Anatomy + Physiology chapter 2

elements

elements

substance composed of only one type of atom that cannot be broken into simpler constituents by chemical means

compounds

chemical combination of two or more elements

atoms

smallest particle of a chemical element that retains the properties of that element; particles that combine to form molecules

subatomic particles

particles that make up atoms; neutrons, protons, electrons

nucleus

dense, central core of an atom

protons

positively charged subatomic particle

neutrons

neutral subatomic particle

electrons

small, negatively charged subatomic particle

atomic number

number of protons in an atom of an element

mass number (atomic mass)

number of protons plus the number of neutrons in an atom of an element

energy level

limited region surrounding the nucleus of an atom at a certain distance containing electrons; shell

octet rule

atoms with fewer or more than eight electrons in the outer energy level will attempt to lose, gain, or share electrons with other atoms to achieve stability

inert

stable element; maximum amount of electrons in outer shell

atomic weight

average atomic mass of an atom of an element as it is found in nature; atomic weights are usually found in the periodic table of elements

radioisotope

unstable isotope that undergoes nuclear breakdown and emits nuclear particles and radiation

decay

emition of nuclear particles and radiation

chemical reaction

interaction between two or more atoms that occurs as a result of activity between electrons in their outermost energy levels

molecules

two or more atoms covalently joined together

chemical bonds

energy relationship joining two or more atoms; involves sharing or exchange of electrons

ions

electrically charged atom or group of atoms

ionic bond (electrovalent bond)

formed by transfer of electrons; strong electrostatic force that binds positively and negatively charged ions together

covalent bond

formed by sharing of electron pairs between atoms

single covalent bond

covalent bond with only one pair of shared electrons

double covalent bond

covalent bond with two pairs of shared electrons

hydrogen bond

weak chemical bond that occurs between the partial positive charge on a hydrogen atom covalently bound to a nitrogen or oxygen atom and the partial negative charge of another polar molecule

polar molecule

molecule in which the electrical charge is not evenly distributed, causing one side of the molecule to be more positive or negative than the other

synthesis reaction

combining of two or more substances to form a more complex substance

A + B -> AB

decomposition reaction

breaking down of a substance into two or more simpler substances

AB -> A + B

exchange reaction

decomposition of two substances and, in exchange, synthesis of two new compounds

AB + CD -> AD + BC

reversible reaction

occur in both directions

A + B <\=\> AB

metabolism

all of the chemical reactions that occur in body cells

catabolism

chemical reactions that break down complex compounds into simpler ones and release energy

anabolism

chemical reactionns that join simple molecules together to form more complex molecules

adenosine triphosphate (ATP)

broken down to supply energy for anabolism

hydrolysis

chemical process in which a compound is split by addition of H+ and OH- portions of a water molecule

dehydration synthesis

anabolic process by which molecules are joined to form larger molecules; often called condensation reaction because it joins molecules together into a denser mass

organic compound

contain covalently bound carbon and hydrogen atoms and are involved in metabolic reactions

inorganic compound

chemical constituents that do not contain both carbon and hydrogen

functional groups

small cluster of atoms in an organic molecule that gives the molecule particular functional characteristics such as certain chemical binding properties; often represented generically by the letter R

property of water

strong polarity

polar water molecules attract other polar compounds, which causes them to dissociate/separate

property of water

high specific heat

hydrogen bonds absorb heat when they break and release heat when they form, thereby minimizing temperature changes

property of water

high heat of vaporation

many hydrogen bonds must be broken for water to evaporate

property of water

cohesion

hydrogen bonds hold molecules of water together

oxygen (O2)

required to complete the decomposition reactions required for the release of energy from nutrients burned by the cell

carbon dioxide (CO2)

involved in cellular respiration; produced as a waste product during the breakdown of complex nutrients and also serves an important role in maintaining the appropriate acid-base balance in the body

electrolytes

substance that dissociates into ions in solution, rendering the solution capable of conducting an electric current

acid

any substance that releases a hydrogen ion (H+) when in solution (proton donor)

strong acid

acid that completely or almost completely dissociates to form H+ ions

weak acid

acid that dissociates very little and therefore produces few excess H+ ions in solution

base (alkaline)

electrolytes that dissociate to yield hydroxide ions (OH-) or other electrolytes that combine with hydrogen ions

pH

indicates degree of acidity or alkalinity (base) of a solution

pH = 7 = neutrality

pH > 7 = alkalinity (base)

pH < 7 = acidic

buffers

minimize changes in concentrations of H+ and OH- ;maintain constancy of pH

salt

compound that results from chemical interaction of an acid and a base

neutralization reaction

reaction between an acid and a base to form a salt and water

carbohydrate

organic compounds containing carbon, hydrogen, and oxygen; commonly called sugars and starches

monosaccharides

simple sugars with short carbon chains (glucose)

hexose

monosaccharides with six carbons

pentoses

monosaccharides with five carbons

disaccharides

two simple sugars (monosaccharides) that are bonded together through a dehydration synthesis reaction

polysaccharides

more than two simple sugars that are bonded together through a dehydration synthesis reaction

polymer

large molecule made up of many identical smaller molecules joined together in sequence

glycogen

polysaccharide; main carbohydrate stored in animal cells

lipids

water-insoluble organic molecules that are critically important biological compounds

nonpolar

describes a covalent chemical bond in which there is equal sharing of electrons and therefore no distinct areas of electrical charge

triglycerides

lipid that is synthesized from fatty acids and glycerol or from excess glucose or amino acids; stored mainly in adipose tissue cells

fatty acids

product of fat digestion; building block of fat molecules

saturated fatty acid

fatty acid in which all available bonds of its hydrocarbon chain are filled, that is, saturated, with hydrogen atoms

unsaturated fatty acid

fatty acid that has one or more double bonds in its hydrocarbon chain because not all the chain's carbon atoms are saturated with hydrogen atoms

phospholipids

phosphate-containing fat molecule; an important constituent of cell membranes

hydrophilic

water loving

hydrophobic

water fearing

steriods

any of a class of lipids related to sterols and forming numerous reproductive and adrenal hormones

prostaglandins (tissue hormones)

any of a group of naturally occurring lipid-based substance that act in a hormone-like way to affect many body functions, including vasodilation, uterine smooth muscle contraction, and the inflammatory response

proteins

large molecules formed by linkage of amino acids by peptide bonds; one of the basic building blocks of the body

enzymes

biochemical catalyst that allows chemical reactions to take place; functional proteins that regulate various metabolic pathways of the body

amino acids

type of chemical unit from which proteins are built; also have other functions made up of a carbon atom to which are bonded an amino group and carboxyl group

peptide bond

bond that forms between the amino group of one amino acid and the carboxyl group of another

primary structure of protein

protein structure is a sequence of amino acids in a chain

secondary structure of protein

protein structure is formed by folding and twisting of amino acid chain

tertiary structure of protein

protein structure is formed when the twists and folds of the secondary structure fold again to from a larger 3D structure

quaternary structure of protein

protein structure is a protein consisting of more than one folded amino acid chain

chaperones

any of a group of globular proteins that are present in every body cell and direct the intracellular steps required for other proteins to achieve the often twisted and convoluted shape required for them to function

structural proteins

any of a category of proteins with the primary function of forming structures of the cell or tissue; contrast with functional protein

functional proteins

category of proteins that affect the functional operations of a cell; contrast to structural protein

denatures

to alter the shape of a protein by a change in pH, heat, or some other manner to change its chemical properties

nucleic acid

any of the high-molecular-weight organic compounds composed of nucleotides, a ribose or deoxyribose sugar, and a phosphate group

nucleotides

monomer made up of three types of chemical groups (sugar, phosphate, nitrogen base) that can act alone or to make up a polymer

deoxyribonucleic acid (DNA)

genetic material of the cell that carries the chemical "blueprint" of the body

ribonucleic acid (RNA)

nucleic acid found in both nucleus and cytoplasm of cells; involved in transmission of genetic information from nucleus to cytoplasm and in cytoplasmic assembly of proteins