Deck 25: Nucleic Acids and Protein Synthesis

Question 1

Supply the missing reagent(s)in the synthesis below.

A) PO₄^-3 and C₆H₅CH₂OH
B) PO₄^-3 and C₆H₅CH₂Cl
C)

D) C₆H₅CH₃ + POCl₃
E) C₆H₅CH₂OH + H₃PO₄

Answer 1

Question 2

An RNA nucleoside will undergo hydrolysis in dilute acid to yield which of the following?

A) 2-Deoxy-D-ribose and a heterocyclic base
B) 2-Deoxy-D-ribose,a heterocyclic base,and phosphate ion
C) D-Ribose and a heterocyclic base
D) D-Ribose,a heterocyclic base,and phosphate ion
E) D-Ribose and phosphate ion

Answer 2

D-Ribose and a heterocyclic base

Question 3

Which statement concerning the monosaccharide portion of nucleotides is true in every case?

A) The monosaccharide is in the pyranose form.
B) The linkage to phosphate is at carbon #3.
C) The heterocyclic base is attached to carbon #1 of the monosaccharide.
D) The monosaccharide - nitrogen base linkage is $\infty$ .
E) The monosaccharide is 2-deoxy-D-ribose.

Answer 3

The heterocyclic base is attached to carbon #1 of the monosaccharide.

Question 4

The following structure represents the less common (in DNA,at least)tautomeric form of __________.

A) Cytosine
B) Thymine
C) Adenine
D) Guanine
E) Uracil

Question 5

Complete hydrolysis of adenylic acid would yield which of these?

A) Adenosine and a phosphate ion
B) Adenine,D-ribose,and a phosphate ion
C) Adenine and D-ribose
D) Adenine and 2-deoxy-D-ribose
E) A pyrimidine,a pentose,and a phosphate ion

Question 6

The primary function of nucleic acids is:

A) the catalysis of biochemical reactions.
B) the regulation of reactions that occur in the body.
C) the preservation,transcription and translation of information.
D) the acid-catalyzed hydrolysis of nucleotides.
E) the neutralization of nucleic bases.

Question 7

Supply the missing reagent in the following synthesis.

A) (CH₃)₂C=O
B) HOCH₂CH₂OH
C) CH₃CHOHCH₃
D) CH₃CCl₂CH₃
E) CH₃CHClCH₃

Question 8

Which is an incorrect statement concerning DNA structure?

A) The base and the phosphate units are linked by phosphodiester bonds.
B) The sugar and the phosphate units are linked by hydrogen bonds.
C) The base and the sugar units are linked by $\beta$ -N-glycosidic bonds.
D) Two of the above statements are incorrect.
E) All of the above statements are incorrect.

Question 9

Which is a correct statement concerning DNA structure?

A) The base and the phosphate units are linked by hydrogen bonds.
B) The sugar and the phosphate units are linked by phosphodiester bonds.
C) The base and the sugar units are linked by $\beta$ -N-glycosidic bonds.
D) Two of the above statements are correct.
E) None of the above statements are correct.

Question 10

The synthesis of adenosine by the reaction shown below likely occurs by what reaction mechanism?

A) An S_N2 reaction
B) An S_NAr reaction
C) An elimination-addition reaction
D) An S_N1 reaction
E) An E₂ reaction

Question 11

The analytical data for DNA samples which led to generalizations such as (%G + %A) $\approx$ (%C + %T)came from the research of what individual?

A) James Watson
B) Francis Crick
C) Edwin Chargaff
D) Arthur Kornberg
E) Maurice Wilkins

Question 12

Hydrolysis of DNA from various species gives which of the following results?

A) The mole percentage of adenine is approximately equal to that of thymine.
B) The mole percentage of cytosine is approximately equal to that of guanine.
C) The total mole percentage of purines is approximately equal to that of pyrimidines.
D) All of the above
E) None of the above

Question 13

In DNA,the lactim form of guanine will pair with which base?

A) Cytosine
B) Adenine
C) Uracil
D) Thymine
E) No pairing is possible.

Question 14

Which are the products of hydrolysis of a RNA nucleotide?

A) D-Ribose,adenine
B) D-Ribose,guanine,phosphate
C) D-Ribose,thymine,phosphate
D) 2-Deoxy-D-ribose,cytosine,phosphate
E) 2-Deoxy-D-ribose,adenine

Question 15

What is the secondary structure of DNA?

A) An alpha-helix
B) A pleated sheet
C) A flat sheet
D) A double helix
E) A random coil

Question 16

In DNA,cytosine can pair via hydrogen bonding to _________?

A) Deoxyribose
B) Uracil
C) Adenine
D) Guanine
E) All of the above

Question 17

The monomeric units of nucleic acids are which of these?

A) D-ribose or 2-deoxy-D-ribose
B) Phosphate ions
C) Purines
D) Nucleosides
E) Nucleotides

Question 18

Consideration of tautomerism in guanine suggests that it can exist in lactam and lactim forms.The form that is typically found in DNA is __________,typically pairs with _____________,while the other form is likely to pair with __________,leading to the possible spontaneous mutations.

A) Lactam,cytosine,thymine
B) Lactam,cytosine,adenine
C) Lactim,cytosine,thymine
D) Lactam,uracil,cytosine
E) Lactim,cytosine,uracil

Question 19

In DNA,thymine can pair via hydrogen bonding to _________?

A) Cytosine
B) Uracil
C) Adenine
D) Guanine
E) Deoxyribose

Question 20

Which bases pair in DNA by hydrogen bonding?

A) Cytosine and thymine
B) Cytosine and uracil
C) Adenine and guanine
D) Adenine and thymine
E) Adenine and uracil

Question 21

The action of nitrous acid on 5-methylcytosine produces which nitrogen base?

A) Adenine
B) Guanine
C) Cytosine
D) Thymine
E) Uracil

Question 22

Where is the sequence of bases termed an "anticodon" found?

A) mRNA
B) tRNA
C) rRNA
D) DNA
E) Polysomes

Question 23

Which is an incorrect statement concerning the DNA double helix?

A) The sugar-phosphate backbone is on the outside of the helix and the base pairs are on the inside.
B) The two strands are identical but proceed in opposite directions.
C) Hydrogen bonding holds together the two strands.
D) Only purine-pyrimidine base pairs can be accommodated.
E) The sugar-phosphate backbone is completely regular.

Question 24

Which of the following is not a pyrimidine?

A) Cytosine
B) Thymine
C) Guanine
D) Uracil
E) All of the above are pyrimidines.

Question 25

Nitrous acid is a suspected mutagen because of its reaction with:

A) amine groups.
B) monosaccharides.
C) phosphates.
D) alcohols.
E) ketones.

Question 26

A purine:

A) contains four nitrogens in the ring system.
B) is bicyclic.
C) can participate in hydrogen bonding.
D) is a heterocyclic base.
E) All of the above

Question 27

Concerning the genetic code,which of the following is an incorrect statement?

A) Not all codons specify amino acids.
B) There are a total of 64 different triplets.
C) For each amino acid there are the same number of codons.
D) The triplet codons are incorporated in messenger RNA.
E) The triplet AUG is a "start" codon.

Question 28

In a nucleotide unit,the components are sequentially linked:

A) monosaccharide--phosphate--heterocyclic base.
B) amino acid--monosaccharide--phosphate.
C) phosphate--monosaccharide--heterocyclic base.
D) monosaccharide--amino acid--phosphate.
E) heterocyclic base--phosphate--monosaccharide.

Question 29

What is the transfer RNA anticodon for the messenger RNA codon,G-C-A?

A) T-A-T
B) G-U-T
C) G-C-A
D) A-C-G
E) C-G-U

Question 30

Which heterocyclic base found in RNA does not occur in DNA?

A) Guanine
B) Thymine
C) Cytosine
D) Uracil
E) Adenine

Question 31

The formation of a new DNA molecule which is an exact copy of a pre-existing one is designated by what term?

A) Duplication
B) Transcription
C) Translation
D) Replication
E) Reproduction

Question 32

In DNA,adenine can be linked to _________ .

A) Deoxyribose via $\beta$ -N-glycosidic bonds
B) Uracil via hydrogen bonds
C) Phosphate via phosphodiester bonds
D) Guanine via amide bonds
E) All of the above

Question 33

During translation,the segment on the mRNA that corresponds to the base sequence C-G-A along a gene segment of DNA,would bind to the anticodon __________ on a tRNA.

A) A-U-C
B) G-C-U
C) U-T-C
D) G-C-T
E) C-G-A

Question 34

Which is the initial N-terminal amino acid in the developing polypeptide in bacteria?

A) Cysteine
B) Methionine
C) N-Formylmethionine
D) Glycine
E) Alanine

Question 35

Which of these has the smallest molecular weight?

A) rRNA
B) mRNA
C) tRNA
D) DNA

Question 36

Which is the predominant tautomeric form of cytosine when it is present in DNA?

A) I
B) II
C) III
D) None of these
E) I,II and III are present in approximately equal amounts.

Question 37

Which is an incorrect statement concerning the DNA double helix?

A) The sugar-phosphate backbone is on the inside of the helix and the base pairs are on the outside.
B) The two strands are identical but proceed in opposite directions.
C) The two strands are linked by glycosidic bonds.
D) Two of the above statements are incorrect.
E) All of the above statements are incorrect.

Question 38

If a tRNA anticodon is GUC,what was the original base sequence in DNA?

A) GUC
B) GTC
C) CAG
D) GAC
E) CTG

Question 39

Which is the messenger codon which calls for the initiation of protein synthesis?

A) AUG
B) GUA
C) UAG
D) AUC
E) CAC

Question 40

In RNA,adenine can be linked to _________ .

A) Deoxyribose via $\beta$ -N-glycosidic bonds
B) Uracil via hydrogen bonds
C) Phosphate via phosphodiester bonds
D) Guanine via amide bonds
E) All of the above

Question 41

Specific amino acids attach to the arm of a tRNA that ends in __________,via a(n)_________ bond.

A) CCG,ester
B) ACG,ether
C) CCA,glycosidic
D) ACA,amide
E) CCA,ester

Question 42

The anticodon is part of

A) mRNA
B) rRNA
C) tRNA
D) DNA
E) None of these

Question 43

Which of the following statements about the polymerase chain reaction are true?

A) It generates a large number of copies of DNA
B) It polymerizes the short oligonucleotide strands formed during biosynthesis
C) It catalyzes the formation of mRNA
D) It needs a minuscule sample of DNA
E) Two of the above

Question 44

The codon consists of

A) A sequence of three bases
B) A sequence of three amino acids
C) A sequence of three purines
D) A sequence of three pyrimidines
E) None of these

Question 45

Amino acids bear the same relation to proteins as __________ do to nucleic acids.

Question 46

The synthesis of proteins according to "the central dogma of molecular genetics" would require:

A) replication then translation.
B) translation then replication.
C) replication then transcription.
D) transcription then translation.
E) Any of these

Question 47

The antisense nucleotide G-A-C-T-C,could be synthesized via a __________ template on ________?

A) T-C-A-G-A ,RNA
B) C-T-G-A-G,DNA
C) C-T-G-A-G,RNA
D) G-A-C-T-U,DNA
E) A-G-T-C-T,RNA

Question 48

Relatively short synthetic strands of DNA complementary to certain portions of a gene are known as:

A) antisense nucleotides.
B) templates.
C) palindromes.
D) endonucleases.
E) polymerases.

Question 49

Separation of the fragments produced in the chemical sequencing of a DNA segment is achieved by the use of which of these techniques?

A) Column chromatography
B) Fractional distillation
C) Thin layer chromatography
D) Gas chromatography
E) Gel electrophoresis

Question 50

The molecular archive of instructions for protein synthesis is called ______.The molecules that transcribe and translate these instructions are called ______.

Question 51

Each section of DNA that codes for a particular protein is called a _______.

Question 52

Which of the following is not a valid application of the PCR (polymerase chain reaction)?

A) Semen analysis in forensic investigations
B) Evolutionary biology
C) Detection of cytomegalovirus
D) Prenatal diagnosis of sickle cell anemia
E) All of these are valid applications of the PCR

Question 53

If the base sequence along a segment of DNA were T-C-G-T-A,what would be the antisense oligonucleotide synthesized from this sequence?

A) G-C-C-A-T
B) C-G-G-T-A
C) U-G-C-U-T
D) A-G-C-A-U
E) A-G-C-A-T

Question 54

If the base sequence along a segment of DNA were G-C-C-A-T,what would be the base sequence of messenger RNA synthesized from this sequence?

A) G-C-C-A-T
B) C-G-G-T-A
C) C-G-G-U-A
D) G-C-C-A-U
E) A-T-T-G-C

Question 55

The four bases that make up the DNA "ladder" are: ____________.

Question 56

The codon is part of

A) mRNA
B) rRNA
C) tRNA
D) DNA
E) None of these

Question 57

In DNA sequencing,what is used to convert DNA molecules into smaller,more manageable fragments?

A) DNA polymerase
B) Dilute HCl
C) Trypsin
D) Chymotrypsin
E) Restriction endonucleases

Question 58

If the base sequence along a segment of DNA were G-C-C-A-T,what would be the base sequence of messenger RNA synthesized from this sequence?

A) C-U-U-T-A
B) C-G-G-T-A
C) C-G-G-U-A
D) G-C-C-A-U
E) A-T-T-G-C

Question 59

The four bases found in RNA are: _________.

Question 60

The time required to synthesize a protein depends on the number of amino acid residues it contains.A rough estimate is that each ribosome can cause _________ peptide bonds to be formed per minute.

A) 30
B) 50
C) 100
D) 150
E) 200

Question 61

Draw structures to represent the bonding between ribose and uracil.

Question 62

What is the meaning of the following abbreviations: UMP and AMP?

Question 63

In the DNA base pairs,adenine always bonds with _________ and cytosine with __________.

Question 64

While proteins are made up of amino acids connected by amide bonds,nucleic acids are made up of nucleotides connected by __________.

Question 65

Draw the structures of two tautomeric forms of guanine,one a lactam,the other a lactim.Explain the possible involvement of the lactim form in causing spontaneous mutation during replication.

Question 66

Draw structures to represent the bonding between deoxyribose and thymine.

Question 67

Draw the structure with hydrogen bonds between Uracil and Adenine.

Question 68

Draw structures to represent the hydrogen bonding between adenine and thymine.

Question 69

Protein synthesis requires that two major processes take place.The first takes place in the cytoplasm involving messenger RNA (mRNA)and is called ___________.The second involves two other types of RNA: __________ and ____________.

Question 70

Draw the structure of the dinucleotide DNA A-G.

Question 71

Draw the structures to represent what is likely to happen when cyclic AMP (3',5'-cyclic adenylic acid)reacts with aqueous sodium hydroxide,briefly explaining your rationale.

Question 72

Draw structures to represent the hydrogen bonding between cytosine and guanine.

Question 73

In the DNA double helix,two strands of nucleic acids are held together by _____________.

Question 74

Draw structures to represent the hydrogen bonding between adenine and uracil.

Question 75

A chemical that causes mutations in DNA is called a _________.

Question 76

The secondary structure of DNA was proposed by Watson and Crick to be a ___________________.

Question 77

The backbone of DNA is made up of __________.

Question 78

2'-Deoxythymine exist in the lactam form rather than in the tautomeric lactim form.Explain.

Question 79

What product is likely to be formed from the reaction between an adenine residue on a nucleotide and nitrous acid? Explain the possible involvement of the product of this reaction in causing spontaneous mutation during replication.

Question 80

Suggest a reasonable strategy for the specific phosphorylation of the 5' -OH group of a nucleoside.