1. Lipid Structure Plasma Membrane Cell Transport Cell Communication

2. Lipids Carbon and hydrogen Store energy
Waterproof coverings on plants and animals
Cell membrane
Steroids/Hormones

3. Lipids Fats, Oils, Waxes Phospholipids Steroids
Glycerol + 2 fatty acids = Triglyceride
Fats – animal, solid, saturated fatty acids (straight)
Oils – plant, liquid, unsaturated fatty acids (kinked)
Waxes – highly saturated solids for waterproofing
Phospholipids
Hydrophilic phosphate head and hydrophobic fatty tail
Cell membranes
Steroids
Carbon rings
Cholesterol
Estrogen (female sex hormone), testosterone (male sex hormone), bile (fat digestion)

6. Checkpoint #1
(You should also use your four fold notes to answer these.)
What are the primary functions of lipids?
Differentiate the three types of lipids.
Create a diagram showing the differences between saturated and unsaturated fats.
How are lipids different than carbohydrates?
Why are lipids insoluble?

7. Plasma Membrane
A layer of phospholipids

8. Plasma Membrane Video Link

9. Checkpoint #2 Describe the primary functions of the cell membrane.
Describe the primary structure of the cell membrane.
Explain why the “fluid mosaic model” is used to explain the cell membrane.
Polar molecules need help getting through the cell membrane. Why?
What role do proteins play in the cell membrane?

10. Cell Transport to maintain homeostasis
Passive Transport
Simple Diffusion
Facilitated Diffusion
Osmosis
Active Transport
Endocytosis
Exocytosis
Transport Pumps

11. Passive Transport
Passive Transport: the process of particles moving through a membrane with NO ENERGY (high to low concentration)
Water, lipids, and some lipid soluble substances can move by passive transport.
Molecules can move through proteins or the membrane itself.

12. Passive: Diffusion
Diffusion : movement of particles from an area of high to low concentration (no energy required)
continues until there is no more concentration gradient.

13. Passive: Facilitated Diffusion
Facilitated Diffusion: proteins helping large molecules across the plasma membrane.
No energy is used by the cell or its parts! (passive)
Movement is powered by the concentration gradient. (hi to lo)
See p. 187 Fig. 7.17

14. Passive: Osmosis
Osmosis: The diffusion of water across a selectively permeable membrane.
Review:
Plasma Membrane- Phospholipid Bilayer
Concentration Gradient
Homeostasis
Fig. 8.1 p. 202

15. 3 Types of Solutions
Isotonic Solution: Concentration of solutes is the same inside and outside the cell.
No osmosis occurs
dynamic equilibrium: molecules are moving across membrane but no concentration gradient created.
Dynamic: Movement or change
Equilibrium: An equality or balance

16. Types of Solutions
Hypotonic Solution: The concentration of solutes is less outside the cell than inside the cell. See p. 186, Fig. 7.16
Water moves by osmosis into the cell!
The cell tends to swell.

17. Types of Solutions
Hypertonic Solution: The concentration of solutes is more outside the cell than inside the cell. See p Fig. 7.16
Osmosis causes water to flow out of the cell.
Cells will shrink or shrivel

18. Comparison of Hypo, Iso, and Hypertonic Solutions

19. Turgor Pressure: The pressure in a plant cell that results from water flowing into the cell.
Occurs with a hypotonic solution.
Gives plants their shape and ability to stand up. Without it they wilt!

20. Plasmolysis: Loss of pressure within a cell causing it to shrivel
Occurs with a hypertonic solution
In plants turgor pressure is lost (wilting occurs), animal cells just shrivel

21. Cell Membrane Proteins
Carrier Proteins: Span through plasma membrane (transport proteins) and change shape to help molecules get from one side to the other.
Their exposed ends open and close like a gate.
Channel Proteins: Span through plasma membrane (transport proteins) and create an opening where molecules can pass through.
They do not change shape.
Carrier
Channel

22. Active Transport
Active Transport: cell uses energy to move molecules across plasma membrane against the concentration gradient.
These molecules are moving the opposite way they would naturally move due to diffusion. (low-high)

23. Active: Ion Pumps
Ion pumps use ATP to move ions against the concentration gradient.
From a low concentration to a high concentration

24. Active: Endo and exocytosis
Endocytosis
Movement into cell
Phagocytosis and Pinocytosis is a form of endocytosis
Phagocytosis: one cell engulfing another.
Pinocytosis: tiny pockets form along the cell membrane fill with liquid and pinch off to form vacuoles
Exocytosis
Movement out of cell; waste or messengers (hormones)

25. Endocystosis (amoeba eats two paramecia)

26. Checkpoint #3 How are active and passive transport different?
Where do cells get the energy required to perform active transport?
What role do you suppose DNA plays in active transport?
What is a concentration gradient?
How would transport help maintain homeostasis for the cell?
*Amoeba video – Once inside the cell, how do you think the paramecia are broken down?
(review video on transport to follow)

27. All you want to know about transport