1. Cells

2. What are the functions of the cell organelles?

3. Structure dictates function in organelles… How does the muscle cells having a lot of mitochondria help it perform its function?
Muscle tissue is responsible for movement and requires large amounts of energy. Therefore, there will be high numbers of mitochondria in these types of cells.

4. Structure dictates function in organelles… How does the neurons having long, narrow extensions (dendrites and axons) help it perform its function?
Neurons are specialized cells that carry messages within the human nervous system. They do share some similarities with other cells, but they also have specialized features, such as dendrites, that enable them to carry out their role of sending messages quickly

5. Structure dictates function in organelles… How does red blood cells lacking many organelles but the cell membrane and cytoplasm help it perform its function?
The primary function of red blood cells is to transport oxygen. Red blood cells do not have nuclei or many other organelles, which leaves more room in the cytoplasm for the hemoglobin needed for transporting oxygen.

6. What’s the difference between a prokaryotic cell and a eukaryotic cell?

7. Which 4 organelles are found in ALL cells (prokaryotic and eukaryotic)?

8. A cell membrane is described as semi-permeable. What does this mean?
This means that the membrane can let some things pass through

9. Draw a phospholipid. Which part of it is polar? Nonpolar?

10. Polar
Non-polar

11. What’s another word to describe a molecule that is polar?
Hydrophilic

12. What’s another word to describe a molecule that is nonpolar?
Hydrophobic

13. Where are the hydrophilic heads and hydrophobic tails located in the phospholipid bilayer that makes up the cell membrane? Why are they arranged this way?
See picture on next slide

14. Phospholipid bilayers form in water because the individual phospholipid molecules arrange themselves due to their hydrophobic and hydrophilic properties. Specifically, the heads of the molecules are hydrophilic and are thus attracted to water, while the tails are hydrophobic and avoid water. By arranging themselves in the bilayer as shown, the tails are protected from water while the heads associate with water.

15. Which molecules can pass through the cell membrane freely? Why?
O2, CO2, H2O= either nonpolar or are small

16. Is the cell membrane rigid or flexible?
It is flexible (often compared to flexible like a fluid). This means the cell membrane can change shape without breaking and that molecules in the membrane can flow like a liquid in it.

17. Which molecules are blocked by the phospholipid bilayer? Why?
Polar & large; amino acids, glucose, proteins, glycogen.

18. If a molecule diffuses through the cell membrane, how is this done
If a molecule diffuses through the cell membrane, how is this done? In other words, why doesn’t it require energy? Which type of molecules can pass through the cell membrane this way?
Molecules move down the concentration gradient (driven by kinetic energy- molecules rebounding off each other). They move from an area of high concentration to low concentration; CO2 and O2

19. What type of molecules are passing through the cell membrane via osmosis? Does this process require energy or the help of cell membrane proteins?
Water; no

20. Outside Cell
Inside Cell
6% glucose
1% glucose
1. What would be the net movement of glucose? Why? 2. What would be the net movement of water? Why? 3. What type of solution is the cell placed in …hypotonic, hypertonic or isotonic? 4. What will be the overall effect on the cell?
The glucose molecules move inside the cell because they move from a higher concentration to a lower concentration
The water molecules would move outside the cell, because they move to where the solute concentration is higher.
The cell has been placed in the a hypertonic solution (because the solution contains MORE solute than what is found inside the cell)
It will cause the cell to plasmolysize

21. Outside Cell
Inside Cell
6% glucose
6% glucose
1. What would be the net movement of glucose? Why? 2. What would be the net movement of water? Why? 3. What type of solution is the cell placed in …hypotonic, hypertonic or isotonic? 4. What will be the overall effect on the cell?
The glucose molecules move inside and outside of the cell at the same speed. The net movement would be equal .
The water molecules would move inside and outside of the cell at the same speed since the glucose concentration is equal. The net movement would be equal .
The cell has been placed in the an isotonic solution (because it contains EQUAL amounts of solute inside and outside of the cell)
It will cause the cell stay flaccid.

22. Outside Cell
Inside Cell
2% glucose
4% glucose
1. What would be the net movement of glucose? Why? 2. What would be the net movement of water? Why? 3. What type of solution is the cell placed in …hypotonic, hypertonic or isotonic? 4. What will be the overall effect on the cell?
The glucose molecules move outside the cell because they move from a higher concentration to a lower concentration
The water molecules would move inside the cell, because they move to where the solute concentration is higher.
The cell has been placed in the a hypotonic solution (because the cell contains MORE solute than what is found outside the cell)
It will cause the cell to hydrolize/burst (if it’s an animal cell); become turgid (if it’s a plant cell)

23. To increase; plant takes in more water vacuole fills up, exerting pressure on cell membrane, which exerts pressure on the cell wall
To decrease vacuole isn’t filled with much water (it leaves the vacuole to go into fluid outside cell) this reduces the pressure on the cell membrane, which reduces the pressure on the cell wall.
1. Placing a plant cell in a hypotonic solution will cause the plant’s turgor pressure to _______________. WHY?
2. Placing a plant cell in a hypertonic solution will cause the plant’s turgor pressure to
_______________. WHY?

24. Which molecules pass through the cell membrane via ion channels (facilitated diffusion)? WHY? Is this a form of active or passive transport?
Ions like Ca2+, Cl- ;They have charges so they are repelled by the cell membrane
It is passive transport (meaning no energy/ATP is required), as they move DOWN the concentration gradient

26. What molecules pass through the cell membrane via a carrier protein (facilitated diffusion)? Why?
Glucose & amino acids; They are too large or are polar (not soluble in non-polar cell membrane)

28. How is active transport different than facilitated diffusion?
It requires energy (ATP) because the molecules are moving AGAINST the concentration gradient (they are moving from an area of low concentration to high concentration.

29. How is ATP used in active transport
How is ATP used in active transport? Use the sodium-potassium pump to explain.

31. What’s the difference between exocytosis and endocytosis
What’s the difference between exocytosis and endocytosis? What types of substances move into/out of the cell this way?
Endocytosis: Cells INGEST large molecules such as external fluid, macromolecules (like proteins and glycogen) & large particles. The cell membrane pinches in and forms a pouch (vesicle) and the material is taken to an organelle.
Exocytosis: Golgi body forms vesicles around fluid, macromolecules & large particles. The vesicle brings the material to the cell membrane, where it fuses with the cell membrane and the molecules are released OUTSIDE of the cell (how out cells gets rid of waste)

33. What is the surface area to volume ratio for the following image?
Side length (mm) 3
Surface area (mm2) 54
Volume area (mm3) 9
54:9= 6:1
Image:

34. Why is it important for cells to have a high surface area to volume ratio?
Gases (CO2 and O2) & food molecules dissolved in water must be absorbed; Waste products must be eliminated. This can only be done efficiently if there is more surface area (cell membrane) and less volume (cytoplasm) for particles to move in and out of.

35. Why is water considered a polar molecule?
Hydrogens are slightly positive and oxygen is slightly negative

36. Water is considered a universal solvent. What does this mean?
Water can dissolve (break down) anything with a charge- this includes other polar molecules as well as ions. Water is called the universal solvent because it can break down so many other kinds of substances.

37. Why do you think the chemical properties of water are important to cellular systems?
Because it breaks down important ions needed for living systems and the cohesive (attraction of water molecules to one another) and adhesive (attraction of water and ions) properties of water allow the transport of those materials through living systems (capillary flow)

38. ________ is the force between water molecules and __________ is the force between water and nutrients
Cohesion; adhesion

39. What is capillary action? How is this important for plants?
Capillary action is the movement of water and all the substances dissolved in it; capillary action moves water and nutrients up the plant (against gravity) through cohesion and adhesion

40. What is the function of the following organ systems… Respiratory
What is the function of the following organ systems… Respiratory? Digestive? Circulatory? Excretory?

41. What is a negative feedback loop
What is a negative feedback loop? Use an example to show how it helps maintain homeostasis.

42. What is a positive feedback loop
What is a positive feedback loop? Use an example to show how it helps maintain homeostasis