1. Unit 2: Cell Transport Objectives:
2.A.3: Organisms must exchange matter with the environment to grow, reproduce and maintain organization.
Surface area-to-volume ratios affect a biological system’s ability to obtain necessary resources or eliminate waste products
2.B.1: Cell membranes are selectively permeable due to their structure.
2.B.2: Growth and dynamic homeostasis are maintained by the constant movement of molecules across membranes.
2.B.3: Eukaryotic cells maintain internal membranes that partition the cell into specialized regions.
4.A.1: The subcomponents of biological molecules and their sequence determine the properties of that molecule.
4.A.2: The structure and function of subcellular components, and their interactions, provide essential cellular processes.

2. Unit 2: Cell Transport Homework: 10 Key Ideas: Section 5.3
Warm-UP: Homeostasis is the effort by life to stay the same even when the environment is changing. Think of an example: What does your body do to maintain homeostasis?
Homework: 10 Key Ideas: Section 5.3

3. Unit 2: Cell Transport
Big Idea: Cells are surrounded by a selectively permeable membrane made of phospholipids and proteins whose structure determines how cells exchange matter with the environment. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.

4. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
The 4 Biomolecules: a molecule made by a living thing
protein– ex: hemoglobin, actin, pepsin, glut-4 transporter
carbohydrate– sugars and starch
nucleic acid– DNA and RNA
lipid– fats, phospholipid

5. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”
fatty acid: saturated

6. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

7. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”
fatty acid: saturated
Can you make this unsaturated?

8. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”
glycerol

9. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.

10. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

11. Compare the two molecules. Similarities and differences?
Warm-UP:
Compare the two molecules. Similarities and differences?
The phospholipid is called amphipathic (polar and non-polar). Explain how?
Why does being amphipathic help it be an ideal molecule for making a cell membrane?
Figure 5.13 The structure of a phospholipid

12. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

13. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

14. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment. O
-O-P=O

15. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

16. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

17. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

18. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

19. Cells are surrounded by a selectively permeable membrane made of phospholipids whose structure determines how cells exchange matter with the environment.
Lipid
hydrophobic and nonsoluble: dominated by hydrocarbon chains
non-ionic and nonpolar covalent bonds
cannot form hydrogen bonds with water
exhibit equal or near equal sharing of e-
2 Types:
fats
long term storage
glycerol head, 3 fatty acid tails
high potential energy bonds (lots of C-H bonds)
saturated (most potential energy): maximum number of C-H bonds; no C-C double bonds
unsaturated (less potential energy): some C-C double bonds, so less C-H bonds
phospholipid
amphipathic: half hydrophobic, half hydrophilic
glycerol head, 2 fatty acid tails (hydrophobic), phosphate group (hydrophilic)
make up the cell membrane: a “bilayer”

20. Warm-UP
What would happen to the red dye molecules over time if you added energy to them? Explain

21. the constant movement of molecules
Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
Diffusion:
the constant movement of molecules
increases with increased input of energy
“never” stops: all matter has “some” energy
Entropy: aka “Chaos Theory”
the tendency of order to become disorganized
as molecules diffuse, they will bump into eachother
the “bumping” causes an energy transfer (one slows down, the other speeds up)
more bumping causes molecules to eventually bounce away from each other
eventually the molecules will “maximize” disorder (get as spread out as possible)

22. Warm-UP:
Imagine 10 minutes into the future for the picture below. Predict how the OUTSIDE of the cell will change AND how the INSIDE will change. Explain.
DUE NOW:
Cell Membrane POGIL: 1st basket
Test Make-UP: 2nd basket: please staple the TEST ON TOP and the CORRECTIONS AND EXPLANATIONS ON BOTTOM
HOMEWORK
Tuesday: 10 Key Ideas: 7.3
Friday: Modeling Diffusion

23. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
Cell Membrane’s are Semipermeable
semipermeable: a “barrier” that allows some molecules to diffuse pass, but not all
Permeable Molecules:
small
ionic
nonpolar
Impermeable Molecules:
large
polar
need an integral protein (doors) to leave or enter
Permeability:
how likely a molecule is to pass through the membrane
can be increased (not often) (a few classes of hormones)
shape change in order to match the membranes polarity
can be decreased
size is increased due to bonding to other molecules
example: water is normally permeable, but when bonded to a solute it becomes “bigger” so is now less permeable
solvents: water
solute: hydrophilic molecules that dissolve in water

24. Whiteboard
Teams:
blood cell with NO hemoglobin AND NO O2 inside, but a lot of O2 outside
blood cell with hemoglobin AND no O2 inside, but a lot of O2 outside
blood cell with NO CO2 outside, but a lot of CO2 inside
muscle cell near a “new” blood cell (lots of O2)
blood cell near an active muscle cell
blood cell near lungs (before and after arrival)
Draw a “before”, then let entropy maximize and draw (by predicting) the “after”
Label your molecules (O2, CO2, hemoglogin, phospholipid, hydrophilic head, hydrophobic tail)
Be ready to explain:
Describe the movement of the molecules. Use terms: entropy, diffusion
How the cell membrane affects the molecule’s movement?
How does the environment affect the change (before vs after)?

25. Warm-UP:
A sailor lost at sea died of dehydration. But she was surrounded by water! Why didn’t she just drink the ocean? See if you can use the picture below to help your explanation.
Homework: Do “Before” drawings for your lab handout

26. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
Permeability:
how likely a molecule is to pass through the membrane
can be increased (not often) (a few classes of hormones)
shape change in order to match the membranes polarity
can be decreased
size is increased due to bonding to other molecules
example: water is normally permeable, but when bonded to a solute it becomes “bigger” so is now less permeable
solution: solvent + solute
solvents: water
solute: hydrophilic molecules that dissolve in water
Movement is affected by other molecules in the environment:
tonicity: concentration of solute in the water
hypotonic: less solute concentration compared to another place
hypertonic: more solute concentration compared to another place
isotonic: equal solute concentration compared to another place

27. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
Permeability:
how likely a molecule is to pass through the membrane
can be increased (not often) (a few classes of hormones)
shape change in order to match the membranes polarity
can be decreased
size is increased due to bonding to other molecules
example: water is normally permeable, but when bonded to a solute it becomes “bigger” so is now less permeable
solution: solvent + solute
solvents: water
solute: hydrophilic molecules that dissolve in water
Movement is affected by other molecules in the environment:
tonicity: concentration of solute in the water
hypotonic: less solute concentration compared to another place
hypertonic: more solute concentration compared to another place
isotonic: equal solute concentration compared to another place

28. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
Permeability:
how likely a molecule is to pass through the membrane
can be increased (not often) (a few classes of hormones)
shape change in order to match the membranes polarity
can be decreased
size is increased due to bonding to other molecules
example: water is normally permeable, but when bonded to a solute it becomes “bigger” so is now less permeable
solution: solvent + solute
solvents: water
solute: hydrophilic molecules that dissolve in water
Movement is affected by other molecules in the environment:
tonicity: concentration of solute in the water
hypotonic: less solute concentration compared to another place
hypertonic: more solute concentration compared to another place
isotonic: equal solute concentration compared to another place

29. Lab: Modeling Osmosis With Differing Solutes
Procedure:
Choose 4 pairs of different solutions.
Pair: Pick 1 solution for the “inside of the cell” and another for the “environment”
For your 1st pair, make a dialysis tubing cell by tying a knot in one end of approximately 20 cm pieces of tubing.
Fill each “cell” with 10 mL of the solution you choose for the inside.
Knot the other end. Approximately ½ your cell should be empty so that pressure ( p) does not affect the movement of molecules.
Mass each cell. Record Mass Day 1.
Place each cell entirely into a 250 mL beaker filled with enough of the 2nd solution to cover the cell completely.
Cover with plastic wrap. Label your beaker.
Repeat for your other 3 pairs.
STOP HERE. Clean up. Homework: DRAW YOUR “BEFORE” PICTURES.
Remove plastic wrap. Remove your cell. DRY GENTLY.
Mass each cell. Record Mass Day 2.
Do math. Do whiteboard. Clean Up: liquids down the drain, garbage in the garbage, beakers washed/rinsed and in the cabinets

30. Warm-UP:
What would happen to the mass of this cell?
How would increasing the salt concentration on the outside affect the rate of change in mass?
Homework: Lab Handout DUE Thursday; Modeling Diffusion DUE Friday

31. Warm-UP: Draw an AFTER “microscope” drawing.
Warm-UP Sheets are due Monday.
Homework: p Key Ideas; Modeling Diffusion DUE Friday

32. Whiteboard Pick ONE of your 4 SET-Ups.
Draw “microscope” view of before and after
Include data: rate of change
Questions:
Which molecules do you suspect were permeable to the membrane? What evidence do you have?
Why does water move in/out of your model cell? Use evidence
What happens to model cells that are in a hypo/hyper/isotonic solution?

33. Whiteboard: Expectations:
Press your classmates with supportive questioning: “Could you tell me about …?”
Paraphrase: “What I hear you saying is…?”
Be ready to present. I will call on people at random. Be ready to answer.

34. Goal Setting
Write a goal statement for your participation in class discussion:
Example:
I typically do BE SPECIFIC.
Because of this, I would like to improve by BE SPECIFIC.
Reflection:
Today, I worked on my goal by doing BE SPECIFIC.
Exemplary
Asks clarifying questions of classmates without teacher help
Paraphrases classmates ideas without teacher help
Participation does not dominate the conversation.
Proficient
Asks clarifying questions of classmates but needs teacher help
Paraphrases classmates ideas but needs teacher help
Participation sometimes dominates the conversation.
Basic
Volunteers, but only to answer teacher questions and ideas.
Participation is infrequent.
Below basic
Only answers questions when called on by the teacher.

35. Warm-UP: Water potential is a way you can use math to determine whether water will move IN or OUT of a cell. It is due to two factors: solute concentration AND pressure. Do you think the cell below is more likely to lose water (have a positive water potential) or gain water (have a negative water potential)? How do you think putting pressure on the cell might change your answer?
Welcome to Monday! Please grab a new warm-up sheet, and get out your old warm-up sheet and your homework.
Tonight’s Homework: Effort Stamp for Water Potential handout

36. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
water potential:
measures the tendency of water to move
inverse relationship:
more positive= less potential= water moves away
more negative= more potential = water moves towards
water moves to areas that have more negative water potential
dependent on
solutes: more solutes, more negative
hypertonic IN, then water will move IN:
causes lysis in animal cells
causes turgidity in plant cells (due to their cell wall)
hypertonic OUT, then water will move OUT:
causes shriveled animal cells
causes plasmolysis in plant cells
pressure: more pressure, more positive
more pressure IN, then water will move OUT
more pressure OUT, then water will move IN

37. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
water potential:
measures the tendency of water to move
inverse relationship:
more positive= less potential= water moves away
more negative= more potential = water moves towards
water moves to areas that have more negative water potential
dependent on
solutes: more solutes, more negative
hypertonic IN, then water will move IN:
causes lysis in animal cells
causes turgidity in plant cells (due to their cell wall)
hypertonic OUT, then water will move OUT:
causes shriveled animal cells
causes plasmolysis in plant cells
pressure: more pressure, more positive
more pressure IN, then water will move OUT
more pressure OUT, then water will move IN

38. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
water potential:
Example:
A plant cell has a solute potential of -4.2 bars. It has a pressure potential of 2.0 bars. What is its water potential?
If the plant cell from #1 is placed in an environment with a solute potential of -2.0 bars, which way will water move? IN or OUT?
Will the cell from #2 become turgid, flaccid, or plasmolyzed? Explain
Explain why the cell didn’t lyse. Use data and the picture to explain.

39. Homeostasis (staying the same when the environment is changing) is maintained by the constant movement of molecules across the cell membrane.
solute potential:
solute potential can be calculated:
i= ionization constant (1.0 for sucrose; 2.0 for salt)
C =molar concentration R=
T= temperature in C + 273
Example:
A plant cell at 25C has a sucrose molar concentration of What is its solute potential? If it’s pressure potential is 1.0, what is its water potential?
The cell from #1 is placed in an environment that has a sucrose molar concentration of 0.3. What is the solute potential of the environment?
Will water move IN or OUT of the plant cell? Explain.

40. Warm-UP:
Talk to your table team about the water potential practice problems. Compare answers to #6 and #15. Were you right? Who else was right? What errors did you or a classmate make?
Explain what happened to the plant cell shown.
Tonight’s Homework: Effort Stamp for 2nd Water Potential handout

41. Lab: A Sweet Test: Potatoes vs Yams
Procedure
Cut 3 approximately 1cm3 potato cubes.
Mass and record
Add enough 0.0M sucrose to a 100mL beaker to submerge the potato cubes.
Repeat Steps #1-4, but adding to: 0.2M, 0.4M, 0.6M, 0.8M, and 1.0M sucrose.
Repeat #1-5 for yams
Wrap in plastic.
Wait until tomorrow.

42. Warm-UP: What can you learn from knowing the point at which the yam/potato is isotonic to a known solution?
Please have your homework out: Water Potential Practice 2
Homework: Finish Lab Handout
Tomorrow: Meet in MATH Computer Lab. Due in class to turnitin.com: Modeling the Role of Surface Area (see directions on my website). There will be a sub.

43. Lab: A Sweet Test: Potatoes vs Yams
Procedure (continued)
Mass and record again.
Clean UP: potatoes and yams in garbage; beakers washed, rinsed, and in cabinet.
Do calculations. Graph data. Determine C (x intercept). Calculate solute potential. Share solute potentials with other groups.
Homework: Stats and Analysis
Tomorrow: Meet in MATH Computer Lab. Due in class to turnitin.com: Modeling the Role of Surface Area (see directions on my website). There will be a sub.

44. Warm-UP:
Can you arrange the squares with:
As many edges facing out as possible
As few of edges facing out as possible
Draw and explain: How does the shape of the squares affect the amount of edges?
DUE: Lab Handout: Potatoes vs Yams
Unit 2 Test: Next Monday, October 27
Homework: Cell Size DUE Tuesday

45. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Surface Area vs Volume Ratio (SA vs V)
as objects (i.e. whole organisms or individual cells) increase in volume, their surface area increases slower
example: big squares have more volume than small square, but a lower SA vs V
example: elephants have a bigger volume than mice, but a lower SA vs V
limits cell size
the lower the SA vs V, the slower that diffusion affects cells
if O2 is needed to diffuse in, cells with a low SA vs V are inefficient
results in adaptations: to increase SA vs V, organisms change to long and skinny or flat (elephant ears, microvilli in small intestine)

46. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Surface Area vs Volume Ratio (SA vs V)
as objects (i.e. whole organisms or individual cells) increase in volume, their surface area increases slower
example: big squares have more volume than small square, but a lower SA vs V
example: elephants have a bigger volume than mice, but a lower SA vs V
limits cell size
the lower the SA vs V, the slower that diffusion affects cells
if O2 is needed to diffuse in, cells with a low SA vs V are inefficient
results in adaptations: to increase SA vs V, organisms change to long and skinny or flat (elephant ears, microvilli in small intestine)

47. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Surface Area vs Volume Ratio (SA vs V)
as objects (i.e. whole organisms or individual cells) increase in volume, their surface area increases slower
example: big squares have more volume than small square, but a lower SA vs V
example: elephants have a bigger volume than mice, but a lower SA vs V
limits cell size
the lower the SA vs V, the slower that diffusion affects cells
if O2 is needed to diffuse in, cells with a low SA vs V are inefficient
results in adaptations: to increase SA vs V, organisms change to long and skinny or flat (elephant ears, microvilli in small intestine)

48. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Surface Area vs Volume Ratio (SA vs V)
as objects (i.e. whole organisms or individual cells) increase in volume, their surface area increases slower
example: big squares have more volume than small square, but a lower SA vs V
example: elephants have a bigger volume than mice, but a lower SA vs V
limits cell size
the lower the SA vs V, the slower that diffusion affects cells
if O2 is needed to diffuse in, cells with a low SA vs V are inefficient
results in adaptations: to increase SA vs V, organisms change to long and skinny or flat (elephant ears, microvilli in small intestine)

49. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Surface Area vs Volume Ratio (SA vs V)
as objects (i.e. whole organisms or individual cells) increase in volume, their surface area increases slower
example: big squares have more volume than small square, but a lower SA vs V
example: elephants have a bigger volume than mice, but a lower SA vs V
limits cell size
the lower the SA vs V, the slower that diffusion affects cells
if O2 is needed to diffuse in, cells with a low SA vs V are inefficient
results in adaptations: to increase SA vs V, organisms change to long and skinny or flat (elephant ears, microvilli in small intestine)

50. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Surface Area vs Volume Ratio (SA vs V)
as objects (i.e. whole organisms or individual cells) increase in volume, their surface area increases slower
example: big squares have more volume than small square, but a lower SA vs V
example: elephants have a bigger volume than mice, but a lower SA vs V
limits cell size
the lower the SA vs V, the slower that diffusion affects cells
if O2 is needed to diffuse in, cells with a low SA vs V are inefficient
results in adaptations: to increase SA vs V, organisms change to long and skinny or flat (elephant ears, microvilli in small intestine)

51. Warm-UP: Notice that the shape of the mouse is as close as it can be to that of a sphere, a shape that produces the minimum amount of surface area. Now notice that the elephant’s skin is covered with wrinkles and the ears are huge and thin, thus increasing the elephant’s surface area. How does each organism’s shape help it maintain homeostasis? Use SA vs V to explain.
Unit 2 Test: Next Monday, October 27
Homework: DUE Tomorrow: Cell Size AND 10 Key Ideas: 7.4

52. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Simple Diffusion (*if water, then called osmosis)
as molecules move, those that can move in can be bonded to other molecules that cannot move out
ex: O2 and hemoglobin
ex: water and salt/sucrose
Facilitated Diffusion
molecules that are too big to enter on their own can enter through substrate specific integral proteins
integral proteins: openings that only fit one substrate
ex: aquaporin for water
ex: glut-4 transporter for glucose
Active Transport
requires energy input
some molecules must be pumped against entropy (against their concentration gradient) because they are too big to diffuse and too rare to “wait” for
ex: proton pump
“pumping” is the result of an energy transfer that changes the shape of the integral protein
creates a concentration gradient

53. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Simple Diffusion (*if water, then called osmosis)
as molecules move, those that can move in can be bonded to other molecules that cannot move out
ex: O2 and hemoglobin
ex: water and salt/sucrose
Facilitated Diffusion
molecules that are too big to enter on their own can enter through substrate specific integral proteins
integral proteins: openings that only fit one substrate
ex: aquaporin for water
ex: glut-4 transporter for glucose
Active Transport
requires energy input
some molecules must be pumped against entropy (against their concentration gradient) because they are too big to diffuse and too rare to “wait” for
ex: proton pump
“pumping” is the result of an energy transfer that changes the shape of the integral protein
creates a concentration gradient

54. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Simple Diffusion (*if water, then called osmosis)
as molecules move, those that can move in can be bonded to other molecules that cannot move out
ex: O2 and hemoglobin
ex: water and salt/sucrose
Facilitated Diffusion
molecules that are too big to enter on their own can enter through substrate specific integral proteins
integral proteins: openings that only fit one substrate
ex: aquaporin for water
ex: glut-4 transporter for glucose
Active Transport
requires energy input
some molecules must be pumped against entropy (against their concentration gradient) because they are too big to diffuse and too rare to “wait” for
ex: proton pump
“pumping” is the result of an energy transfer that changes the shape of the integral protein
creates a concentration gradient

55. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Simple Diffusion (*if water, then called osmosis)
as molecules move, those that can move in can be bonded to other molecules that cannot move out
ex: O2 and hemoglobin
ex: water and salt/sucrose
Facilitated Diffusion
molecules that are too big to enter on their own can enter through substrate specific integral proteins
integral proteins: openings that only fit one substrate
ex: aquaporin for water
ex: glut-4 transporter for glucose
Active Transport
requires energy input
some molecules must be pumped against entropy (against their concentration gradient) because they are too big to diffuse and too rare to “wait” for
ex: proton pump
“pumping” is the result of an energy transfer that changes the shape of the integral protein
creates a concentration gradient

56. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Simple Diffusion (*if water, then called osmosis)
as molecules move, those that can move in can be bonded to other molecules that cannot move out
ex: O2 and hemoglobin
ex: water and salt/sucrose
Facilitated Diffusion
molecules that are too big to enter on their own can enter through substrate specific integral proteins
integral proteins: openings that only fit one substrate
ex: aquaporin for water
ex: glut-4 transporter for glucose
Active Transport
requires energy input
some molecules must be pumped against entropy (against their concentration gradient) because they are too big to diffuse and too rare to “wait” for
ex: proton pump
“pumping” is the result of an energy transfer that changes the shape of the integral protein
creates a concentration gradient

57. To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Simple Diffusion (*if water, then called osmosis)
as molecules move, those that can move in can be bonded to other molecules that cannot move out
ex: O2 and hemoglobin
ex: water and salt/sucrose
Facilitated Diffusion
molecules that are too big to enter on their own can enter through substrate specific integral proteins
integral proteins: openings that only fit one substrate
ex: aquaporin for water
ex: glut-4 transporter for glucose
Active Transport
requires energy input
some molecules must be pumped against entropy (against their concentration gradient) because they are too big to diffuse and too rare to “wait” for
ex: proton pump
“pumping” is the result of an energy transfer that changes the shape of the integral protein
creates a concentration gradient

58. ex: large food particles
To maximize homeostasis with minimum energy investment, organisms use: simple diffusion (osmosis); surface area to volume ratio; facilitated diffusion; active transport; or endo/exocytosis.
Endo/exocytosis:
molecules that are bigger than any integral protein but still must get in/out
ex: large food particles
huge investment of energy b.c. of the need to rebuild the phospholipid bilayer
Steps:
surround molecule with phospholipid bilayer
break in/out of cell
release contents into cytoplasm/out to environment
rebuild section of phospholipid bilayer

59. Draw a microscope view. Add labels
Groups:
O2 and Hemoglobin: oxygen getting into a red blood cell
SV v V: compare diffusion in a long and skinny cell vs a round cell.
water, an aquaporin and salt: water entering a plant cell
Glut – 4 transporter: allowing glucose from blood into muscle cells
proton pump and ATP: moving protons in against their concentration gradient in order to establish a membrane potential
exocytosis: getting rid of destroyed virus particles
Whiteboard:
Draw a microscope view. Add labels
Questions:
What molecules moved and how? Describe this process.
Explain the energy demands on the cell.
How did the cell maintain homeostasis while minimizing energy demands?

60. Watch the video. Write down ONE thing you learned.
Warm-UP:
Watch the video. Write down ONE thing you learned.
Now turn and talk with your team. Write down ONE thing you learned from talking to a neighbor.
DUE: Cell Size POGIL AND 10 Key Ideas Stamp 7.4
Unit 2 Test: Next Monday, October 27
Homework: Passive vs Active Transport

61. Comparing Strategies to Moving Molecules
Energy?
Advantage to Cell?
O2 and Hemoglobin
Surface Area vs Volume
water, an aquaporin and salt
Glut – 4 transporter
proton pump and ATP:
exocytosis

62. The proton pump uses energy. Why does it need energy?
Warm-UP:
The proton pump uses energy. Why does it need energy?
The sucrose cotransporter ONLY can facilitate diffusion (b.c. it’s substrate specific) when BOTH sucrose and H+ attach and cause a shape change. What advantage is the transporter to maintaining homeostasis?
DUE: TWO stamps: page 1 and 2 from Passive and Active Transport handouts
Unit 2 Test: Next Monday, October 27
Homework DUE Monday: Optional Test Review for Optional 10% Grade Fix

63. Comparing Osmosis in Elodea and Yeast
In tap water at 400X
In salt water at 400X
In distilled water at 400X
Elodea
Yeast
Add labels to your drawings: cell wall, cell membrane, chloroplasts

64. Comparing Osmosis in Elodea and Yeast
Analysis
Comparing Osmosis in Elodea and Yeast
Analysis
What happened to the Elodea in salt water? Why?
Compare the solutions to the cells. Which were hypotonic? Which were hypertonic?
How could you determine the water potential of the cells?

65. Fig. 7-7 Fibers of extracellular matrix (ECM) Glyco- Carbohydrate
protein
Carbohydrate
Glycolipid
EXTRACELLULAR
SIDE OF
MEMBRANE
Figure 7.7 The detailed structure of an animal cell’s plasma membrane, in a cutaway view
Cholesterol
Microfilaments
of cytoskeleton
Peripheral
proteins
Integral
protein
CYTOPLASMIC SIDE
OF MEMBRANE

66. The Sucrose/H+ Co-Transporter
Warm-UP:
Draw a hydrogen atom.
Take away it’s electron. What is left?
Show Molecular Workbench Video:

67. Diabetes: A Case Study
Type 1: body's failure to produce insulin (genetics)
Type 2: insulin resistance: insulin receptor no longer “fits” insulin (environment)
Draw and explain the events as you would predict based on the description of Type 1 and Type 2 diabetes.

68. Diabetes: A Case Study Type 1: Drawing Explanation
Blood glucose levels rise
No insulin released
Blood glucose levels remain high; homeostasis not maintained
Type 2:
Drawing
Explanation
Blood glucose levels rise
Insulin released, but cannot bond
Blood glucose levels remain high; homeostasis not maintained

69. Carrier Proteins: Effect of insulin on glucose uptake and metabolism
Carrier Proteins: Effect of insulin on glucose uptake and metabolism. Insulin binds to its receptor (1), which in turn starts many protein activation cascades (2). These include: translocation of Glut-4 transporter to the plasma membrane and influx of glucose (3), glycogen synthesis (4), glycolysis (5) and fatty acid synthesis (6).

70. The Sucrose/H+ Co-Transporter
Sketch
Description
Before
During
After

71. The Sucrose/H+ Co-Transporter
Terms to use in your description:
ATP
ADP P H+
sucrose
diffusion
concentration gradient
proton pump
integral protein
chemical potential energy
electrical membrane potential energy
phospholipid bilayer

72. The Sucrose/H+ Co-Transporter
Analysis
The first law of thermodynamics says “energy cannot be destroyed”. So where is the energy at the start? Where is it at the end?
Why would a cell be willing to “spend” ATP to “earn” sucrose?
Why is this considered active transport?

73. An example
Cystic Fibrosis is due to a misshapen integral protein.

74. Osmoregulation: the control of water balance
Fig. 7-14
50 µm
Filling vacuole
Osmoregulation: the control of water balance
For a cell living in an isotonic environment (for example, many marine invertebrates) osmosis is not a problem.
Similarly, the cells of most land animals are bathed in an extracellular fluid that is isotonic to the cells.
Organisms without rigid walls have osmotic problems in either a hypertonic or hypotonic environment and must have adaptations for osmoregulation to maintain their internal environment.
Contracting vacuole
Figure 7.14 The contractile vacuole of Paramecium: an evolutionary adaptation for osmoregulation

75. water entering the cell
Fig. 7-14
50 µm
Filling vacuole
Osmoregulation: the control of water balance
Hypotonic!:
water entering the cell
fill the vacuole
squeeze the vacuole’s water out of the cell
(a) A contractile vacuole fills with fluid that enters from
a system of canals radiating throughout the cytoplasm.
Contracting vacuole
Figure 7.14 The contractile vacuole of Paramecium: an evolutionary adaptation for osmoregulation
(b) When full, the vacuole and canals contract, expelling
fluid from the cell.