Carbon-based Molecules Part 2: Lipids and Proteins

Objective SWBAT compare and contrast the functions and structure of the carbon-based molecules: carbohydrates, lipids, proteins, and nucleic acids.

Starter We have talked about polymers at great length, I now what you to think about the polymers that you use on a daily basis. What are the polymers that you commonly use? You can discuss this with your neighbor.

A quick explanation of PH Some compounds form acids or bases. An acid releases a hydrogen ion when it dissolves in water. – high H + concentration – pH less than 7 more acidic stomach acid pH between 1 and 3

A quick explanation of PH A base removes hydrogen ions from a solution. –low H + concentration –pH greater than 7 –Pure H 2 o is 7 (neutral) – sea water is 7.4 to 8.4 bile pH between 8 and 9 more basic

Polarity of Molecules Polarity is a physical property of a molecule. – It contributes to physical properties such as boiling and melting points (greater the polarity, higher the boiling and melting points). Two polar molecules, ammonia on the left and water on the right A polar molecule has one pole that is negative and one that is positive (in the water molecule, the red is negative – oxygen - while the purplish region is positive (hydrogen).

Lipids Lipids are nonpolar molecules that include fats, oils, and cholesterol. – Nonpolar molecules do not have charged regions. –Many contain carbon (C) chains, like carbohydrates, called fatty acids. –The fatty acids are C atoms bonded to oxygen and hydrogen. –Fats and oils contain fatty acids bonded to glycerol (which is hydrogen and oxygen bonded to the fatty acid – it is water soluble).

Fatty Acids A saturated fatty acid has no C-C bonds. Unsaturated does. Olive oil is unsaturated fat while butter is very high in saturated fat.

Lipid Functions Lipids have several different functions. They are: –broken down as a source of energy –make up cell membranes (phospholipids) – used to make hormones

Lipids make cell membrane

Cell Membrane - phospholipid Phospholipids make up all cell membranes. –Polar phosphate “head” –Nonpolar fatty acid “tails”

Proteins Proteins are polymers of amino acid monomers – the polymers are created in the cell as part of DNA translation process. Twenty different amino acids are used to build proteins in organisms.

Def. of Amino Acid Amino acids are molecules that contain C, H, O, N, and sometimes sulfur. – Our bodies are able to make 12 of the 20 amino acids, the rest come from what you eat. – The amino acid monomers are linked together by peptide bonds to form protein polymers.

Amino acids give proteins shape Proteins differ in the number and order of amino acids. Amino acids interact to give a protein its shape, which determines its biological function(s).

Entrance Ticket: What is this? What does it do (purpose)? This is homework if not done in class. It is for your entrance ticket tomorrow. It is worth five points and you will turn it in. Use your book