42 terms

Ch. 5: The structure and Function of Large Biological Molecules

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macromolecules
"A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction. Polysaccharides, proteins, and nucleic acids are..."
polymer
"A long molecule consisting of many similar or identical monomers linked together"
monomer
"The subunit that serves as the building block of a polymer"
condensation reaction
"A reaction in which two molecules become covalently bonded to each other through the loss of a small molecule, usually water in which case it is also called a dehydration reaction"
dehydration reaction
"A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule"
enzyme
"A macromolecule serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction"
hydrolysis
"A chemical process that lyses, or splits, molecules by the addition of water, functioning in disassembly of polymers to monomers"
carbohydrate
"A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides)
monosaccharide
"The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, ...have molecular formulas that are generally some multiple of CH2O"
disaccharide
"A double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed during dehydration synthesis"
glycosidic linkage
"A covalent bond formed between two monosaccharides by a dehydration reaction"
polysaccharide
"A polymer of many monosaccharides, formed by dehydration reactions"
starch
"A storage polysaccharide in plants, consisting entirely of glucose monomers joined by alpha glycosidic linkages"
glycogen
"An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch"
cellulose
"A structural polysaccharide of plant cell walls, consisting of glucose monomers joined by (Beta) glycosidic linkages"
chitin
"A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all arthropods"
lipid
"One of a group of compounds, including fats, phospholipids, and steroids, that mix poorly, if at all, with water"
fat
"A lipid consisting of three fatty acids linked to one glycerol molecule; also called a triacylglycerol or triglyceride"
fatty acid
"A long carbon chain carboxylic acid. ...vary in length and in the number and location of double bonds; three ...linked to a glycerol molecule form a fat molecule, also known as a triacylgycerol or triglyceride"
triacylglycerol
"Three fatty acids linked to one glycerol molecule; also called a fat or a triglyceride"
saturated fatty acid
"A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that are attached to the carbon skeleton"
unsaturated fatty acid
"A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton"
trans fat
"An unsaturated fat containing one or more trans (italicized) double bonds"
phospholipid
"A lipid made up of glycerol joined to two fatty acids and a phosphate goup. The hydrocarbon chains of the fatty acids act as nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head. ...form bilayers that function as biological membranes"
steroid
"A type of lipid characterized by a carbon skeleton consisting of four rings with various chemical groups attached"
cholesterol
"A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids, such as hormones"
catalyst
"A chemical agent that increases the rate of a reaction without being consumed by the reaction"
polypeptide
"A polymer (chain) of many amino acids linked together by peptide bonds"
protein
"A functional biological molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure"
amino acid
"An organic molecule possessing both carboxyl and amino groups. ...serve as the monomers of polypeptides"
peptide bond
"The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction"
primary structure
"The level of protein structure referring to the specific sequence of amino acids"
secondary structure
"The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between constituents of the backbone"
alpha helix
"A spiral shape constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding"
beta pleated sheet
"One form of the secondary structure of proteins in which the polypeptide chain folds back and forth. Two regions of the chain lie parallel to each other and are held together by hydrogen bonds"
tertiary structure
"Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges"
hydrophobic interaction
"A type of weak chemical bond formed when molecules that do not mix with water coalesce to exclude water"
disulfide bridge
"A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer"
quaternary structure
"The particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide"
denaturation
"In proteins, a process in which a protein unravels and loses its native shape, thereby becoming biologically inactive; in DNA, the separation of the two strands of the double helix. ...occurs under extreme (noncellular) conditions of pH, salt concentration, and temperature"
chaperonin
"A protein molecule that assists in the proper folding of other proteins"
x-ray crystallography
"A technique that depends on the diffraction of an X-ray beam by the individual atoms of a crystallized molecule to study the three-dimensional structure of the molecule"