Biochemistry and Carbon Compounds

Objectives 1. Relate the structure of a carbon atom to the complexity of carbon compounds. 2. Compare the structures and functions of carbohydrates, lipids, and proteins. 3. Distinguish between condensation and hydrolysis reactions.

Carbon Compounds Most carbon compounds are also known as organic compounds because they are found in almost all living things. Organic compounds usually also contain O and H.

Isomers Isomers are substances that have the same chemical formula, but different structures. Examples are maltose, lactose, and sucrose. All have the formula C12H22O11. Because the structures are different, the properties change.

Biomolecules The four groups of biomolecules (chemical compounds found in and used by living things) are: Carbohydrates Lipids Proteins Nucleic acids

Carbohydrates A carbohydrate is an organic compound composed of C, H, and O with the ratio of 2H:1O. Examples include starch, sugars, glucose. The function of carbs is to serve as an energy source for metabolic functions.

Types of Carbohydrates Simple sugars are called monosaccharides. Glucose is an example. Two simple sugars joined together is called a disaccharide. Lactose is an example. Several simple sugars joined together make up a polysaccharide. Starch and glycogen are examples.

Lipids Lipids are composed of C, H, and O, but the numbers of H are much higher than in carbohydrates. Examples include fats, oils, waxes, cholesterol, and steroids. None of these substances will dissolve in water.

The function of fats is to serve as an energy reserve, provide insulation, and protect nerves. Fat molecules are a combination of fatty acids and glycerol. All lipids have a carboxyl group (-COOH) attached to them.

Proteins Proteins make up the largest group of organic molecules. Their function is to make muscle, carry out chemical reactions by acting as catalysts, fight disease, and transport materials throughout organisms.

All proteins have an amine group (-NH2) attached to them. Amino acids are the building blocks of proteins. There are 20 total and they combine in different ways to produce numerous proteins.

Protein Chains When amino acids bond together, they form a peptide. When two peptides join together, they form a dipeptide. When long chains of amino acids join, they form a polypeptide.

Enzymes Enzymes are proteins that lower the activation energy (energy needed to start a reaction) of a biological reaction, acting as catalysts to speed the reaction up. They allow reactions to occur at normal cell temperatures, rather than being heated up. In a cellular reaction, the reactants are called substrates. Enzymes are named by adding -ase to the name of the substrate involved. For example, in the reaction changing maltose to glucose, the enzyme used is maltase.

Types of Biological Reactions A condensation reaction is when an -OH is broken from one molecule and -H from another to allow them to attach. H2O is a by-product. This forms large molecules from smaller ones, like joining two glucose molecules together to make maltose. A hydrolysis reaction requires the addition of water for the reaction to take place. It breaks large molecules into smaller ones. It’s important because complex substances must be simplified to be digested by the body.

Nucleic Acids There are two nucleic acids: DNA and RNA. DNA - deoxyribonucleic acid; genetic code RNA - ribonucleic acid; carry out instructions in body, like protein synthesis The building blocks of nucleic acids are nucleotides. A nucleotide contains a phosphate group, a 5-carbon sugar, and a nitrogenous base.