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