Nucleic Acids MCQs : This section focuses on the "Nucleic Acids". These Multiple Choice Questions (MCQs) should be practiced to improve the Nucleic Acids skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
A five carbon sugar lacking a hydrogen at the number 2 carbon is found in
Name those purine bases which are commonly found in DNA and RNA?
A. Adenine and guanine
B. Cytosine and thymine
C. Adenine and thymine
D. Cytosine and guanine
The primary structure of DNA and RNA proceeds in which direction?
A. 3’ —–> 5҆’
B. 5’ —–> 3’
C. 4’ —–> 6’
D. 3’ —–> 6’
A. can participate in hydrophobic interactions due to its methyl group
B. is replaced by uracil in RNA
C. normally forms two hydrogen bonds with adenosine
D. all of the above
The unfavourable free energy associated with not satisfying a hydrogen bond after formation of the double helix is approximately
A. 10 kJ/mol
B. 20 kJ/mol
C. 25 kJ/mol
D. 30 kJ/mol
The attachment between the base and sugar in a nucleotide is through ______ bond.
Deoxyribose sugar is found in DNA.
Nucleoside is a pyrimidine or purine base
A. covalently bonded to a sugar
B. ionically bonded to a sugar
C. hydrogen bonded to a sugar
D. none of the above
Which of the following statements is correct?
A. Adenine is a pyrimidine
B. DNA is made of amino acids
C. Nucleosides do not contain phosphorous
D. RNA contains thymine
Which pyrimidine base contains an amino group at carbon 4?
Purines and pyrimidines are different molecules.
What are the types of nucleic acids are found in living organisms?
A. deoxyribonucleic acid & nucleotide acid
B. deoxyribonucleic acid & ribonucleic acid
C. ribonucleic acid & nucleotide acid
D. ribonucleic acid & nucleoside acid
Which of the following is found on RNA but not DNA?
The monomeric unit of nucleic acid are called ___________
The sugar in RNA is __________ , the sugar in DNA is __________
A. deoxyribose, ribose
B. ribose, deoxyribose
C. ribose, phosphate
D. ribose, uracil
RNA on hydrolysis does not yield which of the following?
A. Amino acid
B. Pentose sugar
C. Nitrogen base
D. Phosphoric acid
Two DNA samples A and B have melting temperatures 305K and 320K respectively. Identify the correct statement based on this information.
A. A and B are complementary strands
B. B has more CG pairs than A
C. A has more CG pairs than B
D. A has more hydrogen bonds than B
Which part of the nucleotide is responsible for the formation of bonds in DNA double helix?
C. Phosphate group
D. Hydroxyl group of sugar
A nucleotide consists of
A. a sugar, a base and a phosphate
B. a sugar and a phosphate
C. paired bases
D. a sugar, a base and three phosphates
Name the pyrimidine base which is found in RNA but not in DNA?
Which sugar is present in RNA?
Which monomers compose the strands of nucleic acids?
A. Amino acids
C. Functional groups
Because DNA is a highly charged polyanion, its stability to heat denaturation
A. does not depend on hydrophobic interactions
B. increases with increasing salt
C. is independent of G - C content
D. decreases with increasing salt
Which bond is used to stabilize the double helix of DNA?
A. Hydrophobic bond
B. Hydrogen bond
C. Covalent bond
D. Ionic bond
A purified DNA sample of leaf contains 20.0 mole of guanine. Calculate the approximate percentage of purine residues?
What is the energy currency of the living cell?
The glycosidic bonds in DNA and RNA
A. connect the sugar to the base
B. can be hydrolyzed by OH- ion
C. stabilize Watson-Crick H-bonds
D. are free to rotate over about 180°
Which of the following bases contain two keto groups?
Nucleotide bases and aromatic amino acids absorb light respectively at
A. 280 and 260 nm
B. 260 and 280 nm
C. 270 and 280 nm
D. 260 and 270 nm
How many types of nucleotides are present in DNA?
ATP and GTP are __________
D. nucleic acids
Which of these statements are INCORRECT according to chargaff’s rules?
A. The molar ratio of A to T or C to G = 1
B. The sum of purine = sum of pyrimidine
C. The % C+G ≠ % A+T
D. The composition of DNA remains the same in all the species
The most stabilizing force for nucleic acids is
A. hydrogen bonds
B. electrostatic bond
C. Van der Waals
D. conformational entropy
In gel electrophoresis, what fragments will move most quickly through a gel?
A. Large fragments
B. Small fragments
C. Large genome
D. None of these
Identify the complementary strand of the DNA primary structure ATGCCGATC.
DNA is a polynucleotide.
Which of the following is a purine?
Nucleic acids can be analyzed experimentally by their
A. molecular weight
B. absorption of visible light
C. absorption of uv light
D. none of these
A purine with an amine (NH2) group on the 6th carbon is
Who discovered nucleic acid?
A. Watson and Crick
C. Friedrich Miescher
D. Walter Gilbert
Nucleotides are linked together by bonds between 5’ and 2’ carbons of two different pentose sugars.
Which of the following best describes cytosine?
A. pyrimidine, present in RNA and DNA
B. pyrimidine, present only in DNA
C. purine, present only in RNA
D. purine, present in RNA and DNA