BIO_SC 1010 1st Edition Lecture 3 Outline of Last Lecture I. Scientific MethodII. Theory vs. TheoryIII. Hypothesis vs. TheoryOutline of Current Lecture I. Building Blocks of LifeII. Matter, Atoms, & moleculesIII. Laws of ThermodynamicsIV. The Polar Nature of Water Means That Water Forms Hydrogen BondsV. Buffers Help Reduce Changes in pHVI. Most Biological Macromolecules are PolymersVII. Organic MoleculesVIII. The Sex hormones Estrogen & Testosterone are SteroidsIX. Your Diet Contains Several Different Kinds of FatsCurrent LectureI. Building Blocks of Life• Atom-smallest part of element: made up of a dese, positively charged nucleus surroundedby a system of electrons.• Molecule-smallest part of a chemical compound: the smallest physical unit of a substance thatcan exist independently, consisting of one or more atom held together by chemical forces (bond).II. Matter, Atoms, & molecules• Atoms are usually bonded to each other to form molecules• An element is a basic substance that can’t be broken down-examples of elements include hydrogen, carbon, & gold.-the smallest amount of an element is an atom• Individual elements combine to form compoundsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.• There are two main ways that atoms can bond together to form molecules:-sharing electrons-transferring electrons & creating two oppositely charged atomsII. Laws of Thermodynamics1. Energy is never created or destroyed, but it can change form• Energy is the capacity to do work-kinetic energy: the energy of movement {light, heat, electricity} -potential energy: stored energy• All chemical reactions require energy• Beyond the activation energy, some reactions release energy whereas others require an input of energyIII. The Polar Nature of Water Means That Water Forms Hydrogen Bonds• Water molecules form networks of hydrogen bonds• In liquid water hydrogen bonds constantly break & re-formpH is a Measure of the Acidity of a Solution• The pH scale runs from acidic (0) to basic (14)• Each number in the pH scale represents a tenfold change in H+ ion concentrationBuffers Help Reduce Changes in pH• Cells regulate their pH-by accepting H+ ions• Buffers within our blood counteract a drop in oxygenVI. Organic Molecules•Contain carbon & hydrogen•4 types1. Carbohydrates-include simple sugars & larger molecules made from sugars-important building blocks of plants-consists of one or more monosaccharides joined together2. Lipids-are a diverse group of organic compounds-fats perform essential functions in the human body-all are hydrophobic “water fearing”. Meaning they do not mix with water-cell membranes are made by staking two layers of a molecule called phospholipid (have a phosphate group in a hydrophilic “water loving” head) (two long hydrophobic tails)-cholesterol is produced in your body or taken in from food (maintains fluidity) (synthesizes several hormones) 3. Proteins-most diverse molecules-play important roles in your bodyEach kind of protein in a cell has a unique structure and shape-proteins are broken down into amino acids (reassembled into proteins that vary in function)-proteins are made up of polypeptides, is a chain of amino acids-proteins are polymers made by joining many amino acid monomers together4. Nucleic Acids-form DNA & RNA-& energy carrier molecules (picks up energy in one part of the cell & carry it to another part)-ATP = most important energy carrierVII. The Sex hormones Estrogen & Testosterone are Steroids•Anabolic steroids: synthetic variants of testosterone-can increase body mass-dangerous side effects•Triglyceride: a typical dietary fat-the carbon/hydrogen chains in the tails store energy (calories)VIII. Your Diet Contains Several Different Kinds of Fats•Dietary fats come in two basic varieties -saturated fats-unsaturated fats (trans fat) (omega-3 fats)•Saturated fats lack double bonds I their carbon/hydrogen chains•Unsaturated fats have double bonds in their carbon/hydrogen chains•Unsaturated fat can be made solid by adding chemical bonds-hydrogenation is a process & can produce trans fat (unsaturated fat that can contain an unusual bond)-trans fats are quite