using energy.