Week 2 Lecture 3, Organic Chemistry:

-The study of carbon-based molecules. -Almost all molecules in all organisms are based on carbon. -“Carbon-based lifeforms”

The Molecular Backbone of Biology-Chains of carbon form the skeletons of most organic molecules. -To generate molecular diversity…

-change the organization of the “backbone” -change the “accessories” on the backbone-change the organization of the accessories

Variations of the Backbone

Accessorizing the Backbone-Functional groups are attached to the backbone. -Give complex molecules their characteristics. -Small changes can make a big difference.

Functional Groups-Hydroxyl Group

-polar-likes to hydrogen bond-hydrophilic

-Carbonyl Group-polar-reactive (important for chemical reactions)

-Carboxyl Group (COOH)-acidic-component of amino acids

-Amino Group (N H 2)-basic-component of amino acids

-Phosphate Group-negatively charged ion-crucial for energy transfer-part of DNA backbone-used for signaling

-Sulfhydryl Group-Able to crosslink to stabilize protein structure (disulfide bond).

Organization of Atoms in a Molecule-Two molecules can have the same number of atoms or the same functional groups but behave differently-isomers. -Types of isomers

-structural isomers-geometric isomers-enantiomers

Structural Isomers-Atoms covalently linked in a different order.

Geometric Isomers-Arrangement around a double bond.

Enantiomers-Mirror images. -Cannot be superimposed.

-Contains asymmetric carbon.

Week 2 Lecture 4, Molecules of Life:

Macromolecules-While water is the most abundant molecule in nature, macromolecules define life. -Uncountable number of water molecules in each human cell. -46 molecules of DNA in each human cell. -Water is 3 atoms covalently linked. -The smallest human DNA molecule (chromosome 22) is almost 4 billion atoms.

Types of Macromolecules-Nucleic Acids (DNA and RNA)-Protein-Carbohydrates-Lipids

-Almost all molecules in the cell fall into one of these four categories.

Macromolecule Composition-All macromolecules are made up of smaller subunits. -Except for lipids…

-One “subunit” is a monomer. -Monomers are covalently linked to make polymers.

Making and Breaking Macromolecules-A dehydration reaction builds macromolecules (and makes water!)-A hydrolysis reaction destroys macromolecules (and uses up water!)

Nucleic Acids-Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA)-DNA is the instruction manual for making proteins. -DNA is used as a template to make RNA-RNA is used to make protein

-RNA is both the template and the machinery! -Both are made of nucleotides

Protein-Most proteins are enzymes-the machinery of the cell. -Some proteins are structural; they control the shape of the cell. -Some proteins signal other enzymes to get to work or to stop working. -Proteins are made of amino acids.

Carbohydrates-Store energy.

-Provide energy for enzymes to work. -Structural (plant cell walls). -Signaling-bind proteins to activate or inactivate them (signaling carbohydrates are usually found on the surface of the cell). -Carbohydrate are made of simple sugars.

Lipids-Form the membrane that surrounds all cells. -Store energy-Signaling-active enzymes-Lipids are not polymers-All are hydrophobic-Most lipids are made of fatty acids and glycerol

Other Biological Molecules-Not all molecules in the cell are macromolecules. -Sometimes monomers are important on their own.

-ATP and GTP are the energy currency of the cell-used directly by enzymes in chemical reactions. -Some amino acids are also neurotransmitters.

-Some molecules do not fit into the four categories at all.

Neurotransmitters-Released by neurons to communicate to the next neuron.

Phytochemicals-Chemicals made by plants-usually as a defense. -Many are being studied for their health benefits for human-eat your fruits and veggies!

Phytochemical Examples-Resveratrol

-Defensive chemical in plants.

-Abundant in red wine. -Anti-cancer properties.

-EGCG-Unknown function in plants. -Abundant in tea. -Antioxidant.

Vitamins-Essential chemicals in human died. -Usually act as cofactors for enzymes (combine with the enzyme to make the enzyme functional).

Salts and Ions-Ions-sodium (N a+¿ ¿), chloride (C l−¿ ¿), calcium (C a++¿¿), potassium (K+¿ ¿), hydrogen (H+¿¿, proton)-Large salts-hydroxyapatite (C a10 (PO4 )6 (OH )2¿ is the primary component of bone.