Anatomy 2A, Chemistry

Anatomy 2A, Chemistry - Introduction to Basic Chemistry •...

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Unformatted text preview: Introduction to Basic Chemistry • Matter­ anything that has mass (the amount of matter) and occupies space – Liquid – Solid – Gas • Chemical elements­ chemical substances that cannot be broken down into simpler substances by ordinary chemical reactions • Chemical symbols States of Matter Gas •low density •easy to expand/compress •fills container Liquid •high density •hard to expand/compress •takes shape of container Solid •high density •hard to expand/compress •rigid shape Periodic Table Atoms • All chemical elements are atoms – Analogy­ all people are classified as humans • atom of hydrogen, atom of carbon, etc. • All atoms have similar structure – Analogy­ all people have similar body structure Major Difference Between Atoms • Number of Protons (atomic number) makes each atom unique in its identity Atoms, nucleus, proton, neutron, electron, atomic number, valance Each Atom Will Have a Different Character and Measurable Characteristics •Weight (atomic mass) •Attraction of electrons •Charge •Stable or unstable (radioactivity) All these factors determine the type of chemical bonding or interactions with other atoms (elements). Atomic mass (weight) is the mass of the protons and neutrons not the electrons If the proton and neutron were enlarged, and each had the approximate mass of a hippopotamus, the electron, enlarged to the same scale, would have less mass than an owl. Electronegativity • Refers to the ability of an atom in a molecule to attract shared electrons • Determines the nature of the chemical bond – Ionic – Covalent Ionic Bonds Based of Electronegativity Atomic Charge • Determined by the number of electrons in the outer shell (valence) – Normal equal numbers of electrons (­) and protons (+) • Ion­ Charged atom of element Stable or Unstable Atom • Isotopes­ an atom with different numbers of neutrons Isotopes can be Stable or Unstable • Unstable isotopes are called radioisotopes •All matter is made up of atoms of the various elements •When two or more elements combine in a chemical reaction, the resulting combination is called a molecule. •A molecule may contain two elements of the •same kind H 2 •different H O compound (two or more elements in 2 a fixed ratio) Chemical Bonds of Two or More Elements Make Chemical Units (the various things that exist in our environment) Types of Chemical bonds • Ionic Bonds • Covalent – Non­polar – Polar Ionic Bonds Electron donor, electron acceptor, anion, cation Based on the electronegativity (the ability of an element to hold on or take electrons) of each element Ions • Charged Particles – Electrolytes­salts that ionize in water and form solutions capable of conducting electricity • Many of the bodies operations are electrical • Electrolyte balance is very important in patient care Free Radicals – Free radicals­ chemical particles with odd numbers of electrons • Produced by normal metabolism and exogenous products (carbon tetrachloride, cleaning solvent) and radiation (X­ray, UV light) • Damaging to the body • Antioxidants­ neutralizes free radicals (Vit. C, E, Beta carotene) Antioxidants • Antioxidants­ neutralizes free radicals (Vit. C, E, Beta carotene) Covalent Bond­ sharing of electorns 1. Nonpolar­ equal sharing 2. Polar­ unequal sharing Equal Sharing Oxygen showing unequal sharing of electrons •Electronegativity •Polar covelant bond •Polar molecule Hydrogen Bonding Important properties of water 1. Excellent solvent – solvent­ a liquid that a solid is dissolved in – solute­ the substance that is being dissolved 2. Can participate in chemical reactions 3. Absorbs and releases heat very slowly – important is the body to resist temperature fluctuations 4. Requires a large amount of heat to change from a liquid to a gas – important in cooling the body from perspiration 5. Servers as a lubricant Characteristics of Water • Solvency­ the ability to dissolve other chemicals – Hydrophillic­ substances that dissolve in water – Hydrophobic­ substances that do not dissolve in water • Cohesion­ the tendency of molecules of the same substance to cling to each other • Adhesion­ the tendency of one substance to cling to another • Chemical reactivity­ the ability to participate in chemical reactions • Thermal stability­ helps to stabilize the internal temperature of the body due to its high heat capacity Hydration sphere Water an Excellent Solvent Solutions, Colloids, Suspensions Solution • particles of matter (solute) mixed with more abundant substance, usually water (solvent). – Particles are under 1 nanometer (cannot be visually distinguished from each other – Particles do not scatter light so solution is transparent – The solute particles will pass through most selectively permeable membranes – Solute does not separate from solvent when the solution is allowed to stand Solution Solutions, Colloids, Suspensions Colloid­ example is plasma • • • • proteins (albumin) Particles range from 1­100 nm in size Particles are large enough to scatter light, so colloids are usually cloudy Particles are to large to pass through most selectively permeable membranes Particles remain mixed with solvent when the mixture is allowed to stain Colloid Solutions, Colloids, Suspensions Suspension­ example, • • • • blood cells in plasma Particles exceed 100 nm Suspension is cloudy or opaque Particles are too large to penetrate selectively permeable membrane Particles are too heavy to remain suspended when the mixture is allowed to stand Emulsion • Suspension of one liquid in another, such as oil and vinegar salad dressing Mixture Consists of substances that are physically blended but not chemically combined Concentration • How much solute is present in a given volume of solution • Concentration is expressed in different ways – Weight per volume – Percentages – Molarity – Electrolyte concentration Weight Per Volume • The weight of solute in a given volume of solution • Ex: 8.5 g of NaCl per liter of solution (8.5g/L) Percentages 5g of dextrose and add enough water ot make 100ml of solution = concentration of 5% weight per volume Ex: D5W= 5% w/v dextrose in distilled water Molarity • Mole­ Avogadro’s number of particles (atoms, molecules, etc.) 2 6.023 x 10 3 particles Ex: mole of glucose weighs 180 grams mole of sucrose weighs 342 grams • Molarity­ the number of moles of solute per liter of solution A one molar (1.0 M) solution of glucose contains 180 g/L and a one molar (1.0 M) solution of sucrose contains 342 g/L Electrolytes • A material that dissolves in water to give a solution that conducts an electrical current • major electrolytes of the body are as follows: – – – – – – – – sodium (Na+) potassium (K+) chloride (Cl­) calcium (Ca2+) magnesium (Mg2+) bicarbonate (HCO3­) phosphate (PO42­) sulfate (SO42­) Electrolytes • Important for their chemical, physical (osmotic), and electrical effects on the body • Common disruption due to – sweating – Diarrhea – Vomiting – Hormone imbalance – Kidney disorders Electrolytes in Sweating • Heat control • Two types – Eccrine ­ the most numerous type that are found all over the body, particularly on the palms of the hands, soles of the feet and forehead – Apocrine ­ mostly confined to the armpits (axilla) and the anal­genital area. They typically end in hair follicles rather than pores. • Compared to apocrine glands, eccrine glands: – are smaller – are active from birth (Apocrine glands become active only at puberty) – produce a sweat that is free of proteins and fatty acids + ­ • Loss of Na , Cl , H O 2 Electrolytes in Sweating • the sweat from apocrine glands also contains proteins and fatty acids, which make it thicker and give it a milkier or yellowish color. – This is why underarm stains in clothing appear yellowish. – Sweat itself has no odor, but when bacteria on the skin and hair metabolize the proteins and fatty acids, they produce an unpleasant odor. – This is why deodorants and anti­perspirants are applied to the underarms instead of the whole body. • The maximum volume of sweat that a person who is not adapted to a hot climate can produce is about one liter per hour. • Amazingly, if you move to a hot climate such as the American desert southwest or the tropics, your ability to produce sweat will increase to about two to three liters per hour within about six weeks! This appears to be the maximum amount that you can produce. Electrolyte Measurement • Effects depend on – Concentration – Charge • Equivalent (Eq)­ the amount of electrolyte that would neutralize 1 mole of hydrogen ­ inos (H+ ) or hydroxide ions (OH ) Energy and Work • Energy­ is the capacity to do work – Potential energy­ energy contained in an object because of its position or internal state but is not being used to do work – Kinetic energy­ energy of motion, energy that is doing work • Work­ means to move something whether it’s a muscle or a molecule, breaking chemical bonds, building molecules, etc. Potential and Kinetic Energy Energy and Work • Chemical energy is potential energy stored in the bonds of molecules. – Chemical reactions release this energy and makes it available to do physiological work. – Heat is the kinetic energy of molecular motion • Temperature­ the measure of the rate molecular motion • Electromagnetic energy­ the kinetic energy of moving packets of radiation called photons (Ex: light) • Electrical energy­ has both potential – in a battery when charged particles accumulated at a point – in a cell when charged particles accumulate across a cell membrane kinetic – when electrons move through wires or – sodium moving across a cell membrane All Living Systems Need Energy For Physiological Work (Chemical Reaction) Chemical Reactions • A chemical change whereby compounds are formed or decomposed. – Accomplished by the making or breaking of bonds reactants disappear as chemical change occurs. • products appear as chemical change occurs. • catalysts speed up the reaction, but aren't produced or consumed. There is Energy in Chemical Bonds • Energy is released when bonds are broken. • Energy is needed in order for bonds to form. The Nature of the Chemical Reaction Chemicals must • collide and • collide at the correct orientation A + B Energy Barrier or energy of activation C Types of Chemical Reactions • Decomposition AB A + B • Synthesis A + B AB • Exchange reactions AB + CD AC + BD • Some reactions are reversible A + B AB Endergonic Chemical Reactions (Synthesis or Combination) Energy A + B 2H + O AB H O 2 Exergonic Reation (Disassociation) Energy AB CH 4 A + B C + 2H 2 Law of Mass Action • Pertains to reversible reactions when the reaction proceed from the side with the greater quantity of reactants to the side with the lesser quantity CO2 + H2O H2CO3 H+ + HCO3­ CO2 + H2O H2CO3 H+ + HCO3­ Reaction Rate • The amount of product formed per unit time depends on • Concentration­ the greater the concentration of reactants the greater the rate of reaction • Temperature­ the higher the temperature the greater the rate of reaction • Catalysts­ increases the speed of the reaction. Concentration and Reaction Rate • The greater the concentration of reactants the greater the opportunity for collision Temperature and Reaction Rate Increased temperature causes increased molecular motion causing a greater number of collisions per unit time resulting a higher reaction rate. Catalysts Reduce the Energy of Activation Resulting in a Greater Reaction Rate Catalyst Reduce Energy of Activation Energy Needed for Body Chemical Reactions Food we eat Body’s chemical reactions Energy for The Body’s Chemical Reactions Energy for The Body’s Chemical Reactions Energy For The Body’s Chemical Reactions Physiological Chemical Reactions • Metabolism­ all the chemical reactions in the body – Catabolism­ energy releasing decomposition reactions (exergonic reactions) – Anabolism­ energy storing synthesis reactions (endergonic) – Oxidation­ a reaction in which a molecule gives up electrons and releases energy Physiological Chemical Reactions • Oxidation­ a reaction in which a molecule gives up electrons and releases energy – This molecule is said to be oxidized • Reduction­ a reaction in which a molecule gains electrons and energy – This molecule is said to be reduced • Oxidation/Reduction reaction exist together Oxidation/Reduction (Redox) Chemical Compounds and Life Processes The body’s chemical compounds are divided into two major classed 1. Inorganic­ usually small and lacks carbon and may contain ionic bonds Ex. Water (most abundant), oxygen, carbon dioxide, acids and bases 2. Organic­ always contain carbon, mostly covalent bonds Ex. Proteins, lipids, carbohydrates, nucleic acids Inorganic Acids, Bases, and Salts Ionization (dissociation)­ the breaking apart of the inorganic molecule when dissolved in water + Acid­ a substance that dissociates into H and negative ions (anions) ­ Base­ a substance that dissociates into OH (hydroxide) ions and a positive ion (cation) Salt­ a substance that dissociates into a cation + ­ and anion, neither of which is H or OH Maintaining pH: Buffer Systems Compounds that prevent drastic changes in pH or Acid/Base balance • Normal body pH is between 7.35 and 7.45 • acid base balance depends on the hydrogen ion concentration – majority of hydrogen ions are produced by the metabolic activity of the cell the CO of respiration combines with water to form 2 carbonic aced which dissociates into hydrogen and bicarbonate ions CO + H2O H CO 2 2 3 + H + HCO ­ 3 Buffers Hydrogen ions can also be introduced into the body by other chemical compounds that we consume (whether nutritious or caustic). Buffer Systems consist of weak acids and weak bases that function to prevent drastic changes in the pH by strong acids and strong bases. Systems That Control pH • Respiratory System • Urinary System Buffers Principal buffer systems • carbonic acid­bicarbonate system • phosphate system • hemoglobin system • protein system Organic Compounds Macromolecules • Four major organic compounds of the body – carbohydrates – lipids – proteins – nucleic acids Organic Compounds Macromolecules • Most of the macromolecules are made up of smaller monomer units to form polymers • Dehydration reaction­ building up • Hydrolysis reaction­ breaking down Monomer units Polymer Dehydration Synthesis Combines Monomers into Polymers Hydrolysis Breaks Polymers Into Monomer Units Carbohydrates • Starches and sugars • main use as energy source • composed of a carbon, hydrogen and oxygen – oxygen to hydrogen ratio is 1:2 – multiple of CH2O Ex. Glucose (C H12O6) 6 Monosaccharide (simple sugar) Polysaccharide (complex sugar) Dehydration Synthesis Hydrolysis (digestion) Forming Fructose From Glucose and Fructose Monosaccharides Disaccharide Maltose­2 glucose Sucrose­ glucose and fructose Lactose­ glucose and galactose Storage Forms of Glucose Lipids • Composed of carbon, oxygen, and hydrogen • Does not have 1:2 oxygen to hydrogen ratio • noncharged – hydrophobic – hydrophillic • Classes of lipids – triglycerides (fats and oils)­ the bodies most highly concentrated source of energy over carbohydrates, however, less efficient. Triglyceride Glycerol Fatty acid Saturated fat animal foods (meats, milk, eggs) Unsaturated fats monounsaturated fat olive oil, canola oil, peanut oil polyunsaturated fat corn, dafflower, sunflower,cottonseed, sesame, soybean oils Saturated Fatty Acids Animal foods (meats, milk, eggs) Unsaturated Fatty Acid Monounsaturated fat olive oil, canola oil, peanut oil Polyunsaturated fat corn, dafflower, sunflower, cottonseed, sesame, soybean oils Phospholipids • contain phosphorus • part of cell membrane • charged head • uncharged tail Lipids (cont) • steriods (carbon skeleton bent to form 4 fused rings)­ – cholesterol, vitamin D, E, and K, sex hormones – carotenes­ chemicals used to make vitamin A – eiscosanoids • prostaglandins­ contribute to inflammation, regulate body temperature, help form blood clot • leukotrienes­ participate in allergic and inflammatory reactions Cholesterol • A constituent of all animal fats and oils • Cholesterol is one of a group of compounds known as sterols and is related to such other sterols as the sex hormones and the hormones of the adrenal cortex. Proteins • a biological polymer composed of amino acid monomers • major classes of proteins – structural­ hair, silk of spiders, fibers that of tendons – contractile­ provide muscular movement – defensive­ antibodies which fight infection – transport­ hemoglobin which carries oxygen – hormones – enzymes­ serves as a chemical catalyst (an agent that changes the rate of a chemical reaction without being changed into a different molecule in the process. • Promote and regulate all the chemical reactions in the body General Structure of an Amino Acid Dipeptide, Tripeptide, Polypeptide A Protein’s Specific Shape Determines its Function • a protein consist of one or more protein chains folded into a unique shape • a proteins specificity is dependent on its shape • most proteins are globular, although structural proteins are long and thin (fibrous) Denaturation • the process that alters the three dimensional structure – heat – salt – pH Temperature and Enzyme Activity Primary Structure­ the sequence of amino acids. Secondary Structure­ parts of the polypeptide which are coiled or folded into local patterns. Tertiary Structure­ the overall three dimensional shape. Quaternary Structure­ consist of two or more polypeptide chains or subunits. Enzymes • Catalyst­ Substances that speed up chemical reactions by increasing the frequency of collisions and properly orienting the molecules, without themselves being altered. • Characteristics – Specificity • each enzyme has a special substrate • active site – Efficiency­the number of reactions that can occur per minute (turnover number) – Control­ the rate of synthesis can be altered by cellular mechanisms. Enzyme­Substrate complex Non­organic partner that activates the enzyme Coenzymes • Organic cofactors that are usually derived from niacin, riboflavin, and other water­soluble vitamins • They are electron acceptors and transporters Enzyme Classification • The names of enzymes usually end in the suffix ­ase • Enzymes are grouped according to the types of chemical reactions they catalyze. – oxidases­ add oxygen – dehydrogenases­ remove hydrogen – hydrolases­ add water – transferases­ transfer groups of atoms Nucleic Acids • Polymers of monomers called nucleotides • serves as blueprint for protein synthesis • two types of nucleitides – DNA (deoxyribonucleic acid) • contains all the inheritable genetic information (genes) – RNA (ribonucleic acid) Nucleotide • each nucleotide has three parts – sugar­ ribose (5C sugar) or deoxyribose – phosphate group­ constant – nitrogenous base­ variable OH or H Nucleotides (cont.) 5 different kinds of bases in class into two goups • Purines – adenine, guanine • Pyrimidines – thymine, cytocine, uracis Nucleotides (Cont.) • DNA­ A, G, C, T • RNA­ A, G, C, U Double Stranded DNA DNA Strand With Complimentary Base Paring ATP • The bodies most important energy transfer molecule • Energy is in the phosphate bonds • Bonds hydrolyzed by adenosine triphosphatases (ATPases) • Much of the energy in ATP comes form glucose oxidation Phosphorylation by Kinases Guanosine Triphosphate (GTP) • Nucleotide involved in energy transfer • Activates the G protein in cell signaling Cyclic AMP (cAMP) • Formed from the removal of both second and third phosphate groups from ATP • Acts as second messenger to activate metabolic effects within the cell ...
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