BIOCHEMISTRY Organic compounds Compounds that contain carbon are called organic. Inorganic compounds do not contain carbon. Carbon has 4 electrons in outer shell. Carbon can form covalent bonds with as many as 4 other atoms (elements). Usually with C, H, O or N. Can form an endless diversity of carbon skeletons. Functional Groups There are certain groups of atoms that are frequently attached to the organic molecules and these are called functional groups. They give the molecule its properties; they are centers of chemical reactivity. Macromolecules Large organic molecules. Also called POLYMERS. Made up of smaller building blocks called MONOMERS. Types of Macromolecule: Carbohydrates Proteins Lipids Nucleic acids (DNA and RNA) How Are Macromolecules Formed? Dehydration Synthesis or condensation reaction Polymers formed by combining monomers and removing water. How are Macromolecules separated or digested? Hydrolysis Monomers are separated by adding water
Energy Currency - ATP ATP is used by cells for energy Adenosine triphosphate Made of a nucleotide with 3 phosphate groups Energy is stored in the chemical bonds of ATP The last 2 phosphate bonds are HIGH ENERGY Breaking the last phosphate bond releases energy for cellular work and produces ADP and a free phosphate ADP (adenosine Diphosphate) can be rejoined to the free phosphate to make more ATP Carbohydrates Carbohydrates are sugars which are composed of carbon, hydrogen and oxygen. Monosaccharide: A simple sugar with a ratio of elements normally of 1:2:1 (C:H:O). Examples: Glucose Fructose Galactose Ribose Disaccharides are a combination of two monosaccharides Examples: Sucrose(glucose + fructose) Lactose (glucose + galactose) Maltose (glucose + glucose) Polysaccharides are complex sugars composed of three or more monosaccharides Examples Glycogen - short term energy storage, hundreds of glucose molecules joined together (muscle) Starch (bread, potatoes)
Cellulose (plant walls) Proteins Proteins are polymers made of monomers called amino acids All proteins are made of 20 different amino acids linked in different orders Proteins can be structural (e.g. used to build cells), or act as hormones & enzymes, doing work Proteins are made of 20 different amino acids linked in different orders Amino acids have a central carbon with 4 groups bonded to it: Amino group NH2 Carboxyl group -COOH Hydrogen -H Side group -R Cells link amino acids together to make proteins. The process is called condensation or dehydration Peptide bonds form to hold the amino acids together Protein Structure Four levels of protein structure: 1. Primary Structure Amino acids bonded together by peptide bonds (straight chains) 2. Secondary Structure 3-dimensional folding arrangement of a primary structure into coils and pleats held together by hydrogen bonds. 3. Tertiary Structure
Secondary structures bent and folded into a more complex 3-D arrangement of linked polypeptides Bonds: H-bonds, ionic, disulfide bridges (S-S) Call a subunit. 4. Quaternary Structure Composed of 2 or more subunits Globular in shape Form in Aqueous environments Example: enzymes (hemoglobin) Proteins as Enzymes Many proteins act as biological catalysts or enzymes. Thousands of different enzymes exist in the body. Enzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction. Enzymes are globular proteins. Their folded conformation creates an area known as the active site. The nature and arrangement of amino acids in the active site make it specific for only one type of substrate. Lipids An organic compound that's major biological functions involve energy storage, structural component of cell membrane, and cell signaling. Not soluble in water. Lipids are soluble in hydrophobic solvents. Remember: stores the most energy Examples: Fats Phospholipids Oils Waxes
Steroid hormones Triglycerides Six functions of lipids: 1. Long term energy storage 2. Protection against heat loss (insulation) 3. Protection against physical shock 4. Protection against water loss 5. Chemical messengers (hormones) 6. Major component of membranes (phospholipids) Fatty Acids Saturated fatty acids have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons) Unsaturated fatty acids have less than the maximum number of hydrogens bonded to the carbons (a double bond between carbons) Triglycerides Composed of 1 glycerol and 3 fatty acid chains. Glycerol forms the backbone of the fat High melting point (hard at room temperature) Phospholipids Cell membranes are made of lipids called phospholipids Phospholipids have a head that is polar & attract water (hydrophilic) Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic) Waxes
Typically a long fatty acid connected to a long alcohol chain Waterproof Used as protective coating Steroids Composed of four fused carbon rings with different functional groups attached to them. Cholesterol - base steroid from which your body produces other steroids Needed for normal function of cells Estrogen Testosterone Nucleic Acids Very large complex molecules Store hereditary information Contain information for making all the body s proteins Polymers of nucleotides Two types exist --- DNA & RNA Deoxyribonucleic acid (DNA-double helix) Each DNA nucleotide has one of the following bases: Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Form long chains called DNA Nucleotides are joined by sugars & phosphates on the side Two strands of DNA join together to form a double helix The plans for the whole organism and all cellular activity
Ribonucleic acid (RNA-single strand) Ribose sugar has an extra OH or hydroxyl group It has the base uracil (U) instead of thymine (T) Transfers information from the nucleus to ribosomes for the production of proteins and in some cases can function in a similar way to enzymes