Second Week Notes
Second Week Notes BIOL 2457
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This 15 page Class Notes was uploaded by Sabera Notetaker on Tuesday September 6, 2016. The Class Notes belongs to BIOL 2457 at University of Texas at Arlington taught by Xavier G Aranda in Fall 2016. Since its upload, it has received 45 views. For similar materials see HUMAN ANATOMY AND PHYSIOLOGY I in Biology at University of Texas at Arlington.
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Date Created: 09/06/16
Chapter 2 Chemistry and Biochemistry are important for determining effective solutions for dehydration, fluid loss, and electrolyte imbalances Water follows sodium in a cell, which is why it is important to find the right calculations of sodium into the body to rehydrate patients Chemistry chemical reactions that underlies all physiological processes including movement, digestion, pumping of the heart, and the nervous system Chemistry is broken down into two 2 processes: Basic Chemistry and Biochemistry Basic Chemistry Matter anything that has mass and occupies space Can be seen, smelled, and felt Mass is considered the same as weight with the effects varying with gravity Ex: Elements on a periodic table are all considered matter Matter exists in three (3) states: o Solid definite shape and volume o Liquid definite volume with changeable shape o Gas changeable shape and volume Energy capacity to do work or put matter into motion No mass, doesn’t occupy space, and can only be measured by its effect on matter The greater the work, the more energy it uses Energy exists in two (2) forms: o Kinetic energy energy in action; energy that does work by moving objects o Potential energy stored energy (inactive) When stored (potential) energy is released, it is converted into kinetic energy All living things are composed of matter and they all require energy to grow and function Heat is the random motion of atoms that undergo kinetic energy Forms of energy used in the body: o Chemical energy stored in bonds of chemical substances (releases energy when bonds break) o Electrical energy results from movement of charged particles (found in electrons in house wiring, or in the body as ions in the cell membrane) o Mechanical energy Directly involved in moving matter o Radiant/ electromagnetic energy travels in waves including light (important for vision), infrared waves, radio waves, ultraviolet waves (important for vitamin D synthesis), and X rays Energy can be converted from one form to another, but is virtually ineffective because the energy that is gained is lost in the same amount (ex: electrical energy to light energy) Elements unique substances that can’t be broken down into simpler substances (all matter is composed of elements) The Periodic Table shows all known elements Four (4) major elements make up 96% of the body: o Carbon (C) o Oxygen (O) o Hydrogen (H) o Nitrogen (N) Atoms all elements are made up of atoms; they are: Unique building blocks for each element clusters of smaller particles called protons, neutrons, and electrons The smallest particles of an element with the same properties They give each element its own particular physical and chemical properties > Physical properties: color, texture, boiling and freezing point > Chemical properties: bonding behavior/ interaction with other atoms Atomic Symbol one or two lettered chemical abbreviation for an element Symbols are taken from the Latin name for the element E.g. Na is the atomic symbol for sodium, otherwise known as the Latin word Natrium Subatomic particles particles that make up an atom A central nucleus contains protons and neutrons tightly bound together; orbiting around the nucleus are surrounding electrons There are three (3) types of structures that make up atoms o Proton carries a positive (+) charge and weighs 1 atomic mass unit (1 amu) o Neutron has no electrical charge and weighs 1 amu o Electron carries a negative () charge with weighing nothing (0 amu) All atoms are electrically neutral because the number of protons in an atom is balanced by its number of electrons The number of protons and electrons is always equal: Iron (Fe) has 26 protons and 26 electrons There are two models that show how subatomic particles look: Planetary model Orbital model Each element has a different number of subatomic particles, which can be identified by looking at the atomic and mass number, isotopes, and atomic weight > Hydrogen (H): 1 proton, 1 electron, 0 neutron > Helium (He): 2 protons, 2 electrons, 2 neutrons Atomic Number the number of protons in a nucleus (seen at the top left of the subscript) Mass Number total number of protons and neutrons in the nucleus (seen at the bottom left) Atomic Number 6 Atomic Symbol C Atomic Mass 12.011 Atomic Weight the average mass number of all isotopes of an element Isotopes structural variations of the same element These atoms contain the same number of protons but different neutron Same atomic number but different atomic mass Isotopes of Hydrogen may look like this > Hydrogen (1 proton, 1 electron, 0 neutrons) > Deuterium (1 proton, 0 electrons, 1 neutron) > Tritium (1 proton, 1 electron, 2 neutrons) Radioisotopes heavy, unstable isotopes that decompose into simpler and more stable forms An atom will loses its subatomic particles and may even become a different element As the isotope decays it gives off energy called radioactivity Radioisotopes share the same chemistry as their more stable isotope They can be detected by scanners which makes it a valuable tool in the medical research; used to detect different diseases They can damage living tissue; some can destroy cancers, and some can be the cause of it > Radon from uranium decay causes lung cancer Molecule two (2) or more atoms bonded together H or2O 2 Compound specific molecule that has two (2) or more different atoms bonded together H O 2 Mixtures two (2) or more components physically intermixed True mixtures are transparent (air, salt, sugar solutes); most mixtures in our body are true mixtures of gasses, liquids, or solids dissolved in water Solvent substance present as greatest amount (liquids e.g. water) Solute substance present as smallest amount (e.g. sugar, salt, plasma) Most matter exists as mixtures o Solutions homogenous mixture; particles are evenly distributed (salt in water) o Colloids/ Emulsions heterogeneous mixtures; particles not evenly distributed; give off cloudy or milky appearance (some undergo sogel reaction; from liquid to solid such as JellO or cystol) o Suspensions heterogeneous mixtures with large solutes that don’t settle out (blood) Concentration of True Solutes 1. Percent of solute in total solution > how many parts of solute to solvent in a solution (e.g. 10 parts of salt and 90 parts water makes 10% salt) 2. Milligrams/Deciliter (mg/dl) > 1 deciliter = 1/100 liter 3. Molarity (M) > 1 mole of a compound has the same molecular weight of that compound > 1 mole = 6.02 X 10 this is known as Avogadro’s number > Molarity in body is expressed as millimoles (mM) 1M = 1000mM The differences between compounds and mixtures: Mixtures don’t involve chemical bonds Mixtures can be separated physically (filtering and straining) Compounds can only be separated by breaking chemical bonds Mixtures can be both heterogeneous and homogeneous Compounds can only be homogenous Chemical Bonds “energy relationships” between electrons of the reacting atoms that can be made or broken (they are not physical structures) Electrons determine whether a chemical reaction will happen and what kind of chemical bond will form Electron Shells space around the nucleus where electrons are occupied Shells are referred to as energy levels because each shell has electrons with kinetic and potential energy An atom can have up to 7 electron shells that can hold only a specific number of electrons Shells closes to the nucleus is filled first; > Shell 1 holds 2 electrons > Shell 2 holds a max of 8 electrons > Shell 3 holds a max of 18 electrons Valence shell is the outermost electron shell that holds the most potential energy (because they’re farthest from the nucleus) and are involved in chemical reactions Octet Rule All atoms (except small atoms H and He) desire 8 electrons in their valence shell The desire of 8 electrons is what drives chemical reactions (Noble gasses have 8 electrons so they aren’t as chemically reactive) Most atoms don’t have full valence shells, so atoms will gain, lose, or share electrons from bonds to fill 8 electrons in the valence shell Types of Bonds Ionic Bonds Ions atoms that have gained or lost electrons and become charged In ionic bonds, valence shell electrons are transferred form one atom to another, making them ions An ionic bond is the result of the attraction of opposite charges o Cation atom that lost one or more elections (negatively charged) o Anion atom that has gained one or more elections (positively charged) Most ionic compounds are salts (NaCl) Covalent Bonds The sharing of two or more valence elections between two atoms 2 electrons= Single bond 4 electrons= Double bond 6 electrons= Triple bond This allows the atoms to temporarily fill their valence shell There are two (2) types of covalent bonds: Nonpolar covalent bond equal sharing of electrons (electrically balanced) C O C Polar covalent bonds unequal sharing of electrons (electrically polar molecules) > Electronegative atoms with greater electronattracting ability > Electropositive Atoms with less electronattracting ability O H H Water (H 2) is polar: oxygen is electronegative/ hydrogen is electropositive Dipole molecules with different charges (+, ) such as H O 2 Hydrogen Bonds “Attraction between a hydrogen attached to an electronegative atom on one molecule and an electronegative molecule of another atom of a different molecule” Hydrogen is slightly positive (electropositive), so it can attract other negative molecules Acts as a “bridge” holding large molecules Common between dipoles like H O; 2his is what makes water liquid Surface tension is the result of a strong attraction between water molecules due to hydrogen bonding Chemical reactions chemical bonds being formed, rearrange, or broken Written into a chemical equation containing: o Reactants substances at the beginning of the reaction o Products result of the chemical reaction Molecular formula includes a subscript indicating the atom and a prefix indicating the number of unjointed atoms/molecules Reactants Products H + H H 2(Hydrogen gas) 4H + 1C CH4 (Methane) Three main types of chemical reactions: o Synthesis atoms/molecule combining together to form large molecules *(Anabolic reactions Bondbuilding) A + B AB o Decomposition breakdown of molecules into smaller molecules *(Catabolic reaction bondbreaking) AB A + B o Exchange (displacement) both synthesis and decomposition of molecules AB + CD AD + CB Redox Reaction (reductionoxidation) o Atoms are reduced when they gain an election o Atoms are oxidized when they lose and electron o C H6O 12 66 → 6C2 + 6H O2+ ATP 2(*glucose oxidized, oxygen reduced) Exergonic reactions release/ give off energy (catabolic reaction); products have more potential energy than reactants Endergonic energy absorbs/ uses up energy (anabolic reaction); products have less potential energy than reactants The speed of chemical reactions is affected by: Temperature; increased temperature= increased reaction rate Concentration of reactant; increased concentration= increased reaction rate Particle size; smaller particle= increased reaction rate Biochemistry Biochemistry the study of chemical composition and reactions of all living matter; either organic or inorganic: Inorganic compounds Doesn’t contain carbon o Water o Salt o many acids and bases Organic compounds Contains covalently bonded carbon (except CO , an2 CO) o Carbohydrates o Fats o Proteins o Nucleic acids Water most abundant inorganic compound accounting for 6080% of all living cells; Important for its properties: High heat capacity ability to absorb and release heat without changing temperature much High heat of vaporization evaporation; useful cooling mechanism Polar solvent properties dissolves ionic substances and forms water layers around charged molecules (proteins) as a transport medium Reactivity necessary for hydrolysis and dehydration synthesis reactions Cushioning protects organs from physical trauma (cerebrospinal fluid cushions nerves) Salts ionic compounds that dissociated into separate cations and anions in water All ions are electrolytes: can conduct electrical currents in a solution Ions play specialized role in body functions (sodium, calcium, potassium, iron) Homeostatic Imbalances Ionic balance is vital for homeostasis If electrolyte balance is disrupted, all organ systems will no longer function Acids a substance that releases hydrogen ions in detectable amounts; proton donor > HCl (hydrochloric acid) > HC H O2 (3c2tic acid, abbreviated HAc) > H CO (carbonic acid) 2 3 Bases a substance that takes up hydrogen ions, releasing hydroxyl ion (OH ); proton acceptor HCO a3d NH 3 pH Scale measurement of concentration of hydrogen (H) in a solution The more hydrogen, the more acidic + pH is a negative logarithm of H in moles per liter; ranges form 014 each pH unit represents a 10fold difference (pH of 5 is 10X more acidic than pH of 6) + o Acidic more H but lower pH 06.99 pH o Neutral equal number of H and OH 7 pH o Alkaline less H but higher pH 7.0114 pH Neutralization Reaction acids and bases mixed together *NaOH + HCl → NaCl + H O 2 Buffers compensatory mechanism that stops abrupt changes in pH + Releases hydrogen (H ) if pH gets too high Binds hydrogen (H ) if pH falls too low Converts strong acids/bases into weak acids/bases (carbonic acidbicarbonate system) (weak acid) H 2O 3 H3O (weak base) + H (proton) Organic compounds contains carbon Carbon in electroneutral and only shares electrons to form four (4) covalent bonds with other elements May organic compounds are polymers chains of their smaller units called monomers They are synthesized by dehydrations synthesis and broken down by hydrolysis: o Dehydration synthesis take out water o Hydrolysis adding water Carbohydrates Sugars and starches Contains carbon (C), oxygen (O), and hydrogen (H) 2:1 ratio of carbon and hydrogen Three classifications of carbohydrates: o Monosaccharides one sugar (smallest unit) o Disaccharides two sugars o Polysaccharides three or more sugars; made up of monomers of monosaccharides Monosaccharides simple sugars with 3 sevencarbon atoms (monomers of carbohydrates) > Pentose sugars (Ribose and deoxyribose) > Hexose sugars (Glucose, fructose, galactose, ) Disaccharides double sugars too large to pass cell membrane Important disaccharides: Sucrose, maltose, lactose Formed by dehydration synthesis of two monosaccharides *glucose + fructose → sucrose + water Polysaccharides polymers of monosaccharide (dehydration synthesis); not very soluble > Starch stored carbohydrates used by plants > Glycogen stored carbohydrates used by animals Lipids fatty acids Contain carbon (C), hydrogen (H), and oxygen (O); smaller amounts than carbohydrates Insoluble in water > Triglycerides > Phospholipids > Steroids > Eicosanoids Triglycerides Fats when solid, oils when liquid Three fatty acids bound to a glycerol Functions in energy storage, protection and insulation Saturated fatty acids all carbon linked by a single covalent bond resulting in more H; solid in room temp Unsaturated fatty acids one or more carbons linked by double bonds resulting in reduces H; liquid in room temp > Trans fats unhealthy modified oils > Omega3 fatty acids hear healthy oils Phospholipids Modified triglycerides (glycerol, two fatty acids, and a phosphorous group) Hydrophilic head and hydrophobic tail important for cell structure Steroids Four interlocking ring structures Common steroids: cholesterol, steroid hormones, vitamin D, bile salt Most important steroid is cholesterol for its properties of vitamin D, steroid, and bile salt synthesis Eicosanoids Derived from fatty acids and found in cell membranes Prostaglandin plays important role in blood clotting, control of blood pressure, inflammation, and labor contractions Proteins Proteins basic structural material of the body, making up 2030% of cell’s mass Structural, chemical (enzymes), and contraction (muscles) functions Contain carbon (C), oxygen (O), hydrogen (H), and nitrogen (N), and some contain sulfur (S) and phosphorus (P). Amino acids are the building blocks of proteins; proteins are long chains of amino acids Amino acids held together by peptide bonds and contain amine and acid group (acts and acid or base) They differ there groups by a distinct R group Four (4) structural levels of proteins: o Primary liner sequence of amino acids o Secondary alpha and beta helix resemble how amino acids interact with each other o Tertiary how secondary structures interact o Quaternary how two (2) or more polypeptides interact Protein shape and function divided into two categories: Fibrous and glomerular proteins Fibrous (structural) Proteins Extended and sand like, water insoluble, and stable Most tertiary or quaternary structure Provide mechanical support and strength > Keratin > Elastin > Collagen > Some contractile fiber Globular (functional) proteins compact, spherical, water soluble, and sensitive to environmental changes tertiary or quaternary structure chemically active in specific regions > antibodies > hormones > molecular chaperones (proteins that assist with covalent folding and unfolding) > enzymes Denaturation globular proteins unfolding and losing their shape active sites become inactive caused by decreased pH or increased temperature reversible if normal conditions restored irreversible if changers are extreme (can’t unboil and egg) Enzymes globular proteins that act as catalyst catalyst regulates and accelerate the speed of chemical reactions without being used up they lower the energy needed to initiate a chemical reaction, increasing the speed of the reaction and allowing millions of reaction to occur Holoenzymes most functional enzyme consisting of o Apoenzyme (protein portion) o Cofactor (metal ion) coenzyme (vitamin) Enzymes act on specific substrates Normally ends with –ase to indicate the reaction the catalyze (hydrolase, oxidase) Enzymes lower activation energy (initiate reaction) Three steps of enzyme action: o Substrate binds to enzyme’s active site, temporarily forming enzymesubstrate complex o Complex undergoes rearrangement of substrate, resulting in final product o Product is released from enzyme Nucleic Acids largest molecules in the body Composed of C, H, O N, and P Nucleotides nucleic acid polymers are made up of monomers with nitrogen base, a pentose sugar, and a phosphate group: > Deoxyribonucleic acid (DNA) > Ribonucleic acid (RNA) Deoxyribonucleic Acids (DNA) holds genetic blueprint for synthesis of all protein doublehelix molecule located in nucleus > Purines adenine (A) and guanine (G) > Pyrimidines cytosine (C) and thymine (T) > complementary basepairing: AT and CG Ribonucleic acid (RNA) links DNA to protein synthesis single stranded molecule outside of the nucleus contains ribose sugar Uracil replaces thymine > Messenger RNA (mRNA) > Transfer RNA (tRNA) > Ribosomal RNA (rRNA) ATP adenosine triphosphate Chemical energy released when glucose is broken down is captured in ATP directly powers chemical reactions in cells by offering immediate energy to cells Terminal phosphate group of ATP transferred to other compounds to use energy stored in phosphate bond to do work o Loss of phosphate group converts ATP to ADP o Loss of second phosphate group converts ADP to AMP Ch. 2 Quiz Answers Which organic molecules form the major structural materials of the body? Proteins Electrolytes are charged particles called ions that are dissolved in body fluids. Which of the following ions would be considered a major anion in the body? Chloride Which four elements comprise approximately 96% of our body weight? carbon, oxygen, hydrogen, and nitrogen What is the classification of a solution with a pH of 8.3? alkaline solution Carbohydrates are stored in the liver and muscles in the form of? Glycogen What helps to stabilize blood pH? Buffers Nonpolar molecules are the result of what? unequal electron pair sharing What is the primary energy-transferring molecule in cells? ATP Which is a decomposition reaction? MgO2 → Mg + O2 Which is a bond in which electrons are completely lost or gained by the atoms involved? Ionic bond