Chapter 2

Organic Compounds

Biochemistry: Essentials for LifeBiochemistry: Essentials for Life

1. Organic compounds

• Contain carbon with hydrogen and oxygen

• Most are covalently bonded

• Example: C6H12O6 (glucose)

2. Inorganic compounds

• Lack carbon w/ H & O

• Tend to be simpler compounds

• Example: H2O (water), CO2

Important Inorganic CompoundsImportant Inorganic Compounds

1. Water

• Most abundant inorganic compounds

• Vital properties

• High heat capacity

• Polarity/solvent properties

• Chemical reactivity

• Cushioning

Important Inorganic CompoundsImportant Inorganic Compounds2. Salts

• Easily dissociate into ions in the presence of water

• Vital to many body functions

• Include electrolytes which conduct electrical currents

Important Inorganic CompoundsImportant Inorganic Compounds3. Acids

• Can release detectable hydrogen ions

4. Bases

• Proton acceptors

pHpH

• Measures relative concentration of hydrogen ions

• pH 7 = neutral

• pH below 7 = acidic

• pH above 7 = basic

• Buffers

• Chemicals that can regulate pH change

Important Organic CompoundsImportant Organic Compounds

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

• ATP

1. Carbohydrates

• Contain carbon, hydrogen, and oxygen

• Include sugars and starches

• Classified according to size

• Monosaccharides – simple sugars

• Disaccharides – two simple sugars joined by dehydration synthesis

• Polysaccharides – long branching chains of linked simple sugars

CarbohydratesCarbohydrates

Figure 2.12a, b

2. Lipids

• Contain carbon+, hydrogen+, and oxygen

• C and H outnumber O

• Insoluble in water

Common lipids in the human body

a. Neutral fats (triglycerides)- Found in fat deposits- Composed of fatty acids & glycerol- Source of stored energy

b. Phospholipids- Form cell membranes

c. Steroids - cholesterol, bile salts, vitamin D, & some

hormones

LipidsLipids

CholesterolCholesterol

3. Proteins

• Made of amino acids

• Contain C, O, H, N, and sometimes sulfur

• over ½ of body’s organic matter

• Structural (fibrous) proteins

Ex. keratin

• Functional (globular) proteins

Ex. enzymes, hormones, & antibodies

Enzymes (Functional Proteins)Enzymes (Functional Proteins)

• Act as biological catalysts

• Increase the rate of chemical reactions

4. Nucleic Acids

• Provide blueprint of life

• Nucleotide bases

• A = Adenine

• G = Guanine

• C = Cytosine

• T = Thymine

• U = Uracil

• Make DNA and RNA

5. Adenosine triphosphate (ATP)

• Chemical energy used by all cells

• Energy is released by breaking high energy phosphate bond

• ATP is replenished by oxidation of food fuels

How ATP Drives Cellular WorkHow ATP Drives Cellular Work