Module 3: Molecules of Life! Lecture PowerPoint

Module 3: Molecules of Life! Lecture slides by Jennifer Ripley Stueckle, West Virginia University  Learning Objectives Describe the form and function of each of the four macromolecules. Describe the different categories of carbohydrates and their uses. Compare and contrast diffe...

Module 3: Molecules of Life! Lecture slides by Jennifer Ripley Stueckle, West Virginia University  Learning Objectives Describe the form and function of each of the four macromolecules. Describe the different categories of carbohydrates and their uses. Compare and contrast different categories of lipids and their structures. Understand the importance of shape in the functioning of a protein. Compare and contrast DNA and RNA.  The Four Main Molecules of life are:  carbohydrates  lipids  proteins  nucleic acids Organic Molecules: chemical compounds that contains both carbon and hydrogen Macromolecules: have thousands of atoms in a single molecule  Carbohydrates include macromolecules that function as fuel.  Carbohydrates are the primary fuel for cells.  They form much of the structure of cells in all organisms.  C, H, and O  Carbohydrates  Carbohydrates are composed of monosaccharides.  Monosaccharides = simple sugars  C−H bonds store large amounts of energy.  Glucose provides energy for the body’s cells. “Blood sugar” has one of three fates:  Fuel for cellular activity  Glycogen for temporary storage  Fat for long-term energy storage Water Weight Many complex carbohydrates are time- release packets of energy.  Some carbohydrates are polymers composed of monosaccharides.  Disaccharides lactose; sucrose  Polysaccharides  complex carbohydrates  glycogen; starch Short-term versus Long-term Energy  Not all carbohydrates are digestible by humans.  Carbohydrates serve as structural materials for invertebrate animals and plants.  Chitin  Cellulose Dietary fiber Helps clear the digestive tract Reduces risks for colon cancer and other diseases Lipids store energy for a rainy day.  Contain significantly more C–H bonds than carbohydrates—more stored energy  Insoluble in water  Hydrophobic vs. hydrophilic molecules  Dietary fats differ in degrees of saturation.  Glycerol: hydrophilic “head” region  Fatty acid: hydrophobic “tails”  Triglycerides  Fats  Oils Degrees of Saturation Cholesterol and phospholipids are used to build sex hormones and membranes.  Cholesterol  Cholesterol is an important component of most cell membranes.  Cholesterol can attach to blood vessel walls and cause them to thicken.  Cells in our liver produce almost 90% of the circulating cholesterol from saturated fats in our diets.  Steroid Hormones: Modified Cholesterol Molecules  Estrogen Many functions, including regulation of memory and mood in both sexes  Testosterone Many functions, including muscle growth Synthetic variants of testosterone  Phospholipids  Phospholipids are the major component of the cell membrane.  They differ from fats in that they have only two fatty acid chains and a phosphorous atom in the glycerol “head” region.  Waxes  Waxes are strongly hydrophobic; they repel water.  One long fatty acid chain  Coat the surface of many insects, plants, feathers  Proteins are bodybuilding macromolecules essential in our diet. Amino Acids: the Building Blocks of Proteins  Twenty different amino acids Composed of C, H, O, and N Carboxyl and amino group in all amino acids Differ from each other in side chain composition  Proteins are an essential dietary component.  Growth  Repair  Replacement  Energy storage in bonds  Each different protein has a different composition of amino acids.  Some amino acids must be obtained from our diet — essential amino acids.  Complete, Incomplete, and Complementary Proteins  Complete proteins have all the essential amino acids—usually from animal products  Incomplete proteins —often plant sources  Complementary proteins—eaten together yield all the essential amino acids A protein’s function is influenced by its three-dimensional shape.  Denaturation Egg whites contain a lot of protein. Why does beating or heating them change their texture?  Enzymes are proteins that speed up chemical reactions. Enzymes initiate and accelerate chemical reactions in our body.  Activation Energy Chemical reactions occurring in organisms can either release energy or consume energy. In either case, the reaction needs a little “push” in order to initiate the reaction; this is called activation energy. Enzymes act as a catalyst by lowering the activation energy.  Enzyme activity is influenced by chemical and physical factors. 1. Enzyme and substrate concentration 2. Temperature 3. pH 4. Presence of inhibitors or activators Enzyme and Substrate Concentration Temperature pH Inhibitors and Activators Enzyme Activity!  “Misspelled” Proteins  Incorrect amino acid sequence  Leads to active site disruptions and loss of function  Nonfunctional enzymes are responsible for many diseases and physiological problems:  Phenylketonuria  Nucleic acids encode information on how to build and run a body.  Nucleotides are the building blocks of nucleic acids.  Each nucleotide is composed of three molecules: Sugar Phosphate group Nitrogenous base  Nucleic acids carry genetic information.  Two Types of Nucleic Acids  Deoxyribonucleic acid (DNA)  Ribonucleic acid (RNA)  Both play central roles in directing the production of proteins.  Information Storage  The information in a molecule of DNA is determined by its sequence of bases.  Adenine (A), guanine (G), cytosine (C), and thymine (T)  DNA holds the genetic information to build an organism.  DNA Base Pairing A with T C with G  What is the complimentary strand to this strand: CCCCTTAGGAACC?  RNA is a universal translator, reading DNA and directing protein production.  RNA differs from DNA in three important ways.  The sugar molecule of the sugar-phosphate backbone  Ribose in RNA  Deoxyribose in DNA  Single-stranded  Uracil (U) replaces thymine (T)