![Page 1: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/1.jpg)
CELL MEMBRANE
![Page 2: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/2.jpg)
![Page 3: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/3.jpg)
Cell BoundariesEvery cell is surrounded by a liquid liquid environmentenvironment
and has a liquid insideliquid inside
Two types of boundaries separate:
– Cell membrane (inner)• Thin, flexible layer that surrounds all cells
– Cell wall (outer)• Strong supporting layer outside the cell membrane• Only in some organisms (plants, algae, fungi, prokaryotes)• Porous
![Page 4: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/4.jpg)
Phospholipids
• Cell membranes are mostly built from fat molecules called phospholipids– Have a polar head and
two nonpolar tails• Polar heads
attracted to water• Nonpolar tails
repelled by water
• Movie #1
![Page 5: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/5.jpg)
Lipid Bilayer
• Because there is water inside and outside the cell, the phospholipids form a double layer called the lipid bilayer.
• Polar heads on outside, nonpolar tails on the inside
• Movie #2
![Page 6: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/6.jpg)
Membrane Components
• Membranes also have proteins embedded in the bilayer- act as tunnels or pumps across the membrane- others protect the cell membrane
• Contains carbohydrates, usually attached to the proteins- act as signals to other cells
• Contains cholesterol- Stabilizes the membrane
![Page 7: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/7.jpg)
Cell Membrane
![Page 8: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/8.jpg)
Outsideof cell
Insideof cell(cytoplasm)
Cellmembrane
Proteins
Proteinchannel Lipid bilayer
Carbohydratechains
Section 7-3
Figure 7-12 The Structure of the Cell Membranehttp://www.youtube.com/watch?v=ULR79TiUj80
![Page 9: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/9.jpg)
Inside of cell(cytoplasm)
Cellmembrane
Proteins
Proteinchannel
Lipid bilayer
Carbohydratechains
Section 7-3
Figure 7-12 The Structure of the Cell MembraneFluid Mosaic Model
• Lipid bilayer – double layer of molecules– Lipids are a certain class of C-H molecules – Do not like water ( think of oil + water) – the “tails”– The “heads” are polar molecules
• Has proteins throughout • Can have carbohydrate “ID tags”• Moveable/fluid• Selectively Permeable
![Page 10: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/10.jpg)
Cell Wall
• Cell wall – tough, porous boundary that lies outside the cell membrane; found in plant cells and in some bacteria but NOTNOT in animal cells- Allow water, gases, and other substances to pass
through easily
• Most cell walls are made of carbohydrates and proteins- Specifically composed of cellulose
![Page 11: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/11.jpg)
FUNCTION of Cell Membrane
• Regulates what goes in and
what comes out of a cell– Like a fence or a window screen– Regulation depends on size, concentrations, and
the type of molecule trying to get through
• Protects cell• Supports cell, but also flexible• Recognizes foreign material• Communicates with other cells
![Page 12: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/12.jpg)
What goes in and out? (Transport)Cell membrane is selectively permeable,
it lets some things in, but not other things
Selection depends on…
size (smaller get through easily)
concentrations,
& type of molecule trying to get through
(lipid and nonpolar)
• Substances keep moving till there are ~ equal amounts of them on both sides of the membrane EQUILIBRIUM
![Page 13: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/13.jpg)
Cell Membranes
• Must be able to take in raw materials and eliminate waste products- Like a bouncer at a club
![Page 14: CELL MEMBRANE. Cell Boundaries liquid environment Every cell is surrounded by a liquid environment liquid inside and has a liquid inside Two types of](https://reader036.vdocument.in/reader036/viewer/2022062309/5697bfe31a28abf838cb5285/html5/thumbnails/14.jpg)
Permeabilityhttp://www.youtube.com/watch?v=GW0lqf4Fqpg&feature=related
Do these get through?• H+ or Ca++• CO2
• K+, Cl- • H2O• Glycerol or ethanol (-OH)• O2
• Amino acids• Glucose