Question 1

In the Hershey and Chase experiment designed to determine the molecule of heredity, what was radiolabeled with ³⁵S? A)protein B)DNA C)RNA D)rRNA

Accepted Answer

In the Hershey and Chase experiment, proteins of the bacteriophages were labeled with sulfur-35 (^35S) because proteins contain sulfur in their amino acids, whereas DNA does not. This was part of their strategy to determine that DNA, and not protein, is the molecule of heredity.

Question 2

The step of DNA replication in which the replication proteins open up the double helix and prepare for complementary base pairing is called
A)initiation.
B)elongation.
C)termination.
D)translation.
E)translocation.

Accepted Answer

Initiation is the correct answer because it is the step in DNA replication where proteins bind to the DNA and start the process of unwinding the double helix to make the DNA template accessible for replication.

Question 3

The ratio of ________ in DNA is 1:1.
A)guanine to adenine
B)adenine to thymine
C)cytosine to adenine
D)uracil to cytosine

Accepted Answer

Adenine pairs with thymine in DNA, maintaining a 1:1 ratio due to base pairing rules.

Question 4

Which of the following is not true of DNA?
A)It is acidic.
B)It contains deoxyribose.
C)It is found in cell nuclei.
D)It contains phosphate.
E)It contains amino acids.

Accepted Answer

DNA does not contain amino acids. Amino acids are the building blocks of proteins, not nucleic acids like DNA. DNA is composed of nucleotides, which include a phosphate group, a sugar (deoxyribose), and a nitrogenous base, but not amino acids.

Question 5

Which one of the following is not an element found in DNA?
A)oxygen
B)sulfur
C)nitrogen
D)phosphorous
E)hydrogen

Accepted Answer

Sulfur is not an element found in DNA. DNA is composed of a sugar-phosphate backbone and nitrogenous bases, neither of which contain sulfur.

Question 6

The step of DNA replication in which the proteins connect the correct sequence of nucleotides into a continuous new strand is called
A)initiation.
B)elongation.
C)termination.
D)translation.
E)translocation.

Accepted Answer

Elongation is the phase of DNA replication during which enzymes called DNA polymerases add nucleotides to the 3' end of the newly synthesized strand, effectively lengthening the DNA strand by matching each new nucleotide to its complementary base on the template strand.

Question 7

________-form DNA spirals to the right and is the major form of naturally occurring DNA molecules.
A)A
B)B
C)D
D)Y
E)Z

Accepted Answer

B-form DNA is the most common form of DNA in which the double helix spirals to the right, and it represents the typical structure of DNA as it occurs naturally in cells.

Question 8

The molecule of heredity is usually
A)RNA.
B)DNA.
C)protein.
D)carbohydrate.
E)None of the choices is correct.

Accepted Answer

DNA (Deoxyribonucleic Acid) is widely recognized as the molecule responsible for heredity, containing the genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses.

Question 9

During DNA replication, an incoming nucleotide is enzymatically joined to the preceding nucleotide by a(n)________ bond.
A)hydrogen
B)ionic
C)phosphodiester
D)electrostatic

Accepted Answer

During DNA replication, an incoming nucleotide is joined to the preceding nucleotide by a phosphodiester bond. This bond forms between the phosphate group of the incoming nucleotide and the 3' hydroxyl group of the last nucleotide in the growing chain, catalyzed by DNA polymerase.

Question 10

During the S phase of interphase, the state of a eukaryotic chromosome can be described as
A)a single continuous linear double helix.
B)a double helix replicating semiconservatively.
C)a double helix replicating conservatively.
D)a triple helix replicating semiconservatively.
E)two linear single-stranded molecules.

Accepted Answer

During the S phase of interphase in eukaryotic cells, chromosomes replicate in a semiconservative manner. This means that each of the two new double helices formed contains one original strand and one newly synthesized strand.

Question 11

During early interphase the structure of a eukaryotic DNA chromosome is
A)a single continuous linear double helix.
B)a double helix undergoing semiconservative replication.
C)a double helix undergoing conservative replication.
D)single-stranded.

Accepted Answer

During early interphase, a eukaryotic DNA chromosome is in the form of a single continuous linear double helix, as it has not yet undergone replication.

Question 12

DNA replication occurs through a ________ process.
A)conservative
B)semiconservative
C)dispersive
D)transformative

Accepted Answer

DNA replication is semiconservative, meaning that each new DNA molecule consists of one old strand and one newly synthesized strand.

Question 13

The nucleotide that is present in RNA but not DNA is
A)thymine.
B)uracil.
C)adenine.
D)cytosine.
E)guanine.

Accepted Answer

Uracil is the nucleotide that is present in RNA but not in DNA; in DNA, thymine is used instead.

Question 14

The polarity of DNA synthesis is
A)5'→3'.
B)3'→5'.
C)5'→2'.
D)2'→5'.

Accepted Answer

DNA synthesis occurs in the 5' to 3' direction, meaning that new nucleotides are added to the 3' end of the growing strand.

Question 15

________ bonds are responsible for the chemical affinity between A and T (or G and
A)Ionic
B)Covalent
C)Hydrogen
D)nucleotides.
E)Hydrophobic

Accepted Answer

Hydrogen bonds are responsible for the chemical affinity between base pairs in DNA, such as adenine (A) and thymine (T), or guanine (G) and cytosine (C).

Question 16

DNA is localized mainly in the
A)cell membrane.
B)endoplasmic reticulum.
C)vacuoles.
D)chromosomes.
E)Golgi.

Accepted Answer

DNA is primarily found in the chromosomes, which are located in the cell nucleus in eukaryotic cells and in the nucleoid region in prokaryotic cells.

Question 17

X-ray data showed that the spacing between repeating units along the axis of the DNA helix is
A)2.0 angstroms.
B)3.4 angstroms.
C)20 angstroms.
D)34 angstroms.

Accepted Answer

The spacing between repeating units along the axis of the DNA helix is 3.4 angstroms, as determined by X-ray crystallography studies by Rosalind Franklin and others. This measurement is crucial for understanding the structure and function of DNA.

Question 18

The four subunits that make up DNA are called
A)phosphodiesters.
B)proteins.
C)nucleotides.
D)nucleosides.
E)polymers.

Accepted Answer

Nucleotides are the subunits that make up DNA, consisting of a phosphate group, a sugar (deoxyribose), and a nitrogenous base.

Question 19

The step of DNA replication in which two replication forks moving in opposite directions may meet is called
A)initiation.
B)elongation.
C)termination.
D)translation.
E)translocation.

Accepted Answer

Termination is the step in DNA replication where two replication forks moving in opposite directions meet, signaling the end of the replication process for that segment of DNA.

Question 20

X-ray data showed that the DNA helix undergoes one complete turn every
A)2.0 angstroms.
B)3.4 angstroms.
C)20 angstroms.
D)34 angstroms.

Accepted Answer

The DNA helix undergoes one complete turn every 34 angstroms, as determined by X-ray diffraction studies.

Quiz 6: DNA Structure, Replication, and Recombination

In the Hershey and Chase experiment designed to determine the molecule of heredity, what was radiolabeled with ³⁵S?

The step of DNA replication in which the replication proteins open up the double helix and prepare for complementary base pairing is called

The ratio of ________ in DNA is 1:1.

Which of the following is not true of DNA?

Which one of the following is not an element found in DNA?

The step of DNA replication in which the proteins connect the correct sequence of nucleotides into a continuous new strand is called

________-form DNA spirals to the right and is the major form of naturally occurring DNA molecules.

The molecule of heredity is usually

During DNA replication, an incoming nucleotide is enzymatically joined to the preceding nucleotide by a(n) ________ bond.

During the S phase of interphase, the state of a eukaryotic chromosome can be described as

During early interphase the structure of a eukaryotic DNA chromosome is

DNA replication occurs through a ________ process.

The nucleotide that is present in RNA but not DNA is

The polarity of DNA synthesis is

________ bonds are responsible for the chemical affinity between A and T (or G and

DNA is localized mainly in the

X-ray data showed that the spacing between repeating units along the axis of the DNA helix is

The four subunits that make up DNA are called

The step of DNA replication in which two replication forks moving in opposite directions may meet is called

X-ray data showed that the DNA helix undergoes one complete turn every