Activating Prior Knowledgepathfinder2group3.weebly.com/uploads/4/2/5/3/42535451/...Sodium-Potassium Pump (this allows for nerve function!) 3 Na+ pumped in for every 2 K+ pumped out;

Activating Prior Knowledge

• What is an egg?

• A chicken egg to be

more precise…

• Egg Osmosis

• Soak a chicken egg in

vinegar to

– Remove the cell, and

– Denature the outer protein

• Then you have a big cell

to experiment with!

• View and Interpret

Egg Osmosis Video

After this lesson,

you should be able to

• explain the impact of water on life processes (i.e.,

osmosis, diffusion, SB1d).

• explain the role of the cell membrane, in maintaining

homeostasis (transporting materials in/out of cell).

• Use vocabulary:

– hypertonic, hypotonic, isotonic

– Passive Transport: diffusion, osmosis, facilitated diffusion

– Active Transport: sodium/potassium pump and

endo/exocytosis

Solution Review • Solvent – the larger

material {liquid} that dissolves the solute

• Water is considered the “universal” solvent

• Solute – smaller substance that is dissolved by the solvent. Ex. tea & sugar

• Solution – Complete

mixture of solute and solvent

• Ex. Sweet tea

Quick Check! I mixed Kool-Aid powder in

water. Describe the mixture

using the terms:

solute, solvent, and solution.

Words to know:

Hypertonic

More solute

Hyper means higher

{more concentrated}

Hypotonic

Less solute

Hypo means lower

less concentrated

Isotonic

Solution has

achieved

equilibrium

Equilibrium

achieving

balance or equal

Diffusion Demonstration • Equal volume of cold and

warm water, each in

separate clear cups

• What will happen if we

drop equal amounts of

food coloring in each?

• Let’s try it and observe.

• youtube

• Explain what you see.

• Lead discussion to develop

diffusion definition including

– Movement of a substance

– Random molecular motion

– Kinetic energy

– Concentration gradient

– equilibrium

Diffusion • Movement of substances

from high concentration to

low concentration

• Movement “down a

concentration gradient”

• Due in part to random,

rapid motion of molecules.

• Net Movement

• Equilibrium State

• Simple Diffusion.

• Roles in the Body

• Factors that Affect Rate:

– permeability of membrane

– Size of gradient

– temperature

Passive Transport

• Movement of

materials in & out of

the cell without {NO}

Energy

High Low

Hypertonic hypotonic

Hypertonic

Hypotonic

Diffusion • Passive

• O2, CO2, H2O across

cell membrane

• Smells spreading

• Movement of any

molecules from a high

concentration to a low

concentration.

Osmosis Diffusion of water

across a semi-

permeable

membrane

Osmosis • Diffusion of water through

a selectively permeable membrane.

• Movement of water

– from “less salty” to “more salty” side of membrane

– from low solute concentration to high solute concentration.

– from high water concentration to low water concentration.

• Hypertonic

• Hypotonic

• Isotonic

• In everyday life:

– Preservation of food

– Eating of salty or sugary

foods

– Salt on a slug

– contractile vacuoles

– turgur pressure in plants

Diffusion and Osmosis Experiment

Initial

Contents

Initial

Solution

Color

Final

Solution

Color

Initial

Presence of

Glucose

Final

Presence of

Glucose

Dialysis

Tubing or

Plastic Bag

Beaker or

Clear Cup

OSMOSIS DEMONSTRATION

(DIALYSIS BAGS)

Interpret this experiment!

OSMOSIS IN PLANT CELLS What’s happening to the water in the cell?

HYPERTONIC

SOLUTION=

PLASMOLYSIS

HYPOTONIC SOLUTION=

NORMAL TURGOR

PRESSURE

OSMOSIS IN PLANT CELLS

(Elodea)

Plasmolyzed cells

Solution Concentrations • Isotonic Solution

– When a cell is in a solution that has the same

concentration of water and solutes

• Hypotonic Solution

– A cell is in a solution that has a lower concentration of

solute

• Hypertonic Solution

– A cell is in a solution that has a higher concentration

of solute outside of the cell

Quick Check

Knowing what we know about osmosis,

what would happen to the water in a cell

in:

1. an isotonic solution?

2. a hypotonic solution?

3. a hypertonic solution?

Osmosis • Passive

• Hyper to Hypo

• Diffusion of water

molecules across a

membrane.

• Net movement of

water toward high

solute (hypertonic)

side of membrane

Osmosis and Animal Cells

CRENATION WILL LYSE NO CHANGE

Facilitated Diffusion • Passive

• Diffusion that uses

channel proteins

• Hyper to Hypo

• Large molecules like

glucose

Facilitated Diffusion

• Movement from high concentration to low concentration through carrier proteins.

• Used to move ionic or large substances into or out of cells

• Passive process

• Carrier proteins are

specific (will only

move one substance)

• Important for moving

sugars and amino

acids into cells

Active Transport Low to High

• Movement of materials in & out cell WITH energy

High

Lo

w

Quick Check! What is the main

difference between active

and passive transport?

Ion or Solute pump

• Active

• Protein channel

• hypotonic to

hypertonic

• Ex. Na+ K + pump

• To “pump” means it

uses energy (ATP)

Active Transport

• Movement of substances against a concentration gradient.

– From low concentration to high concentration.

• requires energy

• pumping a substance

• ATP must be hydrolyzed to fuel this process

• Sodium-Potassium Pump

• Pumps sodium out of cells

and potassium into cells.

• Important for the

functioning of nerves and

muscles.

• Pump is a membrane

protein and an enzyme--

ATPase.

Sodium-Potassium Pump

(this allows for nerve function!)

3 Na+ pumped in for every 2 K+ pumped out; creates a membrane potential

Moving the “Big Stuff”

Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.

Exocytosis

- moving things out.

This is how many hormones are secreted and how nerve cells communicate with one another.

Pinocytosis

• Cell forms an invagination

• Materials dissolve in water to be brought into cell

• Called “Cell Drinking”

Endocytosis – Phagocytosis

Used to engulf large particles such as food, bacteria, etc. into vesicles

Called “Cell Eating”

Three Forms of Transport Across the Membrane

Cellular Transport

On-Line Tutorial (11 slides with animated molecules moving across cell

membrane; includes quiz questions along the way)

• ANOTHER ONLINE

TUTORIAL

Closing Challenge – Create a “Cell Transport Concept Map” with these words:

Active Transport ATP

Cell Transport Concentration Gradient

Diffusion Endocytosis Exocytosis

Facilitated Diffusion

Passive Transport Osmosis

O2, CO2, H2O glucose

Na+ & K+ ions