Organic Molecules 1. Traits:

 

a. Usually contain Carbon and Hydrogen.

b. Frequently formed with covalent bonds.

c. Found in living organisms.

d. Usually larger than inorganic molecules (eg: proteins, carbohydrates, lipids, nucleic acids, ATP).

e. Many organic molecules are formed by dehydration synthesis (ie: remove H+ from one molecule and OH- from another to form H2O).

2. Carbon: a. An important organic element.

Often forms carbon chains and rings.b. 4 electrons in outer shell. Tends to bond with oneself. c. Hydrocarbon chains make up backbones of many organic molecules (starch, glycogen, cellulose, fatty acids, DNA, RNA). Reactive groups (functional groups) are attached and responsible for chemical properties of molecule.

d. Functional groups:

-carbonyl-hydroxyl - amino -carboxyl-phosphate

-carbonyl: C=O (ketones)

-hydroxyl: - OH (alcohols)

Amino: - NH2 (amino acids)

Carboxyl:- C=O (organic acids)

Phosphate

3. Proteins:• a very diverse set of molecules

composed of amino acids (20).

•

• Types: Enzymes, antibodies, cell receptors, membrane carriers, hormones, structural molecules.

a. Mainly a structural function in living organisms: - Collagen-- connective tissue protein- Keratin-- hair, nails, skin- Elastin-- connective tissue protein- Actin & Myosin-- muscle proteins- Hemoglobin--red pigment molecule in RBCs

  b. Enzymes: Initiate (catalyze) and accelerate chemical reactions. Act as catalysts to speed up chemical reactions. Enzymes are not destroyed in the reaction and are used repeatedly. Enzymes act upon specific substrates.

c. Hormones: Stimulate functions in various parts of body. Produced in endocrine glands and

transported through the blood to target tissues.

Enzime

•

d. Structure of Proteins: Amino acids (subunits of proteins; building block

molecules joined by peptide bonds).

-Dipeptide= 2 amino acids bonded together covalently.

-Polypeptide= many amino acids covalently bonded.

Denaturation: the breaking of hydrogen bonds that maintain tertiary structure. Enzyme loses proper functional, molecular shape for its substrate.

4. Carbohydrates: Organic molecules that contain carbon, hydrogen, and oxygen (sugars and starches). a. Structure: H-C-OH, 2:1 ratio H to C

Carbohydrates

• Monosaccharides

• Disaccharides

• Polysaccharide

Monosaccharides (simple sugars)-- 1 single-unit sugar molecule comprises the molecule of the compound (glucose, fructose, galactose, deoxyribose). Monosaccharides are the building blocks of carbohydrates.

 

Disaccharides-- 2 monosaccharide molecules covalently bonded

- glucose+ glucose = maltose - glucose + fructose = sucrose - glucose + galactose = lactose

Polysaccharide-- many monosaccharides covalently bonded.

-Glycogen, animal sugar (storage of glucose). Stored in liver and muscle.

-Starch, plant sugar (storage of glucose).

-glucose is stored as a large molecule rather than individual molecules. Prevents osmotic damage to the cell.

• Lipids: All nonpolar molecules insoluble in water.

   

a. In animals, fats function as energy storage molecules that provide protection, insulation, padding, support.

• Fats & Oils (triglycerides)

 

-Glycerol + 3 fatty acids (long carbon chains \

Covalent bond Carbon

• Double covalent

• Triple Covalent bond

• Saturated fatty acids (only single covalent bonds between carbons).

I.g. Beef, pork, lard, butter, whole milk, eggs, cheese, palm oil.

Unsaturated fatty acids (1 or more double covalent bond between carbons).

 -Polyunsaturated: corn, safflower, sunflower, cottonseed, sesame, Soybean oils.-Monounsaturated: olive, canola, and peanut

oils

Other important lipids:

• Steroids • Phospholipids

• Phospholipids

• Vitamins E, A, D, K

Steroids: Cholesterol (structural and precursor molecule to the sex hormones and adrenal cortex hormones.

Phospholipids: components of membranes. Phosphate end of molecule is polar (hydrophilic). Hydrocarbon chain is nonpolar (hydrophobic). Form micelles, surfactant.

Prostaglandins: blood molecules with many functions

Vitamins E, A, D, K (fat soluble vitamins).