Regents Lab Review

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 Note cell membrane has “withdrawn” and the cytoplasm has lost water to the salty environment, making it appear smaller and darker.

The Beaks of Finches NYSED Lab

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

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 TC

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???AAU

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.

And the winner is…..

Species Z