Diffusion & OsmosisDiffusion & Osmosis

Define Diffusion Define Diffusion

Define DiffusionDefine Diffusion

The movement of molecules from a The movement of molecules from a area in which they are highly area in which they are highly concentrated to a area in which they concentrated to a area in which they are less concentrated. are less concentrated.

Draw a diagram of an Draw a diagram of an example of diffusion we example of diffusion we

saw in class.saw in class.

Draw a diagram of an example of Draw a diagram of an example of diffusion we saw in class.diffusion we saw in class.

Define osmosisDefine osmosis

Define osmosisDefine osmosis

The diffusion of The diffusion of waterwater across a across a selectively permeable selectively permeable membranemembrane. .

Define osmosisDefine osmosis    Water moves from a high Water moves from a high

concentration of water (less salt or concentration of water (less salt or sugar dissolved in it) to a low sugar dissolved in it) to a low concentration of water (more salt or concentration of water (more salt or sugar dissolved in it).  This means sugar dissolved in it).  This means that water would cross a selectively that water would cross a selectively permeable membrane from a dilute permeable membrane from a dilute solution (less dissolved in it) to a solution (less dissolved in it) to a concentrated solution (more concentrated solution (more dissolved in it).dissolved in it).

Define osmosisDefine osmosis

Define osmosisDefine osmosis In this picture a red blood In this picture a red blood

cell is put in a glass of cell is put in a glass of distilled water (all water distilled water (all water with no salt or sugar in it).  with no salt or sugar in it).  Because there is a higher Because there is a higher concentration of water concentration of water outside the cell, water outside the cell, water enters the cell by enters the cell by OSMOSISOSMOSIS.  In this case too .  In this case too much water enters and the much water enters and the cell swells to the point of cell swells to the point of bursting open.  In the end bursting open.  In the end pieces of cell membrane pieces of cell membrane are left in the water. are left in the water.

Define selectively permeable Define selectively permeable membranemembrane

A membrane that allows only certain A membrane that allows only certain materials to cross it materials to cross it

Materials pass through Materials pass through porespores in the in the membranemembrane

Two terms to study in Two terms to study in this processthis process

Hypertonic - HypotonicHypertonic - Hypotonic

What is Hypertonic ?What is Hypertonic ?• hypertonic is a solution which contains more hypertonic is a solution which contains more

solvent than solute (example: purified water--solvent than solute (example: purified water--there's almost no solute dissolved in the there's almost no solute dissolved in the solvent(water)solvent(water)

What is Hypotonic? What is Hypotonic? A solution with a lower A solution with a lower salt concentration than in concentration than in

normal cells of the body and the blood. As normal cells of the body and the blood. As opposed to an opposed to an isotonic solution or a or a hypertonic solution..

Why are osmosis & diffusion Why are osmosis & diffusion important?important?

All living things have certain requirements All living things have certain requirements they must satisfy in order to remain alive – they must satisfy in order to remain alive – maintain maintain homeostasishomeostasis

These include exchanging gases (usually These include exchanging gases (usually CO2 and O2), taking in water, minerals, CO2 and O2), taking in water, minerals, and food, and eliminating wastes. and food, and eliminating wastes.

These tasks happen at the cellular level.These tasks happen at the cellular level. Molecules move through the cell Molecules move through the cell

membrane by diffusionmembrane by diffusion

Why are osmosis & diffusion Why are osmosis & diffusion important?important?

All living things have certain All living things have certain requirements they must satisfy in requirements they must satisfy in order to remain alive. These include order to remain alive. These include exchanging gases (usually CO2 and exchanging gases (usually CO2 and O2), taking in water, minerals, and O2), taking in water, minerals, and food, and eliminating wastes. These food, and eliminating wastes. These tasks ultimately occur at the cellular tasks ultimately occur at the cellular level, and require that molecules level, and require that molecules move through the membrane that move through the membrane that surrounds the cell. surrounds the cell.

Why are osmosis & diffusion Why are osmosis & diffusion important?important?

This membrane is a complex This membrane is a complex structure that is responsible for structure that is responsible for separating the contents of the cell separating the contents of the cell from its surroundings, for controlling from its surroundings, for controlling the movement of materials into and the movement of materials into and out of the cell, and for interacting out of the cell, and for interacting with the environment surrounding with the environment surrounding the cell. the cell.

CLASSWORKCLASSWORK

ANSWER THE FOLLOWING QUESTIONSANSWER THE FOLLOWING QUESTIONS 1. What is osmosis?1. What is osmosis? 2. What is passive transport?2. What is passive transport? 3. What happens in exocytosis?3. What happens in exocytosis? 4. What is endocytosis, what happens?4. What is endocytosis, what happens? 5. Make an illustration explaining each one of them.5. Make an illustration explaining each one of them. 6. What happens during osmosis?6. What happens during osmosis? 7. Why is diffusion important?7. Why is diffusion important? 8. Why is osmosis important?8. Why is osmosis important?

THANK YOUTHANK YOU