DNA Replication Flashcards
In DNA replication, the strands on the original molecule are used as ______ for the synthesis of new DNA strands.
templates
The DNA strands that can be copied to produce new DNA strands are called the
template strands.
Which of the following processes proceeds according to the AT/GC rule?
DNA replication
________ synthesis begins at a site within a chromosome called the origin of replication.
DNA
DNA replication proceeds outward from two __ __, which are the sites where the template strands are unwound and new DNA is synthesized.
Blank 1: replication
Blank 2: forks
During what process are parental DNA strands used as templates for the synthesis of new DNA strands?
DNA replication
The term ________ refers to DNA replication proceeding outward from two replication forks.
bidirectional
During DNA replication, the parental DNA strand can also be called a(n) __ strand, because it is used for the synthesis of a daughter strand of DNA.
Blank 1: template
DNA replication of the prokaryotic chromosome
has a single origin of replication and is bidirectional
DNA replication relies on the ________ of DNA strands according to the ________ rule.
complementarity; AT/GC
The __ of replication is a site within a chromosome where DNA replication begins.
Blank 1: origin
During replication, the enzyme DNA __ uses energy from ATP to separate the two strands. This generates additional coiling ahead of the replication fork that is alleviated by another enzyme called DNA __.
Blank 1: helicase
Blank 2: topoisomerase or gyrase
During DNA synthesis, the sites where the two template strands are unwound and new DNA is made are called what?
Replication forks
The enzyme that causes DNA strand separation at the origin of replication is
helicase
DNA replication is described as ______ because DNA replication proceeds outward from two replication forks.
bidirectional
DNA helicase travels toward the replication fork using energy from ATP in this direction
5’ to 3’
Why do eukaryotic cells have multiple origins of replication?
To ensure timely replication of multiple, relatively large chromosomes
Which of the following processes proceeds according to the AT/GC rule?
DNA replication
Which enzyme alleviates the coiling in DNA strands just ahead of the replication fork?
Topoisomerase
Match the proteins involved in DNA replication with their function: helicase
causes DNA strand separation at the origin of replication
Match the proteins involved in DNA replication with their function: topoisomerase
relieves coiling in DNA strands ahead of the replication fork
Match the proteins involved in DNA replication with their function: single-strand binding protein
prevents the two DNA template strands from re-forming the double helix
These coat the strands of template DNA to block the re-formation of the double helix
single-strand binding proteins
The enzyme DNA __ separates the DNA strands and keeps the replication fork moving forward.
Blank 1: helicase
The enzyme responsible for covalently linking nucleotides together to form DNA strands is called DNA
polymerase
At the replication fork, the enzyme DNA helicase binds to one DNA strand and travels in this direction using energy from ATP
from 5’ to 3’
Which enzyme is required to initiate DNA synthesis on a bare template strand?
Primase
DNA replication of the prokaryotic chromosome
has a single origin of replication and is bidirectional
This enzyme works by breaking a bond between the first and second phosphate and attaching a nucleotide dNMP to the 3’ end of the DNA strand via a phosphodiester bond.
polymerase
The enzyme DNA __ relieves coiling in DNA strands ahead of the replication fork.
Blank 1: topoisomerase or gyrase
As DNA polymerase slides along the DNA, individual nucleotides with three phosphate groups, called __ __, hydrogen-bond to the exposed bases in the __ strand according to the AT/GC rule.
Blank 1: deoxynucleoside
Blank 2: triphosphates
Blank 3: template
The function of single-strand __ proteins is to coat the single strands of template DNA to prevent them from re-forming a double helix.
Blank 1: binding
Which are enzymatic features of DNA polymerase?
- It can only function in the presence of topoisomerase
- It is unable to begin DNA synthesis on a bare template strand
- It can only synthesize DNA in the 5’ to 3’ direction
- It is unable to proofread the newly–synthesized DNA
It is unable to begin DNA synthesis on a bare template strand
It can only synthesize DNA in the 5’ to 3’ direction
The enzyme DNA __ covalently links nucleotides to synthesize new DNA strands together during DNA replication.
Blank 1: polymerase
Which of the following statements about DNA replication is TRUE?
- Both the leading strand and the lagging strand are synthesized in a series of small fragments that are later connected
- Both the leading strand and the lagging strand are synthesized continuously
- The leading strand is synthesized continuously while the lagging strand is synthesized in a series of small fragments that are later connected
- The lagging strand is synthesized continuously while the leading strand is synthesized in a series of small fragments that are later connected
The leading strand is synthesized continuously while the lagging strand is synthesized in a series of small fragments that are later connected
The enzyme DNA __ is needed to begin DNA synthesis on a bare template strand. This enzyme makes a short segment of __ called a primer that is complementary to a DNA sequence on the template strand.
Blank 1: primase
Blank 2: RNA
DNA polymerase synthesizes short fragments of DNA on the lagging strand during DNA replication. These are called what?
Okazaki fragments
DNA polymerase cleaves the bond connecting the first two phosphates in an incoming deoxynucleoside triphosphate causing the release of a molecule of __ (PPi).
Blank 1: pyrophosphate
An RNA __ is required to produce each Okazaki fragment in Escherichia coli.
Blank 1: primer
Energy is generated to covalently connect adjacent molecules by breaking the bond between the
first and second phosphates in the dNTP
DNA polymerase III
is the major replication enzyme.
Once synthesis has begun, DNA can only be synthesized in a _______ direction
5’ to 3’
The lagging strand is made
discontinuously in the opposite direction of the replication fork
During DNA replication, the __ strand is synthesized continuously while the __ strand is synthesized as small fragments that are connected to each other to form a continuous strand.
Blank 1: leading
Blank 2: lagging
Which enzyme is responsible for removing the RNA primers?
DNA polymerase I
__ fragments are a series of DNA segments made on the lagging strand during DNA replication.
Blank 1: Okazaki
The replication process is completed when the enzyme DNA __ forms a covalent bond between adjacent DNA fragments.
Blank 1: ligase
In Escherichia coli, what enzyme adds DNA nucleotides during DNA replication?
DNA polymerase III
In DNA replication, the ______ strand is made discontinuously in the direction opposite to the movement of the replication fork.
lagging
DNA polymerase I ______ RNA primers in the ______ direction.
removes; 5’ to 3’
Which enzyme catalyzes the formation of covalent bonds between adjacent DNA fragments to complete the replication process?
Ligase
DNA polymerase III
is the major replication enzyme.
Which enzyme is responsible for removing the RNA primers?
DNA polymerase I
The replication process is completed when the enzyme DNA __ forms a covalent bond between adjacent DNA fragments.
Blank 1: ligase