Eggs-Ercisein Osmosis

Eggs-ercisein Osmosis

Objective: C3 - Identify the parts of the cell membrane including lipids, proteins, & carbohydrates and investigate & explain the transport of molecules through the this membrane such as diffusion & osmosis

One type of passive transport is osmosis. Osmosis is the movement of water across a semi-permeable membrane. The process by which osmosis occurs is when water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration. The direction of osmosis depends on the relative concentration of the solutes on the two sides.
An egg is a large, single cell enclosed in a cell membrane, just under the shell. The cell membrane is semi-permeable.
There are 3 types of osmosis:
Isotonic - The concentration of solutes is the same inside outside the cell; Water moves in and out
Hypertonic - Solution has a higher solute concentration than the cell; Water moves out
Hypotonic - Solution has a lower solute concentration than the cell; Water moves in

Making the Egg Naked:

In order to see the cell membrane on the egg cell, the shell must first be removed.

When an egg is submerged in vinegar, the shell dissolves. Vinegar contains acetic acid, which breaks apart the solid calcium carbonate crystals that make up the eggshell into their calcium and carbonate parts. The calcium ions float free (calcium ions are atoms that are missing electrons), while the carbonate goes to make carbon dioxide—the bubbles that you see.

Once the shell is removed, you will be able to see the colorless and translucent (light is able to pass through) egg cell.

Hypothesis:

If an egg whose shell has been removed by vinegar is placed in syrup, then ______

______.

If an egg whose shell has been removed by vinegar is placed in water, then ______

______.

Procedure:

On day 1, teacher will place 2 raw chicken eggs in vinegar, and let it stand for 24 hours.

On day 2, record the observations of what happened to the egg in the vinegar solution. Teacher will remove the eggs from the vinegar. Teacher will place one egg in a beaker, pouring enough syrup to cover the egg, and let it stand for 24 hours. Teacher will place the other egg in a beaker, pouring enough distilled water to cover the egg, and let it stand for 24 hours. Record the observations of what happened to the eggs in the data table.

On day 3, record the observations of the eggs from the syrup and water solutions.

Data:

Day 2
(draw a picture before) / Day 3
(draw a picture after) / Observations
Egg placed in distilled water
Egg placed in corn syrup

Analysis:

What was the purpose of placing the egg in vinegar? ______

What direction is the water going when the egg is placed in water? ______

What type of osmotic solution is this? ______

What direction is the water going when the egg is placed in syrup? ______

What type of osmotic solution is this? ______

Extension:

Some peeled pieces of apple were placed in distilled water and some in very salty water.

The cells in the apple pieces will - [VA06 EOC]

A / A / gain water in the distilled water and
lose water in the salty water
B / B / lose water in the distilled water and
gain water in the salty water
C / C / gain water in both solutions
D / D / lose water in both solutions