BIO 181 Exam 4 with all Correct & 100% Verified
Answers |Latest Update |Already Graded A+
Chargaff's Rules ✔Correct Answer--1. adenine(A) always make bond with thymine(T) & guanine(G)
always make bond with cytosine(C).
2. A always make double hydrogen bond with T & G always make triple hydrogen bond with C
3. concentration of purine = concentration of pyrimidine i.e. A+G=C+T
4.(A+T)/(G+C)= constant for a species
4 Nitrogenous Bases of DNA ✔Correct Answer--Guanine-Cytosine
Thymine-Adenine
4 Nitrogenous Bases of RNA ✔Correct Answer--Guanine-Cytosine
Uracil-Adenine
Helicases ✔Correct Answer--Helicase is an enzyme that breaks hydrogen bonds between
nucleotides of DNA, unzipping a double -stranded DNA molecule.
Topoisomerase ✔Correct Answer--Enzyme that prevents the twisting of DNA ahead of the
advancing replication fork by cutting the DNA, allowing it to unwind, and rejoining it.
DNA Polymerase ✔Correct Answer--Any enzyme that catalyzes synthesis of DNA from
deoxyribonucleotide triphosphates (dNTPs).
1-removes RNA nucleotides of primer from 5 primed end and replaces them with DNA molecules
3-using parental DNA as a template, synthesizes new DNA strand by covalently adding nucleotides to
the 3 primed end of a pre-existing strand or RNA primer
DNA Ligase ✔Correct Answer--An enzyme that joins pieces of DNA by catalyzing the formation of a
phosphodiester bond between the pieces.
Antiparellel Elongation ✔Correct Answer--DNA polymerases add nucleotides only to the free 3
primed end of a growing strand of DNA therefore a new DNA strand can elongate only in the 5 to 3
primed direction
Leading Strand ✔Correct Answer--along one template strand of DNA, the DNA polymerase
synthesizes this continuously, moving toward the replication fork; only one primer is required for
DNA pol III to synthesize this
Lagging Strand ✔Correct Answer--to elongate the other new strand (called this), DNA polymerase
must work in the direction away from the replication fork; it is synthesized in segments called
Okazaki fragments which are joined together by DNA ligase; each Okazaki fragment must be primed;
DNA pol I replaces the RNA nucleotides of the primers with DNA versions adding them to the 3 end
Okazaki Fragments ✔Correct Answer--segments of the lagging strand
Telomeres ✔Correct Answer--provides no way to complete the 5 primed ends so repeated rounds
of replication produce shorter DNA molecules but this protects the genes from being eroded away
during successive rounds of DNA replication; they are special nucleotide sequences at the ends of
Answers |Latest Update |Already Graded A+
Chargaff's Rules ✔Correct Answer--1. adenine(A) always make bond with thymine(T) & guanine(G)
always make bond with cytosine(C).
2. A always make double hydrogen bond with T & G always make triple hydrogen bond with C
3. concentration of purine = concentration of pyrimidine i.e. A+G=C+T
4.(A+T)/(G+C)= constant for a species
4 Nitrogenous Bases of DNA ✔Correct Answer--Guanine-Cytosine
Thymine-Adenine
4 Nitrogenous Bases of RNA ✔Correct Answer--Guanine-Cytosine
Uracil-Adenine
Helicases ✔Correct Answer--Helicase is an enzyme that breaks hydrogen bonds between
nucleotides of DNA, unzipping a double -stranded DNA molecule.
Topoisomerase ✔Correct Answer--Enzyme that prevents the twisting of DNA ahead of the
advancing replication fork by cutting the DNA, allowing it to unwind, and rejoining it.
DNA Polymerase ✔Correct Answer--Any enzyme that catalyzes synthesis of DNA from
deoxyribonucleotide triphosphates (dNTPs).
1-removes RNA nucleotides of primer from 5 primed end and replaces them with DNA molecules
3-using parental DNA as a template, synthesizes new DNA strand by covalently adding nucleotides to
the 3 primed end of a pre-existing strand or RNA primer
DNA Ligase ✔Correct Answer--An enzyme that joins pieces of DNA by catalyzing the formation of a
phosphodiester bond between the pieces.
Antiparellel Elongation ✔Correct Answer--DNA polymerases add nucleotides only to the free 3
primed end of a growing strand of DNA therefore a new DNA strand can elongate only in the 5 to 3
primed direction
Leading Strand ✔Correct Answer--along one template strand of DNA, the DNA polymerase
synthesizes this continuously, moving toward the replication fork; only one primer is required for
DNA pol III to synthesize this
Lagging Strand ✔Correct Answer--to elongate the other new strand (called this), DNA polymerase
must work in the direction away from the replication fork; it is synthesized in segments called
Okazaki fragments which are joined together by DNA ligase; each Okazaki fragment must be primed;
DNA pol I replaces the RNA nucleotides of the primers with DNA versions adding them to the 3 end
Okazaki Fragments ✔Correct Answer--segments of the lagging strand
Telomeres ✔Correct Answer--provides no way to complete the 5 primed ends so repeated rounds
of replication produce shorter DNA molecules but this protects the genes from being eroded away
during successive rounds of DNA replication; they are special nucleotide sequences at the ends of
