-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membrane*Binds to helical structure of starch (iodines are the
faded purple spheres above), turning the substance or solution a
blue/black, but only binds because structure is helical. Therefore,
will it bind to glucose? explain Lugols solution (essentially
iodine)No, it isnt helical and therefore the solution will not turn
blue-black.
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membraneConclusion: Lugols solution is a starch indicatorLugols
solution (essentially iodine)What is lugols iodine solution?
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membraneDialysis tubing (see below)1. Making the model cellA
synthetic membrane that has microscopic pores (holes) that only let
molecules of a certain size or smaller to pass. The one we are
using only allows monomers or smaller molecules to pass.
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membraneDialysis tubingIf you soak it in water, you will be able to
open up the tubing to put solution inside. Before you can do this,
however, you must1. Making the model cellA synthetic membrane that
has microscopic pores (holes) that only let molecules of a certain
size or smaller to pass. The one we are using only allows monomers
or smaller molecules to pass.
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membraneDialysis tubing1. Making the model cellA synthetic membrane
that has microscopic pores (holes) that only let molecules of a
certain size or smaller to pass. The one we are using only allows
monomers or smaller molecules to pass.
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membraneDialysis tubingArtificial CellThen put glucose and starch
solution in bagGlucose, starch, water1. Making the model cellA
synthetic membrane that has microscopic pores (holes) that only let
molecules of a certain size or smaller to pass. The one we are
using only allows monomers or smaller molecules to pass.
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable membrane2.
Place the model cell into a solution containing lugols
(iodine).Artificial CellGlucose, starch, waterPredict what should
happen:1. The glucose should diffuse out down its concentration
gradient and the iodine should diffuse in down its concentration
gradient since both can pass through the membrane pores. The starch
should stay in too large to pass through pores. Water should
diffuse in and out direction will depend on how much solute you
dissolved in the water.2. How will you observe that the iodine went
in?I-I-I-I-I-I-I-The outside should remain amber (the color of
lugols) since there is no starch present to react with it. 4. How
do we observe that glucose diffused out?The iodine should bind to
the helical starch structure causing the solution inside the
dialysis tubing to turn blue-black.3. How will you observe that the
starch did not diffuse out?
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membraneUse Benedicts solution- Benedicts is a molecule that
reflects blue light that will react with monosaccharides, lactose
and maltose and convert into a molecule that reflects yellow/orange
light. The reaction is endergonic. How we can we get it to happen?
You must heat the Benedicts in the presence of the sugars. Input
ENERGY!
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable membrane2.
Place the model cell into a solution containing lugols
(iodine).Artificial CellGlucose, starch, waterHow do we observe
that glucose diffused out?Take a sample of the outer solution into
a clean test tube, add a few drops of benedicts, and heat it up. If
it turns orange then it diffused out.I-I-I-I-I-I-I-Time to do
it!
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membraneArtificial CellGlucose, starch, waterTake a sample of the
outer solution into a clean test tube, add a few drops of
benedicts, and heat it up. If it turns orange then it diffused
out.I-I-I-I-I-I-I-Time to do it!Q. You have a solution containing
1mM catalase. The pH of the solution is around 6.8 and the salt
(NaCl) concentration is around 400 mM (milli Molar). However, you
have previously determined that this protein functions best at a pH
of 5.7 and a salt concentration of 250 mM. Explain how you can get
your protein into the desired conditions without changing the
concentration of the enzyme much.
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable membraneQ.
You have a solution containing 1mM catalase. The pH of the solution
is around 6.8 and the salt (NaCl) concentration is around 400 mM
(milli Molar). However, you have previously determined that this
protein functions best at a pH of 5.7 and a salt concentration of
250 mM. Explain how you can get your protein into the desired
conditions without changing the concentration of the enzyme
much.
-
Diffusion Through a Membrane State LabPart 1 Build a model cell
and demonstrate diffusion across a selectively permeable
membraneCatalase solution with pH 6.8 and 400mM NaClA. Use a
dialysis tube. Put your protein solution into the dialysis membrane
and tie it off. Place the membrane into the desired solution. Salt
will diffuse out and H+ will diffuse in. Protein will stay inside
as it is too large to fit through poresThis is called Buffer
ExchangeQ. You have a solution containing 1mM catalase. The pH of
the solution is around 6.8 and the salt (NaCl) concentration is
around 400 mM (milliMolar). However, you have previously determined
that this protein functions best at a pH of 5.7 and a salt
concentration of 250 mM. Explain how you can get your protein into
the desired conditions without changing the concentration of the
enzyme much.Aqueous solution with pH 5.7 and 250 mM NaCl
-
Diffusion Through a Membrane State LabPart 2 Demonstrate
diffusion of water across a real membrane (osmosis)Red onion cells
in water (turgid)You want to observe the effect of salt on osmosis
across the plasma membrane of red onion cells under the light
microscope. How will you do this? You look at the cells in water
first. This is your______________.What will you do next?Add salt to
the solution that the cells are in. What would you expect to happen
and why?control groupAll of the cells should be
_____________.turgid
-
Diffusion Through a Membrane State LabPart 2 Demonstrate
diffusion of water across a real membrane (osmosis)Red onion cells
in water (turgid)plasmolysisOsmosis (diffusion of water) should
occur from inside the cell [high] to outside [low] since the salt
CANNOT cross the membrane and will cause the water concentration
outside the cell to now lower than insideyou should observe
plasmolysis. How do we make these cells turgid again?Add salt
(NaCl)
-
Diffusion Through a Membrane State LabPart 2 Demonstrate
diffusion of water across a real membrane (osmosis)Red onion cells
in water (turgid)plasmolysisPut them back into tap water (get rid
of the salt).Remove salt (NaCl)
-
Diffusion Through a Membrane State LabPart 2 Demonstrate
diffusion of water across a real membrane (osmosis)Red onion cells
in water (turgid)plasmolysisRemember: This is a real cell membrane
(phospholipid bilayer with integral membrane protein), which will
only allow small hydrophobic molecules to pass (you should know
why). Sodium chloride (Na+, Cl-) is charged and hence
hydrophilic.Remove salt (NaCl)
********Mess with them about the color change*****Mess with them
about the color change*Mess with them about the color change*Mess
with them about the color change*Mess with them about the color
change