MCQ Questions Chapter 6 Molecular Basis of Inheritance Class 12 Biology

Please refer to MCQ Questions Chapter 6 Molecular Basis of Inheritance Class 12 Biology with answers provided below. These multiple-choice questions have been developed based on the latest NCERT book for class 12 Biology issued for the current academic year. We have provided MCQ Questions for Class 12 Biology for all chapters on our website. Students should learn the objective based questions for Chapter 6 Molecular Basis of Inheritance in Class 12 Biology provided below to get more marks in exams.

Chapter 6 Molecular Basis of Inheritance MCQ Questions

Please refer to the following Chapter 6 Molecular Basis of Inheritance MCQ Questions Class 12 Biology with solutions for all important topics in the chapter.

MCQ Questions Answers for Chapter 6 Molecular Basis of Inheritance Class 12 Biology

Question- Initiation of polypeptide chain takes place through
(a) methionine
(b) lysine
(c) leucine
(d) glycine

Question- The flow of information from DNA to mRNA and then to proteins is called
(a) transcription
(b) translation
(c) genetic code
(d) central dogma

Question- Replication is continuous in
(a) the leading strand
(b) the lagging strand
(c) the strand where okazaki fragments are present
(d) both the strands

Question- Which is required for protein synthesis?
(a) Initiation codon
(b) GTP
(c) Peptidyi transferase
(d) All of these

Question- In 1957, Meselson and Stahl concluded from their studies that
(a) DNA replicates conservatively
(b) DNA replicates semiconservatively
(c) DNA replicates dispersively
(d) DNA does not replicate

Question- Circular ONA is found in
(a) viruses
(b) bacteria, chloroplast and mitochondria
(c) chloroplast and mitochondria alone
(d) all of these

Question- Termination of polypeptide chain is brought about by
(a) UUG,UAGandUCG
(b) UCG,GCGandACC
(c) UAA, UAG and UGA
(d) UUG, UGCandUCA

Question- If in a DNA molecule cytosine is 18%, the percentage of adenine would be
(a) 18%
(b) 32%
(c) 36%
(d) 64%

Question- The process of translation relates to
(a) DNA synthesis
(b) RNA synthesis
(c) ribosome synthesis
(d) protein synthesis

Question- Nucleic acids are polymers of
(a) nucleotides
(b) nucleosides
(c) amino acids
(d) nucleoproteins

Question- Which of the following in Laning SSRNA ?
(a) TMV
(b) T2-bacterioplage
(c) Pox virus
(d) F × 174

Question- DNA is present in
(a) mitochondria
(b) nucleus
(c) chloroplast
(d) All of these

Question- Repressor protein in produced by-
(a) Regulator gene
(b) Operator gene
(c) Structural gene
(d) Promotor gene

Question- Whose experiments cracked the DNA and discovered unequirocally that a genetic code in a triplet ?
(a) Nierenberg and Mathei
(b) Margon and Sturtevant
(c) Fieshey and chose
(d) Beadle and Tatun

Question- What was the finding of Hershey and Chase?
(a) The viral infecting agent is RNA.
(b) The viral infecting agent is DNA.
(c) The viral infecting agent is protein.
(d) The T2 virus has RNA as its genetic material.

Question- How much of DMA base sequence among humans is same?
(a) 50%
(b) 80%
(c) 99.9%
(d) 3.4%

Question- The chain initiating codon is
(a) AUG
(b) UAG
(c) UAA
(d) UUA

Question- Tryptophanoperonof£sc/?erfc/)/aco//is
(a) a repressive system
(b) an inducible system
(c) an unregulated system
(d) monocistronlc

Question- Regulator gene controls chemical synthesis (operoh system) by
(a) inhibiting substrate enzyme action
(b) inhibiting transcription of mRNA
(c) inhibiting passage of mRNA
(d) inhibiting enzymes

Question- A gene that takes part in synthesis of polypeptide is
(a) regulator gene
(b) promoter gene
(c) operator gene
(d) structural gene

Question- DNA replication needs
(a) RNAprimer
(b) DNA template
(c) dNTPs
(d) All are correct

Question- Operator gene of lac-operon is turned on when lactose molecules bind to
(a) represser molecule
(b) promotersite
(c) mRNA
(d) regulator gene

Question- Nucleotide base present in DNA and not in RNA is
(a) cytosine
(b) thymine
(c) uracil
(d) guanine

Question- Restriction endonuclease enzymes are used in genetic engineering because they
(a) are proteolytic enzymes which degrades harmful proteins
(b) can cut DNA at variable sites
(c) can cut DNA at specific base sequence
(d) can join DNA fragments

Question- Feed back repression can be seen in
(a) all operons
(b) lac operon
(c) tryptophan operon
(d) none of these

Question- A particular ‘___ carry the Information for making a particular polypeptide, but ______ can be used to make any polypeptide.
(a) gene and ribosome… a tRNA and an mRNA
(b) gene and mRNA… a ribosome and a tRNA
(c) ribosome and mRNA… a gene and a tRNA
(d) gene and tRNA… a ribosome and an mRNA

Question- The promoter allows
(a) binding of DMA polymerase
(b) binding of repressor
(c) binding of RNA polymerase
(d) folding of structural genes

Question- The smallest gene affected by mutation is
(a) exon
(b) muton
(c) cistron
(d) recon

Question- A. Both DNA and RNA are able to mutate:
B. RNA being unstable, mutates at a faster rate
C. RNA is also known to be catalytic, hence reactive
D. The presence of thymine at place of uracil confers additional stability tcfbNA.
(a) All are correct
(b) All are incorrect
(c) Only A, B and P are correct
(d) Only D is correct

Question- How many structural genes are present in the tryptophan operon?
(a) two
(b) three
(c) four
(d) five

Question- Lac operon and tryptophan operon are the models of gene expression in
(a) bacteria
(b) viruses
(c) eukaryotes
(d) all of these

Question- Bacterial nucleoid has
(a) one single-stranded DNA
(b) one double-stranded DNA
(c) two single-stranded DNA
(d) many double-stranded DNAs

Question- Pre-mRNAorhnRNAfouhdineukaryoticcellis-
(a) formed as result of a replication of DMA
(b) formed due to the transcription of entire length of a gene
(c) a new species of genetic RNA ‘
(d) result of transcription of only introns

Question- Genes that are involved in turning on or off the transcription of structural genes are called
(a) redundant genes
(b) operator genes
(c) regulator genes
(d) polymorphic genes

Question- The transcription of lac operon is controlled by
(a) promoter
(b) only by regulator
(c) operator and promoter
(d) operator; prbmoter and regulator

Question- mRNA direct the building of proteins through a sequence of-
(a) Axons
(b) Intions
(c) Codons
(d) Anticodom

Question- The lac operon consists of
(a) one structural gene
(b) three structural genes
(c) four structural genes
(d) five structural genes

Question- In operon model, regulator gene functions as
(a) represser
(b) regulator
(c) inhibitor
(d) all of these

Question- Genetic material of retrovirus is-
(a) DNA
(b) RNA
(c) Both (a) and (b)
(d) None of these

Question- Transgenic plants are developed by
(a) introducing gene mutation
(b) introducing foreign genes
(c) stopping spindle formation
(d) introducing chromosomal mutation

Question- Cauliflower mosaic virus has-
(a) ssRNA
(b) ss DNA
(c) ds DNA
(d) dsRNA

Question- Viruses possess
(a) RNA
(b) DNA
(c) RNAorDNA
(d) neither RNA nor DNA

Question- The genes present in host cells and viruses which cause cancer are
(a) oncogenes
(b) pro to-oncogenes
(c) house-keeping genes
(d) reverse transcriptase

Question- Lac operon is-
(a) a set of overlapping genes
(b) repressible operon
(c) inducible operon
(d) arabinose operon

Question- In Escherichia coli, lac operon is induced by
(a) l-gene
(b) promoter gene
(c) lactose
(d) p-galactosidase

Question- Imagine an error occurring during DNA replication in a cell, so that where there is supposed to be a T in one of the genes there is instead a G. What effect will this probably have on the cell?
(a) The amino acid sequence of one of its kinds of proteins will be completely changed.
(b) An amino acid will be missing from each of its kinds of proteins.
(c) One of its kinds of proteins might contain an incorrect amino acid.
(d) An amino acid will be missing from one of its kinds of proteins.

Question- Wild type Escherichia coli growing on medium having glucose is transferred to lactose containing medium. Which one of the following change will occur?
(a) The bacterium stops dividing
(b) All operons are induced
(c) Lac operon is suppressed
(d) Lac operon is induced

Question- A sequence of three RNA base can function as –
A. Codon B. gene C. anticodon D. nucleosides
(a) A, C
(b) A, B, C, D
(c) B, C, D
(d) A, B,C

Question- For transcription RNA polymerase attaches to the
(a) regulator
(b) cofactor
(c) represser
(d) promoter

Question- What is a split gene?
(a) A gene with a crack in it
(b) A gene which has no promoter
(c) A jumping gene
(d) A gene whose entire sequences are not retained in the mature RNA

Question- An operon is a
(a) cistron
(b) protein
(c) gene
(d) group of regulated stfucturargenes which controls related functions

Question- Introns are part of DNA which
(a) code for protein synthesis
(b) do not code for protein synthesis
(c) initiate transcription
(d) help in joining pieces of DNA 

Question. The stretch of codons between AUG and a stop codon is called       
(a) open reading frame
(b) TATA box
(c) colinearity
(d) degenerate

Question. The coding sequences found in split genes are called         
(a) Operons
(b) introns
(c) exons
(d) cistrons

Question. If a DNA contains 1000 base pairs, what would be its length?       
(a) 3400 Å
(b) 34000 Å
(c) 6800
(d) 1000 Å

Question. If the sequence of bases in DNA is TACCGACCA, then the sequence of codons on the transcript will be         
(a) ATGGCTGGT
(b) ATCCGAACU
(c) AUGGCUGGU
(d) AUGGACUAA

Question. Genes which are active all the time synthesizing substances needed by the cell are called       
(a) Cellular luxury genes
(b) metabolic genes
(c) house keeping genes
(d) control genes

Question. Pick the right difference between a DNA and RNA       
(a) Sugar and phosphate
(b) sugar and purines
(c) purines and phosphate
(d) sugar and pyrimidines

Question. Match the following         
        Column I                       Column II
(A) Helicase                                (M) activation of amino acid
(B) Peptidyl transferase                (N) joins DNA fragments
(C) DNA polymerase                     (O) unwinds DNA helix
(D) DNA ligase                              (P) peptide bonds between amino acids
(E) Aminoacyl synthetase enzyme (Q) DNA synthesis
(F) RNA primase (R) synthesis of RNA primer
(a) A-O, B-P, C-Q, D-N, E-M, F-R
(b) A-R, B-M, C-N, D-Q, E-P, F-O
(c) A-M, B-R, C-P, D-Q, E-N, F-O
(d) A-R, B- Q, C- A, D- M, E-P, F-N

Question. In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).         
(1) If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (a)
(2) If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark (b)
(3) If Assertion is true but Reason are false, then mark (c)
(4) If both Assertion and Reason are false, then mark (d)
Assertion: In Griffith’s experiment mice were injected by a mixture of heat killed Smooth type bacteria and live Rough type bacteria. Some mice died of pneumonia and their blood contained both live Rough type bacteria and live Smooth type bacteria.
Reason: The dead Smooth type bacteria became alive and caused pneumonia.
Griffith named it as transforming principle.

Question. Enzyme which can break and seal the DNA strand       
(a) Topoisomease II
(b) Helicase
(c) Primase
(d) Restriction endonuclease

Question. In a nucleotide, the nitrogen base is joined to the sugar molecule by         
(a) Phosphodiester bond
(b) Glycosidic bond
(c) Hydrogen bond
(d) (a) &(b)

Question. The percentage of human genome which encodes proteins is approximately   
(a) Less than 2%
(b) 5%
(c) 25%
(d) 99%

Question. Hershey and Chase experiment proving DNA as the genetic material was based on the principle         
(a) Transduction
(b) transformation
(c) transcription
(d) translation

Question. A bacterial colony containing DNA made up of 100% N15 nitrogen bases is allowed to replicate in a medium containing N14 bases. After one round of replication the result would be
(a) All individuals will be identical to parents       
(b) All individuals will be hybrids
(c) Only 50% individuals would be hybrids
(d) All individuals would have DNA made up of 100% N14

Question. Teminism is           
(a) a central dogma reverse
(b) a central dogma of molecular biology
(c) a circular flow of hereditary material
(d) an effect of cytoplasm on functioning of DNA

Question. Read the statements given below and identify the incorrect statement.           
(a) The human genome contains 3164.7 million nucleotide bases.
(b) The average gene consists of 30,000 bp
(c) The total number of genes is estimated at 30,000.
(d) Chromosome Y has 231 genes
(e) Less than 2% of the genome codes for proteins.

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