Question 1

​ Explain how the different densities of DNA can be identified after subjecting a DNA sample to density-gradient centrifugation.

Accepted Answer

The density-gradient centrifugation tech

Question 2

In eukaryotic replication, the RNA primers are degraded by:

Accepted Answer

A)  the 5' to 3' exonuclease activity of pol ä 
B)  DNA ligase 
C)  Helicase 
D)  FEN-1 and RNase H1 
A)  the 5' to 3' exonuclease activity of pol ä 
B)  DNA ligase 
C)  Helicase 
D)  FEN-1 and RNase H1

Question 3

One of the most important ways in which eukaryotic DNA differs from that of prokaryotes is

Accepted Answer

A)  prokaryotic DNA is complexed to proteins whereas eukaryotic DNA is not 
B)  eukaryotic DNA is complexed to proteins whereas prokaryotic DNA is not 
C)  DNA synthesis in eukaryotes takes place in the opposite direction from that in prokaryotes 
D)  there is no requirement for a primer in the synthesis of eukaryotic DNA 
A)  prokaryotic DNA is complexed to proteins whereas eukaryotic DNA is not 
B)  eukaryotic DNA is complexed to proteins whereas prokaryotic DNA is not 
C)  DNA synthesis in eukaryotes takes place in the opposite direction from that in prokaryotes 
D)  there is no requirement for a primer in the synthesis of eukaryotic DNA

Question 4

What is the need for a primer strand in DNA replication?

Accepted Answer

A)  it ensures the fidelity of the newly synthesized DNA strand 
B)  the DNA polymerases require a preexisting strand with a nucleotide having a 3' − OH 
C)  the DNA polymerases require a preexisting strand with a nucleotide having a 5' − OH 
D)  it ensures the integrity of the new DNA 
A)  it ensures the fidelity of the newly synthesized DNA strand 
B)  the DNA polymerases require a preexisting strand with a nucleotide having a 3' − OH 
C)  the DNA polymerases require a preexisting strand with a nucleotide having a 5' − OH 
D)  it ensures the integrity of the new DNA

Question 5

Which of the following is not a function of DNA polymerase I from E. coli ?

Accepted Answer

A)  adding nucleotides to the primer strand 
B)  3' → 5' exonuclease activity 
C)  5' → 3' exonuclease activity 
D)  proofreading 
A)  adding nucleotides to the primer strand 
B)  3' → 5' exonuclease activity 
C)  5' → 3' exonuclease activity 
D)  proofreading

Question 6

The replisome in prokaryotic replication consists of:

Accepted Answer

A)  a protein dimer 
B)  a protein tetramer 
C)  a multisubunit complex of at least 13 different proteins 
D)  more than 100 separate proteins 
A)  a protein dimer 
B)  a protein tetramer 
C)  a multisubunit complex of at least 13 different proteins 
D)  more than 100 separate proteins

Question 7

The duplication process of DNA is called

Accepted Answer

A)  replication. 
B)  transcription. 
C)  translation. 
D)  nucleation. 
A)  replication. 
B)  transcription. 
C)  translation. 
D)  nucleation.

Question 8

In the original Central Dogma of biology, the ordinary flow of genetic information is:

Accepted Answer

A)  DNA → RNA → Protein 
B)  RNA → DNA → Protein 
C)  Protein → RNA → DNA 
D)  DNA → Protein → RNA. 
E)  None of these 
A)  DNA → RNA → Protein 
B)  RNA → DNA → Protein 
C)  Protein → RNA → DNA 
D)  DNA → Protein → RNA. 
E)  None of these

Question 9

Eukaryotic DNA polymerases differ from those of prokaryotes in that

Accepted Answer

A)  they do not require a primer 
B)  they do not always have exonuclease activity 
C)  there is no equivalent to the sliding clamp in prokaryotic replication 
D)  they produce longer Okazaki fragments 
A)  they do not require a primer 
B)  they do not always have exonuclease activity 
C)  there is no equivalent to the sliding clamp in prokaryotic replication 
D)  they produce longer Okazaki fragments

Question 10

Which of the following mechanisms can serve to repair double-stranded breaks in DNA?

Accepted Answer

A)  Non-homologous end joining 
B)  recombination 
C)  base excision repair 
D)  nucleotide excision repair 
E)  both a and b 
A)  Non-homologous end joining 
B)  recombination 
C)  base excision repair 
D)  nucleotide excision repair 
E)  both a and b

Question 11

The process by which an mRNA base sequence directs the amino acid sequence of a protein is called

Accepted Answer

A)  replication. 
B)  transcription. 
C)  translation. 
D)  nucleation. 
A)  replication. 
B)  transcription. 
C)  translation. 
D)  nucleation.

Question 12

Which of the following best describes the process of DNA replication in a prokaryote?

Accepted Answer

A)  Replication begins at a unique site and proceeds in one direction all the way around a typically circular chromosome. 
B)  Replication begins at a unique site and proceeds in two directions, meeting about halfway around a typically circular chromosome. 
C)  Replication begins at multiple sites, spreading outward until the entire typically circular chromosome is replicated. 
D)  Replication begins at multiple sites, spreading outward until the entire typically linear chromosome is replicated. 
A)  Replication begins at a unique site and proceeds in one direction all the way around a typically circular chromosome. 
B)  Replication begins at a unique site and proceeds in two directions, meeting about halfway around a typically circular chromosome. 
C)  Replication begins at multiple sites, spreading outward until the entire typically circular chromosome is replicated. 
D)  Replication begins at multiple sites, spreading outward until the entire typically linear chromosome is replicated.

Question 13

The proofreading of DNA is especially good because "the identity of each base pair is checked before the enzyme moves on to the next base pair."

Accepted Answer

A) True 
 B)False

Question 14

​ The last nucleotide added to a growing DNA chain has a _____ on the sugar.

Accepted Answer

A)  5'-hydroxyl 
B)  5'-triphosphate 
C)  3'-hydroxyl 
D)  3'-triphosphate 
A)  5'-hydroxyl 
B)  5'-triphosphate 
C)  3'-hydroxyl 
D)  3'-triphosphate

Question 15

​ Errors in replication occur spontaneously only once in every _____ base pairs.

Accepted Answer

A)  106 to 107 
B)  109 to 1010 
C)  1018 to 1019 
D)  1021 to 1022 
A)  106 to 107 
B)  109 to 1010 
C)  1018 to 1019 
D)  1021 to 1022

Question 16

_____ is the enzyme that directs the synthesis of DNA on an RNA template.

Accepted Answer

A)  Reverse transcriptase 
B)  Phosphokinase 
C)  Hydrolase 
D)  Acyl transferase 
A)  Reverse transcriptase 
B)  Phosphokinase 
C)  Hydrolase 
D)  Acyl transferase

Question 17

Telomerase activity in cancer cells may explain their longevity.

Accepted Answer

A) True 
 B)False

Question 18

How do the Okazaki fragments of eukaryotes and prokaryotes compare?

Accepted Answer

A)  The Okazaki fragments are much longer in eukaryotes than in prokaryotes. 
B)  The Okazaki fragments are much shorter in eukaryotes than in prokaryotes. 
C)  The Okazaki fragments of eukaryotes are on the leading strand, rather than the lagging strand. 
D)  There is little to no difference between the Okazaki fragments of eukaryotes and prokaryotes. 
A)  The Okazaki fragments are much longer in eukaryotes than in prokaryotes. 
B)  The Okazaki fragments are much shorter in eukaryotes than in prokaryotes. 
C)  The Okazaki fragments of eukaryotes are on the leading strand, rather than the lagging strand. 
D)  There is little to no difference between the Okazaki fragments of eukaryotes and prokaryotes.

Question 19

Repair of DNA is usually carried out by

Accepted Answer

A)  hydrolysis of the entire damaged DNA molecule and synthesis of new DNA 
B)  hydrolysis of one strand of the damaged DNA molecule and synthesis of a new strand 
C)  a cut-and patch process 
D)  introducing additional supercoiling in the molecule 
A)  hydrolysis of the entire damaged DNA molecule and synthesis of new DNA 
B)  hydrolysis of one strand of the damaged DNA molecule and synthesis of a new strand 
C)  a cut-and patch process 
D)  introducing additional supercoiling in the molecule

Question 20

Replication of eukaryotic DNA

Accepted Answer

A)  must occur faster than replication of prokaryotic DNA 
B)  must be controlled to coordinate with the cell cycle 
C)  takes place during mitosis 
D)  takes place twice during each cell cycle 
A)  must occur faster than replication of prokaryotic DNA 
B)  must be controlled to coordinate with the cell cycle 
C)  takes place during mitosis 
D)  takes place twice during each cell cycle

Exam 10: Biosynthesis of Nucleic Acids Replication

​ Explain how the different densities of DNA can be identified after subjecting a DNA sample to density-gradient centrifugation.

In eukaryotic replication, the RNA primers are degraded by:

One of the most important ways in which eukaryotic DNA differs from that of prokaryotes is

What is the need for a primer strand in DNA replication?

Which of the following is not a function of DNA polymerase I from E. coli ?

The replisome in prokaryotic replication consists of:

The duplication process of DNA is called

In the original Central Dogma of biology, the ordinary flow of genetic information is:

Eukaryotic DNA polymerases differ from those of prokaryotes in that

Which of the following mechanisms can serve to repair double-stranded breaks in DNA?

The process by which an mRNA base sequence directs the amino acid sequence of a protein is called

Which of the following best describes the process of DNA replication in a prokaryote?

The proofreading of DNA is especially good because "the identity of each base pair is checked before the enzyme moves on to the next base pair."

​ The last nucleotide added to a growing DNA chain has a _____ on the sugar.

​ Errors in replication occur spontaneously only once in every _____ base pairs.

_____ is the enzyme that directs the synthesis of DNA on an RNA template.

Telomerase activity in cancer cells may explain their longevity.

How do the Okazaki fragments of eukaryotes and prokaryotes compare?

Repair of DNA is usually carried out by

Replication of eukaryotic DNA

Biochemistry and the Organization of Cells

Water the Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins Enzymes

The Behavior of Proteins Enzymes Mechanisms and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids How Structure Conveys Information

Transcription of the Genetic Code the Biosynthesis of Rna

Protein Synthesis Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses Cancer and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism Cellular Signaling

Filters

Explain how the different densities of DNA can be identified after subjecting a DNA sample to density-gradient centrifugation.

The last nucleotide added to a growing DNA chain has a _____ on the sugar.

Errors in replication occur spontaneously only once in every _____ base pairs.