Question 1

Which of the following nitrogenous bases are purines?

Accepted Answer

A)  cytosine and uracil
B)  cytosine and thymine
C)  cytosine,uracil,and thymine
D)  adenine and guanineE) A) and B)
F) A) and C)

Question 2

What is the difference between a ribonucleotide and a deoxyribonucleotide?

Accepted Answer

A)  Ribonucleotides contain a phosphate group.
B)  Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit.
C)  Ribonucleotides contain a sugar with five carbon atoms.
D)  Ribonucleotides have a hydrogen atom on the 1 carbon of their sugar subunit.E) B) and C)
F) None of the above B

Question 3

Why do many researchers consider RNA to be the best candidate for the first life-form?

Accepted Answer

A)  It is simple in structure.
B)  It is capable of self-replication and catalysis.
C)  It carries more information than any other molecule.
D)  All of its nucleotide components have been created under laboratory conditions that mimic early Earth.E) A) and D)
F) A) and C)

Question 4

In the secondary structure of DNA,the α-helical twists are organized into

Accepted Answer

A)  major and minor grooves.
B)  large and small grooves.
C)  major and small grooves.
D)  large and minor grooves.E) None of the above
F) A) and C)

Question 5

The "information system" of the cell involves stable genetic information being stored as ________,which can be used to make a "disposable" (relatively short-lived) copy of this information as ________.

Accepted Answer

A)  RNA;DNA
B)  DNA;DNA
C)  DNA;RNA
D)  RNA;RNAE) B) and C)
F) A) and B) C

Question 6

Which of the following includes all of the pyrimidines found in RNA and/or DNA?

Accepted Answer

A)  cytosine and uracil
B)  cytosine and thymine
C)  cytosine,uracil,and thymine
D)  cytosine,uracil,and guanineE) A) and B)
F) None of the above

Question 7

Which of the following is not a difference between RNA and DNA?

Accepted Answer

A)  One is typically single stranded and the other is typically double stranded.
B)  One contains uracil and the other does not.
C)  One contains ribose sugar and the other contains deoxyribose sugar.
D)  One is made from nucleotide monomers and the other is not.E) None of the above
F) All of the above

Question 8

Which of the following chemical bonds do you think Nakano is referring to in his quote?

Accepted Answer

A)  peptide
B)  glycosidic
C)  phosphodiester
D)  ionicE) A) and B)
F) A) and C) C

Question 9

Nucleic acids are polymers made up of which of the following monomers?

Accepted Answer

A)  nucleotides
B)  sugars
C)  amino acids
D)  nitrogenous basesE) A) and C)
F) B) and C)

Question 10

The term ribozyme describes what property of RNA molecules?

Accepted Answer

A)  single-stranded
B)  catalytic
C)  its shape
D)  the fact that part of RNA molecules can be double-stranded similar to DNAE) B) and C)
F) A) and B)

Question 11

What does it mean when some bands on an autoradiograph are darker than others?

Accepted Answer

A)  The concentration of the radioactive molecule in that band is higher.
B)  This is normal because most of the radioactivity migrates to the same place.
C)  The experiment failed because the radioactivity should be evenly distributed throughout the gel.
D)  The darker bands represent larger molecules.E) A) and C)
F) All of the above

Question 12

Although DNA is the main hereditary material in all life-forms,it lacks one important characteristic to make it a candidate for the first life-form.Why have researchers rejected the idea that DNA was found in the first life-form?

Accepted Answer

A)  It does not function as a catalyst.
B)  It is not stable enough to have withstood early Earth's harsh atmosphere.
C)  Because it has only four different bases,it does not carry enough information;therefore,it cannot adapt and evolve.
D)  The type of sugar found in DNA is much too complicated to have been present early in Earth's history.E) None of the above
F) All of the above

Question 13

In the acid-base reaction described in the preceding paragraph,a proton (H+) is being transferred.What is acting as the proton acceptor?

Accepted Answer

A)  cytosine
B)  magnesium hydroxide
C)  the virus
D)  A,B,or C.Any one of these can act as the acceptor.E) A) and B)
F) B) and D)

Question 14

If the cytosine is positively charged (+) before self-cleavage,what would its charge be after self-cleavage?

Accepted Answer

A)  + (positive) 
B)  - (negative) 
C)  0 (neutral) 
D)  no way to predictE) All of the above
F) A) and C)

Question 15

What forms the "backbone" of a nucleic acid?

Accepted Answer

A)  a chain of sugar and phosphate groups,linked through phosphodiester bonds
B)  purine and pyrimidine pairs,hydrogen-bonded to each other
C)  a chain of amino and carboxyl groups,linked via peptide bonds
D)  a double helix of antiparallel strandsE) None of the above
F) A) and C)

Question 16

If DNA is heated to 95°C,the bonds between complementary strands break,resulting in two single strands of DNA.In this process,which bases will separate first because they have less hydrogen bonds between them?

Accepted Answer

A)  adenine and cytosine
B)  adenine and thymine
C)  guanine and cytosine
D)  guanine and thymineE) C) and D)
F) A) and C)

Question 17

What is gel electrophoresis used for?

Accepted Answer

A)  to denature proteins for further analysis
B)  to separate macromolecules by size or charge
C)  to separate the two helices that make up the DNA double helix
D)  to identify the first self-replicating molecule that formed during chemical evolutionE) B) and D)
F) A) and B)

Question 18

Which factors contributed to the lack of credit often given to Rosalind Franklin in the discovery of the structure of DNA?

Accepted Answer

A)  Wilkins showed her photographs to Watson and Crick without her knowledge or permission.
B)  She died at an early age so her career was shortened.
C)  She was a woman working in a field dominated by men when sexism was more common.
D)  All of the above apply.E) A) and C)
F) B) and C)

Question 19

A nucleotide is made up of which of the following subunits?

Accepted Answer

A)  a 5-carbon sugar,a phosphate group,and a nitrogenous base
B)  a 5-carbon sugar and a phosphate group
C)  a 5-carbon sugar and a nitrogenous base
D)  a 5-carbon sugar,an amino group,and an "R-group"E) A) and D)
F) B) and D)

Question 20

Bartel's research group showed that an RNA replicase ribozyme could be created by

Accepted Answer

A)  carefully synthesizing a novel ribozyme monomer by monomer based on the sequence of known ribozymes.
B)  creating large numbers of random RNA segments and testing each one to see if any replicase activity was present.
C)  starting with random components and allowing natural selection to evolve molecules that were better and better at replicating.
D)  examining protein replicases and reverse-engineering an RNA molecule capable of doing the same job.E) B) and D)
F) A) and D)

Exam 4: Nucleic Acids and the Rna World

Which of the following nitrogenous bases are purines?

Correct AnswerverifiedShow Answer

What is the difference between a ribonucleotide and a deoxyribonucleotide?

Correct AnswerverifiedB

Why do many researchers consider RNA to be the best candidate for the first life-form?

Correct AnswerverifiedShow Answer

In the secondary structure of DNA,the α-helical twists are organized into

Correct AnswerverifiedShow Answer

The "information system" of the cell involves stable genetic information being stored as ________,which can be used to make a "disposable" (relatively short-lived) copy of this information as ________.

Correct AnswerverifiedC

Which of the following includes all of the pyrimidines found in RNA and/or DNA?

Correct AnswerverifiedShow Answer

Which of the following is not a difference between RNA and DNA?

Correct AnswerverifiedShow Answer

Which of the following chemical bonds do you think Nakano is referring to in his quote?

Correct AnswerverifiedC

Nucleic acids are polymers made up of which of the following monomers?

Correct AnswerverifiedShow Answer

The term ribozyme describes what property of RNA molecules?

Correct AnswerverifiedShow Answer

What does it mean when some bands on an autoradiograph are darker than others?

Correct AnswerverifiedShow Answer

Although DNA is the main hereditary material in all life-forms,it lacks one important characteristic to make it a candidate for the first life-form.Why have researchers rejected the idea that DNA was found in the first life-form?

Correct AnswerverifiedShow Answer

In the acid-base reaction described in the preceding paragraph,a proton (H+) is being transferred.What is acting as the proton acceptor?

Correct AnswerverifiedShow Answer

If the cytosine is positively charged (+) before self-cleavage,what would its charge be after self-cleavage?

Correct AnswerverifiedShow Answer

What forms the "backbone" of a nucleic acid?

Correct AnswerverifiedShow Answer

If DNA is heated to 95°C,the bonds between complementary strands break,resulting in two single strands of DNA.In this process,which bases will separate first because they have less hydrogen bonds between them?

Correct AnswerverifiedShow Answer

What is gel electrophoresis used for?

Correct AnswerverifiedShow Answer

Which factors contributed to the lack of credit often given to Rosalind Franklin in the discovery of the structure of DNA?

Correct AnswerverifiedShow Answer

A nucleotide is made up of which of the following subunits?

Correct AnswerverifiedShow Answer

Bartel's research group showed that an RNA replicase ribozyme could be created by

Correct AnswerverifiedShow Answer

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B

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The "information system" of the cell involves stable genetic information being stored as ,which can be used to make a "disposable" (relatively short-lived) copy of this information as .

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C

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C

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