Chapter 13 Smartbook
Which of the following mechanisms can lead to gene conversion?
-DNA gap repair synthesis -DNA mismatch repair
Which are involved in crossing over?
-breakage of non-sister chromatids at analogous locations -alignment of a pair of homologous chromosomes -exchange of corresponding chromosome segments
List the events of DNA synthesis at the replication fork in the correct sequence, placing the earliest event at the top.
1) DNA strands separate at the origin, creating two replication forks 2) RNA primers are added to both the leading and lagging strand 3) DNA polymerase III adds nucleotides to the 3' end continuously on the leading strand, and discontinuously on the lagging strand 4) DNA polymerase I removes the primers and adds DNA 5) DNA ligase catalyzes the phosphodiester bond between adjacent Okazaki fragments
List the steps of eukaryotic DNA replication initiation in the correct sequence, placing the first step at the top.
1. ORC binds to the origin of replication 2. ORC promotes the formation of the prereplication complex including MCM helicase 3. MCM helicase binds to the leading strand 4. the prereplication complex is converted to an active replication site by phosphorylation 5. DNA synthesis begins
How many strands of DNA are wound together in its helical structure?
2
The nucleotides that are added to the growing DNA strand during DNA replication are dNTPs that contain ___ phosphate group(s) attached to the ____'-carbon of deoxyribose.
3 phosphate groups, 5' carbon
DNA polymerase can only add nucleotides in the _____ to ______ direction.
5' to 3' direction
DNA polymerase attaches nucleotides to the newly synthesized strand in the _______.
5' to 3' direction only
The three types of DNA sequences located within the oriC complex are the ____ rich region, _____ box sequence and the _____ methylation site.
AT rich region DNAA box sequence GATC methylation site
Which three types of DNA sequences are located within the oriC complex?
AT-rich region GATC methylation site DnaA box sequence
What rule governs the binding of dNTPs to the template strand during DNA replication?
AT/GC rule
During replication, helicase separates the two strands of a DNA molecule. The energy required for this process comes from the hydrolysis of
ATP
What is the source of energy for the separation of the two strands in a DNA double helix by helicase?
ATP Hydrolysis
single strand binding proteins
Bind to single-stranded DNA and prevent it from re-forming a double-stranded structure
Conservative
Both strands of parental DNA remain together following replication and the daughter molecule consists of only newly synthesized DNA strands.
The name of the enzyme that travels in front of helicase to remove positive supercoiling in the DNA is called
DNA Gyrase
Original DNA strands are used as templates to produce new DNA strands during the process called
DNA Replication
Which components are needed to make up the complex called a primosome?
DNA helicase and primase
Which enzyme synthesizes the DNA of both the leading and lagging strands?
DNA polymerase
During DNA replication in E. coli, which protein is responsible for removing RNA primers and replacing them with DNA?
DNA polymerase I
During replication, an RNA primer is necessary because ______.
DNA polymerase cannot initiate synthesis of a new strand
True or false: DNA replication in eukaryotes occurs unidirectionally from multiple origins of replication.
False
True or false: In both eukaryotes and prokaryotes, RNA primers are removed by DNA polymerase I.
False: Eukaryotes are removed by flap endonuclease
True or false: As is the case for chromosomes in prokaryotes, eukaryotic chromosomes have a single origin of replication.
False: eukaryotic chromosomes have multiple origins of replication
dispersive
Pieces of parental DNA and newly synthesized DNA are interspersed throughout both daughter strands in the newly formed molecule.
What is the role of telomerase?
Prevent the ends of eukaryotic chromosomes from shortening
The enzyme telomerase consists of protein subunits and _____, which is complementary to the DNA sequence in the telomeric repeat.
RNA
Which of the following are components of the enzyme telomerase?
RNA Protein Subunit
The short molecules of RNA that start the DNA replication process are called
RNA primers
In E. coli, DNA polymerase I removes the _ primers and replaces them with
RNA primers, DNA
Two new molecules of DNA are the product of which process?
Replication
What is the function of DNA polymerase?
Synthesis of DNA on both the leading and lagging strands
Which of the following statements correctly describes the chemical reaction that occurs during DNA replication?
The 5'-phosphate group of the incoming nucleotide reacts with the 3'-OH group at the end of the growing DNA strand.
Semiconservative
The daughter molecules of DNA consist of one strand of parental DNA and one complementary strand of newly formed DNA.
The energy used to fuel the endergonic reaction of DNA replication is supplied from the exergonic cleavage of ______.
a deoxyribnucleoside triphosphate (dNTP)
A phosphodiester linkage is a linkage between
a phosphate group and two sugar molecules
DnaC protein
aid DnaA in the recruitment of helicase to the origin
In eukaryotes, DNA replication begins with the ______.
assembly of a prereplication complex (preRC)
Since DNA replication proceeds in both directions from a single origin of replication in the bacterial chromosome, it is said to be
bidirectional replication
As shown in the image, bacterial DNA replication occurs ____ from a single origin of replication.
bidirectionally
In eukaryotes, DNA replication occurs ______ from multiple origins of replication.
bidirectionally
DnaA protein
binds to DnaA boxes within the oriC to initiate DNA replication
Which process involves the exchange of corresponding segments of a homologous chromosome pair?
crossing over
Homologous recombination that produces a new combination of alleles occurs through ______.
crossover between homologous chromosomes during meiosis
The strand of DNA that is produced during DNA replication is generally called the
daughter strand
Which type of cell has chromosomes with multiple origins of replication?
eukaryotic cells
True or false: DNA polymerase can initiate the synthesis of a new strand by linking the first two nucleotides together.
false
In eukaryotes, the enzyme ______ removes the RNA primers.
flap endonuclease
DNA mismatch repair and DNA gap repair synthesis are mechanisms that can lead to ______.
gene conversion
Which process leads to a new combination of alleles in the chromosomal products?
homologous recombination in meiosis
What is the function of oriC in E. coli?
it is a DNA sequence that marks the initiation of replication
During DNA replication, multiple RNA primers are made on the ____ strand, which is produced in the opposite direction from the movement of the replication fork.
lagging strand
Which newly synthesized DNA molecule has a single primer?
leading strand
During DNA replication, synthesis of the ____ strand is continuous while synthesis of the ____ strand is discontinuous.
leading: continuous lagging: discontinuous
What is the name of the origin of replication in E. coli?
oriC
The linkage between a phosphate group and two sugar molecules is called a(n)
phosphodiester linkage
The enzyme that synthesizes the short molecules of RNA, called RNA primers, is called
primase
A complex consisting of DNA helicase and primase is called a(n)
primosome
The ability of DNA polymerase to remove mismatched bases is called
proofreading
During replication, when the 3'-OH group of the last nucleotide in a strand reacts with the phosphate group of the incoming nucleotide, a phosphodiester bond is formed, and ______ is released.
pyrophosphate
Proofreading is the ability of DNA polymerase to ______.
remove mismatched bases during replication
The role of topoisomerase II (DNA gyrase) in replication is to ______.
remove positive supercoiling in the DNA
Topoisomerase II (DNA gyrase)
removes positive supercoiling ahead of the replication forks
DnaB helicase
separates double stranded DNA
Proteins that function to stabilize the replication fork by preventing the reformation of the double strand are called ______.
single-strand binding proteins
The enzyme that synthesizes the short repetitive sequences at the ends of eukaryotic chromosomes is called
telomerase
A combination of specific proteins bound to repeated DNA sequences located at the end of a linear, eukaryotic chromosome comprises the
telomere
The tandemly repeated DNA sequences located at the both ends of eukaryotic chromosomes comprise the ______ sequences.
telomere sequence
During DNA replication, the strand of DNA that contains the information used to make a new strand of DNA is called the
template
During replication, dNTPs bind to the ____ strand according to the AT/GC rule.
template strand
What is the name given to the strand of DNA that contains the information to produce the new strand of DNA during DNA replication?
template strand
What is the name of the new strand of DNA that is produced during DNA replication?
the daughter strand
What is the role of single-strand binding proteins during DNA replication?
to stabilize the replication fork
A DNA polymerase that can replicate over regions with defective DNA structure, such as abnormal bases or covalent crosslinks, is a ______.
translesion-replicating polymerase
To replicate a DNA regions that has abnormalities, a(n) ____-_____ polymerase is attracted to the damaged DNA and can synthesize a complementary strand using the abnormal region as a template.
translesion-replicating polymerase
True or false: The formation of covalent bonds between adjacent nucleotides during DNA replication requires energy input.
true
In the helical structure of DNA, there are ___ strands wound together. (Give a number.)
two
