Lipids https://chelseaharripersad.wordpress.com/tag/lipids/

Lipids – Macromolecule #1 Made up of C, H, and a little bit of O This group has fats and oils (including phospholipids), and steroids They are not water soluble *STOP AND THINK: Write down your answers for the following What does that mean?* How might that be useful for something like a cell membrane?* -What does it mean to be not water soluble? You can show a toy that has two layers (due to solubility) or an oil/vinegar salad dressing, or talk about if someone has ever gotten pitch on their hands before and if they tried to rinse it off their hands…what works when trying to get pitch off your hands? Peanut butter  (another lipid-soluble substance) -How could it be useful? Can help to act as a barrier to things like water or water soluble substances…they may not get this…but maybe worth a shot?

Fats & Oils Structure: Function: Glycerol + fatty acids Fatty acids are chains of carbon atoms bonded to hydrogen atoms Saturated vs. Unsaturated Function: Store large amounts of chemical energy Main component in cell membranes E.g. Triglycerides (i.e. Olive Oil, Beef Fat) How might these molecules become bonded together?? Dehydration Synthesis!! (this is stated in the next slide)

Fats & Oils: Structure Glycerol Many lipids contain 3 fatty acids bonded to the glycerol Called triglycerides These fatty acids are bonded to the glycerol via dehydration synthesis (*Animation*) Fatty Acid 1 Fatty Acid 2 The fatty acids do not need to all be the same kind. They can also be saturated, unsaturated, or polyunsaturated. What do you notice about the differences between the three fatty acid chains shown here? Should we tell them to kink the double bonded areas or not yet? **ANIMATE THIS so it labels these…and then goes away and asks them to draw it in their notes. Fatty Acid 3 Glycerol http://www.spaceflight.esa.int/impress/text/education/Images/Glossary/GlossaryImage%20052.png

Now draw this triglyceride in your notes

Fatty Acids Fatty acids have long hydrocarbon chains Twig: Hydrocarbons http://burnanenergyjournal.com/tag/hydrocarbons/

Hydrocarbons There is a shorthand for drawing this part of the fatty acid chains To simplify a hydrocarbon, we draw a kinked line Each bend or end of a line is a carbon atom Stearic acid is mainly used in the production of detergents, soaps, and cosmetics such as shampoos and shaving cream products. 

Practice Shorthand for Hydrocarbons Try drawing the two molecules below: Chemical Name Ethanol Heptane Chemical Formula Ball & Stick Model Abbreviated (Shorthand) Model C2H5OH C7H16 Heptane is found in gasoline OH

Example Triglyceride Sketch Now draw The triglyceride in your notes USING THE SHORTHAND METHOD

Saturated vs. Unsaturated A lipid’s function can be affected by the saturation of the fatty acids Saturated: it is “saturated” with hydrogen atoms (maximum number of hydrogen, every spot filled). Unsaturated: at least one double bond between carbon atoms thus the chain has fewer hydrogen.

Saturated vs. Unsaturated Saturated fats are solid at room temperature and unsaturated fats are liquid. Saturated fats are found in animals E.g. butter and meat. Unsaturated fats are found in plants E.g. olive or peanut oils. Based on their structure (right) can you guess why saturated fats are solid and unsaturated are liquid at room temp? Share with a neighbor. Can use a deck of cards to show how the molecules stack together – bend some of the cards to show the unsaturated fatty acids. http://yourbestyou90.com/wp-content/uploads/2011/07/saturated_unsaturat_c_la_784.jpg

“Butter Manatee and Diver” sculpted by Jim Victor, Palmetto, FL Manatee County Fair, Jan. 2012 Anyone eat straight butter as a child? Ms. Turner’s family had to hide the butter…she would climb up on the counter and scoop it out with her hands.  http://www.jimvictor.com/AssetsFood/foodsculpture.html

Natural peanut butter can separate into both types! Unsaturated Saturated

Saturated vs. Unsaturated Saturated and unsaturated fats have different properties because of how the molecules pack together. Which molecule do you think would pack together more closely?

Saturated vs. Unsaturated Unsaturated fatty acids have lower melting points than saturated fatty acids. What does it mean to melt on a molecular level? What would that look like? If molecules are stacked closer to each other do you think the substance would melt faster or slower? Note that as a group, the unsaturated fatty acids have lower melting points than the saturated fatty acids. The reason for this phenomenon can be found by a careful consideration of molecular geometries. The tetrahedral bond angles on carbon results in a molecular geometry for saturated fatty acids that is relatively linear although with zigzags. See graphic on the left. This molecular structure allows many fatty acid molecules to be rather closely "stacked" together. As a result, close intermolecular interactions result in relatively high melting points. (MEANING it is harder to get them moving and away from each other…the more moving a.k.a. kinetic energy, the more “melting”….thus if they have strong interactions it is harder to get the substance to melt). On the other hand, the introduction of one or more double bonds in the hydrocarbon chain in unsaturated fatty acids results in one or more "bends" in the molecule. The geometry of the double bond is almost always a cis configuration in natural fatty acids. These molecules do not "stack" very well. The intermolecular interactions are much weaker than saturated molecules. As a result, the melting points are much lower for unsaturated fatty acids. (If they have weak interactions it is easier to break them away from each other and get them moving!) http://www.elmhurst.edu/~chm/vchembook/551fattyacids.html

How would the bottom 3 fatty acids look different from stearic acid? Of the 4, which one would be able to pack together the most? THUS, which melting point would be highest??? Share your thoughts with your neighbor! Don’t forget to give them time to think it out on their own.  stearic acid oleic acid linoleic acid linolenic acid stearic acid m.p. 70ºC oleic acid m.p. 16ºC linoleic acid m.p. -5ºC linolenic acid m.p. -11ºC

Melting Point Wrap-Up THINK, PAIR, SHARE: What statement can you make about the relationship between the number of double bonds in fatty acid chains and its melting point? What evidence could you gather to support your claim? stearic acid - m.p. 70ºC oleic acid - m.p. 16ºC linoleic acid - m.p. -5ºC linolenic acid - m.p. -11ºC

Saturated vs. Unsaturated Fatty Acids in Fats and Oils THINK, PAIR, SHARE: If you want the most unsaturated fatty acids in your diet, which is the most healthy oil you should use the most? Which fat or oil contains the most saturated fatty acids? Most unsaturated fatty acids = olive oil Most saturated fatty acids = beef fat http://www.elmhurst.edu/~chm/vchembook/551fattyacids.html

Phospholipid Cell membranes are made up of a lipid similar to triglycerides; a phospholipid Structure: Glycerol backbone attached to a phosphate group “head” and 2 fatty acid “tails” The tails can be saturated or unsaturated (*Animation*) About 80% of the way down… Function: Provide a selective barrier between the inside and outside of the cell and cellular compartments. http://media1.shmoop.com/images/module_images/PhospholipidFlashcard_640x480.jpg

in your notes USING BOTH Methods Phospholipid draw The Phospholipid in your notes USING BOTH Methods http://myhome.sunyocc.edu/~weiskirl/cell_membrane2.gif

How we will picture a Phospholipid

Steroids Structure: Function: 4 interconnected rings Aids in fluidity/flexibility of cell membrane (cholesterol) Hormones that act as signaling molecules (i.e. testosterone and estrogen) Cholesterol works similar to unsaturated fatty acid chains in phospholipids. They make it harder for the phospholipids to pack together thus increasing the fluitidy. http://2012books.lardbucket.org/books/principles-of -general-chemistry-v1.0/s28-06-the-molecules-of-life.html http://www.people.vcu.edu/~urdesai/intro.1.gif

Hormones = Signaling Molecules Androgens (male sex hormones) Produced in the testes Responsible for development of male sex characteristics Estrogens (female sex hormones) Produced in the ovaries Responsible for development of female sex characteristics Cortisone Hormones Produced in the adrenal cortex Regulate metabolism of carbohydrates, decrease inflammation, involved in reaction to stress Someone who dresses “androgenous” is a female dressing more masculine i.e. wearing a suit jacket and tie.

Let’s Fill in Your Macromolecule Table for Lipids! Types of Atoms Monomers made of Function(s) Examples Sketch