A&P 2: Chemistry Comes Alive Flashcards
Matter
anything that occupies space and has mass
Energy
capacity to do work, or to put matter in motion
Kinetic energy
energy in action
Potential energy
stored energy; inactive energy that has the capability to do work but is not presently doing so
Chemical energy
form of energy stored in the bonds of chemical substances
Electrical energy
results from the movement of charged particles
Mechanical energy
energy directly involved in moving matter
Radiant energy (electromagnetic energy)
energy that travels in waves
Elements
all matter is composed of these unique substances that cannot be broken down into simpler substances by ordinary chemical methods
Periodic table
provides a more complete listing of the known elements and helps to explain the properties of each element that makes it react as it does with other elements
Atoms
each element is composed of more or less identical particles (building blocks)
Physical properties
those we can detect with our senses, e.g. color, texture
Chemical properties
pertain to the way atoms interact with other atoms (bonding behavior) and account for the facts that iron rusts, animals can digest their food, etc.
Atomic symbol
each element is designated by a 1 or 2 letter chemical shorthand, usually the 1st letter of the element’s name
Nucleus
atom has a central one of these containing protons and neutrons tightly bound together
Protons
bear a positive charge
Neutrons
neutral part of the nucleus
atomic mass unit (amu)
protons and neutrons are heavy particles and have approximately the same mass, 1 of these
Electrons
bear a negative charge equal in strength to the positive charge of the proton
Planetary model
simplified, outdated model of atomic structure
Orbitals
regions around the nucleus in which a given electron or electron pair is likely to be found most of the time
Orbital model
modern model of atomic structure; depicts probable regions of greatest electron density by denser shading (electron cloud)
Atomic number
equal to the number of protons in its nucleus and is written as a subscript to the left of its atomic symbol
Mass number
sum of the masses of its protons and neutrons
Isotopes
nearly all known elements have two or more of these structural variations, which have the same number of protons (and electrons) but differ in the number of neutrons
Atomic weight
average of the relative weights (mass numbers) of all the isotopes of an element, taking into account their relative abundance in nature; approximately equal to the mass number of its most abundant isotope
Radioisotopes
isotopes that exhibit radioactivity
Molecule
combination of 2 or more atoms held together by chemical bonds
Compound
when 2 or more different kinds of atoms bind
Mixtures
substances composed of 2 or more components physically intermixed
Solutions
homogeneous mixtures of components that may be gases, liquids, or solids
Solvent
substance present in the greatest amount in a solution; usually liquids
Solutes
substances present in smaller amounts in a solution
Percent
parts per 100 parts
Molarity (M)
moles per liter
Mole
a ____ of any element or compound is equal to its atomic weight or sum of the atomic weights
Molecular weight
sum of atomic weights in grams
Avogadro’s number
6.02 x 10^23; number of particles in one mole of a substance
Colloids
emulsions; heterogeneous mixtures; composition is dissimilar in different areas of the mixture; often appear translucent/milky; scatter light but do not settle
Sol-gel transformations
ability to change reversibly from a fluid state to a more solid state
Suspensions
heterogeneous mixtures with large, often visible solutes that tend to settle out
Chemical bonds
when atoms combine with other atoms, they are held together by these
Electron shells
electrons forming the electron cloud around the nucleus of an atom occupy these regions of space that consecutively surround the atomic nucleus
Energy level
each electron shell represents a different one of these
Valence shell
indicates an atom’s outermost energy level or that portion of it containing the electrons that are chemically reactive
Octet rule (rule of 8’s)
except for shell 1 which is full when it has 2 electrons, atoms tend to interact in such a way that they have 8 electrons in their valence shell
Ions
charged particles that form due to the transfer of electrons
Ionic bond
chemical bond between atoms formed by the transfer of 1 or more electrons from 1 atom to another
Anion
gains 1 or more electrons; electron acceptor; acquires a net negative charge
Cation
atom that loses electrons; electron donor; acquires a net positive charge
Crystals
large arrays of cations and anions held together by ionic bonds
Covalent bonds
electron sharing produces molecules in which the shared electrons occupy a single orbital common to both atoms, which constitutes this type of bond
Nonpolar molecules
equal sharing of electrons (do not have separate + and - poles of charge)
Polar molecule
unequal electron pair sharing, especially in non-symmetrical molecules containing atoms with different electron-attracting abilities
Electronegativity
electron-hungry; capability to attract electrons very strongly
Electropositive
electron-attracting ability is so low that an atom usually loses its valence shell electrons to other atoms; potassium and sodium are good examples
Dipole
a polar molecule; one with two poles of opposite charge where the charges are not cancelled out
Reactants
substances that react together to form products
Products
the end result of reactants coming together or breaking apart
Molecular formula
element symbols and numbers that represents a molecule
Synthesis
combination reaction that always involves bond formation; when atoms or molecules combine to form a larger, more complex molecule
Anabolic
pertaining to the construction or building up of compounds/molecules
Decomposition reaction
occurs when a molecule is broken down into smaller molecules or its constituent atoms
Catabolic
degradative reaction; pertaining to the breaking down of compounds/molecules
Exchange/displacement reactions
involve both synthesis and decomposition; bonds are both made and broken
Oxidation-reduction reactions (redox reactions)
decomposition reactions; basis of all reactions in which food fuels are broken down for energy (ATP is produced)
Oxidized
reactant losing electrons is referred to as the electron donor and is said to be this
Reduced
reactant taking up the transferred electrons is called the electron acceptor and is said to become this
Exergonic reactions
reactions that release energy; reactions yield products with less energy than the initial reactants
Endergonic reactions
energy-absorbing reactions; products contain more potential energy in their chemical bonds than did the reactants
Chemical equilibrium
neither the forward nor the reverse reaction is dominant; for each molecule of product formed, one product molecule breaks down, releasing the reactants
Catalysts
substances that increase the rate of chemical reactions without themselves becoming chemically changed or part of the product; if biological = enzymes
Biochemistry
study of the chemical composition and reactions of living matter
Organic compounds
compounds containing carbon; all are covalently bonded, many are large
Inorganic compounds
all other chemicals in the body, including water, salts, and many acids and bases
Universal solvent
water b/c unparalleled solvent
Hydration layers
water forms layers of its molecules around large charged molecules such as proteins, shielding them from the effects of other charged substances in the vicinity and preventing them from settling out of solution
Hydrolysis reactions
decomposition reactions made by adding a water molecule to each bond to be broken; “water splitting”
Dehydration synthesis
when large carbohydrate or protein molecules are synthesized from smaller molecules, a water molecule is removed for every bond formed
Electrolytes
ions; substances that conduct an electrical current in solution
Acids
substance that releases hydrogen ions (H+) in detectable amounts; proton donor; sour taste
Bases
bitter taste, slippery feel; proton acceptors; take up hydrogen ions in detectable amounts
Hydroxyl ions
OH-; hydroxides dissociate in water and liberate OH- and cations
Bicarbonate
HCO3-; important base in the body; particularly abundant in blood
Ammonia
NH3; common waste product of protein breakdown in the body; a base with 1 pair of unshared electrons that strongly attracts protons
pH units
relative concentration of hydrogen ions in various body fluids is measured in these
Neutralization reaction
joining an acid and a base to form water, which neutralizes a solution
Buffers
resist abrupt and large swings in the pH of body fluids by releasing hydrogen ions (acting as acids) when the pH begins to rise and by binding hydrogen ions (acting as bases) when the pH drops
Strong acids
acids that dissolve completely and irreversibly in water; can dramatically change the pH of a solution
Weak acids
acids that do not dissociate completely; ex. carbonic acid (H2CO3), acetic acid (HAc)
Strong bases
those, like hydroxides, that dissociate easily in water and quickly tie up H+
Weak base
a base, like sodium bicarbonate, that ionizes incompletely and reversibly; accepts relatively few protons
Carbonic acid-bicarbonate system
major blood buffer; dissociates reversibly, releasing bicarbonate ions and protons
Electroneutral
never losing or gaining electrons, like carbon; always shares electrons
Polymers
chainlike molecules made of similar or repeating units (monomers), which are joined together by dehydration synthesis
Monomers
base unit of a polymer
Carbohydrates
group of molecules that includes sugars and starches; represents 1-2% of cell mass; contain carbon, hydrogen, and oxygen in a 2:1 ratio; classified according to size and solubility
Monosaccharides
simple sugars; single-chain or single-ring structures containing 3-7 carbon atoms; carbon, hydrogen, and oxygen in a 1:2:1 ratio; named according to number of carbons they contain
Isomers
having the same molecular formula but with differently arranged atoms, thus giving them different chemical properties
Disaccharide
double sugar; formed when 2 monosaccharides joined by dehydration synthesis; sucrose (glucose + fructose), lactose (glucose + galactose), maltose (glucose + glucose); too large to pass through cell membranes so must be broken down to simple sugars to be absorbed into the blood
Polysaccharides
polymers of simple sugars linked together by dehydration synthesis; large, fairly insoluble molecules so ideal storage products; lack the sweetness of simple/double sugars; ex. starch, glycogen
Lipids
insoluble in water but dissolve readily in others of its kind and in organic solvents such as alcohol and ether
Triglycerides
neutral fats; commonly known as fats when solids or oils when liquid; composed of 3 fatty acids and glycerol
Fatty acids
linear chains of carbon and hydrogen atoms (hydrocarbon chains) with an organic acid group (-COOH) at one end
Glycerol
modified simple sugar (a sugar alcohol)
Saturated
fatty acid chains with only single covalent bonds between carbon atoms; chain is straight; at room temperature = solid
Unsaturated
fatty acids that contain 1+ double bonds between carbon atoms; can be monounsaturated or polyunsaturated; chain is kinked so they can’t be packed closely enough to solidify; liquid at room temperature, typical of plant lipids; ex. olive oil, peanut oil, corn/soybean/safflower oils
Trans fats
common in many margarines and baked products; oils that have been solidified by addition of H atoms at sites of carbon double bonds; increase the risk of heart disease more so than the solid animal fats
Omega-3 fatty acids
found naturally in cold-water fish; appear to decrease the risk of heart disease and some inflammatory diseases
Phospholipids
modified triglycerides, specifically diglycerides with a phosphorus-containing group and two fatty acid chains; tail is nonpolar, phosphorus head is polar; chief material for building cellular membranes
Steroids
flat molecules made of 4 interlocking hydrocarbon rings; fat soluble, contain little oxygen; most important = cholesterol, which is essential for life (cell membranes, raw material for synthesis of vitamin D, steroid hormones, and bile salts); vital to homeostasis
Eicosanoids
diverse lipids chiefly derived from a 20-carbon fatty acid (arachidonic acid) found in all cell membranes; most important of these are the prostaglandins and their relatives, which play roles in various body processes, including blood clotting, regulation of blood pressure, inflammation, and labor contractions; synthesis and inflammatory actions are blocked by NSAIDs and COX-2 inhibitors
Protein
10-30% of cell mass; basic structural material of the body; not all are construction materials; vital role in cell function; include enzymes, hemoglobin, contractile ___ in muscle; varied functions; all contain carbon, oxygen, hydrogen, and nitrogen; many contain sulfur
Amino acids
building blocks of proteins; 20 common types; 2 important functional groups - (1) an amine group (-NH2) and an organic acid group (-COOH); may act as either a base (proton acceptor) or acid (proton donor); all are identical except for a single group of atoms called their R group
Peptide bond
characteristic arrangement of linked atoms in proteins; can be di-, tri-, or poly- (10+)
Macromolecules
most proteins are these large, complex molecules containing from 100 to over 10,000 amino acids
Alpha helix
most common type of secondary structure of a protein (coiled); stabilized by hydrogen bonds formed between NH and CO groups in amino acids in the primary chain (4 amino acids apart); hydrogen bonds in these always link different parts of the same chain together
Beta-pleated sheet
secondary structure of a protein; primary polypeptide chains do not coil, but are linked side by side by hydrogen bonds to form a pleated, ribbonlike structure that resembles an accordion; hydrogen bonds may link together different polypeptide chains as well as different parts of the same chain that has folded back on itself
Fibrous proteins
extended, strandlike; some exhibit only secondary structure; most have tertiary or quaternary structure; ex. collagen; insoluble in water, very stable; ideal for providing mechanical support and tensile strength for the body’s tissues; other examples = keratin, elastin, and certain contractile proteins of muscle
Structural proteins
AKA fibrous proteins because they are the chief building materials of the body
Globular proteins
compact, spherical proteins that have at least tertiary structure; some have quaternary structure; water-soluble, chemically active; play crucial roles in virtually all biological processes; AKA functional proteins; some help provide immunity (antibodies), some regulate growth & development (protein-based hormones), others are catalysts that oversee just about every chemical reaction in the body (enzymes)
Denatured
protein’s hydrogen bonds begin to break when the pH drops or the temperature rises above normal (physiological) levels, causing proteins to unfold and lose their specific 3D shape; usually reversible (when desired conditions are restored)
Active sites
function of globular proteins depends on the presence of specific arrangements of atoms on their surfaces; regions that fit and interact chemically with other molecules of complementary shape/charge
Molecular chaperones
all cells contain this class of unrelated globular proteins which help proteins achieve their functional 3D structure; aid in folding process of proteins, helps translocate proteins and certain metal ions (Cu, Fe, Zn) across cell membranes, promotes breakdown of denatured proteins, interacts with immune cells to trigger the immune response to diseased cells
Enzymes
globular proteins that act as biological catalysts
Holoenzyme
collective name for the 2 parts of a functional enzyme, consists of an apoenzyme and a cofactor
Apoenzyme
protein portion of an enzyme
Cofactor
may be an ion of a metal element (Cu/Fe) or an organic molecule needed to assist the reaction in some particular way
Coenzyme
organic cofactor derived from vitamins, esp B Complex
Substrate
substance on which an enzyme acts
Activation energy
every chemical reaction requires that a certain amount of energy be absorbed to prime the reaction; amount of energy needed to break the bonds of the reactants so they can rearrange themselves and become the product
Nucleic acids
composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus; largest molecules in the body; 2 major classes - DNA & RNA
DNA
deoxyribonucleic acid
RNA
ribonucleic acid; 3 types - messenger, ribosomal, & transfer; small molecules are called micro-_____ & appear to control genetic expression by shutting down genes or altering their expression
Nucleotides
structural units of nucleic acids; quite complex; 3 components - nitrogenous base, pentose sugar, phosphate group
5 Nitrogenous Bases
adenine, guanine, cytosine, thymine, uracil
Adenine & Guanine
large, 2-ring bases (purines)
Cytosine, Thymine, Uracil
smaller, single-ring bases (pyrimidines)
Double helix
spiral staircase-like structure of DNA
Complementary bases
adenine/thymine, guanine/cytosine
ATP
adenosine triphosphate; primary energy-transferring molecules in cells, provides a form of energy that is immediately usable by all body cells; RNA nucleotide in which 2 additional phosphate groups have been added unstable energy-storing molecule b/c 3 negatively charged phosphate groups are closely packed and repel each other
