Q&A Hero

Q: How many RNA nucleotides are in a codon? A) 1 B) 5 C) 2 D) 4 E) 3

Q: Which type of molecule attaches itself to a ribosome, where it serves as a pattern for protein biosynthesis? A) transfer RNA B) protein C) DNA D) ribosomal RNA E) messenger RNA

Q: Which type of molecule is responsible for carrying an amino acid to a ribosome? A) protein B) DNA C) ribosomal RNA D) messenger RNA E) transfer RNA

Q: Which of the following is(are) not necessary for protein synthesis at the time and place where synthesis occurs? A) ribosomes B) DNA C) mRNA D) amino acids E) tRNA

Q: What is the significance of a "stop codon"? A) When it appears in messenger RNA, it is a signal to stop protein biosynthesis. B) When it appears in transfer RNA, it is a signal to stop transferring amino acids to the growing protein chain. C) When it appears in DNA, it is a signal to stop chromosome biosynthesis. D) When it appears in a protein, it is a signal for the protein to unfold. E) When it appears in ribosomal RNA, it is a signal to stop catalyzing protein biosynthesis.

Q: Where in the cell does protein synthesis cell take place? A) ribosome B) nucleus C) gene D) chromosome E) codon

Q: What is the cell structure that contains the cell's DNA? A) chromosome B) codon C) ribosome D) gene E) nucleus

Q: Which of the following 2'-deoxynucleotides contains the base thymine?A) B) C) D) E)

Q: Double stranded DNA may be represented as a double helix with the two strands held together by A) hydrogen bonds. B) covalent bonds. C) disulfide bonds. D) hydrophobic bonds. E) ionic bonds.

Q: What is the nitrogenous base that is found in RNA but not in DNA? A) thymine B) guanine C) uracil D) cytosine E) adenine

Q: Which of the following units is not found in a DNA molecule?A) a phosphate groupB) a peptide bondC) an organic baseD) a five-membered ringE) a ribose sugar

Q: What is the charge on each phosphate group in DNA in an aqueous solution near physiological pH?A) 0B) 1C) 2D) -1E) -2

Q: The nucleic acid sequence that is complementary to the DNA sequence GAC TAC GTT AGC is A) CTG ATG CAA TCG. B) GAC TAC GTT AGC. C) CGA TTG CAT CAG. D) TCA GCA TGG CTA. E) none of these

Q: A fragment of a DNA molecule has the base sequence CTGA. What is the complementary sequence? A) ATGC B) AGTC C) TCAG D) GACT E) CTGA

Q: What are the building blocks of nucleic acids? A) proteins B) monosaccharides C) lipids D) nucleotides E) amino acids

Q: A hemiacetal is formed from A) an alcohol and a ketone. B) a carboxylic acid and a mercaptan. C) an alcohol and an ether. D) an aldehyde and an alcohol. E) an ester and an amine.

Q: The overall shape of a protein is maintained by A) hydrogen bonding. B) ionic bonds. C) dipole"dipole bonding. D) covalent bonds. E) all of these

Q: The alpha helix and beta sheet are examples of A) protein denaturation. B) protein primary structure. C) complementary bases. D) protein tertiary structure. E) protein secondary structure.

Q: Which of the following statements is correct? A) Fibrous proteins tend to form long, water-soluble fibers, while globular proteins tend to form compact, water-soluble shapes. B) Fibrous proteins tend to form long, water-insoluble fibers, while globular proteins tend to form compact, water-soluble shapes. C) Fibrous proteins tend to form long, water-insoluble fibers, while globular proteins tend to form compact, water-insoluble shapes. D) Both fibrous proteins and globular proteins tend to form water-soluble structures of about the same shape. E) Fibrous proteins tend to form long, water-soluble fibers, while globular proteins tend to form compact, water-insoluble shapes.

Q: Which of the following types of structure in proteins always has/have covalent bonds? 1) primary structure 2) secondary structure 3) tertiary structure A) 1 only B) 2 only C) 3 only D) 1, and 2 E) 1, 2, and 3

Q: How many different tripeptides can be made from two molecules of the amino acid valine (val) and one molecule of the amino acid alanine (ala)? A) 4 B) 3 C) 1 D) 5 or more E) 2

Q: The sequence of amino acids held together by peptide bonds in a protein is the A) tertiary structure. B) hydrogen bonding. C) primary structure. D) quaternary structure. E) secondary structure.

Q: Which of the following statements concerning protein structure is/are correct? 1) The primary structure of a protein is defined as its sequence. 2) Secondary protein structures include the alpha helix and beta sheet. 3) Disulfide linkages are sometimes formed by the glycine which can significantly effect the protein shape. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1, 2, and 3

Q: Which of the following represents the linkage connecting amino acids in proteins?A) B) C) D) E)

Q: What is the functional group corresponding to a peptide bond? A) amine B) ether C) amide D) hemiacetal E) carboxylic acid

Q: Which of the following structures is the best representation for the amino acid cysteine under physiological conditions?A) B) C) D) E)

Q: Near a pH of 5.5, L-lysine (R = -(CH2)4NH2) the major species in aqueous solution is the diprotonated zwitterion. Given the following acid dissociation constants, what is the correct structure of the zwitterion?FunctionalGroup Kacarboxylic acid1.7 x10-2amine8.5 x10-10side chain amine1.51 x10-11A) B) C) D) E)

Q: When L-lysine (R = -(CH2)4NH2) is reacted with a large excess of strong acid, which of the following ions is the predominant species in solution?A) B) C) D) E)

Q: Which of the following is the zwitterionic form of glycine (R = H)?A) -NHCH2CO2HB) NH2CHCO2H+C) +NH2CH2CO2-D) +NH3CH2CO2-E) NH2CH2CO2-

Q: Polymers of amino-acid units are called A) metabolites. B) nucleic acids. C) lipids. D) carbohydrates. E) proteins.

Q: Which of the following is an amino acid?A) B) C) D) E)

Q: Which of the following amino acids has a hydrophilic side chain?A) B) C) D) E)

Q: Which of the following amino acids has a hydrophobic side chain?A) B) C) D) E)

Q: The side chain on the amino acid tyrosine is classified as A) hydrophobic. B) nonpolar. C) a zwitterion. D) polar. E) asymmetric.

Q: The amino acid L-lysine has the amine side chain R =-(CH2)4NH2. At low pH, all ionizable groups are protonated. What is the net charge on this fully protonated form of L-lysine?A) 2B) 1C) -1D) -2E) 0

Q: The side chain on the amino acid phenylalanineis classified asA) polar.B) asymmetric.C) hydrophilic.D) nonpolar.E) chiral.

Q: Which of the following is not an electrically conducting polymer?A) B) C) D) E)

Q: Which of the following statements about conductive polymers is/are correct?1) Alternating single and double bonds are required for a polymer chain to conduct electricity.2) Doping of trans-polyacetylene with I2facilitates the conduction of electrical charge between individual polymer molecules.3) trans-Polyacetylene is an addition polymer.A) 1 onlyB) 2 onlyC) 3 onlyD) 2 and 3E) 1, 2, and 3

Q: In an electrically conducting polymer, what is a "hole"?A) It is a region of negative charge.B) It is a delocalized electron.C) It is an antibonding molecular orbital.D) It is a molecular orbital from which a electron has been abstracted.E) It is an ion, such as I3-, added to increase the conductivity of the polymer.

Q: What is the type of polymer formed when 1,5-pentanediol, HOCH2CH2CH2CH2CH2OH, reacts with 1,6-hexanedicarboxylic acid, HOOCCH2CH2CH2CH2COOH? A) polyacetylene B) polyester C) polyamide D) polypropylene E) polyolefin

Q: What is the type of polymer formed when 1,4-butanecarboxylic acid, HOOCCH2CH2COOH, reacts with 1,4-diaminobutane, H2NCH2CH2CH2CH2NH2? A) polyacetylene B) polyolefin C) polystyrene D) polyester E) polyamide

Q: What is the polymer formed by the condensation of 1,3-propanedicarboxylic acid, HOOCCH2COOH, with 1,2-diaminoethane, NH2CH2CH2NH2?A) B) C) D) E)

Q: What is the polymer formed by the condensation of ethylene glycol, HOCH2CH2OH, with 1,3-propanedicarboxylic acid, HOOCCH2COOH?A) B) C) D) E)

Q: Which of the following pairs of substances could form a polyester? A) H2NCH2COOH + H2NCH2CH2COOH B) HO(CH2)4COOH + HOCH2CH=CHCH3 C) HOCH2CH2OH + HOOCCOOH D) H2C=CHCH3+ HOCH2CH2COOH E) H2C=CHCN + H2C=CHCH3

Q: Elimination of a small molecule such as water is involved in formation of which type of polymer? A) condensation polymer B) addition polymer C) free-radical polymer D) homopolymer E) copolymer

Q: The polymer formed from ethylene glycol (HOCH2CH2OH) and1,3-propanedicarboxylic acid (HOOCCH2COOH) is what type of polymer? I. addition polymer II. condensation polymer III. homopolymer IV. copolymer A) II and IV B) II and III C) I and IV D) I and III E) None of these; it's a polyamide.

Q: Which of the following statements does not describe natural rubber?A) It is a copolymer.B) Isoprene is the monomer.C) It may be sticky unless it has been vulcanized.D) It is a homopolymer.E) It can be made from the sap of a certain tree.

Q: For the addition polymer poly(vinyl chloride) shown below, what is the chemical structure of the monomer?A) B) C) D) E)

Q: What of the following polymers could be produced by the free-radical addition of 1,1-difluoroethylene, F2C=CH2?A) B) C) D) E)

Q: For a free-radical addition polymerization, which of the following statements is true?A) Upon polymerization, -bonds are transformed into -bonds.B) The final polymer is a free radical.C) A copolymer is formed between the monomer and the initiator.D) Upon polymerization, -bonds are transformed into -bonds.E) The final polymer must be electrically conducting.

Q: The polymeris formed by addition of which of the following?A) CH3CH2CH3B) CH2= CH - CH3C) CH3CH = C(CH3)2D) H2C = CH - CH - CH2E) CH3- CH = CH - CH3

Q: Which of the following combinations can produce a condensation polymer? (R and R- are alkyl groups)A) R-OH + HOOC-R--COOHB) HO-R-OH + R--COOHC) H2N-R-NH2+ HOOC-R--COOHD) A and CE) A, B, and C

Q: Which of the following is not an addition polymer?A) poly(vinyl chloride)B) polyethyleneC) polystyreneD) polypropyleneE) polyester

Q: The structure of the polymer used in a freezer wrap can mainly be described as follows:[CCl2CH2CCl2 CH2CCl2CH2CCl2CH2]nWhich monomer could produce this polymer?A) Cl2C - CH2B) CCl2C) CCl2= CH2D) Cl2C = CH2= CCl2E) none of these

Q: Which of the following statements about polymers is/are correct? 1) Condensation polymers are always formed from a single monomer. 2) Addition polymerization sometimes requires an initiator, such as an organic peroxide. 3) Polyesters are formed from amines and carboxylic acid monomers which have two or more amine and carboxylic acid functional groups per monomer. A) 1 only B) 2 only C) 3 only D) 2 and 3 E) 1, 2, and 3

Q: Which of the following statements about polymers is/are correct? 1) Polypropylene and polyethylene are high molecular weight alkenes. 2) Addition polymers must be made from monomers which have at least one double or triple bond somewhere in the molecule. 3) Condensation polymerization reactions produce small molecules, like H2O, as byproducts to the polymer formation. A) 1 only B) 2 only C) 3 only D) 2 and 3 E) 1, 2, and 3

Q: Consider the polymer drawn below: What monomer(s) could produce the above polymer? A) CH2= CH2and CH3CH = CH2 B) CH3CH = CHCH3 C) CH2= C(CH3)2 D) CO and CH2= CH2 E) none of these

Q: What are the products of a condensation reaction between a primary amine and a carboxylic acid? A) water and an amide B) water and an ester C) ammonia and an amid D) ammonia and an ester E) an ammonium cation and a carboxylate anion

Q: Which substance is a weak Brnsted"Lowry base in aqueous solution? A) CH3COOCH3 B) CH3OCH3 C) CH3COOH D) CH3NH2 E) CH3OH

Q: What is the functional group classification of a compound with the general formula given below? A) amide B) ester C) primary amine D) secondary amine E) tertiary amine

Q: What is the condensed structural formula for 3-ethyl-2-methyloctanoic acid?A) B) C) D) E)

Q: What is the IUPAC name for the substance having the following condensed structural formula? (CH3)3CCH2COOH A) 3,3-dimethyl-1-butanone B) 3,3-dimethylbutanoic acid C) 4,4-dimethylpentanal D) 3,3-dimethylpropanoic acid E) hexanoic acid

Q: Which substance is a weak Brnsted"Lowry acid in aqueous solution? A) CH3OCH3 B) CH3COOCH3 C) CH3OH D) CH3NH2 E) CH3COOH

Q: Which of the following alcohols is a tertiary alcohol? A) HOCH2CH(OH)CH2OH B) CH3CH2CH2OH C) HOCH2CH2OH D) (CH3)3COH E) CH3CH2CH(OH)CH3

Q: The functional group is characteristic of A) ketones. B) peptide linkages. C) organic acids. D) aldehydes. E) esters.

Q: The functional group is characteristic of A) esters. B) organic acids. C) peptide linkages. D) aldehydes. E) ketones.

Q: What is the correct condensed structural formula for 2,4-dimethyl-3-hexanone?A) B) C) D) E)

Q: What is the IUPAC name for the compound having the following condensed structural formula? A) 3,4-dimethylpentyl methyl ether B) 3,4-dimethyl-2-hexanol C) 3,4-dimethyl-5-hexanone D) 4-ethyl-3-methyl-2-pentanone E) 3,4-dimethyl-2-hexanone

Q: Which compound is a ketone? A) (CH3)2C(OH)CH3 B) (CH3)2CHCOOH C) (CH3)2CHOCH3 D) (CH3)2CHCHO E) (CH3)2CHCOCH3

Q: The functional group is characteristic of A) aldehydes. B) esters. C) organic acids. D) peptide linkages. E) ketones.

Q: The functional group is characteristic of A) aldehydes. B) esters. C) ketones. D) alcohols. E) acids.

Q: Which of the following compounds is a ketone? A) CH3OOCH3 B) CH3CH2COCH3 C) CH3CH2COOH D) CH3OCH3 E) CH3CH2OH

Q: What is the common name for the following compound? CH3CH2OCH2CH2CH3 A) 2-pentanone B) pentyl ether C) 2-pentanol D) propoxyethane E) ethyl propyl ether

Q: What is the IUPAC name for the alcohol (CH3)3CCH2CH2OH? A) 3,3-dimethyl-1-butanol B) isopentyl alcohol C) 3,3-dimethyl-1-propanol D) 2-isopropyl-1-ethanol E) isoamyl alcohol

Q: Name the following: A) ethanol B) propanol C) butanol D) 2-butanol E) 2-propanol

Q: What is the hybridization of the carbon in the aldehyde functional group? A) sp2 B) sp3 C) sp D) sp3d E) sp3d2

Q: Which of the following is a secondary alcohol?A) B) CH3CH2CH2OCH3C) (CH3)3COHD) E)

Q: How many structural isomers possessing the ether functional group have the molecular formula C5 H12 O? A) 3 B) 5 C) 4 D) more than 5 E) 2

Q: How many structural isomers possessing the alcohol functional group have the molecular formula C4 H10 O? A) 3 B) 4 C) 1 D) 5 E) 2

Q: What is the general structural representation of a carboxylic acid?A) B) C) D) E)