Question 1

Two circular DNAs are isolated,both with 1000 bp.One is supercoiled; the other is not.The two DNAs are placed in an ultracentrifuge.

Accepted Answer

A)  The supercoiled DNA should sediment faster. 
B)  The nonsupercoiled DNA should sediment faster. 
C)  They should sediment at the same rate. 
D)  The information provided is not enough to determine which will sediment faster. 
A)  The supercoiled DNA should sediment faster. 
B)  The nonsupercoiled DNA should sediment faster. 
C)  They should sediment at the same rate. 
D)  The information provided is not enough to determine which will sediment faster.

Question 2

Where can drugs or polypeptides bind to DNA?

Accepted Answer

A)  The minor groove only. 
B)  The major groove only. 
C)  Either the minor or major groove. 
D)  Neither the minor or major groove. 
A)  The minor groove only. 
B)  The major groove only. 
C)  Either the minor or major groove. 
D)  Neither the minor or major groove.

Question 3

Which of the following statements concerning small nuclear RNA is true?

Accepted Answer

A)  This RNA is usually found in snurps. 
B)  This RNA is involved in removing exons from the RNA. 
C)  This RNA was the first RNA shown to have catalytic activity. 
D)  This RNA is small in size. 
E)  All of these describe small nuclear RNA. 
A)  This RNA is usually found in snurps. 
B)  This RNA is involved in removing exons from the RNA. 
C)  This RNA was the first RNA shown to have catalytic activity. 
D)  This RNA is small in size. 
E)  All of these describe small nuclear RNA.

Question 4

What distinguishes nucleotides from nucleosides?

Accepted Answer

A)  Nucleosides lack the phosphate group. 
B)  Nucleosides lack the sugar group. 
C)  Nucleosides lack a nitrogenous base. 
A)  Nucleosides lack the phosphate group. 
B)  Nucleosides lack the sugar group. 
C)  Nucleosides lack a nitrogenous base.

Question 5

Which conclusion can be drawn from the experimental observation that a single strand of DNA contains 2100 dA residues and 1800 dT residues?

Accepted Answer

A)  There must have been some loss of material in the extraction because the number of dA and dT residues must be the same. 
B)  This is a palindromic sequence. 
C)  There must be 2100 dT and 1800 dA residues on the complementary strand. 
D)  none of these 
A)  There must have been some loss of material in the extraction because the number of dA and dT residues must be the same. 
B)  This is a palindromic sequence. 
C)  There must be 2100 dT and 1800 dA residues on the complementary strand. 
D)  none of these

Question 6

The study of DNA changes that are not reflected in the base sequence is called:

Accepted Answer

A)  Molecular biology 
B)  Histology 
C)  Epigenetics 
D)  Physical genetics 
A)  Molecular biology 
B)  Histology 
C)  Epigenetics 
D)  Physical genetics

Question 7

The hydrogen bonding interactions in a Watson-Crick AT base-pair involve what units in the adenine base?

Accepted Answer

A)  N-1 and the amino group on C-6 
B)  N-1 and N-3 
C)  N-7 and the amino group on C-6 
D)  N-7 and C-8 
A)  N-1 and the amino group on C-6 
B)  N-1 and N-3 
C)  N-7 and the amino group on C-6 
D)  N-7 and C-8

Question 8

Which of the following statements is true for double-stranded DNA?

Accepted Answer

A) The amount of A is the same as the amount of T,and the amount of G is the same as the amount of C. 
B) The amount of A is the same as the amount of G,and the amount of T is the same as the amount of C. 
C) The amount of A is the same as the amount of C,and the amount of G is the same as the amount of T. 
D) More than one of the above is true. 
A) The amount of A is the same as the amount of T,and the amount of G is the same as the amount of C. 
B) The amount of A is the same as the amount of G,and the amount of T is the same as the amount of C. 
C) The amount of A is the same as the amount of C,and the amount of G is the same as the amount of T. 
D) More than one of the above is true.

Question 9

The A and B forms of DNA

Accepted Answer

A)  both have 10 base pairs per turn of the helix 
B)  both have 11 base pairs per turn of the helix 
C)  are both left-handed helices 
D)  are both right-handed helices 
A)  both have 10 base pairs per turn of the helix 
B)  both have 11 base pairs per turn of the helix 
C)  are both left-handed helices 
D)  are both right-handed helices

Question 10

The double helix of DNA is which level of structure?

Accepted Answer

A)  primary 
B)  secondary 
C)  tertiary 
D)  quaternary 
A)  primary 
B)  secondary 
C)  tertiary 
D)  quaternary

Question 11

The three-dimensional structure of transfer RNA has been determined by

Accepted Answer

A)  analytical ultracentrifugation 
B)  gel electrophoresis 
C)  ultraviolet spectroscopy 
D)  x-ray crystallography 
A)  analytical ultracentrifugation 
B)  gel electrophoresis 
C)  ultraviolet spectroscopy 
D)  x-ray crystallography

Question 12

The strands in the double helix

Accepted Answer

A)  both run in the same 3' 5' direction, i.e., they are parallel. 
B)  have their 3' 5' directions opposed, i.e., they are anti-parallel. 
C)  can be either parallel or anti-parallel. 
D)  are perpendicular to one another. 
A)  both run in the same 3' 5' direction, i.e., they are parallel. 
B)  have their 3' 5' directions opposed, i.e., they are anti-parallel. 
C)  can be either parallel or anti-parallel. 
D)  are perpendicular to one another.

Question 13

Which is the dominant form of DNA found in the cell?

Accepted Answer

A)  A 
B)  B 
C)  Z 
D)  H 
A)  A 
B)  B 
C)  Z 
D)  H

Question 14

The fundamental differences between RNA and DNA are

Accepted Answer

A)  the organic bases only 
B)  bases, ribose units, and the phosphodiester linkage 
C)  bases, ribose units, and the glycosidic bond type 
D)  bases and the ribose units only 
A)  the organic bases only 
B)  bases, ribose units, and the phosphodiester linkage 
C)  bases, ribose units, and the glycosidic bond type 
D)  bases and the ribose units only

Question 15

The three dimensional structure of nucleic acids can include all except:

Accepted Answer

A)  Supercoiling 
B)  Base stacking 
C)  Hairpin loops 
D)  Circular molecules 
E)  All of these can be included in the three dimensional structure 
A)  Supercoiling 
B)  Base stacking 
C)  Hairpin loops 
D)  Circular molecules 
E)  All of these can be included in the three dimensional structure

Question 16

Which of the following RNAs is the least abundant in a typical cell?

Accepted Answer

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

Question 17

Which of the following is the most common modification of nucleic acid bases?

Accepted Answer

A)  addition of a methyl group 
B)  addition of a carboxylic acid 
C)  addition of a fluorine 
D)  reduction of a carbonyl to an alcohol 
A)  addition of a methyl group 
B)  addition of a carboxylic acid 
C)  addition of a fluorine 
D)  reduction of a carbonyl to an alcohol

Question 18

In a melting profile for DNA,the absorbance at 260 nm increases as result of the disruption of the DNA structure.What is the fundamental physical basis for the absorbance increase?

Accepted Answer

A)  the effective concentration of DNA changes 
B)  denatured DNA absorbs light more strongly than native DNA because the bases have become unstacked 
C)  native DNA absorbs light more strongly than denatured DNA because the bases are stacked 
D)  the absorbance of DNA is highly sensitive to temperature 
A)  the effective concentration of DNA changes 
B)  denatured DNA absorbs light more strongly than native DNA because the bases have become unstacked 
C)  native DNA absorbs light more strongly than denatured DNA because the bases are stacked 
D)  the absorbance of DNA is highly sensitive to temperature

Question 19

RNA is hydrolyzed in basic solution,but DNA is not.This occurs because

Accepted Answer

A)  thymine is found in DNA, and uracil is not 
B)  DNA is double stranded, and RNA is single stranded 
C)  DNA contains 2'-deoxyribose, but RNA does not 
D)  RNA has modified bases, but DNA does not 
A)  thymine is found in DNA, and uracil is not 
B)  DNA is double stranded, and RNA is single stranded 
C)  DNA contains 2'-deoxyribose, but RNA does not 
D)  RNA has modified bases, but DNA does not

Question 20

Quaternary structure refers to the non-covalent interaction(s) between polymeric units,such as two or more monomer protein units that noncovalently interact.Which of the following scenarios for nucleic acids most closely resembles quaternary structure?

Accepted Answer

A)  self-assembly of subunits in the tobacco mosaic virus 
B)  interaction of DNA with proteins 
C)  RNA and protein association in ribosomes 
D)  All of these 
A)  self-assembly of subunits in the tobacco mosaic virus 
B)  interaction of DNA with proteins 
C)  RNA and protein association in ribosomes 
D)  All of these

Exam 9: Nucleic Acids: How Structure Conveys Information

Two circular DNAs are isolated,both with 1000 bp.One is supercoiled; the other is not.The two DNAs are placed in an ultracentrifuge.

Where can drugs or polypeptides bind to DNA?

Which of the following statements concerning small nuclear RNA is true?

What distinguishes nucleotides from nucleosides?

Which conclusion can be drawn from the experimental observation that a single strand of DNA contains 2100 dA residues and 1800 dT residues?

The study of DNA changes that are not reflected in the base sequence is called:

The hydrogen bonding interactions in a Watson-Crick AT base-pair involve what units in the adenine base?

Which of the following statements is true for double-stranded DNA?

The A and B forms of DNA

The double helix of DNA is which level of structure?

The three-dimensional structure of transfer RNA has been determined by

The strands in the double helix

Which is the dominant form of DNA found in the cell?

The fundamental differences between RNA and DNA are

The three dimensional structure of nucleic acids can include all except:

Which of the following RNAs is the least abundant in a typical cell?

Which of the following is the most common modification of nucleic acid bases?

In a melting profile for DNA,the absorbance at 260 nm increases as result of the disruption of the DNA structure.What is the fundamental physical basis for the absorbance increase?

RNA is hydrolyzed in basic solution,but DNA is not.This occurs because

Quaternary structure refers to the non-covalent interaction(s) between polymeric units,such as two or more monomer protein units that noncovalently interact.Which of the following scenarios for nucleic acids most closely resembles quaternary structure?

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

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: 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

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