Biochem

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stereoisomers

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isomers that have atoms bonded in the same order, but w/different arrangements in space

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aldose

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monosaccharides that contain an aldehyde group

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chiral

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objects or molecules that have mirror images that cannot be superimposed

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achiral

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molecules w/mirror images that are superimposable

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amylose

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an unbranched polymer of starch composed of glucose units joined by alpha-1,4-glycosidic bonds

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fructose

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a monosaccharide found in honey and fruit juices; it it combined w/glucose in sucrose. Also called levulose and fruit sugar

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glycogen

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a polysaccharide formed in the liver and muscles for the storage of glucose as an energy reserve. It is compsed of glucose in a highly branched polymer joined by a a-1,4- and a-1,6-glycosidic bonds

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Haworth structure

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the cyclic structure that represents the closed chain of a monosaccharide

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lactose

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a disaccharide consisting of glucose and galactose found in milk and milk products

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maltose

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a disaccharide consisting of 2 glucose units; it is obtained from the hydrolysis of starch and in germination grains

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mutarotation

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the conversion btwn a and B anomers

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sucrose

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a dissacharide composed of glucose and fructose; a nonreducing sugar, commonly called table sugar or "sugar."

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cerebroside

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a glycolipid consisting of sphingosine, a fatty acid, and a monosaccaride (usually galactose)

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esterification

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the rxn of an alcohol such as glycerol w/acids to form ester bonds

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fat

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another term for solid triacyglycerols

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fluid mosaic model

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the concept that cell membranes are lipid bilayer structures that contain an assorment of polar lipids and proteins in a dynamic, fluid arrangement

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glycerophospholipids

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polar lipids of glycerol attached to two fatty acids and a phosphate group connected to an amino group such as choline, serine or ethanolamine

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hydrogenation

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the addition of hydrogen to unsaturated fats

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lipid bilayer

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a model of a cell membrane in which phospholipids are arranged in two rows interspersed w/proteins arranged at different depths

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lipids

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a family of compounds that in nonpolar in nature and not soluble in water; includes fats, waxes, phospholipids and steroids

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monounsaturated fatty acids

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fatty acids that contain two or more double bonds

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polyunsaturated fatty acids

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fatty acids that contain two or more double bonds

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saturated fatty acids

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fatty acids that have no double bonds; they have higher melting points than unsaturated lipids and are usually solid at room temps

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steroids

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types of lipid composed of a multicyclic ring system

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wax

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the ester of a long-chain alcohol and a long-cahin saturated fatty acid

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a helix

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a secondary level of protein structure, in which hydrogen bonds connect the NH of one peptide bond w/the C=O of a peptide bond later in the chain to form a coiled or corkscrew structure

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amino acid

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the building blcok of proteins, consisting of an amino grp, a carboxylic acid trp and a unique side group attached to the alpha carbon

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B-pleated sheet

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a secondary level of protein structure that consists of hydrogen bonds btwn peptide links in parallel polypeptide chains

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collagen

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the most abundant form of protein in the body, which is composed of fibrils of triple helixes w/hydrogen bonding btwn -OH grps of hydroxyproline and hydroxylysine

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disulfide bonds

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covalent -S-S- bonds that form btwn the -SH grp of cysteines in a protein to stabilize the tertiary structure

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essential amino acids

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amino acids that must be supplied by the diet b/c they are not synthesized by the body

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globular proteins

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proteins that acquire a compat shape from attractions btwn the R grp of the aa residues in the protein

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hydrogen bonds

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attractions btwn the polar R grps such as -OH, -NH2, and -COOH of aa's in a polypeptide chain

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hydrophilic aa

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an aa having polar, acidic or basic R groups that are attracted to water; "water-loving"

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hydrophilic interactions

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the attraction btwn polar R groups on the protein surface and water

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hydrophobic aa

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a nonpolar aa w/hydrocarbon R groups; "water-fearing"

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hydrophobic interactions

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the attraction btwn nonpolar R grps in a tertiary structure of a globular protein

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isoelectric poin (pI)

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the pH at wich an aa is in the neutral zwitterion form

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N terminal

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the aa in a peptide written on the left w/the unreacted or free amino grp (-NH3+)

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nonpolar aa's

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aa's that are not soluble in water b/c they contain a nonpolar R grp

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peptide

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the combination of two or more aa's joined by peptide bonds; depeptide, tripeptide, and so on

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peptide bond

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the amide bond that joins aa's in polypeptides and proteins

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polar aa's

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aa's athat are soluble in water b/c their R grp is polar: hydroxyl (OH), thiol (SH), carbonyl (C=O), amino (NH2), or carboxyl (COOH)

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chiral carbon

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a carbon atom that is bonded to four different atoms or groups of atoms

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galactose

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a monosaccharide that occurs combined w/glucose in lactose

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glycosides

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acetal products of a monosaccharide reacting w/an alcohol or another sugar

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achiral

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molecules w/mirror images that are superimposable

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cellulose

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an unbranched polysaccharide composed of glucose units linked by B-1,4-glycosidic bonds that cannot be hydrolyzed by the human digestive system

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monosaccaride

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a polyhydroxy compound that contains an aldehyde or ketone grp

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enantiomers

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stereoisomers that are mirror images that cannot be superimposed on eachother

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amylopectin

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a branched-chain polymer of starch composed of glucose units joined by alpha-1,4- and alpha-1,6- glycosidic bonds

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anomers

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the isomers of cyclic hemiacetals of monosaccharides that have a hydroxyl grp on C1 (or C2). In the alpha anomer, the OH is drawn downward; in the beta isomer the OH is up

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disaccharides

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carbohydrates composed of 2 monosaccharides joined by a glycosidic bond

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iodine test

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a test for amylose that forms a blue-black color after iodine is added to the sample

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Fischer projection

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a system for drawing stereoisomers that shows horizontal lines for bonds coming forward, and vertical lines for bonds going back w/the chiral atom at the center

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carbohydrate

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a simple or complex sugar composed of carbon, hydrogen and oxygen

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fermentation

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a rxn of glucose, fructose, maltose, or sucrose in which the sugar reacts w/enzymes in yeast to give ethanol and carbon dioxide gas

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glucose

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the most prevalent monosaccharide in the diet. An aldohexose that is found in fruits, vegetables, corn syrup and honey. Also known as blood sugar and dextrose. Combines in glycosidic bonds to form most of the polysaccharides

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glycosidic bond

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the acetal bond that forms when an alcohol or hydroxyl grp of monosaccharide adds to a hemiacetal. It is the type of bond that links monosaccharide units in di- or polysaccharides

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ketose

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a monosaccharide that contains a ketone grp

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polysaccharides

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polymers of many monosaccharide units, usually glucose. Polysaccharides differ in the types of glycosidic bonds and the amount of branching in the polyer

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reducing sugar

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a carbohydrate w/a free aldehyde grp capable of reduding the Cu2+ in Benedict's reagent

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saccharide

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a term from the Latin word saccharum, meaning "sugar"; is is used to describe the carbohydrate family

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cephalins

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phospholipids found in brain and verve tissues that incorporate the amino alcohol serine or ethanolamine

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cholesterol

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the most prevalent of the steroid compounds found in cellular membranes; needed for the synthesis of vitamin D, hormones, and bile acids

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fatty acids

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long-chain carboxylic acids found in fats

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ganglioside

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a glycolipid consisting of sphingosine, a fatty acid, and two or more monosaccharides

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glcyosphingolipids

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the phospholipid that combines sphingosine w/a fatty acid bonded to the nitrogen grp and one or more monosacchareides bonded by a glycosidic link, which replaces the -OH group of sphingosine

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lecithins

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glycerophospholipids containing choline as the amino alcohol

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lipidoses

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genetic diseases in which a deficiency of an enzyme for the hydrolysis of a lipid causes the accumulation of that lipid to toxic levels

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lipoprotein

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a combination of nonpolar lipids w/glycerophospholipids and proteins to form a polar complex that can be transported thru body fluids

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oil

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another term for liquid triaclglycerols

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prostagladins

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a number of compounds derived from arachidonic acid that regulate several physiological processes

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sphingolipids

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phospholipids in which spingosine has replaced glycerol

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triacylglycerols

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a family of lipids composed of three fatty acids bonded thru ester bonds to glycerol, a trihydroxy alcohol

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acidic amino acid

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an amino acid that has a carboxylic acid side chain (-COOH), which ionizes as a weak acid

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a-keratins

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fibrous proteins that contain mostly a-helixes found in hair, nails, and skin

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basic amino acid

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an amino acid that contains an amino (-NH2) group that can ionize as a weak base

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C terminal

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the amino acid that is the last amino acid in a peptide chain w/an unreacted or free carboxyl grp (-COO-)

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denaturation

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the loss of secondary and tertiary protein strucure caused by heat, acids, bases, organic compounds, heavy metals, and/or agitation

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electrophoresis

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the use of electrical current to separate proteins or other charged molecules w/different isoelectric points

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fibrous protein

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a protein that is insoluble in water; consistes of polypeptide chains w/a-helixes or B-pleated sheets, that make up the fibers of hair, wool, skin, nails, and silk

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primary structure

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the sequence of the aa's in a protein

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protein

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a term used for biologically active polypeptides that have may aa's linked together by peptide bonds

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quanternary structure

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a protein structure in which 2 or more protein subunits form an active protein

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salt bridge

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the ionic bond formed btwn side grps of basic and acidic aa's in a protein

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secondary structure

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the formation of an a-helix, B-pleated sheet, or triple helix

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tertiary structure

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the folding of the secondary structure of a protein into a compact structure that is stabilized by the interactions of R groups such as ionic and disulfide bonds

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triple helix

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the protein structure found in collagen consisting of three polypeptide chains woven together like a braid

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zwitterion

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the dipolar form of an aa consisting of two oppositely charged ionic regions, -NH3+ and -COO-

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active site

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a pocket in a part of the tertiary enzyme structure that binds substrate and catalyzes a rxn

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triple helix

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the protein structure found in collagen consisting of three polypeptide chains woven together like a braid

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active site

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a pocket in a part of the tertiary enzyme structure that binds substrate and catalyzes a rxn

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activity

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the rate at which an enzyme catalyzes the rsn that converts subtrate to product

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allosteric enzyme

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an enzyme that regulates the rae of a rxn when a regulator molecule attaches to a site other than the active site

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antibiotic

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an irreversible inhibitor produced by a bacteria, mold, or yeast that is toxic to bacteria

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catalyst

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a substance that takes part in a rxn to lower the activation energy, but is not changed

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coenzyme

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an organic molecule, usually a vitamin, required as a cofactor in enzyme action

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competitive inhibitor

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a molecule w/a structure similar to the substrate that inhibits enzyme action by competing for the active site

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enzymes

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globular proteins that catalyze biological rxns

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enzyme-substrate (ES) complex

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an intermediate consisting of an enzyme-catalyzed rsn

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fat-soluble vitamins

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vitamins that are not soluble in water and can be stored in the liver and body fat

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feedback control

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a type of inhibition in which an end product inhibits the first enzyme in a sequence of enzyme-catalyzed rxns

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induced-fit model

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a model of enzyme action in which a substrate induces an enzyme to modify ifts shape to give an optimal fit w/the substrate structure

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inhibitors

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substances that make an enzyme inactive by interfering w/its ability to react w/a substrate

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irreversible inhibition

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an inhibition caused by the covalent binding of an inhibitor to a part of the active site that cannot be reversed by adding more substrate

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isoenzymes

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isoenzymes catalyze the same rxn, but different combinations of polypeptide subunits

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lock-and-key model

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a model of an enzyme in which the substrate , like a key, exactly fits the shape of the lock, wich is the specific shape of the active site

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negative regulator

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a molecule or end product that slows down or stops a catalytic rsn by binding to an allosteric enzyme

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noncompetitive inhibitor

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a substance that changes the shape of the enzyme, which prevents the active site from binding substrate properly

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opitmum pH

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the pH at which an enzyme is most active

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optimum temp

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the temp at which an enzyme is most active

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positive regulator

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a molecule that increases the reate of an enzyme-catalyzed rsn by making the catalysis more favorable

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reversible inhibition

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inhibition of an enzyme that is reversed by increasing the substrate concentration

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simple enzyme

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an enzme that is active as a polypeptide only

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substrate

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the molecule that reacts in the active site in an enzyme-catalyzed rxn

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vitamins

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organic molecules, which are essential for normal health and growth, obtained in small amounts from the diet

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water-soluble vitamins

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vitamins that are soluble in water, cannot be stored in the body, are easily destroyed by heat, ultraviolet light, and oxygen, and function as coenzymes

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zymogen

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an inactive form of an enzyme that is activated by removing a peptide portion from one end of the protein

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acetyl CoA

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a 2-C acetyl unit from oxidation of pyruvate that bonds to coenzyme A

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ADP

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adenosine diphosphate, a compound of adenine, a ribose sugar, and 2 phosphate grps, it is formed by the hydrolysis of ATP

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aerobic

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an oxygen-containing environment in the cells

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amylase

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an enzyme that hydrolyzes the glycosidic bonds in polysaccharides during digestion

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anabolic rxn

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a metabolic rxn that requires energy

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anaerobic

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a condition in cells when there is no oxygen

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ATP

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adenosine triphosphate, a high-energy compound that stores energy in the cells, sonsists of adenine, a ribose sugar, and three phosphate groups

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catabolic rxn

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a metabolic rxn that produces energy for the cell by the degradation and oxidation of glucose and other molecules

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coenzyme A (CoA)

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a coenzyme that transports acyland acetyl grps

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Cori cycle

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a cyclic process in which lactate produced in muscle is transferred to the liver to be synthesized to glucose, which can be used again by muscle

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cytoplasm

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the material in eukaryotic cells btwn the nucleus and the plasma membrane

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cytosol

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the gluid of the cytoplasm, which is an aqueous solution of electrolytes and enzymes

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decarboxylation

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the loss of a carbon atom in the form of CO2

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digestion

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the processes in the gastrointestinal tract that break down large food molecules to smaller ones that pass thru the intestinal membrane into the blood stream

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FAD

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a coenzyme (flavin adenine dinucleotide) for dehydrogenase enzymes that form C=C

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fermentation

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the anaerobic conversion of glucose by enzymes in yeast to yield alcohol and CO2

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gluconeogenesis

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the synthesis of glucose from noncarbohydrate compounds

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glycogenesis

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the synthesis of glycogen from glucose molecules

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glycogenolysis

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the breakdown of glycogen into glucose molecules

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glycolysis

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the 10 oxidation rxns of glucose that yield 2 pyruvate molecules

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metabolism

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all the chemical rxns in living cells that carry out molecular and energy transformations

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mitochondria

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the organelles of the cells where energy-producing rxns take place

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NAD+

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the hydrogen acceptor used in oxidation rxns that form carbon-oxygen double bonds

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oxidation

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the loss of hydrogen as hydrogen ions and electrons or the gain of oxygen by a substrate that is degraded to smaller molecules or a coenzyme

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reduction

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the gain of hydrogen ions and electrons or the loss of oxygen by a substrate or a coenzyme

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ATP synthase (F0F1)

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an enzyme complex that links the energy released by protons returning to the matrix w/the synthesis of ATP from ADP and Pi. The F0 section contains the channel for proton flow, and the F1 section uses the evergy from the proton flow to drive the synthesis of ATP

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chemiosmotic model

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the conservation of energy from transfer of electrons in the electron transport chain by pumping protons into the intermembrane space to produce a proton gradient that provides the energy to synthesize ATP

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citric acid cycle

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a series of oxidation rxns in the mitochondria that convert acetyl CoA to CO2 and yield NADH and FADH2. It is also called the tricarboxylic acid cycle and the Krebs cycle

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coenzyme Q (CoQ, Q)

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a mobile carrier that transfers electrons from NADH and FADH2 to cytochrome b in complex III

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cytochromes (cyt)

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Iron-containing proteins that transfer electrons from QH2 to oxygen

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electron carriers

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a grp of proteins that accept and pass on electrons as they are reduced and oxidized. Most of the carriers are tightly attached to the inner mitochondrial membrane, but two are mobile carriers, which move electrons btwn the complexes containing the other carriers

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electron transport chain

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a series of rxns in the mitochondria that transfer electrons from NADH and FADH2 to electron carriers, which are arranged from higher to lower energy levels, and finally to O2, which produces H2O. Energy changes during these transfers provide energy for ATP synthesis

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Fe-S (iron-sulfur) clusters

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proteins containing iron and sulfur in which the iron ions accept electrons form FMNH2 and cytochrome b

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FMN (flavin mononucleotide)

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an electron carrier derived from riboflavin (vitamin B2) that transfers hydrogen ions and electrons from NADH entering in the electron transport chain

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oxidative phosphorylation

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the synthesis of ATP from ADP and Pi using energy generated by the oxidation rxns in the electron transport chain

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proton pumps

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the enzyme complexes I, III, and IV that move protons from the matrix into the inermembrane space, creating a proton gradient

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acidosis

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low blood pH resulting from the formation of acidic ketone bodies

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adipose tissue

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tissues containing cells in which triacyglycerols are stored

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beta (B) oxidation

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the degradation of fatty acids that removes 2-C segments from an oxidized B carbon in the chain

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chylomicron

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lipoproteins formed by coating triacyglycerols with proteins for transport in the lymph and bloodstream

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essential aa

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an aa that must be obtained from the diet b/c it cannot be synthesized in the body

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fat mobilization

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the hydrolysis of triaclglycerols in the adipose tissue to yield fatty acids and glycerol for energy production

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glucogenic aa

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an aa that provides carbon atoms for the synthesis of glucose

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ketogenesis

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the pathway that converts acetyl CoA to 4-C acetoacetate and other ketone bodies

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ketogenic aa

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an aa that provides C atoms for the fatty acid synthesis or ketone bodies

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ketone bodies

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the products of ketogenesis: acetoacetate, B-hydroxybutyrate, and acetone

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ketosis

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a condition in which high levels of ketone bodies cannot be metabolized, leading to lower blood pH

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lipogenesis

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the synthesis of fatty acid in which 2-C acetyl units link together to yield palmitic acid

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nonessential aa

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an aa that can be synthesized by rsns including transamination of a-keto acids in the body

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oxidative deamination

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the loss of ammonium ion when glutamate is degraded to a-ketoglutarate

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protein turnover

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the amt of protein that we break down from our diet and utilize for synthesis of proteins and nitrogen-containing compounds

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transamination

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the transfer of an amino grp from an aa to an a-keto acid

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urea cycle

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ammonium ions from the degradation of aa's and CO2 form carbamoyl phosphate, which is converted to urea