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Intro to Endocrine
What do you know about these terms?
• Membrane• Transport• Hormone• Negative and positive feedback• Cholesterol• Membrane protein• phosopholipid• Selective Permeability• Cholesterol• Membrane protein• Hydrophilic• Hydrophobic
Review of the Membrane
Key Membrane Terms
• Phospholipid Molecule– Hydrophilic/hydrophobic (polar/non-polar)
• Cholesterol
• Membrane protein
• Plasma Membrane: the outer boundary of a cell that encloses the cells contents.
• Selective Permeability: some molecules are able to pass while others are not.
– Tea bags, colanders, plasma membranes(!!)
• Hydrophilic: water loving
• Hydrophobic: fear of water
What kind of reaction occurs when you put a hydrophobic substance in water?– Think oil and vinegar
Fluid Mosaic Model
Three Parts to a Cell Membrane
• Phospholipid molecules – (formed into a phospholipid bilayer)
• Cholesterol molecule
• Membrane protein
Phospholipid Molecule
Structure• Two fatty acids and one
phosphate head.• The fatty acids are
hydrophobic and the phosphate head is hydrophilic.
Function• The phospholipids
pair up, and form a bilayer with the fatty acids touching, and the phosphate heads facing outwards. This creates the cell membrane
Phospholipid Molecule
Unsaturated fatty acidwhat’s this?
Cholesterol Molecule
Structure• Rigid molecules
embedded in the lipid bi-layer
Function• Helps keep the
structure of the membrane and keeps the fatty acid tails anchored together.
Cholesterol in Plasma Membrane
Where is the hydroxyl of the cholesterol?
Membrane Proteins
Structure• Proteins are located
throughout the membrane (like raisins in a slice raisin bread)
Function• Regulation of what
passes through the membrane
• Serve as enzymes and take part in chemical reactions
• Act as markers that are recognized by chemicals in and out of the cell
Membrane Proteins
Passive Transport
• Diffusion
• Facilitated diffusion
• ligand-gated ion channel
• osmosis
Active Transport
• http://programs.northlandcollege.edu/biology/Biology1111/animations/transport1.html
• proton pump
• Endo and exocytosis
Steroid Signals
• http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter47/animations.html#
Protein Signals
• http://entochem.tamu.edu/G-Protein/index.html
Intro to Endocrine/Negative Feedback
• http://health.howstuffworks.com/adam-200092.htm