Bio 1330: TXST Exam 4 Test Questions
with Quality/Verified Answers 2026
Updated.
Short segments of newly synthesized DNA are joined into a continuous strand by _____. -
Answer ligase
After DNA replication is completed, _____. - Answer each new DNA double helix consists of
one old DNA strand and one new DNA strand
The first step in the replication of DNA is catalyzed by _____. - Answer helicase
The action of helicase creates _____. - Answer replication forks and replication bubbles
Why is the new DNA strand complementary to the 3' to 5' strands assembled in short
segments? - Answer DNA polymerase can assemble DNA only in the 5' to 3' direction
The synthesis of a new strand begins with the synthesis of a(n) _____. - Answer RNA primer
complementary to a preexisting DNA strand
An old DNA strand is used as a _____ for the assembly of a new DNA strand. - Answer
template
In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the
complementary strand, and a guanine of one strand always pairs with a(n) _____ of the
complementary strand. - Answer thymine ... cytosine
What phase of cell cycle are we mostly at, while learning this chapter? - Answer S Phase
Why do we say that DNA replication is semi-conservative? - Answer It has one of the old
strands and one of the new ones
If you add radioactive thymine to a cell during DNA replication, will both sister chromatids of
each chromosome carry radioactive thymine? Why or why not? - Answer No, only one of
them will get that specific strand
Will both strands of DNA double heiix in each sister chromatid contain radioactive thymine?
Why or why not? - Answer ...
, What are replication origins?
Why are these regions rich in A-T pairs? - Answer the point where DNA is pulled apart
forming a replication bubble.
A-T pairs have 2 hydrogen bonds so they are easier to break or pull apart
What is a replication bubble? - Answer where the DNA separates and opens
What is the difference between bacteria and eukaryotes, if you count the number of replication
bubbles during DNA replication? - Answer Bacteria has one while DNA can have many
DNA is synthesized at the _______ end of the growing strand, and the _______ group at this
end is essential for the addition of a new nucleotide to the growing chain. - Answer 5" 3"
The template DNA strand and newly produced DNA strand are ________________________to
each other. - Answer Anti-parallel
What is the name of the enzyme that catalyzes the polymerization of DNA? - Answer DNA
Polymerase
Why does DNA synthesis needs an RNA primer to begin the process?
What is the name of the enzyme that makes these RNA primers?
Why are two RNA primers added at the middle of the replication bubble in opposite orientation
to each other? - Answer 1. to open up template
2. Primase
Find difference between leading strand and lagging strand while they are made: - Answer
Leading strand is synthesized first being the 3' to 5', always directed into the fork. Lagging is
second being 5' to 3' and is always directed away from the fork.
Give the functions of these enzymes/proteins during DNA replication:
Helicase
DNA polymerase III
DNA polymerase I
Topoisomerase
Single stand DNA binding proteins
DNA ligase - Answer 1. Opens up the Double Helix
with Quality/Verified Answers 2026
Updated.
Short segments of newly synthesized DNA are joined into a continuous strand by _____. -
Answer ligase
After DNA replication is completed, _____. - Answer each new DNA double helix consists of
one old DNA strand and one new DNA strand
The first step in the replication of DNA is catalyzed by _____. - Answer helicase
The action of helicase creates _____. - Answer replication forks and replication bubbles
Why is the new DNA strand complementary to the 3' to 5' strands assembled in short
segments? - Answer DNA polymerase can assemble DNA only in the 5' to 3' direction
The synthesis of a new strand begins with the synthesis of a(n) _____. - Answer RNA primer
complementary to a preexisting DNA strand
An old DNA strand is used as a _____ for the assembly of a new DNA strand. - Answer
template
In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the
complementary strand, and a guanine of one strand always pairs with a(n) _____ of the
complementary strand. - Answer thymine ... cytosine
What phase of cell cycle are we mostly at, while learning this chapter? - Answer S Phase
Why do we say that DNA replication is semi-conservative? - Answer It has one of the old
strands and one of the new ones
If you add radioactive thymine to a cell during DNA replication, will both sister chromatids of
each chromosome carry radioactive thymine? Why or why not? - Answer No, only one of
them will get that specific strand
Will both strands of DNA double heiix in each sister chromatid contain radioactive thymine?
Why or why not? - Answer ...
, What are replication origins?
Why are these regions rich in A-T pairs? - Answer the point where DNA is pulled apart
forming a replication bubble.
A-T pairs have 2 hydrogen bonds so they are easier to break or pull apart
What is a replication bubble? - Answer where the DNA separates and opens
What is the difference between bacteria and eukaryotes, if you count the number of replication
bubbles during DNA replication? - Answer Bacteria has one while DNA can have many
DNA is synthesized at the _______ end of the growing strand, and the _______ group at this
end is essential for the addition of a new nucleotide to the growing chain. - Answer 5" 3"
The template DNA strand and newly produced DNA strand are ________________________to
each other. - Answer Anti-parallel
What is the name of the enzyme that catalyzes the polymerization of DNA? - Answer DNA
Polymerase
Why does DNA synthesis needs an RNA primer to begin the process?
What is the name of the enzyme that makes these RNA primers?
Why are two RNA primers added at the middle of the replication bubble in opposite orientation
to each other? - Answer 1. to open up template
2. Primase
Find difference between leading strand and lagging strand while they are made: - Answer
Leading strand is synthesized first being the 3' to 5', always directed into the fork. Lagging is
second being 5' to 3' and is always directed away from the fork.
Give the functions of these enzymes/proteins during DNA replication:
Helicase
DNA polymerase III
DNA polymerase I
Topoisomerase
Single stand DNA binding proteins
DNA ligase - Answer 1. Opens up the Double Helix
