Diffusion through a Membrane Simulation
Feb 16, 2016
The cell loses water through osmosis as it tries to create a ratio
of water:salt inside the cell that matches the
outside
If salt water is added, there will be
more salt outside the cell than in.
Diffusion and Osmosis
• Designed to help you understand the concepts of Diffusion and Osmosis and how these cell processes effect the cell;
• Define: diffusion, osmosis, hypertonic, isotonic, hypotonic, saline, selectively permeable, molecule size;
Part 1: Diffusion• Diffusion: movement of molecules from an area of
high concentration to an area of low concentration along the concentration gradient.
• Example is when you put your Lugol’s solution into the water and the water began to turn the “rust/tea” color.
Before diffusion occurs… After diffusion occurs…
Part 2: Create a “cell”• Soak 10 inches of dialysis tubing;• Tie knot in one end;• Put 10mL of glucose solution in and 20mL of starch solution in;• Pinch/clamp closed and put into cellular environment (Lugol’s and
water) for 15 minutes;• Observe the changes and infer what happened
Insert into “cellular
environment”
Wait about 15 minutes
and observe.
After 15 minutes, observe…
• What happened to the glucose in the “cell”? …the starch in the “cell”? …the Lugol’s iodine outside the “cell”? Why?
Starch solution (S)
Iodine solution (I)Glucose solution (G)
G
S
I
IG
S
I
I
G
GG
G
S S
At the beginning… After 15 minutes…
II
I
I
And now, the part that makes you cry (ok, not really, but the “Red Onion” part of the lab)…
• Prepare a wet mount slide of the inner epidermis of a red onion section;
• Observe the red onion and draw what you see;
• Add a couple of drops of saline (salt) solution to the epidermis. Wait 5 minutes;
• Observe under microscope again, note any changes;
• Add freshwater to the slide, wait 5 minutes, observe changes again.
Red Onion Plasmolysis Observation• Before and after observations of red onion
epidermis under the microscope (400X)
Red onion under in isotonic (normal) solution. Note cell membrane and cytoplasm almost completely “fill” the boundary of the cell wall.
Red onion under in hypertonic (salt) solution. Note cell membrane has “withdrawn” and the cytoplasm has lost water to the salty environment, making it appear smaller and darker.
4. Why does the inside of the “cell” turn purple or black?
Starch indicator diffused into the tubing
High s.i.conc.Low s.i. conc.
6. How can we find out if glucose moved into the beaker?
Glucose (high conc.)
?
Do a glucose indicator test using the fluid in the beaker
7. After placing 10 drops of the amber solution into a test tube, what do we add to it?
Glucose indicator
9. If there is glucose in the solution, what will happen to the blue color after heating the tube for 2 minutes?
The color changes
11. Glucose indicator solution was added to these test tubes, and then the tubes were heated. Which will change color?
starch glucose C6H12O6
“Making Connections” NYSED Lab
The new NYSED monument, possibly?
(LE teacher humor, you wouldn’t understand…)
How many times in one minute can you squeeze a
clothespin??• An interesting take on the
entire lactic acid build-up argument.
First, Look for a pattern…
Taking your pulse is rather simple. Use the index and middle finger of one hand to palpate (feel) the arterial pulse in your radial artery on your wrist. Count for 15 seconds and multiply by 4 to determine the number of times your heart beats in one minute.
Pulse RateTrial #1 ____X 4 = _____ bpm
Trial #1 ____X 4 = _____ bpm
Trial #1 ____X 4 = _____ bpm
Note: The NYSED “Making Connections” Lab measures for 20
seconds and multiplies by 3, but any calculation that leads to a
count of 60 seconds is acceptable.
Collect “Class Data” and prepare a “histogram” of your results…
Pulse Rate per minute (range of averages)
<51 51-60 61-70 71-80 81-90 >90
Number of students in this range
And now, develop and draw your histogram…
<51 51-60 61-70 71-80 81-90 >90
Average Pulse Rate Range
And now, make a hypothesis…
Student AIf you exercise first, then you should be able to squeeze a clothespin more times in one minute.
Student BIf you rest first, then you should be able to squeeze a clothespin more times in one minute.
Explain why… Explain why…
Now, do your “experiment” and collect your data…
3... 2… 1… GO!!! Start counting the number of Squeezes for one FULL minute and record your data.
What is the “goal” of the lab?
• Demonstrate how Darwin’s Finches (those that he observed on the Galapagos Islands) have adapted new beaks yet remain similar to the shared common ancestor that most likely came from the mainland.
Required Supplies for “B of F”A randomly assigned “beak”
Timer
Petri dish
Small seed island
Large seed island
Round 1
• Only one seed at a time may be eaten. To be “eaten” it must land inside your stomach.
• If you scoop seeds or eat more than one at a time, you “choke” and vomit all of your seeds out.
• Average is taken from four trials, 60 seconds each.
And now, Round 1…Seeds Collected
Partner #1 Trial #1
Partner #1 Trial #2
Partner #2 Trial #3
Partner #2 Trial #4
Average
Did you average over 13 seeds?
YES NO
Go to Round 2 Increased
Competition
Repeat Round 1 on the “big seed”
island with the same beak
Successful in Round 1? Welcome to Round 2!!!
Seeds Collected
Partner #1 Trial #1
Partner #1 Trial #2
Partner #2 Trial #3
Partner #2 Trial #4
Average
Repeat the same procedure but this time have another “bird” to compete against!
Compete the table and move on to Round 3 where there is “Increased Competition” if you average over 13 seeds.
Round 2 - Increased Competition
Unsuccessful in Round 1?Seeds Collected
Partner #1 Trial #1
Partner #1 Trial #2
Partner #2 Trial #3
Partner #2 Trial #4
Average
Did you average over 13 seeds this time?
YES NO
Go to Round 2, but with another large
seed eater as competition on the “large seed” island
Get a new “beak” and try yet again(not a possibility
in nature)
Go to a “large seed” island and start over (even though you have starved to death, you are resurrected)
Successful in Round 2?Welcome to Round 3!!
Increased Competition (more than 1 other bird)
Seeds Collected
Partner #1
Trial #1
Partner #1
Trial #2
Partner #2
Trial #3
Partner #2
Trial #4
Average
Repeat the same procedure but this time have even more birds to compete against!
Don’t fret. It is almost over!
Not successful in Round 2?
“Here endeth the lesson…”
So, what did you learn?• Birds have evolved many different mechanisms and
modifications that make them more well-adapted to the environment in which they live.
• Structural differences (in beaks) are significant enough to make you into a new species, but you did descend from a common ancestor.
• The adaptations that are contribute to the most success allow that individual to survive and reproduce.
• The adaptations that are contribute to a lack of success are not passed on since they either starve or have no “breeding rights”.
Relationships and
Biodiversity NYSED Lab
Review
Please note:• “Curol” is a fictitious plant extract mentioned in
the NYSED lab that has the ability to effectively treat cancer. IT DOES NOT EXIST. Likewise, any “Curol” images included in this presentation are simply images taken from an internet search and are not a cancer cure. It is simply a product found with a similar name. I do not know what it is used for as the website was not translated into the English language.
What does this lab entail?
• Seven tests that look at the physical, chemical, and microscopic characteristics of three plants that may be able to create Curol, even though they are not Botana curus (the plants that does produce it).
• Comparison of data to determine relationships.
• Define the crucial need for biodiversity.
Test 1 - Structural Characteristics of Plants
Species Y
Species Z
Species X
Botana curus
QUESTION:
Which leaves most closely resemble the leaves produced by Botana curus?
Record your observations in the data table.
Test 2 – Structural Characteristics of Seeds
Botana curus seeds Species X seeds
Species Y seedsSpecies Z seeds
QUESTION:
Which seeds most closely resemble the seeds produced by Botana curus?
Record your observations in the data table.
Test 3 – Microscopic Internal Structures of Stems
QUESTION:
Which stem structures most closely resemble the stem structures of Botana curus?
Record your observations in the data table.
Species Y Species Z
Botana curus Species X
Test 4 – Paper Chromatography to Separate Plant Pigments
“Spot” your chromatography paper and label it with a pencil.
B.curus X Y Z
Water migrates up paper via
capillary action and carries
plant pigments with it.
B.curus X Y Z
Test 5 – Indicator Tests for Enzyme M
Botana curus
Species X
Species Y
Species Z
Put two drops of each plant Extract in separate wells of
the well tray.
Indicator Enzyme
M
Botana curus(“fizzed” a little)
Species X(no “fizz”)
Species Y(“fizzed” a little)
Species Z(“fizzed” a little)
Add a small sprinkle of “Indicator
Enzyme M”
Record your results.
Test 6 – Using Simulated Gel Electrophoresis to Compare DNA
Botana curus A T T C C G G A T C G A T C G C C G G A T A T A C T C C G G T A A T A T C
Species X A T T G T A C C G G G A T C C G G A C G T C G C G A C T A A T A T A G C A
Species Y A C C G G T C C G G G A T C G C A C C C G G T A C T C C T G T A A T A T C
Species Z A T T C C G G A T C G A T C G C C G G A T A T T C T C C G G T A A T A T
The strips below represent the DNA strands extracted from each plant (B. curus, X, Y, and Z). Each strand will be “cut” between a double C/double G. Therefore, lines are drawn below where each strip should be cut. Then, count up the number of bases and paste appropriately in the simulated Gel Electrophoresis table on the next slide.
Simulated Gel Electrophoresis# of
BasesBotana curus Species X Species Y Species Z
24
23
22 G G A C G T C G C G A C T A A T A T A G C A
21
20
19
18
17 G G T A C T C C T G T A A T A T C
16
15
14
13
12 G G A T C G A T C G C C G G G A T C G C A C C C G G A T C G A T C G C C
11 G G A T A T A C T C C G G A T A T A C T C C
10
9 G G T A A T A T C G G T A A T A T C
8 A T T G T A C C
7 G G G A T C C
6
5 A T T C C G G T C C A T T C C
4
3 A C C
2
1
-
+
Test 7 – Molecular Evidence for Relationships
Botana curus CAC GTG GAC TGA GGA CTC CTC
mRNA GUG CAC CUG ACU CCU GAG GAG
Amino acid Val His Leu Thr Pro Glu Glu
Species X CAC GTG GAC AGA GGA CAC CTC
mRNA GUG CAC CUG UCU CCU GUG GAG
Amino acid Val His Leu Ser Pro Val Glu
Species Y CAC GTG GAC AGA GGA CAC CTC
mRNA GUG CAC CUG UCU CCU GUG GAG
Amino acid Val His Leu Ser Pro Val Glu
Species Z CAC GTA GAC TGA GGA CTT CTC
mRNA GUG CAC CUG ACU CCU GAA GAG
Amino acid Val His Leu Thr Pro Glu Glu
And where did you get those Amino Acids from???
Your friend and mine… The Universal Genetic Code Chart
So, what is the closest and most probable alternative source for Curol???
Test Most similar to Botana curus?
Test 1 – Structural Characteristics of Plants Species Z as it has the same kind of parallel veination in the leaves.
Test 2 - Structural Characteristics of Seeds Species Z seeds are flat and striped, much the same as Botana curus seeds are.
Test 3 – Microscopic Internal Structure of Stems Species Z vascular bundles closely resemble those of Botana curus.
Test 4 – Paper Chromatography of Pigments Species Z and Botana curus share a similar pattern of pigmentation in paper chromatography.
Test 5 – Indicator Tests for Enzyme M While many “fizzed”, once again Species Z and Botana curus reacted the same.
Test 6 – Simulated Gel Electrophoresis Identical banding pattern in both Botana curus and Species Z.
Test 7 – Amino Acid Comparison Species Z and Botana curus have the most similarities.