Chem 26 exam 3

glucose structure

primary energy source in animal systems

galactose structure

a component monosaccharide in milk sugar

fructose structure

a component monosaccharide in fruit sugar

2'-deoxyribose structure

ribose structure

structural sugar in RNA

maltose structure

alpha 1--\>4 glycosidic linkage (1st must be alpha, second doesn't matter); alpha-D-glucose plus D-glucose; a metabolic intermediate in the digestion of dietary starch; positive Benedict's test (can still open up)

lactose structure

milk sugar; beta 1--\>4 linkage (1st must be beta, 2nd doesn't matter); D-galactose + D-glucose

sucrose structure

table sugar; alpha 1--\>beta 2 linkage (1st must be alpha, 2nd must be beta); look on Flemer's flashcards; alpha-D-glucose plus beta-D-fructose

amylose structure

straight-chain polymer of glucose (linear); alpha 1--\>4 linkages

amylopectin structure

branched polymer of glucose (branches); alpha 1--\>6 linkages; need to hydrolize amylopectin to break 1-4 bonds and turn into glucose monomers

cellulose structure

beta 1--\>4 glycosidic bond

saturated fatty acid

unsaturated fatty acid

all double bonds are cis (never trans)

arachidonic acid

unsaturated fatty acid precursor of the eicosanoid hormones; 20 carbon esesntial fatty acid

prostaglandin

hormones which mediate the following functions: inflammation response, reproductive health, gastrointestinal function, renal (kidney) function

thromboxane

hormones which mediate the following functions: blood coagulation (clotting) cascade

leukotriene

hormones which mediate the following functions: bronchial constriction; least modified from original arachidonic acid

phosphatidate

phosphoglyceride: diglyceride bearing phosphate group at a terminal hydroxyl; structural precursor to the 3 major structural building blocks of cell membranes (phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine)

sphyngomyelin

sphyngolipid:specialized structural component specific for nerve cell membranes; 2 strucutral differences--direct C-C connection to 3-carbon connector and amide connection to 3-carbon connector

steroid

ultimately synthesized from lipid and carbohydrate metabolites; contain the steroid carbon skeleton (collection of 4 fused carbon rings) biological applications: cholesterol, bile salts, sex hormones

glycine (Gly)

hydrophobic classification (the only non-chiral amino acid)

valine (Val)

hydrophobic classification

isoleucine (Ile)

hydrophobic classification

proline (Pro)

hydrophobic classification; the only secondary amine-containing amino acid

methionine (Met)

hydrophobic classification

serine (Ser)

polar neutral classification

asparagine (Asn)

polar neutral classification

cysteine (Cys)

polar neutral classification

histidine (His)

polar positively-charged classification

aspartate (Asp)

polar negatively-charged classification

alanine (Ala)

hydrophobic classification

leucine (Leu)

hydrophobic classification

phenylalanine (Phe)

hydrophobic classification

tryptophan (Trp)

hydrophobic classification

tyrosine (Tyr)

polar neutral classification

threonine (Thr)

polar neutral classification

glutamine (Gln)

polar neutral classification

lysine (Lys)

polar positively-charged classification

arginine (Arg)

polar positively-charged classification

glutamate (Glu)

polar negatively-charged classification

simple sugars (monosaccharides)

smallest monomer building block of higher levels of intricacy; possess empirical formula of (CH2O)n; named firstly on basis of the functional groups they contain and secondly on the number of carbon atoms they contain; longer linear sequences can exist as cyclic (Haworth) or linear (Fischer) form

chiral carbon

all bonds radiating from that carbon must be single bonds; all bonds radiating from that carbon must be connected to different enviornments; any molecule containing a \______ can exist as stereoisomers; molecules often have more than one chiral carbon

Conventions of the Fischer projection

in monosaccharides, THE chiral carbon is the \_________

chiral carbon furthest from the most oxidized end in a Fischer Projection; in a Fischer projection of a monosaccharide, all carbons b/w carbonhyl carbon and bottom carbon are always chiral

D vs L stereoisomers for carbohydrates

based upon which direction the OH projects; D-steroisomer if it points right, L if it points left

D-steroisomer is...

most prevalent form in nature and is the stereoisomer utilized in biological systems

equilibrium b/w linear and cyclic forms of monosaccharides

cyclic form predominates in solution; cyclic form possesses a hemiacetal linkage (C-O-C-O-H) which allows the reopening/reclosing of ring between the cyclic/linear form

complex sugars (disaccharides)

dimers of monosaccharide units; 2 monosaccharides (always assumed D designation) covalently bonded together via glycosidic bond aka oxygen bridge; glycosidic bond (oxygen bridge) caps the hemiacetal or hemiketal with a carbon atom, converting it to an acetal/ketal; capping such as this locks the linkage and prevents reopening to the linear form at that particular anomeric carbon

5 representative monosaccharides

three 6-carbon: beta-D-glucose, beta-D-galactose, beta-fructose; two 5-carbon: beta-D-ribose; beta-D-2'-deoxyribose; always in Haworth projection

3 representative disaccharides

maltose, lactose, sucrose

polysaccharides (complex carbohydrates)

polymers of monosaccharides (D-glucose); starch (amylose and amylopectin), glycogen, cellulose

starch

dietary starches: amylose and amylopectin

glycogen

the body's method of glucose storage (glucose storage polymer in animals); stored in liver (primarily) and skeletal muscle (lesser extent); similar in structure to amylopectin, but possessing a higher degree of branching

cellulose

structural polysaccharide in plants; most abundant organic molecule on the planet; can't be digested by humans b/c we don't have cellulase; beta 1-4 glycosidic bond

lipids functions

energy source and storage system, cell-membrane structural component, steroid structures/hormones

fatty acids

saturated and unsaturated; unsaturated C\=C double bonds always cis

melting point difference b/w saturated and unsaturated fatty acids

unsaturations disrupt favorable packing potenital, lowering melting point

omega-3 and omega-6 fatty acids classification

omega nomenclature derived from measuring the carbon number of the first unsaturation encountered from the opposite (methyl) end of the fatty acid

derivatives of unsaturated fatty acids

3 types of eicosanoids derived from arachadonic acid: prostaglandins, thromboxanes, leukotrienes

long fatty acid esters

waxes, e.g. bee's wax or carnauba wax (carnauba seen in picture)

glycerides

mono, di, and tri*(*considered neutral glycerides); primary use is energy storage (fat deposits in adipose tissues)

monoglyceride

glycerol plus one fatty acid

diglyceride

glycerol plus 2 fatty acids

triglyceride

glycerol plus 3 fatty acids

charged glycerides

phosphoglycerides; primary use: structure of cell membranes (lipid bilayer)

phosphatidylethanolamine

ethanolamine

phosphatidylcholine

choline

phosphatidylserine

serine

fluidity of inner membrane controlled by

1) ratio of unsaturated fatty acids to saturated fatty acids within lipid membrane tails (higher amount of unsaturated tails, more fluid membrane)
2) cholesterol affects fluidity of membranes (higher amount of impregnated cholesterol, less fluid membrane)

sphingosine-derived: sphingolipids

component of nerve cell membranes primarily; charged headgroup, amide (not ester) linkage, and direct connection to a 3-carbon unit

terpene-derived lipids (steroids)

derived from squalene lipid intermediate; image of steroid nucleus; include cholesterol, bile salts, human sex hormones

squalene

lipid precursor--\>3 steroids (cholesterol, bile salts, human sex hormones)

cholesterol

found in cell membranes of most animal cells--regulates the fluidity of the membrane; high blood cholesterol is linked to heart disease and other health problems

bile salts

help to emulsify dietary fats in digestive tract; synthesized in liver and stored in gallbladder; 2 types are cholate and chenodeoxycholate

human sex hormones

important signaling molecules in development of male and female sex characteristics; testosterone and estrogen

testosterone structure

estrogen structure

amino acids (basic structure)

alpha amino group, side chain R group, alpha carbon in center, alpha carboxylate group

amino acids have a chiral carbon

D vs L stereoisomers for proteins

based upon which direction the NH3+ projects; D if points right, L if points left; only L AA's are naturally-occurring

glycine is the....

only non-chiral amino acid

proline is the...

only secondary amine-containing amino acid (all the rest have primary amines)

a peptide bond (almost always secondary amide linkage)

amide connectivity b/w amino acids; occurs between COOH on one amino acid and the amine on the other amino acid; N-terminus always on left, C-terminus on right

writing structure of a tripeptide from free amino acids

1) write out series of N C C and connect them all w/ a single covalent bond
2) draw in the ionized N and C terminal
3) draw in the peptide (amide) bond carbonyls and N-H's
4) draw in the H's and the side chains on the central carbons

primary structure of proteins

linear sequence of amino acids (N term--\>C term AA sequence); e.g. ALA-ARG-GLY-SER-THR (between SER and THR is peptide bond, ALA is N term, THR is C term)**cannot turn this around, there is meaning in order (directionality)

resonance hybrid of peptide amide bond

gives amide backbone some rigidity--not as flexible as one might thing; rigid C\=N double bond (partial double bond character)

secondary structure of proteins

areas within a protein's primary structure which adopt predictable and ordered patterns: 2 types alpha helix and beta sheet/helix; both structures are stabilized by hydrogen bonds b/w carbonyl O's and NH's only within the amide backbone of the protein, NOT between R-groups

tertiary structure of (globular) proteins

referring to globular proteins; overall 3-D shape of the protein; the linear protein polymer, with any regions of secondary structure, folds upon itself to form a defined 3-D shape; crucial that the integrity of this shape is maintained

4 attractive forces which stabilize tertiary structure (only b/w R groups)

hydrophobic interactions b/w AA and side chains, hydrogen-bonding interactions, ionic salt-bridge interactions, disulfide bonds b/w cysteine side chains (covalent)

quaternary structure of proteins

some proteins; association of separate peptide chains into a larger overall 3-D structure; same forces which hold tertiary structure together hold the separate polypeptide chain tertiary structures together in one massive unit; associations of separate copies of a proteins tertiary structure; **Voltron (defender of the universe)--Flemer's favoritism cartoon (greater than the sum of its parts; hemoglobin is an example of a quaternary structure

enzyme's effect on activation energy of a reaction

no effect on equilibrium constant, but great enhancement of the rate of reaction

oxidoreductases

catalyze redox reactions; dehydrogenase

transferases

catalyze functional group transfers; see review guide or notes for example; (norepinephrine to epinephrine or vise versa with PNMT as enzyme)

hydrolases

catalyze hydrolysis reactions; lipase; see review guide or notes for example (triglyceride to glycerol plus 3 fatty acids with lipase as enzyme)

lyases

catalyze addition of a functional group (usually water) across a C\=C double bond or removal of a group to form a double bond; fumarase

isomerases

catalyzes rearrangement of functional groups within a molecule, converting one isomer to another; mutase

ligases

catalyze C-C, C-S, C-O, or C-N bond formation or breaking; accompanied by ATP--\>ADP interconversion; see review guide or notes for example

proteolytic enzymes

hydrolase-class enzymes which cleave amide bonds at specific AA in a protein chain; 3 enzymes with 3 different amino acid-type cleavage sites; always cleave peptide bond on carbonyl side of AA; chymotrypsin, trypsin, elastase

Chymotrypsin

specific for aromatic side chains; cleave at large hydrophobic sites; phe, trp, tyr, met

trypsin

specific for basic side chains cleaves at basic sites; lys, arg