Explore topic-wise MCQs in Life Sciences.

This section includes 27 Mcqs, each offering curated multiple-choice questions to sharpen your Life Sciences knowledge and support exam preparation. Choose a topic below to get started.

1.

ATP and GTP are __________

A. cells
B. receptors
C. nucleotides
D. nucleic acids
Answer» D. nucleic acids
2.

Ribozymes are _____________

A. cell organelle
B. enzymes
C. nucleotide
D. nucleoside
Answer» C. nucleotide
3.

Purines and pyrimidines are different molecules.

A. True
B. False
Answer» B. False
4.

How many types of nucleotides are present in DNA?

A. 1
B. 2
C. 3
D. 4
Answer» E.
5.

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
Answer» C. ribonucleic acid & nucleotide acid
6.

Which monomers compose the strands of nucleic acids?

A. Amino acids
B. Ribose
C. Functional groups
D. Nucleotides
Answer» E.
7.

A purified DNA sample of leaf contains 20.0 mole of guanine. Calculate the approximate percentage of purine residues?

A. 30%
B. 40%
C. 60%
D. 20%
Answer» B. 40%
8.

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
Answer» E.
9.

Which of these statements are TRUE for a glycosidic bond?

A. The bond between sugar and the nitrogenous base
B. The bond between the two sugar residues
C. The bond between sugar and phosphate
D. The bond between base and phosphate
Answer» B. The bond between the two sugar residues
10.

The sugar in RNA is __________ , the sugar in DNA is __________

A. ribose, deoxyribose
B. deoxyribose, ribose
C. ribose, uracil
D. ribose, phosphate
Answer» B. deoxyribose, ribose
11.

Nucleoside is a pyrimidine or purine base

A. ionically bonded to a sugar
B. covalently bonded to a sugar
C. none of the above
D. hydrogen bonded to a sugar
Answer» C. none of the above
12.

Which of the following is found on RNA but not DNA?

A. Deoxyribose
B. Uracil
C. Adenine
D. Phosphate
Answer» E.
13.

Which pyrimidine base contains an amino group at carbon 4?

A. Thymine
B. Cytosine
C. Adenine
D. Uracil
Answer» C. Adenine
14.

Thymidine

A. is replaced by uracil in RNA
B. can participate in hydrophobic interactions due to its methyl group
C. all of the above
D. normally forms two hydrogen bonds with adenosine
Answer» D. normally forms two hydrogen bonds with adenosine
15.

Which of the following is a purine?

A. Adenine
B. Cytosine
C. Uracil
D. Thymine
Answer» C. Uracil
16.

The most stabilizing force for nucleic acids is

A. electrostatic bond
B. hydrogen bonds
C. conformational entropy
D. Van der Waals
Answer» B. hydrogen bonds
17.

WHICH_OF_THESE_STATEMENTS_ARE_INCORRECT_ACCORDING_TO_CHARGAFF‚ÄÖ√Ñ√∂‚ÀÖ√Ë‚ÀÖ¬•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
Answer» E.
18.

A purified DNA sample of leaf contains 20.0 mole of guanine. Calculate the approximate percentage of purine residues?$

A. 30%
B. 40%
C. 60%
D. 20%
Answer» B. 40%
19.

Which bond is used to stabilize the double helix of DNA?

A. Hydrophobic bond
B. Hydrogen bond
C. Covalent bond
D. Ionic bond
Answer» C. Covalent bond
20.

The primary structure of DNA and RNA proceeds in which direction?

A. 3’ —–> 5҆’
B. 5’ —–> 3’
C. 4’ —–> 6’
D. 3’ —–> 6’
Answer» C. 4‚Äö√Ñ√∂‚àö√ë‚àö¬• ‚Äö√Ñ√∂‚àö√ë‚àö√Ü‚Äö√Ñ√∂‚àö√ë‚àö¬®> 6‚Äö√Ñ√∂‚àö√ë‚àö¬•
21.

What is the energy currency of the living cell?

A. GTP
B. NADH
C. FADH
D. ATP
Answer» E.
22.

Which of these statements are TRUE for a glycosidic bond?

A. The bond between sugar and the nitrogenous base
B. The bond between the two sugar residues
C. The bond between sugar and phosphate
D. The bond between base and phosphate
Answer» B. The bond between the two sugar residues
23.

Deoxyribose sugar is found in DNA.

A. True
B. False
Answer» B. False
24.

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
Answer» B. Cytosine and thymine
25.

Name the pyrimidine base which is found in RNA but not in DNA?

A. Thymine
B. Uracil
C. Adenine
D. Guanine
Answer» C. Adenine
26.

Who discovered nucleic acid?

A. Watson and Crick
B. Griffith
C. Friedrich Miescher
D. Walter Gilbert
Answer» D. Walter Gilbert
27.

The monomeric unit of nucleic acid are called ___________

A. Nucleotides
B. Nucleosides
C. Pyrimidines
D. Purines
Answer» B. Nucleosides