PART 3 OF T

HE

EGGSPERIMENT

LAB

DIRECTIONS FOR PART 3• Remove your eggs from the cups and

CAREFULLY rinse them with water.

• Measure the circumference of your egg with the string

• Make observations of your eggs. • Place your egg on a weighing boat and

weigh it on the scale.

• Dispose your eggs in the trash, but place the plastic cups in the sink.

DISCUSSION OF EGGSPERIMENT• Day 2 Observations:

What happened to the eggs when they were soaked in vinegar?

They expanded (bigger circumference). The mass increased. The shell disappeared.

DISCUSSION OF EGGSPERIMENT• Day 2 Observations continued:

How come this happened? Think about what vinegar is consisted of.

The shell disappeared because vinegar contains acid, which attacks the calcium shell, breaking it down. The egg expanded and weighed more because the vinegar contains more water than the egg. The water particles from the vinegar moved into the egg to create equilibrium.

DISCUSSION OF EGGSPERIMENT• Day 3 Observations:

What happened to the eggs that were soaked in water?

They expanded (the circumference was bigger) and the mass increased.

DISCUSSION OF EGGSPERIMENT• Day 3 Observations continued:

Why did this happen?

The egg expanded and got heavier because the water molecules in the cup moved into the egg. There is more water in the cup than in the egg.

DISCUSSION OF EGGSPERIMENT• Day 3 Observations continued:

What happened to the eggs that were soaked in karo syrup?

The mass of the eggs decreased and the circumference decreased.

DISCUSSION OF EGGSPERIMENT• Day 3 Observations continued:

Why did this happen?

The egg shrunk and its mass decreased because karo syrup contains a lot of sugar (close to pure sugar). There is more water in the egg than in the cup, so the water in the egg moves out into the cup.

MOVEMENT IN

AND OUT OF T

HE

CELL

THE CELL MEMBRANE• Fluid Mosaic Model (Cell Membrane)

• Two layers of phospholipids (Lipid bilayer)

• Proteins are embedded into the bilayer; act as channels or small pumps

• Carbohydrates act as chemical identification cards.

PASSIVE TRANSPORT – NO ENERGY REQUIRED

• Diffusion• Molecules move from high

concentration to low concentration to reach equilibrium.

• Depends on concentration of materials from either side.

• Depends on permeability of the membrane – some substances can pass, others can’t.

PASSIVE TRANSPORT – NO ENERGY REQUIRED

• Osmosis • The diffusion of water molecules through a selectively permeable membrane.

• Water goes from more dilute solution to a more concentrated solution (the side with more molecules.

High Salt ConcentrationLow Salt

Concentration

BLOOD CELLS – EXAMPLE OF OSMOSIS• Osmosis • Isotonic = Equal solutions

• Hypertonic = Salty solution (environment) - water leaves the cell and goes into the environment.

• Hypotonic = Low salt solution (environment) – water goes into the cell and it can burst!

• COMPARE TO EGG CELL – WHEN WAS IT IN EACH OF THESE STAGES?

OSMOSIS IN YOUR KITCHEN - LETTUCE• Osmosis

http://www.youtube.com/watch?v=H6N1IiJTmnc

FACILITATED DIFFUSION– NO ENERGY REQUIRED

• Facilitated Diffusion

• A process that uses a carrier molecule (protein) to transport a substance into the cell through the cell membrane.

• There has to be a concentration difference.

ACTIVE TRANSPORT – ENERGY REQUIRED• Active Transport

• A process that requires energy to move materials against a concentration difference.

• There are many types of active transport.

• Type 1: Membrane-Associated pumps – require chemical energy.

ACTIVE TRANSPORT – ENERGY REQUIRED• Type 2 – Particles transported by movements of cell membrane

• Endocytosis - Process of taking material into the cell by infoldings or pockets of the cell membrane.

• Exocytosis – process of removing large molecules of the cell.Exocytosis

HOMEWORK

• I am going to assign you a type of cell movement.

• With your knowledge of cell movement – from the notes today, online, and the book, create a story (2 paragraphs), song, skit or comic strip about the cell movement you are assigned.

• DO NOT include the cell movement name and keep yours a secret.

• On a separate piece of paper, write your cell type and include an explanation of how your story or comic represents the movement.

• We will share these in class on Monday.

EXAMPLE

Cell Membrane