BELL WORK: Answer the following questions on your bell work page: 1.Name two major differences between prokaryotic and eukaryotic cells. 2.Draw a picture to illustrate the Endosymbiotic Theory. **I will collect ALL your bell work tomorrow!!**

CO: I will investigate cellular processes such as homeostasis and molecule transport. LO: I will begin a lab and take notes on osmosis and diffusion.

The Egg Demo

Potato Lab Day 1 Each station has 3 cups of solution and 3 pieces of potato. Choose one person from your group to record your data on the chart – you will keep this chart until tomorrow, so don’t lose it! Weigh each piece of potato, write down the weight, and put the potato into one of the cups. DO NOT MIX UP THE PIECES! One person from your group will bring the cups to me when you are finished.

All cells are surrounded by a thin, flexible barrier known as a cell membrane.

What is the cell membrane’s function (job)? (2 things)

The two main functions are: 1) to regulate what enters and leaves the cell 2) to provide protection and support.

What is the cell membrane made (composed) of? (3 types of molecules)

The composition of cell membranes is a double-layered sheet called a lipid bilayer. Bi- means 2 Also called the phospholipid bilayer

Proteins are embedded in the lipid bilayer. Proteins form channels or pumps that help move large materials across the cell membrane.

Carbohydrates are attached to many proteins embedded on the outside of the bilayer. The carbohydrates allow individual cells to identify one another.

How do substances move into/out of the cell membrane? (4 ways)

Why does food coloring spread out in water?

In a solution, particles are constantly moving. They collide with one another and spread out randomly.

Particles move from an area of high concentration to an area of low concentration. This is known as diffusion.

The concentration is the amount of a substance dissolved into water.

A concentration gradient is a difference between two concentrations. Diffusion is the movement of particles down the concentration gradient. High Concentration Low Concentration

When the concentration of a solute is the same throughout a system, the system has reached equilibrium. When equilibrium is reached, particles do continue to move across the membrane.

Substances that diffuse across a membrane do not require the cell to use energy.

If a substance is able to diffuse across a membrane, it is permeable. If a substance cannot diffuse across a membrane, it is impermeable.

Selectively permeable means that some substances can pass across while others cannot. Biological membranes are selectively permeable.

Diffusion of water through a selectively permeable membrane is called osmosis. Remember: SALT SUCKS

HOMEWORK TONIGHT! If you are watching tonight’s video on your PHONE, you will need to search for the video directly on YouTube… Search Defining Diffusion and Osmosis (by Stephanie Castle) If you STILL need to complete Tuesday’s homework and you will be using your PHONE, you will need to search for the video directly on YouTube… Search Compartmentalization (by Bozeman Science)

BELL WORK: Answer the following question on your bell work page: What three molecules make up a cell membrane? (hint: look at yesterday’s notes!) Take out your homework (for me to check) and ALL your bell work (for me to collect).

The Egg Demo

HYPOTONIC SOLUTIONS Hypotonic means “below strength” Water (outside the cell) = HIGH Solute (outside the cell) = LOW REMEMBER… “Hypo means LOW, makes the cell GROW!” Like the egg in distilled water…

HYPERTONIC SOLUTIONS Hypertonic means “above strength” Water (outside the cell) = LOW Solute (outside the cell) = HIGH REMEMBER… “Hyper means HIGH, makes the cell DRY!” or….SALT SUCKS! Like the egg in syrup…

ISOTONIC SOLUTIONS Like the egg in vinegar… Isotonic means “same strength” Water (outside the cell) = SAME Solute (outside the cell) = SAME REMEMBER… in ISOTONIC solutions, water is still moving, you just can’t see it!

What would happen if you put a freshwater fish into the ocean? Why? What would happen if you put a saltwater fish into fresh water? Why?

Potato Lab Day 2 Send ONE person from your group to collect your potatoes. Take each potato out of the solution, pat it dry, and weigh it again. Write TODAY’S weight in the “After soaking” column. Calculate the difference (if any) in weight. Based on today’s notes, label the three solutions as hypertonic, hypotonic, or isotonic. With your group, answer the lab questions. Be sure to turn in your papers before you leave!!