1/21/ Your Roadmap for Success in Chapter 6. Preview the chapter:

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1 1. Your Roadmap for Success in Chapter 6 Preview the chapter: 1. Read Summary (p. 171). 2. Skim the Assessment questions (p ). 3. Rewrite Learning Objectives for the chapter and each section in the form of possible test questions. (So, four sets of questions.) 4. Look at pictures. 2. Your Roadmap for Success in Chapter 6 You are expected to read all parts of each section (1, 2, 3) on your own. You are responsible for knowing this material. We will be covering most of the book content during class with slides, discussions, demos, and other activities. However, we can t possibly cover all chapter content during class. 3. Your Roadmap for Success in Chapter 6 Assignments will include (at minimum): 1. Reading the chapter 2. Questions from each Section Assessment 3. Questions from the Chapter Assessment 4. Chapter notes (more later) 5. Class activities or labs 1

2 4. Your Roadmap for Success in Chapter 6 Assessments will include (at minimum): 1. The assignments mentioned 2. Quiz for each section 3. Test at the end of the chapter 4. Behavior/positive participation There will be at least one extra credit opportunity offered per chapter. Biology Chapter 6: The Chemistry of Life 1. Atoms and Their Interactions 2. Water and Diffusion 3. Life Substances processes vhs p html Biology Chapter 6: The Chemistry of Life What You ll Learn (p. 144) (Turn these statements into test questions; write them down.)

3 Chapter 6.1 Atoms & Their Interactions Learning Objectives (p. 145): (Turn these objectives into test questions.) Vocabulary: Matter is anything that has mass and takes up space. Examples? Energy is anything that brings about change. can hold matter together or break it apart. Atoms All matter (whether solid, liquid, or gas) is made of atoms. Center of atom is called the nucleus. The nucleus consists of: protons (have a + charge) neutrons (have no charge) 3

4 Matter vs. Energy Matter Energy Definition Examples atoms, electrons, protons, and neutrons;,,,, sunlight, electricity, heat, chemical energy Atoms Electrons Around the nucleus is a cloud of electrons (have a charge). Constantly moving VERY small mass compared to protons and neutrons! The mass of 1,837 electrons = the mass of 1 proton Involved in CHEMICAL REACTIONS pointer/how laser works freaklasers 1.jpg Parts of an Atom Protons Electrical Charge? Location in Atom? Relative Mass? Neutrons Electrons 4

5 Elements are made up of only one kind of atom. can t be broken down into simpler form by chemical reactions. are known by their own one or two letter symbol. make up everything in the Universe. content/uploads/2009/07/periodic tableelements au ring.jpg table.gif table 2.jpg How many of these elements can you identify? O C H N Ca P K S Na Cl Mg 5

6 Elements that make up the human body 0.4% 0.3% 0.2% 0.1% 1.5% 1.0% 0.2% 0.1% 3.2% 18.5% 9.5% 65.0% Percent in Human Body Oxygen Carbon Hydrogen Nitrogen Calcium Phosphorus Potassium Sulfur Sodium Chlorine 99% of living matter is made up of six (6) elements. That makes these elements pretty important! S P O N C H Compounds and Molecules A Compound is a substance that is composed of atoms of two or more different elements that are chemically combined. Example: Water 6

7 Compounds and Molecules A Compound is a substance that is composed of atoms of two or more different elements that are chemically combined. These elements are in exact proportions. Example: Water is always made up of hydrogen atom(s) and oxygen atom(s), bonded together in exactly the same way, to form a water molecule. Compounds and Bonding Most matter is in the form of compounds. Why and how do atoms combine? Atoms combine with other atoms: Only when conditions are right To become more stable When is an atom usually most stable? How does an atom become more stable? Covalent Bonds vs. Ionic Bonds Covalent bonds form when two atoms share electrons in their outermost shell (energy level). Atoms are held together by the attraction between the positively charged nuclei and the shared, negatively charged electrons. Most compounds in organisms have covalent bonds (ex. sugars, fats, proteins, water). Molecule: Group of atoms held together by covalent bonds and having no overall charge. 7

8 Compounds and Molecules Molecular Compounds form when different atoms share their outermost electrons. Hydrogen atoms have 1 electron. How many electrons does an oxygen atom have? (see pg. 147) On Earth, oxygen and hydrogen normally exist as gases. But as a compound (water), they can be liquid, solid, or gas. **When a compound is formed, changes occur and a new substance forms. Covalent Bonds vs. Ionic Bonds Most atoms have an equal # of electrons and protons; therefore, they have an electrical charge of. Ionic bonds form when atoms gain or lose an electron from their outer energy level. An ion is an atom (or group of atoms) that or electrons and has an. An ion is a charged particle. Covalent Bonds vs. Ionic Bonds Ions are held together by a different kind of chemical bond than covalent bonds. An ionic bond is the attractive force between two ions of opposite charge. Example: NaCl Sodium atom (11e, 11p, 12n) Chlorine atom (17e, 17p, 18n) 8

9 Ionic Bonds, cont d Ionic compounds are less abundant in living things than are covalent molecules. However, ions are very important in biological processes. Examples: Sodium and potassium ions are required for transmission of nerve impulses. Calcium ions are necessary for muscles to contract. Plant roots absorb essential minerals in the form of ions. Chemical Reactions What is going on during a chemical reaction? Bonds between atoms are formed or broken, causing substances to combine and recombine as different molecules. Chemical reactions occur over and over again inside cells. Metabolism: All of the chemical reactions that occur within an organism. These chemical reactions are essential for the organism s function. 9

10 Chemical Reactions and Chemical Equations Chemical reactions are represented by chemical equations. Symbols and formulas are used to represent each element or substance. 2H 2 + O 2 2H 2 O (Reactants) (Products) Chemical Reactions and Chemical Equations Reactants: Substances that undergo chemical reactions Products: Substances formed by chemical reactions Atoms are neither created nor destroyed by chemical reactions! Just rearranged. Same number of atoms should appear on both sides of the equation (if balanced). chemistry.wikispaces.com/combustion +keedy+mccormack Showing a Chemical Reactions With a Chemical Equation 2H 2 + O 2 2H 2 O How many molecules are involved with this chemical reaction? Number before each chemical formula indicates the # of molecules of each substance. Subscript numbers indicate the # of atoms of each element in a molecule of the substance. If no # before or under a symbol, then only one atom or molecule is present. 10

11 Showing a Chemical Reactions With a Chemical Equation 2H 2 + O 2 2H 2 O Mixtures When substances combine, but DON T combine chemically (no chemical reaction) Mixture: A combination of substances in which the individual components retain their own properties. Solution: Type of mixture in which one or more substances (solutes) are distributed evenly in another substance. Solutions Solution: Type of mixture in which one or more substances (solutes) are distributed evenly in another substance (solvent). Basically, one substance is completely dissolved in another and won t settle out of solution. Solvent means to loosen or dissolve. Water is known as the universal solvent. 11

12 Concentration of a Solution The more solute in a given amount of solvent, the HIGHER the concentration of the solution (i.e., stronger ). To dilute a solution means that you add more solvent. Ex. Adding more water to a pitcher of Kool Aid makes it weaker. What does this mean for living organisms? Organisms have very specific requirements for the concentrations of solutions in their bodies usually an extremely narrow range of tolerance. Ex. Blood sugar level, cellular contents 6.2 Water and Diffusion Look at the Section Preview to find the Learning Objectives. Students will be able to: Relate water s unique features to polarity. Explain how the process of diffusion occurs and why it is important to cells. Vocab: polar molecule, hydrogen bond, diffusion, dynamic equilibrium 12

13 6.2 Water and Diffusion Why is water (perhaps) the most important compound in living organisms? Most life processes can occur only when molecules and ions are free to move and collide with one another. This condition is met in water. Material transportation (blood, plant sap) Water makes up 70 95% of most organisms. Three (3) important characteristics of water 1. Water is polar. What does this mean? In a covalent bond, electrons are not always shared equally. For example: In water molecules, electrons are more strongly attracted to the O atom than to the H atoms). Polar molecule: unequal distribution of charge resulting in a positive end (+) and a negative end ( ) Why can water dissolve so many things? Polar water molecules attract: Ions (so ionic compounds like NaCl dissolve easily) Other polar molecules (like sugar) Water molecules Hydrogen bond: A weak bond formed by the attraction of opposite charges between hydrogen and oxygen Hydrogen bonds hold many large molecules (e.g., organic compounds like proteins) together. 13

14 Because of water s polarity: Creeps up thin tubes (capillary action) Surface tension 2. Water resists temperature changes. Good insulator Cells are in an aqueous environment, so they are protected from sudden changes in temperature. 3. Water expands when it freezes. Rare characteristic among substances. Ice is less dense than liquid water floats. Allows life to continue underwater in winter. Helps make soil. Diffusion Water is one way to move substances in living systems. Diffusion is another way. Kinetic energy of objects in motion applies to matter Ping Pong balls Random motion of molecules = Brownian motion Characteristic of gas, liquid, and some solid molecules 14

15 Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration. Result of random movement of atoms. Three KEY factors: 1. Concentration (primary controlling factor) 2. Temperature 3. Pressure Results of diffusion Two substances (e.g., colored corn syrup and pure corn syrup) will eventually be evenly distributed (concentration same everywhere). Atoms continue to move randomly and collide, but no changes in overall concentration. This condition is called dynamic equilibrium. Concentration gradient: difference in concentration of a substance across space. Ions and molecules diffuse from area of high concentration to low concentration move with the gradient If no interference, diffusion continues until there is NO concentration gradient (dynamic equilibrium). One IMORTANT way cells move stuff in and out of cell! 15

16 Osmosis /Chapter04 Rabitoy.aspx Animation: Diffusion, Concentration Gradient, Dynamic Equilibrium online.com/objects/viewobject.aspx?id=ap Life Substances Look at the Section Preview to find the Learning Objectives. Students will be able to: Classify the variety of organic compounds. Describe how polymers are formed and broken down in organisms. Compare the chemical structures of carbohydrates, lipids, proteins, and nucleic acids, and relate their importance to living things. Vocab: isomer, polymer, carbohydrate, lipid, protein, amino acid, peptide bond, enzyme, nucleic acid, nucleotide 16

17 Role of Carbon in Organisms The compounds that form the cells and tissues of the body are produced from similar compounds in the foods you eat. Most of these foods (and most substances found in organisms) contain carbon. Organic compounds Atomic Structure of Carbon Why does carbon play such an important role for living things? Or maybe how does carbon combine with other elements in so many different ways? Carbon is versatile. Carbon atoms can bond to form straight chains, branched chains, or rings. These chains and rings: contain almost any number of carbon atoms can include atoms of other elements ii/carboncompounds/saturated unsaturated.php 17

18 Carbon is versatile. Lots of carbon structures possible! Isomers: Compounds that have the same simple formula but different 3 D structures. The Greek root word iso appeared in another vocabulary word in Ch. 6: iso means meros means Isomers, cont d Example: glucose and fructose (p. 162) Both C 6 H 12 O 6 Different structures Fructose Glucose %20review.htm Molecular Chains Carbon compounds vary greatly in size. One or two C atoms to thousands of C atoms Large molecules are called. Polymer: large molecule formed when many smaller molecules bond together. Poly means. SKIP the Condensation and Hydrolysis paragraphs on p

19 Organic and Inorganic Compounds What s the difference? Characteristic ORGANIC COMPOUNDS INORGANIC COMPOUNDS Contain elements: Associated with: Relative # of atoms: Examples Organic Compounds Found in All Living Things There are four groups: Carbohydrates Elements: carbon, hydrogen, oxygen Examples: sugars, starch, cellulose What function do they have? 1. Supply energy for cell processes 2. Form plant structures 3. Short term energy storage 19

20 1. Carbohydrates (p. 163) Monosaccharide Simplest type of carbohydrate A simple sugar Examples: glucose and fructose Mono means or Disaccharide Two monosaccharide molecules linked together. A two sugar carbohydrate Example: glucose and fructose joined sucrose 1. Carbohydrates Polysaccharide Largest carbohydrate molecules Polymers composed of many monosaccharide units Examples of glucose polymers: 1. Starch food storage in plants; highly branched chains; e.g., seeds, bulbs 2. Glycogen food storage in mammals; more highly branched; e.g., liver 3. Cellulose cell walls and structural support in plants; long chains hooked together like chain link fence. 2. Lipids Elements: carbon, hydrogen, oxygen, phosphorus Examples: fats, oils, waxes, phospholipids, cholesterol What function do they have? 1. Store large amounts of energy long term 2. Form major part of cell membranes 3. Insulation and protection 20

21 2. Lipids Because lipids consist of non polar molecules, they in water, or are known to be. SKIP Figure 6.20 (about lipids) on p Proteins Elements: carbon, hydrogen, oxygen, nitrogen, sulfur Examples: enzymes, skin, hair, hormones, What function do they have? 1. Regulate cell processes 2. Carry out chemical reactions 3. Build cell structures 4. Control immune system 5. Turn genes on or off 3. Proteins: Structure A protein is a large, complex polymer containing C, H, O, N, and usually S. Basic building blocks of proteins are amino acids. 20 amino acids in various combinations make thousands of proteins. Vary more in structure than other types of organic molecules. Protein chains often 100s of amino acids KIND of protein determined by the and of amino acids in chain. 21

22 20 amino acids combine in specific sequences to form different proteins Many proteins consist of two or more amino acid chains. Protein chains can contain 100s of amino acids in a particular sequence Example: Hemoglobin is a protein that helps transport oxygen in your blood. The chemical reactions in your cells need enzymes. Enzyme: A protein that changes the rate of a chemical reaction. Enzymes are like can openers. You need a can opener to open the can. The can changes, but the can opener doesn t it can be used over and over again. Enzymes can break molecules apart (like a can opener), but enzymes also can cause molecules to join (unlike a can opener). BUT just any old enzyme won t do! There has to be a perfect fit between a particular molecule and a particular enzyme. +Baking+Enzyme 22

23 Enzymes: An important type of protein See (and know) Action of Enzymes on p Nucleic Acids Elements: carbon, hydrogen, oxygen, nitrogen, phosphorus Examples: DNA & RNA What function do they have? 1. Carry hereditary information 2. Used to make proteins 4. Nucleic Acids A nucleic acid is a complex that stores in the form of a code. Are polymers made up of smaller subunits: nucleotides Nucleotides consist of C, H, O, N, P atoms arranged in 3 groups: Base Simple sugar Phosphate group 23

24 Nucleic Acids: DNA and RNA Deoxyribonucleic acid (DNA) Master copy of organism s info code used to form enzymes and structural proteins Genetic code that determines how organism looks and acts Passed on every time a cell divides and from one generation of the organism to the next Ribonucleic acid (RNA) Nucleic acid that forms copy of DNA for use in making proteins Inorganic Compounds Made from elements other than carbon. that living things need. Example: Plants take up inorganic compounds from soil. These I.C. contain the elements nitrogen, phosphorus, and sulfur. Some Inorganic Compounds Important in Humans: Compound Water Calcium phosphate Hydrochloric acid Sodium bicarbonate Salts containing S, Cl, and K Use in Body Blood; chemical reactions Bone strength Breaks down foods in stomach Digestion Nerve messages 24