1. Cellular Structure and Function
Chapter 7
Cellular Structure and Function

2. Cell Structures and Organelles
Chapter 7.3
Cell Structures and Organelles

3. Cell Organelles Cell Part Function Cytoplasm
Semfluid material that surrounds the organelles and provides a place for chemical reactions to take place.
Cytoskeleton
A network of long, thin protein fibers that form a framework and support system for the cell; anchors all the organelles
Nucleus
Control center of the cell; contains the cell’s DNA; surrounded by nuclear membrane (envelope)
Ribosomes
Produces proteins
Nucleolus
Produces ribosomes
Endoplasmic reticulum
Folded membrane system that is the site for protein and lipid production
Smooth ER
Area with no ribosomes attached; place where many carbohydrates and lipids are produced
Rough ER
Ribosomes are attached and produce proteins

4. Cell Organelles Cell Part Function Golgi Apparatus
Flattened membranes that modified, sorts, and packages proteins
Vacuoles
Temporary storage for the cell; used to store food, enzymes, and other materials needed for the cell
Lysosomes
Structure containing enzymes used to digest waste
Centrioles
Used in cell reproduction
Mitochondria
Produce energy by breaking down sugars
Chloroplasts
Capture light energy and convert it to chemical energy (food); found in plant cells
Cell wall
Thick, rigid fibers that surround the plasma membrane and protects the cell
Cilia and Flagella
Used for cell movement in some eukaryotic cells

6. Cytoplasm and Cytoskeleton

7. Nucleus and Nucleolus

8. Endoplasmic Reticulum
Ribosomes
Smooth and Rough
Endoplasmic Reticulum

9. Golgi Apparatus

10. Vacuole
Animal Cell
Plant Cell

11. Lysosomes

12. Centrioles

13. Mitochondria

14. Chapter 7.4
Cellular Transport

15. Predict Food coloring demonstration
Drops of red and blue food coloring are added to opposite ends of a container of water.
What will happen when the food colorings are added?
What will happen a few minutes later?

17. Diffusion
Substances dissolved in water (solutes) move constantly in random motion; this is call Brownian Motion
Causes diffusion
net movement of particles from an area where there are many particles of the substance (high concentration) to an area where there are few particles of the substance (low concentration)
How can you tell this is happening/has happened in our experiment?

18. Diffusion
Movement of substances from high concentration to low concentration
Caused by the RANDOM movement of particles
Requires no energy input!

19. Observe & Hypothesize What happened to our food colorings?
How can this result be explained?
Figure 7.20 © Glencoe-McGraw Hill (2007)

23. Interactive Diffusion Activity:

24. Dynamic Equilibrium
Once a uniform purple color is reached, the food coloring particles continue to move randomly.
However, at some point, all particles of a substance (in this case food coloring) will be as spread out as they can and there will no longer be areas of high and low concentration.
When this occurs, dynamic equilibrium has been reached.

25. Diffusion in Cells

26. Factors that Affect Diffusion
Three main factors affect the rate (speed) of diffusion:
Concentration of the diffusing particles
Temperature
Pressure
If any of these three increases, the diffusion rate will increase. Why?
Set up some demonstrations to show students these:
1.) Add differing amounts of food coloring to two beakers to see how fast diffusion occurs in each.
2.) Place food coloring in a beaker of boiling water.
3.) Place food coloring into the bottom of a 2-liter bottle that is under pressure/ or use vacuum to reduce pressure.

27. Facilitated Diffusion
Water can pass easily through the plasma membrane – most substances cannot
In facilitated diffusion, special transport proteins move ions and small molecules across the plasma membrane

28. Transport Processes
Passive transport – movement of a substance across the plasma membrane without the use of the cell’s energy.
Active transport – requires the use of the cell’s energy to move substances into or out of a cell across the cell membrane.
No Energy
Required
Requires Energy

29. Cellular Transport Videos

30. Osmosis is the DIFFUSION OF WATER

32. Osmosis
The diffusion of water across a selectively permeable membrane.
Cells must regulate this in order to maintain homeostasis.
One of three situations exists.
Figure 7.22 © Glencoe-McGraw Hill (2007)

33. Isotonic Solution
Cell is in a solution that has the same concentration of water and solutes
Iso – Greek meaning “equal”
cell is in dynamic equilibrium with environment
Water enters and leaves the cell at the same rate.
Figure 7.23 © Glencoe-McGraw Hill (2007)

34. http://www. stolaf. edu/people/giannini/flashanimat/transport/osmosis

35. Hypotonic Solution
Cell is in a solution that has a lower concentration of solute than the cell
hypo – Greek meaning “under”
Net movement of water is into the cell
Causes osmotic pressure
In animals – cell could burst
In plants, cell wall prevents bursting; cell becomes firmer
Figure 7.24 © Glencoe-McGraw Hill (2007)

36. Hypertonic Solution
Cell is in a solution that has a higher concentration of solute than the cell.
hyper – Greek meaning “above”
Net movement of water is out of the cell
Results:
In animals – cells shrivel
In plants, central vacuole pulls away from cell wall; plant wilts
Figure 7.25 © Glencoe-McGraw Hill (2007)

37. Red Blood Cells – A Comparison
Is your blood pure water?
What would happen to your red blood cells if pure water were to be injected into your blood stream?