Molecular biology Exam questions
with answers graded A+
What features of the structure of DNA enable it to be replicated? - ANS✅✅The two features that
allow DNA to be replicated are its double-stranded structure and the base pairing between A and T
and between G and C.
The DNA strand is known as the __________ strand. The RNA strand is known as the __________
strand. - ANS✅✅template; daughter
1. Conservative Model:
2. Semiconservative Model:
3. Dispersive Model: - ANS✅✅1. both parental strands of DNA remain together and the two newly
made daughter strands also remain together following replication
2. the newly made double-stranded DNA contains one parental strand and one daughter strand
3. segments of parental DNA and newly made DNA are interspersed in both strands following the
replication process
The complementarity of DNA strands is based on __________. - ANS✅✅the AT/GC rule (Chargaff's
rule)
To make a new DNA strand, which of the following is/are necessary?
a) a template strand
b) nucleotides
c) heavy nitrogen
d) both a and b - ANS✅✅d) both a and b
The model that correctly describes the process of DNA replication is __________. - ANS✅✅the
semiconservative model
The experiment of __________ showed that DNA replication results in two double helices, each one
containing an original parental strand and a newly made daughter strand. - ANS✅✅Meselson and
Stahl
, Three types of DNA sequences are found within oriC: - ANS✅✅1. AT-rich region
2. DnaA box sequences
3. GATC methylation sites
What are the functions of the AT-rich region and DnaA boxes? - ANS✅✅The DnaA boxes are
recognized by DnaA proteins, which bind to them and cause the DNA strands to separate at the AT-
rich region.
How many replication forks are formed at the origin of replication? - ANS✅✅Two replication forks
are formed at the origin.
A site in a chromosome where DNA replication begins is __________. - ANS✅✅an origin of
replication
The origin of replication in E. coli contains __________.
a) an AT-rich region
b) DnaA boxes
c) GATC methylation sites
d) all of the above - ANS✅✅d) all of the above
Why is primase needed for DNA replication? - ANS✅✅Primase is needed for DNA replication
because DNA polymerase cannot initiate DNA replication on a bare template strand.
DnaA proteins function: - ANS✅✅bind to DnaA box sequences within the origin of replication to
initiate DNA replication
DnaC proteins function: - ANS✅✅aid DnaA in the recruitment of DNA helicase to the origin
DNA helicase (DnaB) function: - ANS✅✅separates double-stranded DNA
Topoisomerase II (DNA gyrase) function: - ANS✅✅removes positive supercoiling ahead of the
replication fork
with answers graded A+
What features of the structure of DNA enable it to be replicated? - ANS✅✅The two features that
allow DNA to be replicated are its double-stranded structure and the base pairing between A and T
and between G and C.
The DNA strand is known as the __________ strand. The RNA strand is known as the __________
strand. - ANS✅✅template; daughter
1. Conservative Model:
2. Semiconservative Model:
3. Dispersive Model: - ANS✅✅1. both parental strands of DNA remain together and the two newly
made daughter strands also remain together following replication
2. the newly made double-stranded DNA contains one parental strand and one daughter strand
3. segments of parental DNA and newly made DNA are interspersed in both strands following the
replication process
The complementarity of DNA strands is based on __________. - ANS✅✅the AT/GC rule (Chargaff's
rule)
To make a new DNA strand, which of the following is/are necessary?
a) a template strand
b) nucleotides
c) heavy nitrogen
d) both a and b - ANS✅✅d) both a and b
The model that correctly describes the process of DNA replication is __________. - ANS✅✅the
semiconservative model
The experiment of __________ showed that DNA replication results in two double helices, each one
containing an original parental strand and a newly made daughter strand. - ANS✅✅Meselson and
Stahl
, Three types of DNA sequences are found within oriC: - ANS✅✅1. AT-rich region
2. DnaA box sequences
3. GATC methylation sites
What are the functions of the AT-rich region and DnaA boxes? - ANS✅✅The DnaA boxes are
recognized by DnaA proteins, which bind to them and cause the DNA strands to separate at the AT-
rich region.
How many replication forks are formed at the origin of replication? - ANS✅✅Two replication forks
are formed at the origin.
A site in a chromosome where DNA replication begins is __________. - ANS✅✅an origin of
replication
The origin of replication in E. coli contains __________.
a) an AT-rich region
b) DnaA boxes
c) GATC methylation sites
d) all of the above - ANS✅✅d) all of the above
Why is primase needed for DNA replication? - ANS✅✅Primase is needed for DNA replication
because DNA polymerase cannot initiate DNA replication on a bare template strand.
DnaA proteins function: - ANS✅✅bind to DnaA box sequences within the origin of replication to
initiate DNA replication
DnaC proteins function: - ANS✅✅aid DnaA in the recruitment of DNA helicase to the origin
DNA helicase (DnaB) function: - ANS✅✅separates double-stranded DNA
Topoisomerase II (DNA gyrase) function: - ANS✅✅removes positive supercoiling ahead of the
replication fork
