BIOCHEM 501 UNIT 4 QUIZZES || ZERO FLAW ON ANSWERS.
When DNA "melts," which bonds are broken? correct answers hydrogen
In a topoisomerase reaction, the _____ is used as the first nucleophile and the _____ is used as
the second nucleophile. correct answers hydroxyl in tyrosine, 3' OH
ALL of the following changes would decrease the melting temperature of DNA EXCEPT:
Increasing the number of base pair mismatches
Increasing the concentration of magnesium (Mg2+) a cation
Increasing the pH
Addition of non-polar solvents correct answers Increasing the concentration of magnesium
(Mg2+) a cation
Which component of an RNA nucleotide makes it more prone to hydrolysis than DNA? correct
answers 2' OH
Deoxyribonucleotides are so named because they lack a hydroxyl at which position? correct
answers C2'
Deoxyribonucleotides lack a hydroxyl at C2', giving them the name "deoxy" (no hydroxyl).
Adenine N1: correct answers hydrogen bond acceptor
Adenosine in the anti position correct answers
What is a substrate for DNA polymerase? correct answers dATP
, DNA synthesis occurs in the 5'-to-3' direction. The 5' end is synonymous with ____ while the 3'
end is synonymous with ____. correct answers the phosphate group, a hydroxyl
Nucleotide base tautomerization: correct answers disrupts base pairing by changing hydrogen
bond donors to acceptors, or vice versa
Telomerase lengthens the ends of chromosomes. Telomerase is a(n) _______ polymerase that is
associated with a(n) _____ template correct answers DNA, RNA
DNA polymerase fails to recognize that an incorrect nucleotide has been incorporated, resulting
in a mismatch. Which repair pathway will correct this mistake? correct answers mismatch repair
5-methyl-cytosine base. Is methylation of cytosine mutagenic? correct answers No! Methylation
of cytosine at C5 does not disrupt any hydrogen bond donors or acceptors between nitrogenous
bases.
A nucleoside with a hypoxanthine base is called correct answers inosine.
Which of the following enzymes in base excision repair is NOT required to repair depurinated
nucleotides? correct answers Glycosylase cleaves the glycosidic bond between the base and
ribose sugar. Depurinated nucleotides lack a base (specifically a purine base, either adenine or
guanine). Thus, there is no bond for glycosylase to cleave.
In response to a double-stranded DNA break, which type of nuclease generates the 3' overhangs
that will go on a homology search? correct answers 5'-to-3' Exonuclease
When does recombination occur? correct answers During meiosis
In response to a single- or double-stranded break in DNA
During antibody formation
When catalyzed by a recombinase
When DNA "melts," which bonds are broken? correct answers hydrogen
In a topoisomerase reaction, the _____ is used as the first nucleophile and the _____ is used as
the second nucleophile. correct answers hydroxyl in tyrosine, 3' OH
ALL of the following changes would decrease the melting temperature of DNA EXCEPT:
Increasing the number of base pair mismatches
Increasing the concentration of magnesium (Mg2+) a cation
Increasing the pH
Addition of non-polar solvents correct answers Increasing the concentration of magnesium
(Mg2+) a cation
Which component of an RNA nucleotide makes it more prone to hydrolysis than DNA? correct
answers 2' OH
Deoxyribonucleotides are so named because they lack a hydroxyl at which position? correct
answers C2'
Deoxyribonucleotides lack a hydroxyl at C2', giving them the name "deoxy" (no hydroxyl).
Adenine N1: correct answers hydrogen bond acceptor
Adenosine in the anti position correct answers
What is a substrate for DNA polymerase? correct answers dATP
, DNA synthesis occurs in the 5'-to-3' direction. The 5' end is synonymous with ____ while the 3'
end is synonymous with ____. correct answers the phosphate group, a hydroxyl
Nucleotide base tautomerization: correct answers disrupts base pairing by changing hydrogen
bond donors to acceptors, or vice versa
Telomerase lengthens the ends of chromosomes. Telomerase is a(n) _______ polymerase that is
associated with a(n) _____ template correct answers DNA, RNA
DNA polymerase fails to recognize that an incorrect nucleotide has been incorporated, resulting
in a mismatch. Which repair pathway will correct this mistake? correct answers mismatch repair
5-methyl-cytosine base. Is methylation of cytosine mutagenic? correct answers No! Methylation
of cytosine at C5 does not disrupt any hydrogen bond donors or acceptors between nitrogenous
bases.
A nucleoside with a hypoxanthine base is called correct answers inosine.
Which of the following enzymes in base excision repair is NOT required to repair depurinated
nucleotides? correct answers Glycosylase cleaves the glycosidic bond between the base and
ribose sugar. Depurinated nucleotides lack a base (specifically a purine base, either adenine or
guanine). Thus, there is no bond for glycosylase to cleave.
In response to a double-stranded DNA break, which type of nuclease generates the 3' overhangs
that will go on a homology search? correct answers 5'-to-3' Exonuclease
When does recombination occur? correct answers During meiosis
In response to a single- or double-stranded break in DNA
During antibody formation
When catalyzed by a recombinase
