2.4 & 7.3 Notes
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The document provides an overview of protein structure and function, detailing the four levels of protein structure: primary, secondary, tertiary, and quaternary. It explains amino acid properties, peptide bonds, and the significance of the amino acid sequence in determining a protein's conformation and function. Additionally, it highlights examples of proteins and their functions within living organisms, emphasizing the uniqueness of individual proteomes.
2.4 & 7.3 Notes
- 1. IB Biology Chapter 2 Notes: Proteins (2.4 & 7.3) NAME: Word Definition Amino acids The monomer of proteins—they are identical except for their side chains Primary structure The first level of protein structure—consists of a long chain of amino acids held together by peptide bonds. This determines the remaining levels (what the protein will be) Secondary structure The second level of protein structure—consists of hydrogen bonds between the carboxyl and amine group on the central chain. Tertiary structure The third level of protein structure—consists of bonds between the side chains— causes the protein to fold upon itself Quaternary structure When multiple polypeptides join together using a variety of bonds. Peptide bond The bond that holds amino acids together—formed through condensation Proteome Side chains (R groups) The variable part of amino acids—determines the properties of the amino acid -helix One type of secondary structure—forms a coil -pleatedsheet One type of secondary structure—folds like a fan Polypeptide A long chain of amino acids Covalent bond Bonds formed by sharing electrons, usually formed by two non-metals Van der Waals Attractions between molecules that are non-polar Hydrophobic Things that don’t mix with water (they are non-polar) Hydrophilic Things that mix with water (they are polar) Ionic bonds Bonds formed by an attraction between opposite forces—usually formed between one metal and one nonmetal Conjugated protein A protein formed by joining together multiple polypeptide chains Fibrous protein A protein whose over all structure is long and thin Globular protein A protein whose overall structure is like a big clump/ball .
- 2. 2.4.1 Amino acids are linked togetherby condensation to form polypeptides. 2.4.11 Draw molecular diagrams showing the formation of a peptide bond. 2.4.2 There are twenty different amino acids in polypeptides synthesized on ribosomes. 2.4.3 Amino acids can be linked togetherin any sequence giving a huge range of possible polypeptides. 2.4.4 The amino acid sequence of polypeptides is coded for by genes. 2.4.5 A protein may consist of a single polypeptide or more than one polypeptide linked together. 2.4.6 The amino acid sequence determines the three dimensional conformation of a protein. 2.4.10 Explain the denaturation of proteins by heat or deviation of pH from the optimum. Draw formation of a peptide bond: What is different between each of the 20 amino acids? What are some of structuraland/or chemical differences between the different amino acids? Number of Polypeptides Example Description Lysozyme Collagen Hemoglobin Globular proteins (describe and give example): Fibrous proteins (describe and give example):
- 3. 2.4.7 Living organisms synthesize many different proteins with a wide range of functions. 2.4.9 Identify rubisco, insulin, immunoglobulins, rhodopsin,collagen, and spider silk as examples of the range of protein functions. 2.4.8 Every individual has a unique proteome. Protein Function Description Catalysis Muscle contraction Cytoskeleton Tensile strength Blood clotting Transport of nutrients/ gas Cell adhesion Membrane transport Hormones Receptors Packing DNA Immunity Protein Example Function Rubisco Insulin Immunoglobulin (Antibodies) Collagen Rhodopsin Spider silk Describe what is meant by a ‘proteome:’
- 4. 7.3.7 The sequence and number of amino acids in the polypeptide is the primary structure. 7.3.8 The secondary structure is the formation of alpha helices and beta pleated sheets stabilized by hydrogen bonds. 7.3.9 The tertiary structure is the further folding of the polypeptide stabilized by interactions between R groups (side-chains). 7.3.10 The quaternary structure exists in proteins with more than one polypeptide chain. What types of bonds form the secondary structure? What are the two secondary structures? What types of bonds/ interactions form the tertiary structure?