Chapter 2, Chemistry Review 1 PDF

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SI APHY 101 Spring 2019 Ch 2 Chemistry Review: Matter – anything that has mass and occupies space; exists in three states: solid, liquid, or gas Energy – capacity to do work or put matter into motion Smallest unit of matter is atom Electron (e-) have a negative charge and are located outer side of nucleus Protons (p+) have a positive charge and are located nucleus Neutrons have a neutral charge and are located nucleus Mass number equal sum of protons and neutrons in nucleus Atom number # of protons Isotopes are elements with same atomic # (# of p+) & different mass # (# of neutrons) Radioisotopes unstable isotope Four major elements of the human body: Hydrogen, Oxygen, Carbon, Nitrogen Chemical Bonds are formed when valance electrons (outermost shell) of atoms interact Valance electrons determine if the atom will chemical bond “Breakdown of matter breaks down chemical bonds to release energy” Molecule formed by chemical bonding between two or more atoms of the same element Compound formed by chemical bonding between two or more atoms from different elements Octet rule the atom is most stable when 8 electrons are in the valance shell (outer shell) Ionic bonding - electrons (e-) are transferred from metal to nonmetal atoms results in the formation of ions: ion is permanently charged atom do to ionic bonding – cation and anion A cation is a positive charged ion. (metal lose 1 or more e-) An anion is a negative charged ion. (nonmetal gains 1 or more e-) Attraction between opposite charges bonds ions to one another forming salt

Covalent Bonds occur when 2 or more nonmetal share electrons; strongest bond Nonpolar covalent bond – share electrons equally at equal distance (CO2) Nonpolar molecules occur in 3 situations: Atoms sharing electrons are same element Arrangement of atoms makes one atom unable to pull more strongly than another atom (CO2) Bond is between carbon and hydrogen Polar covalent bond – share electrons unequally; forms polar molecules (H2O) Atom with higher electronegativity become partially negative; pulls shared e- close to self Atom with lower electronegativity become partially positive; pulls shared e- towards other atom Electronegativity affinity of having the shared electrons more of the amount of time Dipoles - polar molecules with partially positive and negative ends Hydrogen Bond – weak attractions between partially positive end of one dipole and partially negative end of another dipole; responsible for key property of water surface tension Chemical notation – series of symbols and abbreviations; demonstrates what occurs in a reaction; chemical equation (basic form of chemical notation) has two parts: Reactants (left side of equation) – starting ingredients; will undergo reaction (H+H+O) Products (right side of equation) – results of chemical reaction (H2O) Chemical reaction – when chemical bond is formed, broken, or rearranged, or electrons are transferred between two or more atoms (or molecules) Energy - puts matter into motion or fuel chemical reaction Potential – stored; can be released later Kinetic – potential energy released, set in motion (faster movement/greater energy) Endergonic reactions – require input of energy from another source; products contain more energy than reactants (energy invested so reaction could proceed) Exergonic reactions – release excess energy; products have less energy than reactants 3 types of energy - chemical, electrical, mechanical Chemical energy – in bonds between atoms; drives nearly all chemical processes Electrical energy – generated by movement of charged particles or ions Mechanical energy – energy directly transferred from one object to another

Homeostasis & chemical reactions Catabolic reactions (decomposition) – large substance is broken down into smaller substances usually exergonic; chemical bonds are broken Exchange reactions – one or more atoms from reactants are exchanged for one another Anabolic reactions (synthesis) – small simple subunits united by chemical bonds; make large complex substances; Reactions are endergonic; fueled by chemical energy Oxidation-reduction reactions (redox reactions) – special kind of exchange reaction; electrons and energy are exchanged instead of atoms – usually exergonic and release large amounts of energy Oxidized – reactant that loses electrons (use of O2 to break down Reduced – reactant that gains electrons (use of O2 to build up) Energy and Enzymes Activation energy (Ea) – energy required for all chemical reactions Factors that increase reaction rate – concentration (more particles, more energy), temperature (higher temp, more energy), size and phase -solid, liquid, gas (smaller, move faster) (gases, higher energy) Catalyst – increases reaction rate by lowering activation energy; not consumed or altered in reaction Enzymes – biological catalysts; most are proteins; Speed up reactions by lowering activation energy

Inorganic compounds generally do not contain carbon bonded to hydrogen; water, acids, bases, and salts Organic compounds do contain carbon bonded to hydrogen Hydrophobic solutes – do not have full or partially charged ends; do not dissolve in water; include uncharged nonpolar covalent molecules (oils and fats) Water (H2O) makes up 60–80% of mass of human body; body’s primary solvent Acid – hydrogen ion donor; number of hydrogen ions increases in water when acid is added Base (alkali) – hydrogen ion acceptor; number of hydrogen ions decreases in water when base is added pH scale – ranges from 0–14 Simple way of representing hydrogen ion concentration of a solution pH = 7; solution is neutral; number of hydrogen ions and base ions are equal pH less than 7 is acidic; hydrogen ions outnumber base ions pH greater than 7 is basic or alkaline; base ions outnumber hydrogen ions

Buffer – chemical system that resists changes in pH; prevents large swings in pH when acid or base is added to solution Consists of weak acid and corresponding anion; major buffer is carbonic acid – bicarbonate buffer system Salt – any metal cation and nonmetal anion held together by ionic bonds Can dissolve in water to form cations and anions called electrolytes; capable of conducting electrical current organic compound in body (carbohydrate, lipid, protein, or nucleic acid) consists of polymers built from monomer subunits: Monomers – single subunits; combined to build larger structures (polymers) by dehydration synthesis (links monomers together; makes molecule of water) Hydrolysis – catabolic reaction; uses water to break polymers into smaller subunits Carbohydrates – composed of carbon, hydrogen, and oxygen; function primarily as fuel; Monosaccharides – monomers from which all carbohydrates are made (Glucose, fructose, galactose, ribose, and deoxyribose are most abundant) Disaccharides – formed by union of two monosaccharides by dehydration synthesis Polysaccharides – many monosaccharides joined to one another by dehydration synthesis reactions Glycogen – storage polymer of glucose; mostly in skeletal muscle and liver cells Polysaccharides covalently bound to proteins or lipids form glycoproteins and glycolipids; various functions in body Lipids – group of nonpolar hydrophobic molecules composed primarily of carbon and hydrogen; include fats and oils Fatty acids – lipid monomers; 4 to 20 carbon atoms; may have none, one, or more double bonds Saturated fatty acids – solid at room temperature; no double bonds between carbon atoms; carbons are “saturated” with maximum number of hydrogen atoms Monounsaturated fatty acids – generally liquid at room temperature; one double bond between two carbons in hydrocarbon chain Polyunsaturated fatty acids – liquid at room temperature; two or more double bonds between carbons in hydrocarbon chain Triglyceride – three fatty acids linked by dehydration synthesis to modified 3-carbon carbohydrate, glycerol; storage polymer for fatty acids (neutral fat) Phospholipids – glycerol backbone, two fatty acid “tails” and one phosphate “head” in place of third fatty acid Molecule with polar group (phosphate head) and nonpolar group (fatty acid tail) is amphiphilic Makes phospholipids vital to structure of cell membranes Steroids – nonpolar; share four-ring hydrocarbon structure called steroid nucleus

Cholesterol – steroid that forms basis for all other steroids Proteins - Two basic types of proteins by 3D structure: Fibrous proteins – long rope-like strands; mostly nonpolar amino acids; add strength and durability to structures Globular proteins – spherical or globe-like; mostly polar amino acids; function as enzymes, hormones, and other cell messengers Four levels of complex protein structure: Primary structure – amino acid sequence of polypeptide chain Secondary structure – one or more segments of primary structure folded in specific ways; held together by hydrogen bond Alpha helix – coiled spring Beta-pleated sheet – Venetian blind Tertiary structure – three-dimensional shape of peptide chain (twists, folds, and coils, including secondary structure); stabilized by hydrogen bonding Quaternary structure – linking together more than one polypeptide chain in specific arrangement; critical to function of protein Protein denaturation – destroying protein’s shape by heat, pH changes, or exposure to chemicals Disrupts hydrogen bonding and ionic interactions that stabilize structure and function Nucleotides – monomers of nucleic acids; named for abundance in nuclei of cells; make up genetic material Nucleotide structure: Nitrogenous base with hydrocarbon ring structure Five-carbon pentose sugar (ribose or deoxyribose) Phosphate group Types of nitrogenous bases: Purines – double-ringed molecule; adenine (A) and guanine (G) Pyrimidines – single-ringed molecule; cytosine (C), uracil (U), and thymine (T) Adenosine triphosphate (ATP) Body’s energy currency molecule Synthesized from adenosine diphosphate (ADP) and phosphate group (Pi); energy from oxidation of fuels (like glucose) Not stored significantly by cells; entire supply exhausted in 60–90 seconds; cells must continually replenish ATP supply Production of large quantities of ATP requires oxygen; reason we breathe air

DNA – extremely large molecule in nuclei of cells; composed of two long chains that twist around each other to form double helix Contains genes – recipe (code) for protein synthesis (process to make every protein) Structural features of DNA: Pentose sugar deoxyribose (lacks oxygen-containing group of ribose) forms backbone of strand; alternates with phosphate group Bases: adenine, guanine, cytosine, and thymine Double helix strands – held together by hydrogen bonding between bases of each strand Each base faces inside of double helix as strands run in opposite directions DNA exhibits complementary base pairing; purine A always pairs with pyrimidine T; purine G always pairs with pyrimidine C A = T (where = denotes 2 hydrogen bonds) and C = G (where denotes 3 hydrogen bonds) RNA – single strand of nucleotides ; moves between nucleus and cytosol; critical to making proteins RNA contains pentose sugar ribose RNA contains uracil instead of thymine; still pairs with adenine (A = U)...