Organic Macromolecules: Proteins and Nucleic Acids

I. Levels of Protein Structure polymers monomersamino acids A. Proteins are polymers made up of monomers called amino acids. an organic compound of the general formula H 2 N-CHR-COOH where R can be one of 20 side proteins Amino Acids – an organic compound of the general formula H 2 N-CHR-COOH where R can be one of 20 side proteins

An illustration of how the atoms in a CARBOXYL group are arranged would be: Note: The “R” shows represents where the carboxyl group attaches to an amino acid (also where it would attach to carbohydrates, lipids, and nucleic acids)

R (“residue”) alter the functions of the amino acid chain simply by changing how it interacts with other amino acids. 1. Amino acids have different R (“residue”) groups that can alter the functions of the amino acid chain simply by changing how it interacts with other amino acids. 20 chainspolypeptides 2. There are 20 different amino acids (with 20 different R-groups) that can form long chains called polypeptides. a large molecule made up of many amino acids; joined by peptic linkages (peptide bonds) Polypeptides – a large molecule made up of many amino acids; joined by peptic linkages (peptide bonds)

4 primary (1 o ), secondary (2 o ), tertiary (3 o ), and quaternary (4 o ). B. Protein structure can be discussed on 4 basic levels: primary (1 o ), secondary (2 o ), tertiary (3 o ), and quaternary (4 o ). The specific sequence of amino acids in a protein that is determined by your DNA. Primary Structure – The specific sequence of amino acids in a protein that is determined by your DNA. localized regularities of structure (H-bonds between amino acids effect secondary structure) Secondary Structure – localized regularities of structure (H-bonds between amino acids effect secondary structure) the relative locations in space of all atoms in the molecule Tertiary Structure – the relative locations in space of all atoms in the molecule the arrangement of polypeptide chains (in proteins with multiple polypeptide chains) Quaternary Structure – the arrangement of polypeptide chains (in proteins with multiple polypeptide chains)

II. How Protein Structure is determined primary level (1 o ) A. The simplest level of protein structure is the primary level (1 o ). the specific order of amino acids dictated by mRNA during protein synthesis. 1. This level of protein structure describes the specific order of amino acids dictated by mRNA during protein synthesis. the information for primary protein structure comes directly from DNA. 2. Since mRNA is transcribed (“written”) directly off of a DNA strand then the information for primary protein structure comes directly from DNA.

a dehydration synthesis forming peptide bonds between the amino acids 3. Amino acids are joined together through a dehydration synthesis forming peptide bonds between the amino acids a covalent bond formed between two amino acids when the carboxyl group of one amino acid reacts with the amine group (NH 2 ) group of another amino acid and a molecule of water is released. Peptide bond (peptic linkage) – a covalent bond formed between two amino acids when the carboxyl group of one amino acid reacts with the amine group (NH 2 ) group of another amino acid and a molecule of water is released.

secondary (2 o ) level B. The next level of protein structure is the secondary (2 o ) level. how the amino acids interact with each other 1. This level of protein structure is determined by how the amino acids interact with each other. location and types of amino acids in the polypeptide chain. 2. The interactions depend on the location and types of amino acids in the polypeptide chain. Hydrogen bonds 3. When certain amino acids are placed in a specific order, Hydrogen bonds form between them causing the polypeptide chain to twist and bend.

tertiary level (3 o ) C. The third level of protein structure is the tertiary level (3 o ) causes the polypeptide to take on an overall three dimensional shape. 1. The folding of the secondary level causes the polypeptide to take on an overall three dimensional shape. the 3-D shape of proteins determines the protein’s purpose within the body. 2. This level of protein structure is used to classify proteins because the 3-D shape of proteins determines the protein’s purpose within the body. form structures are functional 3. Proteins usually form structures (will have rigid shapes) or are functional (will have twisted shapes)

quaternary level (4 o ) D. The Fourth level of protein structure is the quaternary level (4 o ). not all proteins are composed of more than one polypeptide chain. 1. Not all proteins can be described at this level because not all proteins are composed of more than one polypeptide chain. containing more than one polypeptide chain join together like pieces to a puzzle to form the final product. 2. At this level proteins containing more than one polypeptide chain join together like pieces to a puzzle to form the final product. hemoglobin 3. A common protein with quaternary structure is hemoglobin.

III. Enzymes A. Enzymes A. Enzymes are protein catalysts that help speed up chemical reactions in living things only. a type of protein in all living things that speed up the rate of chemical reactions Enzyme – a type of protein in all living things that speed up the rate of chemical reactions substrates 1. Enzymes work by manipulating substrates a reactant that an enzyme acts on to speed up a chemical reaction Substrate – a reactant that an enzyme acts on to speed up a chemical reaction

2. An enzyme can speed up chemical reactions by: Twisting and breaking bonds to make the number of products greater than the number of substrates.(catabolic) Twisting and breaking bonds to make the number of products greater than the number of substrates.(catabolic) Holding substrates together making the number of products less than the number of substrates.(anabolic) Holding substrates together making the number of products less than the number of substrates.(anabolic)

unique and only specific substrates will fit into its active site. B. The shape of the enzyme is unique and only specific substrates will fit into its active site. the part of an enzyme where manipulation of the substrate occurs Active site – the part of an enzyme where manipulation of the substrate occurs the enzyme is free to act on another substrate until it is metabolized (chemically destroyed). 1. Once an enzyme acts on a substrate the enzyme is free to act on another substrate until it is metabolized (chemically destroyed). then the enzyme will have the wrong shape which means the substrate won’t fit into the active site. 2. If during protein synthesis amino acids are not placed in the proper order then the enzyme will have the wrong shape which means the substrate won’t fit into the active site. *Cause of many recessive traits and genetic disorders.

I. Nucleic Acids polymers monomersnucleotides A. Nucleic Acids are polymers made up of monomers called nucleotides. unit of a nucleic acid that is made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base (which varies) Nucleotides – unit of a nucleic acid that is made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base (which varies)

B. There are two basic kinds of nucleic acids: Ribonucleic Acid contain nucleotides with 5-carbon sugar ribose RNA - Ribonucleic Acid contain nucleotides with 5-carbon sugar ribose Deoxyribonucleic acid contains nucleotides with the 5-carbon sugar deoxyribose DNA – Deoxyribonucleic acid contains nucleotides with the 5-carbon sugar deoxyribose

complementary nucleotide C. Nucleotides can only form base pairs with a complementary nucleotide. Hydrogen bonds 1. Two DNA molecules are held together by Hydrogen bonds that form between the nitrogenous bases. Hydrogen bonds 2. When mRNA is being translated, the nucleotides form Hydrogen bonds with the complementary DNA nucleotide. 5-carbon sugars dehydration synthesis sugar-phosphate backbone 3. The 5-carbon sugars form covalent bonds through dehydration synthesis to form the sugar-phosphate backbone of the nucleic acid molecule. store transmit D. The only function of nucleic acids is to store and transmit genetic information.