1. Question of the Day OCT 21
The cell membrane contains which of the following sets of three organic compounds.
A. Carbs, Lipids, Nucleic Acids
B. Lipids, Proteins, Enzymes
C. Carbs, Lipids, Proteins
D. Carbs, Lipids, Fatty Acids

2. DO NOW OCT 21
Compare the processes of diffusion and facilitated diffusion.

3. ANSWER OCT 21
Diffusion and facilitated diffusion move molecules across the cell membrane from an area of high concentration to low concentration.
Both processes do NOT require energy.
Facilitated diffusion uses protein channels to allow larger molecules such as glucose to cross the cell membrane.

4. AGENDA OCT 21
BIG Question: What are the main functions of the cell membrane and the cell wall?
1. QoD and DO NOW
2. Homework Check
3. Section 7-3 Cell Boundaries
4. Cell membrane, Cell Wall, and Diffusion
5. Review and HOMEWORK
STUDY your notes!!! QUIZ/TEST this week!

5. CELL STRUCTURE and FUNCTION
CHAPTER 7
CELL STRUCTURE and FUNCTION

6. Cell Membrane separates the cell from its surroundings
regulates what enters and leaves the cell
aids in the protection and support of the cell
composed of a double layer of lipids, known as a bilayer
contain proteins that act as channels through which molecules pass or pumps to push molecules through
carbohydrates are also attached to proteins or lipids and act like identification cards
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8. Cell Wall
cell structure that surrounds the cell membrane for protection and support
found in plants, algae, and some bacteria
very porous and allows water, oxygen, carbon dioxide, and other substances through
Made of a tough fibrous material called cellulose: makes the wall elastic so it can stretch and grow
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9. 7-3 CELL BOUNDARIES Movement of Materials Across the Cell Membrane
diffusion: process by which molecules move from areas of higher concentration to areas of lower concentration
equilibrium occurs when the concentrations on both sides of the membrane are the same
permeability determines which substances move across the membrane
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10. OSMOSIS
diffusion of water molecules through a selectively permeable membrane
pass through rapidly
Water moves from an area of low solute concentration to high solute concentration.

11. OSMOSIS osmotic pressure: water pressure
cells protect themselves with:
cell walls
bathing cells in blood
contractile vacuoles to pump out water

12. Effects of Osmosis on a Cell
Concentration of Solutes
ISOTONIC: concentration of solutes is same inside/outside cell
Cell does NOT gain or lose water.
HYPERTONIC: solution has higher solute concentration than the cell
Cells shrink as water moves from an area of lower concentration (the cell) to a higher concentration (outside the cell).
HYPOTONIC: solution has lower solute concentration than the cell.
Cells will burst as water moves into the cell.

13. OSMOSIS VIDEO CLIP http://www.youtube.com/watch?v=7-QJ- UUX0iY
0:59 Hypotonic – Water molecules enter the cell
3:10 Hypertonic – Water molecules exit the cell
4:20 Isotonic – Net movement of water molecules is equal

14. Facilitated Diffusion
some molecules are too large to pass through cell membrane
molecules too large must pass through a protein channel embedded in the cell membrane
still driven by diffusion
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15. Active Transport requires energy
allows material to move against a concentration difference
two types:
carried through membrane-associated pumps (proteins)
large amounts of material are transported through movements of the cell membrane
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16. Active Transport
endocytosis – the engulfing of large molecules to be taken into the cell.
TWO EXAMPLES of Endocytosis
phagocytosis: extensions of cytoplasm surround and engulf large food particles.
Means “Cell eating”
pinocytosis: tiny pockets form along the membrane fill with liquid and pinch off to form vacuoles within the cell.
exocytosis: the removal of large molecules from the cell

17. EXIT PASS REVIEW 1. Describe the composition of the cell membrane?
2. Why is the cell membrane important to a cell?
3. What is diffusion?

18. DO NOW
What are the four levels of cell specialization found within an organism?

19. 7-4 Diversity of Cellular Life
Cell Specialization: cells within an organism develop in different ways to perform different tasks.
Red Blood Cells contain hemoglobin.
Protein that binds oxygen in the lungs and transports it throughout the body.
Pancreatic cells produce enzymes to assist in the digestion of foods.
Packed with ribosomes and Rough ER.
Proteins are made and packaged for this specialized job.
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20. 7-4: Levels of Organization
cells: basic unit of life
tissues: group of similar cells that perform similar functions
organs: a group of similar tissues that perform similar functions
organ systems: group of similar organs that perform similar functions
muscular, skeletal, digestive, circulatory, etc.
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