Please refer to Molecular Basis of Inheritance Class 12 Biology Important Questions with answers below. These solved questions for Chapter 6 Molecular Basis of Inheritance in NCERT Book for Class 12 Biology have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these solved problems properly as these will help them to get better marks in your class tests and examinations. You will also be able to understand how to write answers properly. Revise these questions and answers regularly. We have provided Notes for Class 12 Biology for all chapters in your textbooks.

Important Questions Class 12 Biology Chapter 6 Molecular Basis of Inheritance

All Molecular Basis of Inheritance Class 12 Biology Important Questions provided below have been prepared by expert teachers of Standard 12 Biology. Please learn them and let us know if you have any questions.

Objective Type Questions

Question. Choose the correct statement
A. Thymine is present in DNA at the place of uracil which makes it more stable than RNA
B. 2’–0H group present at every nucleotide in RNA
C. RNA is more stable than DNA
D. DNA is less reactive and it is better genetic material
E. DNA is more reactive and it is better genetic material
Options :
(a) All are true
(b) A, B, C are true
(c) A, B are correct
(d) A, B, C are correct

Question. Which of the following are the criteria for a molecule to act as genetic material?
A. It should be able to generate its replica
B. It should be chemically and structurally less stable
C. It should be able to provide slow changes required for mutation
D. It should follow mendel’s law of inheritance
Options :
(a) A, B, C are true
(b) A, C, D are true
(c) All are true
(d) None of these

Question. Which is preferred for transmission of genetic material?
(a) RNA
(b) DNA
(c) protein
(d) DNA, RNA, protein

Question. In replication
A. The new daughter DNA are formed each having one stand of parent DNA and one new
B. The replication of new strand is in 3’ ® 5’ polarity
C. Enzyme required is RNA dependent DNA polymerase
D. There is continuous synthesis in one strand with 5’ polarity and discontinuous strand in 5’–3’ polarity
Options :
(a) All are true
(b) A, B, D are true
(c) A, C, D are true
(d) None of these

Question. DNA replication semi conservatively was first observed in
(c) Bacteriophages
(c) Viruses
(c) E. Coli
(c) S. Pneumoniae

Question. Monomer of nucleic acid is :
(a) Nucleoside
(b) Nitrogenous bases
(c) Sugar molecules
(d) Nucleotides

Question. Which of the following have RNA as genetic material?
(a) Human
(b) Insects
(c) Pants
(d) Tobacco mosaic virus

Question. Which is the most abundant genetic material in living organisms?
(a) DNA
(b) RNA
(c) Both
(d) None of these

Question. Monomeric unit of DNA is
(a) Deoxyribonucleoside
(b) Ribonucleoside
(c) Deoxyribonucleotide
(d) Ribonucleotid

Question. Nucleosides contains :
(a) Pentose Sugar+ phosphate group + nitrogenous bases
(b) Phosphate group + nitrogenous bases
(c) Pentose Sugar + nitrogenous bases
(d) Pentose Sugar phosphate group

Question. Which of the following is a nucleoside common in RNA and DNA?
(a) Adenosine
(b) Cytosine
(c) Thymidinylate
(d) None of theses

Question. Which of the following has 5386 respectively nucleotides and 46×105 nucleotides?
(a) Haploid human genome
(b) E.Coli and f × 174 bacteriophage
(c) Bacteriophage f × 174 and E.Coli
(d) None of these

Question. Two nucleotides are joined by :
(a) Glycosidic linkage
(b) Phosphodiester linkage
(c) Peptide pond
(d) Hydrogen Bond

Question. Bacteriophage lambda and human have base pairs:
(a) 48502 and 3.3 × 10⁹ bp
(b) 48502 and 4.6 × 10⁶ bp
(c) 5386 and 48502 bp
(d) 24623 and 3425 bp

Question. RNA is chemically different from DNA in having
(a) OH group at 1’ position in ribose
(b) OH group at 2’ position in ribose
(c) OH group at 3’ position in ribose
(d) None of these

Question. 5’ end of DNA molecule have :
(a) Ribose sugar
(b) Purine base
(c) Phosphate group
(d) None of these

Question. Who gave the name nuclein to the acidic substance present in nucleus and when?
(a) James Watson in 1953
(b) Maurice Wilkins in 1950
(c) Friedrich Meischer in 1869
(d) G.J. Mendel 1856

Question. According to Watson and Crick properties of DNA structure are :
A. It is right handed double helical structure
B. The two strands are antiparallel in polarity
C. Bases in the two strands are paired by hydrophobic bonds
D. Purine on one base is paired with pyrimidine on other strand
Oprtions :
(a) All are correct
(b) A, B, C are correct
(c) A, B, D are correct
(d) A, C, D are correct

Question. The pitch of DNA helix is :
(a) 0.34 nm
(b) 3.4 mm
(c) 34 × 10^–10 m
(d) None of these

Question. Watson and Cricks proposition for base pairing between two strands was based on observation of which scientist :
(a) Maurice Wilkins and Rosalind Franklin
(b) Friedrich Meischer
(c) E. Chargaff
(d) Griffith

Question. If in genome A content is 20% then what is the content of T, G and C taking whole genome as 100%
(a) 20%, 30%, 30%
(b) 30%, 30%, 20%
(c) 30%, 20%, 30%
(d) None of these

Question. If the sequence of the one strand of DNA is known then the sequence of other strand can be predicted due to which property :
(a) The two chains are complementary due to base pairing
(b) The backbone is made up of sugar and phosphate
(c) The bases from the core
(d) None of these

Question. Distance between bp of helix is :
(a) 0.34 nm
(b) 3.4 nm
(c) 34 A
(d) All of the above

Question. Property of DNA helix as postulated by Watson and Crick, Central Dogma states flow of genetic information in the direction :
(a) RNA ® DNA ® Protein
(b) DNA ® RNA ® Protein
(c) Protein ® RNA ® DNA
(d) None of these

Question. DNA forming DNA is called ________, DNA to m RNA ______ m RNA to protein.
(a) Replication, translation, transcription
(b) Replication, transcription, translation
(c) Translation, replication, transcription
(d) Transcription, translation, replication

Question. The length of DNA in mammalian cell :
(a) 2.2 metre
(b) 1.2 metre
(c) 3.2 metre
(d) 0.2 metre

Question. Histone proteins are :
(a) –ve, acidic
(b) +ve, basic
(c) –ve, basic
(d) +ve, acidic

Question. In prokaryotes DNA is packaged in a specified region called :
(a) Nucleus
(b) Nuclei
(c) Nucleolus
(d) Nucleoid

Question. How many base pairs of DNA wrap around histone octamer to form nucleosome?
(a) 100
(b) 1000
(c) 200
(d) 2000

Question. For higher level of Packaging of chromatin which proteins are required?
(a) Non–histone chromosomal proteins
(b) Non–acidic chromosomal proteins
(c) Histone chromosomal proteins
(d) None of these

Question. Transcriptionally inactive chromatin is called
(a) Euchromatin
(b) Heterochromatin
(c) Nucleosome
(d) None of these

Question. Proteases and RNAses are
(a) Protein synthesis and RNA degrading enzymes
(b) Protein synthesizing and RNA synthesising enzymes
(c) Protein degrading and RNA synthesising enzymes
(d) None of these

Question. Hershey and chase experiment was performed in which year and which genetic material was confirmed as transforming principle
(a) 1952,RNA
(b) 1932, DNA
(c) 1952, DNA
(d) 1952, protein

Question. Which set of bacteria showed radioactivity in hershey chase experiment?
(a) Bacteria infected with phages in 14N medium
(b) Bacteria infected with phages grown in 35P medium
(c) Bacteria infected with phages grown in 32P
(d) Bacteria infected with phages grown in 35S medium

Question. Which of the following has RNA as genetic material?
(a) QB bacteriophage
(a) E.coli
(a) Streptococcus pneumonia
(a) None