MasteringBiology: DNA Replication
Which of the following occurs during DNA replication?
DNA polymerase elongates the daughter strand, adding new nucleotides to the 3' end of the molecule. The molecule grows 5' to 3' but is therefore read 3' to 5'. (DNA polymerase can only add to the 3' end of the molecule, which has an OH group. The molecule therefore grows 5' to 3'.)
Who is generally credited with discovering that the DNA molecule is constructed as a double helix?
Watson and Crick
Which of the following build(s) new strands of DNA? a) DNA polymerases b) The origins of replication c) Parental DNA d) The lagging strand e) The leading strand
a) DNA polymerases (DNA polymerases build new strands of DNA by adding DNA nucleotides one at a time.)
Monomers for the synthesis of DNA are called _____. a) nucleotides b) nitrogenous bases c) fatty acids d) amino acids
a) nucleotides (Each nucleotide unit of DNA consists of a nitrogenous base (A, G, C, or T), the sugar deoxyribose, and a phosphate group.)
Drag the labels onto the diagram to identify the components of replicating DNA strands.
a) parental dna b) dna polymerase c) leading strand d) lagging strand e) dna ligase f) replication fork
During replication, the original "parent" DNA _____. a) serves as the template for the creation of two complete sets of DNA b) is incorporated into the new DNA strand c) is converted to RNA d) is broken down as a new DNA strand forms
a) serves as the template for the creation of two complete sets of DNA (As replication occurs, each side of the double helix acts as a template. Thus, each new DNA molecule includes one parent strand and one new strand.)
The four bases contained in DNA are _____.
adenine, guanine, cytosine, thymine
Which statement about DNA replication is CORRECT? a) The lagging strand is one of the strands of parental DNA. b) The leading strand is built continuously, and the lagging strand is built-in pieces. c) The leading strand is one of the strands of parental DNA. d) DNA ligase helps assemble the leading strand. e) The lagging strand is built continuously.
b) The leading strand is built continuously, and the lagging strand is built in pieces
The results of which of the following techniques were most helpful to Watson and Crick in determining the structure of DNA? a) cloned DNA b) X-ray crystallography c) radioactive labeling d) electrophoresis
b) X-ray crystallography
The statement that each new molecule of DNA contains one parental and one newly synthesized strand of DNA refers to _____. a) Chargaff's rule about DNA b) a model of DNA replication c) the one gene - one enzyme hypothesis d) the de novo synthesis of DNA
b) a model of DNA replication (In DNA replication, the two strands of the parental molecule separate, and each functions as a template for the synthesis of a new, complementary strand. This is called semiconservative DNA replication)
Which of the following describes a complete nucleotide? a) a sugar and a pyrimidine or purine b) a nitrogenous base, a sugar, and a phosphate group c) a sugar and a phosphate group d) a nitrogenous base and a sugar
b) a nitrogenous base, a sugar, and a phosphate group
Which statement about DNA replication is FALSE? a) DNA polymerase builds a new strand by adding DNA nucleotides one at a time. b) The lagging strand is made of a series of pieces that must be joined together to make a continuous strand. c) DNA ligase adds nucleotides to the lagging strand. d) Because the two strands of parental DNA run in opposite directions, the new strands must be made in different ways. e) The two strands of parental DNA are separated during DNA replication
c) DNA ligase adds nucleotides to the lagging strand. (DNA ligase seals the gaps between segments of DNA in the lagging strand. It does not add nucleotides to the lagging strand.)
Which of the following statements is true about double-stranded DNA? a) It contains ionic bonds. b) Adenine and uracil are present in equal amounts. c) The strands run in opposite directions. d) The two strands are said to be identical
c) The strands run in opposite directions.
The two strands of a DNA molecule are joined to each other through a) covalent bonds between carbon atoms in deoxyribose molecules b) covalent bonds between nitrogen atoms in adenine and in thymine c) hydrogen bonds between nucleotide bases d) ionic bonds between guanine and cytosine
c) hydrogen bonds between nucleotide bases
The molecule that seals the gaps between the pieces of DNA in the lagging strand is a) the leading strand. b) RNA. c) the replication fork. d) DNA ligase. e) DNA polymerase.
d) DNA ligase
Which of the following accurately reflects complementary base pairing in the DNA molecule? a) Guanine forms two hydrogen bonds with adenine. b) Adenine forms three hydrogen bonds with cytosine. c) Cytosine forms three hydrogen bonds with thymine. d) Guanine forms three hydrogen bonds with cytosine.
d) Guanine forms three hydrogen bonds with cytosine.
Prokaryotic organisms have a single origin of replication, whereas eukaryotic organisms have many origins where replication occurs simultaneously. Which of the following is the most probable reason for this observation? a) Prokaryotic DNA is single-stranded. b) Prokaryotic DNA is replicated more slowly than eukaryotic DNA. c) Prokaryotes do not replicate their DNA. d) Prokaryotic DNA is much smaller than eukaryotic DNA.
d) Prokaryotic DNA is much smaller than eukaryotic DNA.
The information in DNA is contained in _____. a) the types of sugars used in making the DNA molecule b) the positioning variation of the phosphate groups in the DNA molecule c) the sequence of amino acids that make up the DNA molecule d) the sequence of nucleotides along the length of one strand of the DNA molecule
d) the sequence of nucleotides along the length of one strand of the DNA molecule
During DNA replication, which nucleotide will bind to an A nucleotide in the parental DNA?
t
If you analyzed the nucleotide content of DNA, you would expect to find that _____.
the ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1
