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Flashcards in Chapter 2 Deck (90):
1

4 major elements of the body

O, C, H, N

2

8 lesser elements of the body

Ca, P, K, S, Na, Cl, Mg, Fe

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isotope

atoms of an element that have different numbers of neutrons and therefore different mass numbers

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Ion

an atom that has a positive or negative charge because of unequal numbers of protons and electrons

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molecule

when two or more atoms share electrons

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compound

a substance that contains atoms of two or more different elements

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free radical

an atom or group of atoms with an paired electron in the outermost shell

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valence shell of electrons

outermost shell of electrons

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ionic bond

the force of attraction that holds together ions with opposite charges

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cation

ion with a positive charge

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anion

ion with a negative charge

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electrolyte

an ionic compound that breaks apart into positive and negative ions in solution

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covalent bond

two or more atoms share electrons

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polar

the sharing of electrons is unequal - one atom attracts the electrons more strongly than the other

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nonpolar

the sharing of electrons is equal

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hydrogen bond

forms when a hydrogen atom with a partial positive charge attracts the partial negative charge of neighbouring electronegative atoms (F/O/N)

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chemical reaction

occurs when new bonds form or old bonds break between atoms

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metabolism

all the chemical reactions occurring in the body

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catalyst

chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur.

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anabolism/ synthesis reaction

when two or more atoms, ions or molecules combine to form two new and larger molecules
A + B = AB

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catabolism/ decomposition reaction

split up large molecules into smaller atoms, ions or molecules
AB = A + B

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exchange reaction

AB + CD = AD + BC

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reversible reaction

the products can revert to the original reactants (indicated by two half arrows pointing in opposite directions) - sometimes reversible only under certain conditions
AB = A + B

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inorganic compound

usually lack a carbon and are structurally simple. Can contain ionic and covalent bonds

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organic compounds

always contain carbon, usually contain hydrogen and always have covalent bonds

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water

most abundance inorganic compound in all living systems

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water as a solvent

versatile solvent because its polar covalent bonds, in which electrons are shared unequally, create positive and negative regions.

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hydrophillic

water loving (dissolve easily)

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hydrophobic

water fearing ( not very water soluble)

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hydrolysis

decomposition reactions break down large molecules into smaller molecules by the addition of a water molecule

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dehydration synthesis

when two smaller molecules join to form a larger molecule where water is a product

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heat capacity of water

high heat capacity - water can absorb or release a large amount of heat with only a modest change in its own temperature

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water as a lubricant

water is a major component of mucus and lubricating fluids

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mixture

combination of elements or compounds that are physically blended together but not bound by chemical bonds

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solution

combination of elements that are bound by chemical bonds

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solvent

dissolves another substance

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solute

dissolves in another substance

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acid

dissociates not one or more hydrogen ions

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base

dissociates into one or more hydroxide ions (OH)

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salt

dissociates into cations and anions (not H or OH)

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acid base balance

there is an optimum pH level for interstitial fluid that needs to be maintained for optimal functioning (7.35-7.45)

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pH scale

solution's acidity or alkalinity is expressed on the pH scale

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acidic solution

pH < 7

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basic/ alkaline solution

pH > 7

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buffer system

function to convert strong acids or bases into weak acids or bases (which change pH less drastically)

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carbonic acid- bicarbonate buffer system

carbonic acid acts as a weak acid and bicarbonate ion acts as a weak base. This system can compensate for either excess or shortage of H+ ions.

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carbohydrate

sugars, glycogen, starches and cellulose

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monosaccharide

monomer of carbohydrate - contains 3-7 carbon atoms

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disaccharide

molecule formed from combo of 2 monosaccharides

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polysaccharides

contains tens or hundreds of monosaccharides joined through dehydration synthesis

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glycogen

main polysaccharide in the body- made entirely of glucose monomers linked together in branching chains

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lipid

contain carbon, hydrogen and oxygen

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lipoproteins

lipid molecules join with hydrophilic protein molecules (to become more soluble in blood)

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fatty acid

simplest lipid - used to synthesize triglycerides or catabolized to generate ATP

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triglyceride

most plentiful lipid in the body- consists of a single glycerol and 3 fatty acid molecules

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glycerol

3 carbon glycerol forms the backbone of a triglyceride

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phospholipid

glycerol backbone and 2 fatty acid chains attached to the first 2 carbons, form many membranes

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steroid

4 rings of carbon atoms

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elcosanoids

lipids derived from a 20 carbon fatty acid

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prostaglandins

subclass of elcosanoid - modify responses to hormones, contribute to inflammatory response, prevent stomach ulcers

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leukotrienes

subclass of elcosanoid - participate in allergic and inflammatory response

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protein

large molecules that contain carbon, hydrogen, oxygen and nitrogen - largely responsible for the structure of body tissue

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structural function of proteins

form structural framework of various parts of body i.e. collagen in bone and other connective tissue

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regulatory function of proteins

function as hormones that regulate various physiological processes; control growth and development; as neurotransmitters, mediate responses of nervous system

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contractile function of proteins

allow shortening of muscle cells which produces movement i.e. actin and myosin

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immunological function of proteins

aid responses that protect body against foreign substances and invading pathogens

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transport function of proteins

carry vital substances throughout body

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catalytic function of protein

act as enzymes that replace biochemical reactions i.e. salivary amylase

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amino acid

monomers of proteins

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peptide bond

covalent bond joining each pair of amino acids

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dipeptide

2 amino acids combined

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tripeptide

3 amino acids combined

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polypeptide

4+ amino acids combined

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primary structure

unique sequence of amino acids that are linked by covalent bonds to form a polypeptide chain

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secondary structure

repeated twisting or folding of neighbouring amino acids in the polypeptide chain

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tertiary structure

3D shape of a polypeptide chain determines how it will function

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quaternary structure

the arrangement of the individual polypeptide chains relative to one another

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denaturation

if a protein encounters an altered environment it may unravel and lose its characteristic shape

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DNA

forms inherited genetic material inside each human cell

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RNA

relays instructions from the genes to guide each cell's synthesis of proteins from amino acids

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nucleotide

monomer of nucleic acid

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nitrogenous base

Adenine, Thymine, Cytosine and Guanine

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deoxyribose

5C sugar attaches to each base in DNA

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double helix

DNA resembles a spiral ladder

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ribose

5C sugar attaches to each base in RNA

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ATP

energy currency of all living things - 3 phosphate groups attached to adenosine

87

ADP

removal of the third phosphate group from ATP

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enzyme

highly specific, very efficient and subject to a variety of cellular controls

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substrate

reactant molecule on which the enzyme acts

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active site

the place on the enzyme where the substrate binds