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Molecules of Life. Chapter 3 Part 1. Impacts, Issues: Fear of Frying. Trans fats in hydrogenated vegetable oil raise levels of cholesterol in our blood more than any other fat, and directly alter blood vessel/harden arteries – atheroslcerosis
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Molecules of Life Chapter 3 Part 1
Impacts, Issues:Fear of Frying • Trans fats in hydrogenated vegetable oil raise levels of cholesterol in our blood more than any other fat, and directly alter blood vessel/harden arteries – atheroslcerosis • Trans fats are found in red meats, chocolate, and large amounts in hydrogenated oils (cakes, cookies, etc.)
3.1 Carbon – The Stuff of Life • Organicmolecules (macromolecules, molecules of life) are complex molecules of life, built on a framework of carbon atoms • Carbohydrates - simple sugar/mono (glucose) • Lipids - fatty acids • Proteins – amino acids • Nucleic acids - nucleotides
Carbon – The Stuff of Life • Carbon atoms can be assembled and remodeled into many organic compounds • Can covalently bond with one, two, three, or four atoms • Can form polar or nonpolar bonds • Can form chains or rings
3.2 From Structure to Function • The function of organic molecules in biological systems begins with their structure • The building blocks of carbohydrates, lipids, proteins, and nucleic acids bond together in different arrangements to form different kinds of complex molecules
Functional Groups • Hydrocarbon • An organic molecule that consists only of hydrogen and carbon atoms; hydrophobic • Most biological molecules have at least one functional group – Know structure and group • A cluster of atoms that imparts specific chemical properties to a molecule
What Cells Do with Organic Compounds • Metabolism • Activities by which cells acquire and use energy to construct, rearrange, and split organic molecules • Allows cells to live, grow, and reproduce • Requires enzymes
What Cells Do to Organic Compounds • Condensation • Covalent bonding of two molecules to form a larger molecule (polymer) • Produces two water molecules and a polymer • Study figure 3.6 • Hydrolysis aka Cleavage • The reverse of condensation • Cleavage reactions splits or breaks down larger molecules (polymers) into smaller ones (monomers) • H2O added
What Cells Do to Organic Compounds • Monomers • Molecules used as subunits to build larger molecules (polymers) • Polymers • Larger molecules (macromolecules) that are composed of smaller units called monomers • May be split and used for energy
3.3 Carbohydrates • Carbohydrates are the most plentiful biological molecules in the biosphere • Cells use some carbohydrates as structural materials; others for stored or instant energy
Carbohydrates • Carbohydrates • Organic molecules that consist of carbon, hydrogen, and oxygen in a 1:2:1 ratio • Three types of carbohydrates in living systems • Monosaccharides – glucose, ribose, fructose • Oligosaccharides – lactose, sucrose (most plentiful sugar) • Polysaccharides – starch (plants), cellulose, glycogen (animals)
Simple Sugars • Monosaccharides (one sugar unit) are the simplest carbohydrates • Used as an energy source • Backbones of 5 or 6 carbons • Dissolves in H2O because H2O forms H+ bonds with OH- group
Short-Chain Carbohydrates • Oligosaccharides • Short chains of monosaccharides • Example: sucrose, a disaccharide
Complex Carbohydrates • Polysaccharides • Straight or branched chains of many sugar monomers • The most common polysaccharides are cellulose, starch, and glycogen • All consist of glucose monomers • Cellulose – cell walls of plants • Starch – plants store excess carbs in the form of starch • Glycogen – energy storage in animals.
Chitin • Chitin • A nitrogen-containing polysaccharide that strengthens hard parts of animals such as crabs, and cell walls of fungi
3.4 Greasy, Oily – Must Be Lipids • Lipids function as the body’s major energy reservoir, and as the structural foundation of cell membranes • Lipids • Fatty, oily, or waxy organic compounds that are insoluble in water
Fatty Acids • Many lipids incorporate fatty acids • Simple organic compounds with a carboxyl group joined to a backbone of 4 to 36 carbon atoms • Essential fatty acids are not made by the body and must come from food • Omega-3 and omega-6 fatty acids
Fatty Acids • Saturated, monounsaturated, polyunsaturated
Fats • Fats • Lipids with one, two, or three fatty acids “tails” attached to glycerol • Triglycerides • Neutral fats with three fatty acids tails attached to glycerol • The most abundant energy source in vertebrates • Insulator (adipose tissue in penguins and humans) • Study Figure 3.11a (ppts)
glycerol + 3H2O triglyceride, a neutral fat three fatty acid tails Fig. 3-11a, p. 42
Saturated and Unsaturated Fats • Saturated fats (animal fats) • Fatty acids with only single covalent bonds • Packed tightly; solids at room temperature • Unsaturated fats (plant fats) • Fatty acids with one or more double bonds • Kinked; liquids at room temperature (oils)
Phospholipids • Phospholipids • Molecules with a polar head containing a phosphate and two nonpolar fatty acid tails • Heads are hydrophilic, tails are hydrophobic • Study Figure 3.14
Waxes • Waxes • Complex mixtures with long fatty-acid tails bonded to long-chain alcohols or carbon rings • Protective, water-repellant covering ( cuticle of fruits and vegetables). • Dehydration
Cholesterol and Other Steroids • Steroids/Sterols • Lipids with a rigid backbone of four carbon rings and no fatty-acid tails • Cholesterol • Component of eukaryotic cell membranes • Remodeled into bile salts, vitamin D, and sex hormones (estrogen and testosterone)
