Molecules in solids, liquids, and gases are always moving. In which state of matter are molecules moving the fastest?

• GasSlowest?

• Solid

• http://www.harcourtschool.com/activity/states_of_matter/

Some things to consider before we start

Substances must go through the cell membranecell membrane in order to get in or out of a cell.

Some things to consider before we start

• What substances need to go IN to a cell?– Water, food/glucose/, oxygenWater, food/glucose/, oxygen

• What substances need to go OUT of a cell? – Wastes, carbon dioxideWastes, carbon dioxide

• Cell Membrane Movie

Some things to consider before we start

CELL MEMBRANES• … are selectively permeable, which

means that they allow some substances to pass through but not others.

• Selective means “choosy” and • Permeable means “to go through”

Cell Transport Videohttps://app.discoveryeducation.com/search?Ntt=cell+transport

AIM : Cell Transport – Passive Transport

Do Now:What would happen if cell membrane was fully permeable to all substances in the cell’s environment?

Diffusion

• Molecules will always move from an area where they are moremore CONCENTRATED to an area where they are lessless CONCENTRATED. This is called diffusiondiffusion.

What does concentrated mean?

• How many particles are packed in an area

D iffusion continues until the molecules of a substance are evenly distributed in an area.

• This state of “evenly spread” is called equilibrium.

• Do molecules stop moving once equilibrium is reached?

• NOhttp://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

http://www.wisc-online.com/objects/index_tj.asp?objid=AP1903

Diffusion by Brainpop

… is a special kind of diffusion that is very important to living things.Osmosis is the diffusion of water through a selectively permeable membrane. This is the manner in which water gets into and out of cells.

Animation: How Osmosis Works

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

• Water molecules will naturally flow from an area in which the water molecules are in greater numbers to an area where they are in fewer numbers.

http://www.biologycorner.com/bio1/diffusion.html

• Which way are water molecules moving when a plant begins to wilt?

• Out of the cells

Passive transport requires no ENERGY from the cell.Diffusion and osmosis are examples of

passive transport. Molecules in the cell membrane called

transport proteins help to move LARGER molecules into or out of the cell. This still does not require energy. Think of this as being like taking a ferry ride without having to pay. This is called Facilitated transport

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion_works.html

facilitated transport

AIM : What is Active Transport ?

Do Now Predict Outcome – What would happen if the cell was exposed to a drug that disabled the transport proteins in the cell membrane?

Active transport requires ENERGY and uses transport

proteins in the cell membrane.

Used when cells need to move substances from areas of lower concentration to an area of higher concentration. This is the opposite of DIFFUSION and requires energy.

Other types of active transportendocytosisendocytosis o Endocytosis occurs when VERY LARGE

THINGS need to move INTO a cell. o A vesicle fuses to the cell membrane

and then releases an object into the cell.

o A white blood cell “eating” a BACTERIA would be an example of endocytosis.

o What does “endo” mean? “IN”

Exocytosiso Occurs when VERY LARGE molecules

need to move OUT of a cell.o A vesicle fuses to the cell membrane

and then releases an object out of the cell.

o An example of exocytosis is when proteins packaged by the GOLGI BODIES need to move out of the cell, to get to another cell.

o What does “exo” mean? OUT OF

Let’s get some practice:Tell if each of the following as diffusion, osmosis, facilitated transport, active transport, endocytosis, or exocytosis.

• Large waste molecules stored in vacuoles need to be moved out of a cell:

• exocytosis

Water concentration outside a cell is 85%. Water concentration inside the cell is 70%. Water flows into the cell:

• Osmosis

70%85%

• You can smell the cookies baking in the oven even before you enter the kitchen:

• Diffusion

The concentration of Na ions outside the cell is 10%. The concentration of Na ions inside the cell is 25%. Na ions move into the cell.

• Active Transport

25%

10%

A one-celled organism “eats” another one-celled organism:

• Endocytosis

• Glucose molecules are helped to move into the cell by transport proteins in the cell membrane, but no energy is used to do this:

• Facilitated transport

Great Animationhttp://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html

Some additional facts about cell transport:

Simple Diffusion – only small, nonpolar molecules e.g. Oxygen, Carbon Dioxide, Steroid Hormones.Facilitated diffusion – Ions and polar molecules e.g. sugars, amino acids, water. Uses two types of transport proteins –Channel proteins and carrier proteins.

AIM : What are solutions ?

Do Now : Predict what would happen to the concentration of the solution if we will add more of a substance dissolved in it ?

Solution• a mixture of two or more substances

that is identical throughout• can be physically separated• composed of solutes and solvents

the substance in the smallest

amount and the one that dissolves in the

solvent

the substance in the larger

amount that dissolves the solute

milk, fog, jello are considered solutions

Iced Tea Mix(solute)

Water(solvent)

Iced Tea(solution)

Salt water is considered a

solution. How can it be physically separated?

Solutes Change Solvents

• The amount of solute in a solution determines how much the physical properties of the solvent are changed

• Examples:

Lowering the Freezing Point

The freezing point of a liquid solvent decreases when a solute is dissolved in it.

Ex. Pure water freezes at 320F (00C), but when salt is dissolved in it, the freezing point is lowered.

This is why people use salt to melt ice.

Raising the Boiling Point

The boiling point of a solution is higher than the boiling point of the solvent.

Therefore, a solution can remain a liquid at a higher temperature than its pure solvent.

Ex. The boiling point of pure water is 2120F (1000C), but when salt is dissolved in it, the boiling

point is higher. This is why it takes salt water longer to boil than fresh water.

Concentration • the amount of solute dissolved in a

solvent at a given temperature

•described as dilute or unsaturated if it has a low concentration of solute

•described as saturated if it has a high concentration of solute

•described as supersaturated if contains more dissolved solute than normally possible

Solubility• the amount of solute that dissolves

in a certain amount of a solvent at a given temperature and pressure to produce a saturated solution

• influenced by:Temperature Pressure

Solids increased temperature causes them to be more soluble and vice versa

Gases increased temperature causes them to be less soluble and vice versa

Ex. Iced Coffee

Solids increased pressure has no effect on solubility

Gases increased pressure causes them to be more soluble and vice versa

Ex. Soda,

AIM : How can we use solubility curves?DO NOW :Explain why it would be possible to dissolve much more NaCl in hot water than in cold water?Because an increase in temperture will increase the solubility of the substance.

Solubility curve

Saturated

Unsaturated

Supersaturated

Solubility curve• Any point on a line

represents a saturated solution.

• In a saturated solution, the solvent contains the maximum amount of solute.

• Example

• At 90oC, 40 g of NaCl(s) in 100g H2O(l) represent a saturated solution.

Solubility curve• Any point below a line

represents an unsaturated solution.

• In an unsaturated solution, the solvent contains less than the maximum amount of solute.

• Example• At 90oC, 30 g of NaCl(s) in

100g H2O(l) represent an unsaturated solution. 10 g of NaCl(s) have to be added to make the solution saturated.

Summary :1. Name a solute and a solvent in following solutions :Sugar Water , Club Soda, Sea Water.

2. A solution that contains less solute than it can hold at a given temperature is said to be ________________3. Name two factors that affect solubility.