Introduction to Biochemistry 3 Biology, Ch. 2 “Molecules of Life”

Classes of Organic Compounds There are four main groups of molecules needed for life. They are Carbohydrates Lipids Proteins Nucleic acids

Carbohydrates Organic molecules that provide energy for living things Building Block: Monosaccharides Many times, but not always, carbs are build of repeating monosaccharides (ex. Starch) Made of Carbon, Hydrogen, & Oxygen Basic chemical formula is (CxH2nOn) Ratio of atoms in a molecule is 2 Hydrogens: 1 Oxygen Ex: C6H12O6 and C3H6O3

Carbohydrates Carbohydrates on the Internet There are 3 size classifications for carbs: Monosaccharide-single monomer of carbohydrate Example: one glucose molecule Disaccharide-2 monosaccharides bonded together Example: Sucrose (glucose + fructose) Polysaccharide-3 or more monosaccharides bonded Example: Cellulose (glucose + starch)

Carbohydrates Functional Groups Carbohydrate + Hydroxyl Group (OH) Makes an alcohol Also creates a polar molecule

Lipids Organic molecules that store energy for living things Made of Carbon, Hydrogen, and Oxygen Basic ratio is WAY more than 2 Hydrogen: 1 Oxygen More C—H bonds than C—O because C—H bond stores more energy

Lipids Lipids on the Internet Lipids are Fats! Fatty Acids-chains of carbon that make lipids Polar Functional Group: COOH (carboxyl group) Nonpolar Functional Group: C-H (hydrocarbon) Saturated Fats-all carbons single bonds Unsaturated Fats-contain carbon double bonds

Lipids

Why Know Lipids? Steroids are made from lipid Triglycerides Fat compounds found in food and the body Saturated & Unsaturated varieties Phospholipids Main component of the cell membrane Wax Protective agent for ears and leaf exteriors

Proteins An organism’s DNA contains the instructions to make proteins, and proteins are what make individuals unique. Organic compounds made of Hydrogen, Carbon, Oxygen, and Nitrogen Skin, muscles, and enzymes are composed of proteins

Proteins Amino Acid –building block of protein Bond by peptide bonds to form proteins Many peptide bonds = “polypeptide,” another name for protein There are 20 different amino acids 11 can be made by the body 9 are considered “essential” because they must be obtained through diet

Proteins Amino Acid Functional Groups Amino Group: NH2 Carboxyl Group: COOH R Group: Varies per amino acid

Proteins Proteins on the Internet Amino acids bonded together give proteins their shape Protein shape determines function of the protein Many proteins are enzymes

Nucleic Acids Large complex organic molecules that store genetic information Composed of long chains of bonded nucleotides Nucleotide = sugar + phosphate + nitrogen containing base

Nucleic Acids A Nucleotide

Nucleic Acids: DNA Building a DNA Molecule DNA (Deoxyribonucleic Acid) Stores the genetic code in an arrangement of 4 nitrogen bases Nitrogen bases by Hydrogen Bonds to hold two chains of nucleotides into a ladder shape The ladder twists into a spiral DNA is located in the nucleus of the cell

Nucleic Acids: RNA RNA (Ribonucleic Acid) Single chain of nucleotides Transfers genetic message (the DNA message) from nucleus out into the cell

Some Good Cornell Note ?’s What are the 4 classes of organic molecules? Carbohydrates What do carbs do for an organism? What is the atom ratio used to identify a carb? How does adding an OH to a carb affect it? What is the (sometimes repeating) subunit (building block) of a carbohydrate? How would you test for the presence of carbon in a substance? What is a positive test result for carbon? How would you test for the presence of sugar in a substance? What is a positive test result for sugar? How would you test for the presence of starch in a substance? What is a positive test result for starch?

Some Good Cornell Note ?’s Lipids What do lipids do for the body? What is the atom ratio in a lipid? How can you tell the chemical or structural formula for a lipid apart from that of a carb? Which bond in a lipid is the most energetic? How can you tell a plain old lipid apart from a fatty acid? How can you test for the presence of lipid in a substance? What is a positive test result?