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Biochemistry Chapter 2 1
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Atoms and their interactions 2
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Elements Substances that cannot be broken down into simpler chemical substances 92 naturally occurring 25 essential to life 3
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Carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) 96% of human body Trace elements present in small amounts Iron, magnesium, iodine 6
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Atoms Smallest particle of an element that has the characteristics of that element Nucleus central portion Protons positive charge Neutrons no charge 8
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Atoms cont. Electron cloud surrounds the nucleus Negative charge Travel in energy levels 1 st level 2e- 2 nd level 8e- 3 rd level 8e- (18e- total) Most atoms have equal numbers of protons and electrons no net charge 9
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Isotopes Atoms of the same element containing different numbers of neutrons Effects mass only (not charge) Some are unstable radioactive 11
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Carbon 12 6p and 6n Carbon 14 6 p and 8n 12
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Compounds and bonding 13
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Compound Composed of atoms of 2 or more different elements that are chemically combined Water H 2 O Bonding occurs between atoms to reach stability Stability = outermost energy level is full 14
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Covalent bonding sharing e- H 2 O: O 6e- in 2 nd level H 1e- in 1 st level Most compounds in living organisms have covalent bonds strong 15
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Hydrogen gas covalent bond 16
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Ionic bonding gaining or losing e- Produces ions charged particles NaCl: Na 1e- in 3 rd level Cl 7e- in 3 rd level 18
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How an ionic bond forms 20
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Chemical reactions Breaking and forming bonds Atoms are rearranged to form new substances Metabolism all the chemical reactions in an organism 21
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Chemical reactions cont. Represented by chemical equations 2H 2 + O 2 2H 2 O 2H 2 + O 2 are the reactants 2H 2 O is the product The numbers of each atom must be = on each side of the equation 22
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Mixtures and solutions 23
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Mixture Combination of substances that each retain their own properties Can easily be separated Salt and iron 24
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Solution 1 or more substances (solutes) are distributed equally in another (solvent) Cannot easily be separated Kool-Aid sugar dissolved in water 25
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Acids and bases The pH scale 26
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Water and diffusion 28
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The importance of water Essential for most life processes Universal solvent Means of transport 29
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Polarity unequal distribution of charge e- not shared equally positive and negative ends to a molecule Polar molecules attract other polar molecules and ions (opposites attract) 30
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Polarity continued Form weak hydrogen bonds 31
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Cohesion water molecules stick together 32
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Surface Tension 33
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Adhesion water sticks to other molecules 34
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Capillary action water creeps up thin tubes 35
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Water resists temperature changes Requires a lot of heat to increase water temperature Insulator helps maintain homeostasis Expands when freezes ice is less dense than water and floats 36
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Diffusion Movement of particles from an area of high concentration to an area of lower concentration 38
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Diffusion continued Due to random movement of all molecules slow Continues until equilibrium is reached equal concentration on each side 39
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Diffusion cont. Concentration gradient difference in concentration No energy required to move with the gradient 41
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Rate is affected by Concentration higher concentration of molecules = faster diffusion Temperature higher temperatures = faster diffusion Pressure higher pressure = faster diffusion 42
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Life substances 43
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Role of carbon organic compounds (C-H bonds) Can form 4 different bonds versatile Straight chains, branched chains, rings Any number of C atoms infinite number of structures 44
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Isomer same formula, different structures C 6 H 12 O 6 45
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Role of carbon cont. Polymers long chains of repeating units 46
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Polymer production Made from smaller molecules bonded together by the removal of water dehydration synthesis Hydrolysis breaking apart polymers by adding water 47
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Opposite Reactions Dehydration SynthesisHydrolysis 48
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Carbohydrates C:H:O in a 1:2:1 ratio Used to store and release energy Monosaccharides simple sugars Building blocks of carbs Glucose C 6 H 12 O 6 49
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Forms of glucose Linear (dry) formRing (dissolved) form 50
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Disaccharides 2 monosaccharides linked together Glucose + glucose maltose 51
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Carbs cont. Polysaccharides polymers of monosaccharides Used for food storage Starch (plants), glycogen (animals), and cellulose 52
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Lipids CHO Less O than carbs Used for energy storage, insulation, protection, cell membrane components 54
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Nonpolar insoluble in water Building blocks 3 fatty acids and 1 glycerol molecule Fats, oils, and waxes 55
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Lipids cont. Saturated fats C-C bonds are single Maximum amount of H Solid at room temperature Increase cholesterol levels cardiovascular disease 57
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A saturated fat no C=C in tails 58
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Unsaturated fats some C-C double bonds Liquid at room temperature Plant products Hydrogenation converting unsaturated to saturated by adding hydrogen 59
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An unsaturated fat at least 1 C=C in tails 60
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Proteins CHON Used for tissue structure and cell metabolism Building blocks amino acids Humans need 20 different amino acids Held together by peptide bonds 61
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Proteins cont. Number and order of amino acids determines the protein Each protein has a specific 3-D shape Shape determines function Denaturation changing the shape of a protein impairs it’s function 63
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Proteins cont. Enzymes protein catalysts that change the rates of chemical reactions, but are not changed themselves Most reactions will occur without enzymes, but at a slower rate 65
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Highly specific 1 enzyme per substrate Lock and key model enzyme and substrate fit together precisely to form an enzyme-substrate complex 66
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Factors affecting enzyme action: Concentrations of enzyme and substrate Temperature 37 o C (human body temp.) pH of environment Homeostasis must be maintained in order for enzymes to function 68
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Nucleic acids DNA and RNA Store cellular information in code form Building blocks nucleotides 5-C sugar Nitrogenous base Phosphate group 69
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DNA deoxyribonucleic acid Double helix structure Watson and Crick Sugar is deoxyribose Bases: cytosine, guanine, adenine, thymine 70
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RNA ribonucleic acid Single strand Sugar is ribose Bases: cytosine, guanine, adenine, uracil 71
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The End!! 74
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