![Page 1: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/1.jpg)
Chapter 5: Homeostasis and
TransportNOTES
![Page 2: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/2.jpg)
The Cell Membrane
• Regulates what enters and leaves a cell (gatekeeper)
• Provides protection and support• Made of a double layer of phospholipids
(with proteins embedded)• Semi/Selectively Permeable – some
substances can cross, others cannot
![Page 3: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/3.jpg)
Diagrams
• Arrangement of Phospholipids:
• Fluid Mosaic Model: The accepted model of cell membrane structure
![Page 4: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/4.jpg)
REVIEW
Regulates what enters and leaves the cell
Protects and supports the cell
Composed of Lipids = bilayerProteins = channelsCarbs = identification cards
![Page 5: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/5.jpg)
Types of Transport (2) – Passive Transport & Active Transport
• Passive TransportPassive Transport – does NOT require energy; move substances DOWN a concentration gradient (more less) (includes: diffusion, osmosis and facilitated diffusion)
– Diffusion – process where molecules move from an area of HIGH concentration (more) to LOW concentration (less) until equilibrium is reached ex. dye in a beaker, tart burner in class
![Page 6: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/6.jpg)
Passive Transport
– Osmosis – the diffusion of WATER across a semi-permeable membrane (high low)
OSMOTIC SOLUTIONSType of Solution Plant Cell Animal CellHYPOTONIC- net flow of water is INTO a cell
Turgor Pressure Cytolysis
ISOTONIC – water moves in and out of the cell at equal rates
Flaccid
HYPERTONIC- net flow of water is OUT of the cell
Plasmolysis Shrink/shrivel
![Page 7: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/7.jpg)
Isotonic Solution
“Iso” = the same
Water will move both ways in equal amounts
Why is important that contact lens solution is isotonic?
![Page 8: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/8.jpg)
Hypotonic Solution
"Hypo" = less Less solute (salt) molecules
outside the cell Water will move in both directions BUT more water will move into the
cell causing it to grow larger (cytolysis)
In plant cells, the central vacuoles will fill and the plant becomes stiff and rigid (turgid), the cell wall keeps the plant from bursting
In animal cells, the cell may be in danger of bursting, organelles called CONTRACTILE VACUOLES (only on paramecium) will pump water out of the cell to prevent this
![Page 9: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/9.jpg)
Hypertonic Solution "Hyper" = more More solute (salt) molecules
outside the cell Water will move in both directions BUT more will move out of the cell
causing it to shrink (plasmolysis) In plant cells, the central vacuole
loses water and the cells shrink, causing wilting (loss of turgor pressure)
In animal cells, the cells shrink In both cases, the cell may die Why is it dangerous to drink sea
water? This is also why "salting fields"
was a common tactic during war, it would kill the crops in the field, thus causing food shortages
![Page 10: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/10.jpg)
Which type of solution is it? A B C
![Page 11: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/11.jpg)
![Page 12: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/12.jpg)
Jack puts a partially eaten tuna-fish sandwich in the wastebasket. The custodial staff won't empty the trash again until Monday evening. The room is closed up all weekend. What might you notice when you first come in on Monday morning? Why?
Warm-Up
![Page 13: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/13.jpg)
• Diffusion is the movement of molecules from an area of high concentration to an area of low concentration
Warm-Up
![Page 14: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/14.jpg)
• The relative concentration of one solution to another is called tonicity
Warm-Up
![Page 15: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/15.jpg)
1. What type of solution is this “cell” in?
Hypotonic solution
2. What will happen to this “cell” over time?
The cell will expand and possibly burst (CYTOLYSIS)
Warm-Up
10 g/L sugar solutio
n
2 g/L sugar solutio
n
![Page 16: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/16.jpg)
Passive Transport
– Facilitated Diffusion – diffusion with assistance or help of a carrier/transport protein (ex: glucose)• Speed up diffusion• Carry large molecules that can’t diffuse
quickly across cell membrane
Still moving from high low
DOWN the concentration
gradient
![Page 17: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/17.jpg)
Facilitated Diffusion
• http://www.youtube.com/watch?v=-Ul2oJ_TkNw
![Page 18: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/18.jpg)
![Page 19: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/19.jpg)
Active Transport – movement of molecules from LOW to HIGH WITH THE USE OF CHEMICAL ENERGY (UP concentration gradient)
Requires energy (ATP)Against the concentration gradient – moving low to high (paddling up a river)
Cell Membrane Pumps – Special transport molecules in the cell membrane move molecules across the cell membrane
Moves particles from low concentration to high concentration
Active Transport
![Page 20: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/20.jpg)
Sodium-Potassium Pump
![Page 21: Chapter 5: Homeostasis and Transport NOTES. The Cell Membrane Regulates what enters and leaves a cell (gatekeeper) Provides protection and support Made](https://reader034.vdocuments.site/reader034/viewer/2022051401/56649e875503460f94b8acd9/html5/thumbnails/21.jpg)
Active Transport
• Bulk Transport - large substances in/out of cell
Endocytosis – bringing large particles INTO the cell “ENTER”
Exocytosis –moving large particles OUT of the cell “EXIT”
•Phagocytosis – “Cell Eating” moving large food particles or whole microorganisms into the cell (ex. amoeba feeding or wbc engulfing bacteria)
Pinocytosis – “Cell Drinking” moving solutes or fluids into the cell