Brainteaser

What has wheels and flies, but is not an aircraft)?

Study the diagram below.

Which arrow shows the direction the solute molecules would move to achieve homeostasis?

If the membrane shown is permeable to molecules of X, but impermeable to molecules of Y, what will be the result of diffusion over time?

A. Molecules of X on each side of the membrane will become equal in concentration.

B. Molecules of Y on each side of the membrane will become equal in concentration.

C. Molecules of X will increase in concentration on the right side.

D. Molecules of Y will increase in concentration on the right side.

Today you will review

1. Passive Transport2. Osmosis3. Osmosis within the 3

types of solutions.

Types of Cellular Transport

Passive Transport cell doesn’t use energy

1. Diffusion2. Facilitated Diffusion3. Osmosis

Active Transportcell does use energy

1. Protein Pumps2. Endocytosis3. Exocytosis

high

low

This is gonna

be hard work!!

high

low

Weeee!!!

3 Types of Passive Transport

1. Diffusion – molecules move high to low.

2. Facilitative Diffusion – diffusion with the help of transport proteins.

3. Osmosis – Water moves high to low.

1.Osmosis: diffusion of water through a selectively permeable membrane.

Water moves from high to low concentrations.

•Water moves freely through pores.

•Solute (green) too large to move across.

Passive Transport: 1. Osmosis

Effects of Osmosis on Life

Osmosis- diffusion of water through a selectively permeable membrane.

There are 3 types of solutions:IsotonicHypertonicHypotonic

Isotonic Solution Solutions that contain the same

concentration of solutes as the cytoplasm are called isotonic (or normal saline) solutions.

There is no net movement of water either into or out of the cell.

Cells maintain their normal shape.

WATCH VIDEO OF BLOOD IN AN ISOTONIC SOLUTION

Isotonic Solution

Isotonic: The concentration of solutes in the external solution is equal to the concentration of solutes inside the cell.

Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium)

• Osmosis Animations for

isotonic, hypertonic, and

hypotonic solutions

Hypertonic Solution A hypertonic solution is a solution that

contains more (hyper) solutes than the cytoplasm of the cell.

Has less water than the cell and water moves out of the cell. The cells shrink.

WATCH VIDEO OF NORMAL RBCs SUBJECTED TO A HYPERTONIC SOLUTION

Hypertonic Solution

Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (High solute; Low water)

Result: Water moves from inside the cell into the solution: Cell shrinks (Plasmolysis/crenation)!

• Osmosis Animations for

isotonic, hypertonic, and

hypotonic solutions

shrinks

Hypotonic Solution A hypotonic solution contains

less solute (thus, more water) than the cytoplasm of the cells.

The water will move into the cells resulting in the swelling and lysis of the cells. 

WATCH VIDEO OF CRENATED RBCs SUBJECTED TO A HYPOTONIC SOLUTION

Hypotonic Solution

Hypotonic: The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water)

Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)!

• Osmosis Animations for

isotonic, hypertonic, and

hypotonic solutions

Let’s take a closer look!

http://www.coolschool.ca/lor/BI12/unit4/U04L06/rbc.html

What type of solution are these cells in?

A CB

Hypertonic Isotonic Hypotonic

Summary What is osmosis?

Is osmosis considered passive or active transport?

What are the 3 types of solutions involved in osmosis?

○ 1.○ 2.○ 3.

How well did you do today?What is Osmosis?A. The movement of molecules.B. The movement of molecules from an

area of high concentration to low concentration.

C. The movement of water from a low concentration to a high concentration.

D.The movement of water from a high concentration to a low concentration.