Please refer to below Exam Question for Class 12 Biology Chapter 6 Molecular Basis of Inheritance . These questions and answers have been prepared by expert Class 12 Biology teachers based on the latest NCERT Book for Class 12 Biology and examination guidelines issued by CBSE, NCERT, and KVS. We have provided Class 12 Biology exam questions for all chapters in your textbooks. You will be able to easily learn problems and solutions which are expected to come in the upcoming class tests and exams for standard 12th.

Chapter 6 Molecular Basis of Inheritance Class 12 Biology Exam Question

All questions and answers provided below for Exam Question Class 12 Biology Chapter 6 Molecular Basis of Inheritance are very important and should be revised daily.

Objective Type Questions

Question. Which base make DNA more stable than RNA?
(a) Thymine
(b) Uracil
(c) Guanine
(d) Cytosine

Question. Which of the following have RNA as genetic material?
(a) E.coli
(b) Tobacco mosaic virus
(c) Streptococcus pneumonia
(d) S. Cerviciae

Question. Which molecule is preferred for storage of genetic material and why?
(a) RNA, unstable
(b) DNA, double helical
(c) DNA, more stable than RNA
(d) None of these

Question. Which is the first genetic material
(a) RNA
(b) DNA
(c) Protein
(d) None of these

Question. Semiconservative replication was proposed by
(a) Watson and Crick
(b) Jacob and Monad
(c) Wilkins and Franklin
(d) None of these

Question. According to Mendel the inheritance of Characters was performed by :
(a) Genes
(b) Replication
(c) Factors
(d) Transformation

Question. RNA functions as :
(a) Adapter molecule and genetic material
(b) Structural molecule
(c) Catalytic molecule
(d) All of these

Question. Which nucleic acid is genetic material?
(a) DNA
(b) DNA is most organism while RNA in some viruses
(c) Only RNA
(d) None of these

Question. Length of DNA molecule is defined as :
(a) Number of nucleotides present in it
(b) Number of base pairs present in it
(c) Number of uracil base present
(d) Both (a) and (b)

Question. Total human genome content (haploid) is :
(a) 330 × 10⁷ bp
(b) 1.65 × 10⁹ bp
(c) 66 × 10⁸ bp
(d) None of theses

Question. Which of the following is not a nucleoside?
(a) Adenosine
(b) Deoxyguanosine
(c) Deoxythymidine
(d) Cytidiylate

Question. RNA contains a pyrimidine base which is absent in DNA :
(a) 5– methyl uracil
(b) Adenine
(c) Cytosine
(d) None of these

Question. Linkage of base to sugar and sugar to phosphate is:
(a) O–glycosidic linkage and phosphoester bond
(b) N– glycosidic linkage and phosphoester bond
(c) O– glycosidic linkage and peptide bond
(d) None of these

Question. In a nucleotide 5’ end phosphate of the 5’ end of DNA is Joined to first sugar molecule
(a) 3’ OH group
(b) 2’ OH group
(c) 5’ OH group
(d) 1’ OH group

Question. Nucleotide is made of :
(a) a nitrogenous base
(b) a nitrogenous base + pentose sugar
(c) a nitrogenous base + pentose sugar + phosphate
(d) All correct

Question. At 3’ end of DNA which free group of sugar is present
(a) Free 1’ OH group
(b) Free 2’ OH group
(c) Free 3’ OH group
(d) None of these

Question. The Polynucleotide backbone is formed by :
(a) Sugar + purines
(b) Sugar + pyrimidines
(c) Sugar + Phosphate
(d) Phosphate + purines

Question. Data for DNA structure was first given by –––––– using technique.
(a) Maurice Wilkins and Rosalind Franklin, density gradient centrifugation
(b) Maurice Wilkins and Rosalind Franklin, X–ray diffraction
(c) Maurice Wilkins and Rosalind Franklin, X–ray crystallography
(d) James Watson and Francis Crick, X–ray diffraction

Question. Approximately how many base pairs are present per turn of DNA helix in Watson and Crick double helix model of DNA :
(a) 8
(b) 16
(c) 10
(d) None of these

Question. Which of the following base pairs are bonded by 2 hydrogen bonds in DNA ?
(a) AC
(b) AT
(c) GC
(d) Both (a) and (b)

Question. Chargaff rule states for a double standard DNA:
(a) A:T and G:C is constant
(b) A:T and G:C is equal to one
(c) A:G and C:T is constant
(d) Both (a) and (b)

Question. There is almost constant distance between the two DNA strands because
(a) Base from the inner core of DNA
(b) Sugar and phosphate forms the backbone
(c) There is hydrogen bonding between two bases
(d) A purine base is always hydrogen bonded to a pyrimidine base

Question. What made possible to Watson and Crick to know about double helix structure of DNA :
(a) Backbone is made of sugar and phosphate
(b) Discovery of compound microscope
(c) Based on X–ray diffraction data by M.Wilkins and R. Franklin
(d) None of above

Question. A transcription unit consists of
(a) origin, promoter, terminator
(b) origin, promoter, terminator, structural gene
(c) promoter, terminator, structural gene
(d) None of these

Question. Flow of information from RNA to DNA is known as:
(a) Replication
(b) Reverse transcription
(c) Transcription
(d) Forward transcription

Question. In the some viruses the flow of genetic information in the direction :
(a) DNA→ mRNA → Protein
(b) Protein → RNA → DNA
(c) DNA → Protein → RNA
(d) RNA → DNA → Protein

Question. If the length of E.coli DNA is 1.36 mm, calculate the number of base pair in E.Coli :
(a) 4 × 10⁶ bp
(b) 0.4 × 10⁸ bp
(c) 3.3 × 10⁶ bp
(d) 4.6 × 10⁹ bp

Question. Histones are rich in basic amino acid residues :
(a) Lysines and arginine
(b) Aspartic and Glutamic acid
(c) Glutamic acid and Valine
(d) All the above

Question. Which statement is true, for the packaging of DNA in eukaryotes?
(a) DNA is packaged with a set of basic proteins called histone
(b) Histone contains negatively charged amino acids in its side chain
(c) DNA packaged with histone octamer are called Nucleosome
(d) Both (a) and (c)

Question. Search to chromosomes were narrowed by scientists
(a) Oswald avery, Maceod, McCarty
(b) Hershey, chase, Friedrich, Griffith
(c) Gregor Mendel, Waiter Sutton, T. Morgan
(d) Darwin, Oparin, Devries

Question. Euchromatin is
A. Transcriptionally active
B. Stains light
C. Packaged densely
D. Stains dark
Options :
(a) A, B, C are true
(b) A, B, D are true
(c) A, B are true
(d) A, D are true

Question. Which statement is true for the transforming principle experiment of griffith?
A. Streptococcus pneumonia was taken for experiment
B. S strain was virulent and have smooth coat due to presence of mucous
C. The heat killed S strain when injected in mice did not show any adverse effect on mice
D. The transforming principles biochemical nature was totally clear from experiment
Options :
(a) All are true
(a) A, B, D are true
(a) A, B, C are true
(a) None of these

Question. Experiment of Avery, Macleod and Mc Carty action of which enzyme inhibited the transformation of R strain to S strain
(a) RNAses
(b) DNAses
(c) Protease
(d) Peptidase

Question. In Hershey Chase experiment the two sets of bacteriophages were grown in radioactive medium containing
(a) 14N and 35S
(b) 30P and 35S
(c) 32P and 35S
(d) 14N and 32P

Question. Debate of DNA versus protein as genetic material was resolved by experiment of
(a) Griffith
(b) Sutton and bovery
(c) Franklin and wilkins
(d) Hershey and chase