Chemical Compounds of Life Section 4-2 and 4-3 Chemical Compounds of Life

Inorganic vs. Organic Compounds C, H, N, and O make up almost all chemical compounds in living organisms. Organic compounds - contain carbon. Carbon can form long carbon chains by bonding to other carbon atoms. Unique because they are very strong/stable! Inorganic compounds - do not contain carbon. Exception: CO2

Carbon Compounds Polymerize Polymerization - process by which large compounds are constructed by joining together smaller compounds (monomers). Monomers are joined by chemical bonds to form polymers. Very large polymers are called macromolecules.

Carbohydrates Carbohydrates - macromolecules that are composed of the atoms carbon, hydrogen, and oxygen in the proportion of 1:2:1. 1 carbon : 2 hydrogen : 1 oxygen. Examples: sugars and starches.

Carbohydrates - Monosaccharides Monosaccharide – simple, single sugar molecule. Examples: glucose (produced by green plants), fructose (fruits), and galactose (milk). Sugars are important for living things because they contain a great deal of energy.

Carbohydrates - Disaccharides Disaccharide – 2 sugar molecules bonded together by a covalent bond. Examples: lactose or sucrose.

Carbohydrates - reactions Dehydration synthesis - reaction that joins two monosaccharides into a disaccharide and involves the loss of water. Hydrolysis - reaction that breaks a disachharide into monosaccharides by using a water molecules.

Carbohydrates - Polysaccharides Polysaccharides – macromolecules formed from linking many monosaccharides together. Ex. Starch – a polysaccharide plants use to store energy; many glucose molecules bonded together. Ex. Glycogen - stored form of glucose from starch; stored for energy in liver of animals. Ex. Cellulose – chains of glucose, structurally different from starch, tough flexible molecule found in plants.

Nucleic Acids Nucleic acids - Polymers made of building blocks (monomers) called nucleotides. Contain H, O, P, C, and N. Nucleic acids store and transmit hereditary information. Example – DNA and RNA. DNA has a deoxyribose sugar, RNA has a ribose sugar.

Lipids Lipids - organic compounds that are oily or waxy. Common examples: fats, oils, and waxes. Lipids are made of C, H, and O (no ratio H to O). Lipids function in energy storage, form biological membranes, and act as chemical messengers. Lipids have more energy than carbohydrates because lipids have more hydrogens bonded to the carbon chain. Lipids have a water loving portion, and a water hating portion.

Types of Lipids Lipids are polymers made of monomers of fatty acids and glycerol. Saturated Lipids: contain the maximum number of carbon to hydrogen bonds. Example – animal fats. Also called “bad fats”.

Types of Lipids Unsaturated Lipids: Contain carbon to carbon double bonds; less hydrogen. Example – plant oils (corn oil, vegetable oil) Also called “good fats”.

Types of Lipids Sterols - ringed structures that play roles in building cells and carrying messages. Example – cholesterol; hormones. Phospholipids - contain parts that dissolve well in water and parts that do not. Spontaneously form bilayers to keep water hating portions protected and water loving portions in contact with water.

Proteins Proteins - polymers made of building blocks (monomers) called amino acids. Amino acids have an amino group, carboxyl group and an R group. Differences in R groups make each of the 20 amino acids different. List of Amino Acids and their structure

Peptides Peptides - short polymers of amino acids linked by peptide bonds. Peptide bonds are covalent bonds that join together amino acids. Once a polypeptide (long chain of amino acids) is formed, it must be folded into a 3-D shape before it is called a protein. The shape is important for recognition of the protein by the cell and for the actions of the protein.

Proteins Used to form skin, muscle, hair. Proteins play a role in metabolism, help fight disease, used to assist chemical reactions (enzymes), and signaling other cellular functions. Enzymes are special proteins.

Enzymes Enzymes – proteins that act as biological catalyst and speed up the rate of a chemical reaction. Enzymes are not changed by the reaction (so they can be re-used). Enzymes are very specific – they will only speed up one chemical reaction. Enzymes speed up chemical reactions by lowering the “start-up” energy of a reaction. The names of most enzymes will end in “ase” such as ligase, amylase, polymerase.

Enzymes Enzymes will bind to the reactants of the chemical reaction that it will catalyze. The reactants that enzymes bind to are called substrates. The site in which the substrates are brought to is called the active site. Substrates will fit into the active site like a lock and key. If the substrates do not fit in the active site, it is the wrong enzyme and it will not catalyze a reaction!

Enzymes Enzymes function in regulating chemical pathways, making materials that cells need, releasing energy, and transferring information. Enzyme Animation