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This text discusses the four classes of macromolecules and provides examples for each type. It also explains the four levels of protein structure and the bonds formed in each level. Additionally, it mentions the protein involved in the curds and whey lab and explains the process of curd and whey formation. The chapter covers the role of dehydration synthesis and hydrolysis in organic compound formation and digestion, as well as the functions of carbohydrates, lipids, proteins, and nucleic acids.
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Warm-Up What are the 4 classes of macromolecules? Give an example of each type of macromolecule.
Warm-Up What are the 4 levels of protein structure? What bonds are formed in each level? Which protein was involved in the curds & whey lab yesterday? Explain what happened to the milk to form the curds and whey.
Chapter 5 The Structure and Function of Large Biological Molecules
You Must Know • The role of dehydration synthesisin the formation of organic compounds and hydrolysis in the digestion of organic compounds. • How to recognize the 4 biologically important organic compounds (carbs, lipids, proteins, nucleic acids) by their structural formulas. • The cellular functions of all four organic compounds. • The 4 structural levels of proteins • How proteins reach their final shape (conformation) and the denaturing impact that heat and pH can have on protein structure
ie. amino acid peptide polypeptide protein larger smaller
+ H2O + + H2O + https://www.youtube.com/watch?v=ZMTeqZLXBSo
I. Proteins Myoglobin protein • “Proteios” = first or primary • 50% dry weight of cells • Contains: C, H, O, N, S
Protein Functions (+ examples) • Enzymes (lactase) • Defense (antibodies) • Storage (milk protein = casein) • Transport (hemoglobin) • Hormones (insulin) • Receptors • Movement (motor proteins) • Structure (keratin)
Four Levels of Protein Structure • Primary • Amino acid (AA) sequence • 20 different AA’s • peptide bonds link AA’s
Amino Acid • R group = side chains • Properties: • hydrophobic • hydrophilic • ionic (acids & bases) • “amino” : -NH2 • “acid” : -COOH
Four Levels of Protein Structure (continued) • Secondary • Gains 3-D shape (folds, coils) by H-bonding • Alpha (α) helix, Beta (β) pleated sheet
Basic Principles of Protein Folding Hydrophobic AA buried in interior of protein (hydrophobic interactions) Hydrophilic AA exposed on surface of protein (hydrogen bonds) Acidic + Basic AA form salt bridges (ionic bonds). Cysteines can form disulfide bonds.
Four Levels of Protein Structure (continued) • Tertiary • Bonding between side chains (R groups) of amino acids • H bonds, ionic bonds, disulfide bridges, van der Waals interactions
Four Levels of Protein Structure (continued) • Quaternary • 2+ polypeptides bond together
amino acids polypeptides protein Bonding (ionic & H) can create asymmetrical attractions
Protein structure and function are sensitive to chemical and physical conditions • Unfolds or denatures if pH and temperature are not optimal
II. Nucleic Acids Function: store hereditary info
Nucleotides: monomer of DNA/RNA Nucleotide = Sugar + Phosphate + Nitrogen Base
Nucleotide phosphate A – T G – C Nitrogen base 5-C sugar
III. Carbohydrates Differ in position & orientation of glycosidic linkage • Fueland building material • Include simple sugars (fructose) and polymers (starch) • Ratio of 1 carbon: 2 hydrogen: 1 oxygen or CH2O • monosaccharide disaccharide polysaccharide • Bonds that hold together = glycosidic linkages • Monosaccharides = monomers (eg. glucose, ribose) • Polysaccharides: • Storage (plants-starch, animals-glycogen) • Structure (plant-cellulose, arthropod-chitin)
Cellulose vs. Starch Two Forms of Glucose: glucose & glucose
Cellulose vs. Starch • Starch = glucose monomers • Cellulose = glucose monomers
Storage polysaccharides of plants (starch) and animals (glycogen)
Structural polysaccharides: cellulose & chitin (exoskeleton)
II. Lipids Hydrophilic head Hydrophobic tail • Fats (triglyceride): store energy • Glycerol + 3 Fatty Acids • saturated, unsaturated, polyunsaturated • Steroids: cholesterol and hormones • Phospholipids: lipid bilayer of cell membrane • hydrophilic head, hydrophobic tails
Hydrophobic/hydrophilic interactions make a phospholipid bilayer