Transcript Chapter 6
Chapter 6 The Chemistry of Life Atoms & Their Interactions Organic compounds are molecules in which Carbon(C) combines with other elements All living systems contain Carbon (C), Oxygen (O), Hydrogen (H), and Nitrogen (N) Element A substance that cannot be broken down into a simpler substance - Periodic Table Elements are made up of hundreds of atoms Atoms smallest particle of an element (building blocks) Periodic Table •The number of particles in an atom determine the element •The number of electrons in the outer ring determines how reactive it is •If all electrons are paired then they are stable and will not react Noble Gases Atoms contain the following: 1. Nucleus - center of an atom it contains A. Proton - positively charged + B. Neutrons - no charge 2. Electrons - located in a cloud around the nucleus with a negative charge - Bohr Model of an atom Isotopes- atoms of the same element with different numbers of neutrons Chemical Bonding •Free electrons, that are unpaired, are also unstable and looking to form a chemical bond •Electrons are very important to the chemical bonding process •Chemical bonding occurs when an electron moves from one atom to another •When this happens the atom giving up the electron becomes positive and the atom gaining the electron becomes negative Covalent bond occurs when two atoms share electrons to become more stable Molecule group of atoms held together by covalent bonds and having no overall charge Compound Substance that is composed of atoms of two or more different elements that are chemically combined example H2O The physical and chemical properties of a compound differ from the physical and chemical properties of the individual elements that compose it Ion A charged particle it has gained or loss electrons Ionic Bond Chemical bond formed by the attractive forces between two ions of opposite charge NaCl Chemical reactions - bonds formed or broken Metabolism – all of the chemical reactions that occur within an organism Elements combine to form compounds the elements do not have their original properties Mixture – a combination of substances in which the individual components retain their own properties Solutions – mixture in which one is dissolved into the other (Kool-aid) Acids and Bases pH – measure of how acidic or basic a solution is pH scale is from 0-14 Must remain very stable for biological reactions to occur Organisms have a tendency to remain stable under a wide range of conditions Acid – substances with a pH < 7 forms H+ ions Bases – substances with a pH > 7 forms OH- ions Water and Diffusion Water makes up 70-95% of most organisms Polar molecule – molecule with an unequal distribution of charge one end is positive, one is negative (attraction causes it to dissolve many ionic compounds like salt, sugar) Hydrogen Bond H+ attract the O- holds many large molecules together, proteins, also water tension allows water to creep, plants use this to water from ground called capillary action Characteristics of Water 1. Polar Molecule – has a slight charge 2. Water resists temperature changes – requires more heat to increase , insulator, cells exist in an aqueous environment helps maintain an optimum environment 3. Water expands when it freezes therefore ice is less dense than water and it floats Diffusion Diffusion – net movement of particles from an area of higher concentration to an area of lower concentration Kinetic energy – the energy of motion Brownian motion – 1827 observed the evidence of random motion of molecules 3 factors affect diffusion: 1. Concentration – internal factor 2 external factors which speed molecular motion are: 2. Temperature 3. Pressure Dynamic equilibrium – concentration distributed evenly through molecules still in motion Concentration gradient – area between the two levels of concentration November 19, 2010 Differentiate between a mixture and a solution. Stamp on Vocab 6.3 Collect McMush Lab Grade Notes on 6.3 Protein Building.. 6.3 Life Substances Carbon © is the central element for all living things and combines with H, O, N, S and Ph to form organic compounds Organic compounds are essential building blocks for living things and are also a major source of energy Carbon is able to form single, double and triple covalent bonds this gives it greater strength, diversity and energy potential Isomers – compounds with the same chemical formula but different structures Isomers Polymer – large molecule formed when many smaller molecules bond together Condensations – chemical reaction by which polymers are formed covalent bond formed when water removed Hydrolysis – method that polymers are broken apart OH and H ions come from water to break it apart 4 Basic Carbon Containing Molecules: 1. Carbohydrates – sugars starch 2. Lipids – oils, fats 3. Proteins – cell structure, muscles, enzyme 4. Nucleic Acids – hereditary or genetic material coordinates cell activity Carbohydrates Contain only C,H,O in same proportions as water H2O Building blocks are simple sugars or monosaccharides ex: glucose, fructose C6H12O6 Glucose can change its molecules (hydrolysis) within the cell and is a major source of energy Disaccharide – double sugar sucrose formed by the synthesis of glucose and fructose Synthesis reactions of glucose build complex carbohydrates like starch and cellulose Polysaccharides – largest carbohydrate molecules composed of many monosaccharide subunits Starch is a storage compound in plants used by humans Cellulose is part of wood and cotton and gives plant cell walls rigidity Carbohydrates are stored as glycogen in human liver and muscle (animal starch) Starch, cellulose and glycogen consist of thousands of glucose molecules Lipids Contain only C,H,O abut fewer O ex C57H110O6 Building blocks fatty acids and glycerol Non polar molecule – doesn’t dissolve in water Essential structural part of all cells Include simple fats, oils, plant waxes and cholesterol Contain 2x the energy per gram of carbohydrates LIPIDS Unsaturated – double bond Saturated – Single bond Proteins Contain C,H,O,N and some S Building blocks – amino acids there are 20 different types =1 protein Green plants can synthesize amino acids, animals cannot produce all of them Polypeptide- Long chain of amino acids Amino Acids Peptide Enzymes Enzymes are made up of proteins and used as catalysts in specific biochemical reactions Enzymes: Promote reactions Not used up Need only small amounts Enzymes in Action