Unit 3 Lecture 3. Diffusion Diffusion movement of substances from an area of high concentration to an area of low concentration works to balance the.

Unit 3 – Lecture 3

DiffusionDiffusion – movement of substances from an

area of high concentration to an area of low concentration

works to balance the concentration gradients of substances

ex: perfume in a room, dye in a glass of water…

Diffusion – cont’dConcentration Gradient – difference in

concentration of a substance over a certain area

“with/down” the gradient = particles move from area of high conc. to low conc.typical diffusion; natural movement

“against” the gradient = particles move from area of low conc. to high conc.non-natural movement; requires E

Diffusion – cont’dDynamic Equilibrium – a balance of the

distribution of particles in an area acknowledging the constant movement of the particles

dynamic – opposite of sta(tic/sis)indicates constant change

Diffusion – cont’dDiffusion often occurs through one of two types

of membranes:permeable membrane

allows all molecules [solute, solvent, or other particle] to pass through

semi/selectively permeable membraneallows only certain substances to pass

throughwhich type of membrane do cells have?

Diffusion DrawingsProblem: In a membrane selectively

permeable to X molecules, there are:4 particles of X [3 left, 1 right]12 particles of O [2 left, 10 right]

Based on the given information, identify & understand the type of membrane draw before & after beaker with membrane

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

Based on the given information, identify & understand the type of membrane draw before & after beakers with membrane

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

before beaker:under beaker, record # of particles per sidedraw # particles in beaker

X = 3 X= 1O = 2 O = 10

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

before beaker:determine directions of particle movement

X = 3 X= 1O = 2 O = 10

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

before beaker:above, draw arrows specifying how particles

will move

X = 3 X= 1O = 2 O = 10

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

before beaker:large arrow = larger movement [specify type of

particle]

X = 3 X= 1O = 2 O = 10

X

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

before beaker:small arrow = smaller movement [specify type

of particle]

X = 3 X= 1O = 2 O = 10

X

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

after beaker:under beaker, record new # of particles per

side

X = 3 X= 1O = 2 O = 10

X

X = 2 X= 2O = 2 O = 10

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

after beaker:draw # of particles in beakers

X = 3 X= 1O = 2 O = 10

X

X = 2 X= 2O = 2 O = 10

Problem: In a membrane selectively permeable to X molecules, there are: 4 particles of X [3 left, 1 right]; 12 particles of O [2 left, 10 right]

after beaker:draw appropriate arrows [specify type of

particle]

X = 3 X= 1O = 2 O = 10

X

X = 2 X= 2O = 2 O = 10

X

OsmosisOsmosis – diffusion of water across a

selectively permeable membranemembrane allows ONLY water to go through

solute particles NEVER movewater must be used to reach dynamic

equilibriummore water moves to where there is more

solute

Osmosis – cont’dEx: which has the higher concentration of solute?

how can you make the concentrations equal?

5 scoops of lemonade in a pitcher filled with 8 ounces of water5 scoops of lemonade in a pitcher filled with 1 gallon of water

Osmosis DrawingsProblem: With a membrane selectively

permeable to water, there are:4 particles of X [3 left, 1 right]

Based on the given information, identify & understand the type of membrane draw before & after tubes with membrane

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

Based on the given information, identify & understand the type of membrane draw before & after tubes with membrane

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

before tube:under tube, record # of particles per sidedraw # particles in tube

X = 3 X= 1

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

before tube:determine directions of particle movement

X = 3 X= 1

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

before tube:above, draw arrows specifying how particles

will move

X = 3 X= 1

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

before tube:large arrow = larger movement [specify type of

particle]

X = 3 X= 1

H2O

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

before tube:small arrow = smaller movement [specify type

of particle]

X = 3 X= 1

H2O

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

after tube:under tube, record # of particles per side

X = 3 X= 1

H2O

X = 3 X= 1

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

after tube:draw # of particles in beakers AND water level

X = 3 X= 1

H2O

X = 3 X= 1

Problem: With a membrane selectively permeable to water, there are: 4 particles of X [3 left, 1 right]

after tube:draw appropriate arrows [specify type of

particle]

X = 3 X= 1

H2O

X = 3 X= 1

H2O

What happens to cells?Hypertonic Solution – solution outside of the

cell has a higher concentration of solute than inside of the cell.

“hyper” = more than normalwater moves out of cellcell shrinks

Why is this bad for the cell?

What happens to cells? – cont’dIsotonic Solution – solution outside of the cell

has the same concentration as the solution inside of the cell.

concentrations are equalcell remains the same size

What happens to cells? – cont’dHypotonic Solution – solution outside of the cell

has a lower concentration of solute than inside of the cell.

“hypo” = less than normalwater moves into the cellcell swells [possibly bursts]