MCQ Molecular Basis of Inheritance for ISC Class 12 Biology

MCQ Molecular Basis of Inheritance These MCQ  / Objective Type Questions is based on latest reduced syllabus according 2021-22 session on bifurcated pattern. Main motto of MCQ Type Question is cracking the next upcoming exam of council. Visit official website CISCE for detail information about ISC Board Class-12 Biology.

MCQ Type Question  for ISC Class 12 Biology Molecular Basis of Inheritance

Board ISC
Class  12th (XII)
Subject Biology
Molecular Basis of Inheritance
Syllabus  on bifurcated syllabus (after reduction)
Session 2021-22
Topic MCQ / Objective Type Question

ISC Class-12 Biology MCQ Molecular Basis of Inheritance


Question 1: Initiation codon of protein synthesis (in eukaryotes) is

(a) GUA

(b) GCA

(c) CCA

(d) AUG

Answer: (d) AUG

Question 2: In eukaryotes, mRNA is synthesized with the aid of

(a) RNA polymerase III.
(b) RNA polmerase II.
(c) RNA polymerase I.
(d) reverse transcriptase.

Answer: (b) RNA polmerase II.

Question 3: Lactose operon produces enzymes

(a) b-galactosidase, permease and glycogen synthetase.
(b) b-galactosidase, permease and transacetylase.
(c) permease, glycogen synthetase and transacetylase.
(d) b-galactosidase, permease and phosphoglucose isomerase.


Answer: (b) b-galactosidase, permease and transacetylase.

Question 4: In Hershey and Chase experiments, radioactive 32P was used to culture bacteriophages which resulted in radioactive

(a) Protein capsule of bacteriophage
(b) Viral DNA
(c) Bacterial capsule
(d) Viral proteins
Answer: (b) Viral DNA

Question 5: Commonly used vectors for human genome sequencing are:

(a) T-DNA
(b) BAC and YAC
(c) Expression Vectors
(d) T/A Cloning Vectors

Answer: (b) BAC and YAC

Question 6: Nucleic acids are polymer of


(a) Nucleosides
(b) Proteins
(c) Glycoproteins
(d) Nucleotides

Answer: (d) Nucleotides

Question 7: DNA structure was discovered by

(a) Weismann
(b) Watson and Crick
(c) Har Gobind Khorana
(d) Sutton

Answer: (b) Watson and Crick

Question 8: Enzyme responsible for DNA replication\

(a) Polymerase
(b) Proteolytic
(c) Ligase
(d) Carboxylase

Answer: (a) Polymerase

Question 9: In a DNA strand the nucleotides are linked together by

(a) glycosidic bonds
(b) phosphodiester bonds
(c) peptide bonds
(d) hydorgen bonds.

Answer: (b) phosphodiester bonds

Question 10: The net electric charge on DNA and histones is

(a) both positive
(b) both negative
(c) negative and positive, respectively
(d) zero.

Answer: (c) negative and positive, respectively

Question 11: The human chromosome with the highest and least number of genes in them are respectively

(a) chromosome 21 and Y
(b) chromosome 1 and X
(c) chromosome 1 and Y
(d) chromosome X and Y.

Answer: (c) chromosome 1 and Y

Question 12: Who amongst the following scientist had no contribution in the development of the double helix model for the structure of DN A ?

(a) Rosalind Franklin
(b) Maurice Wilkins
(c) Erwin Chargaff
(d) Meselson and Stahl

Answer: (b) Maurice Wilkins

Question 13: Represser Lac-Operon protein attached to:

(a) Operator
(b) Inducer
(c) Regulator
(d) β-Glacto sidase

Answer: (b) Inducer

Question 14: Following is important in Ïranscription:

(a) DNA Methylase
(b) CAAT Box
(c) Promotar
(d) DNA Polymerase

Answer: (d) DNA Polymerase

Question 15: In eukaryotes which of the following is removed from initially transcribed RNA before it is transported to the cytoplasm for translation ?

(a) Intron

(b) 3′ Poly A tail

(c) Ribosome binding site

(d) 5′ cap

Answer: (a) Intron

Question 16: The process of splicing in eukaryotes :

(a) is reminiscent of antiquity

(b) represents dominance of RNA world

(c) is an indicator of the complexity of human genome

(d) is a legacy of organic evolution

Answer: (b) represents dominance of RNA world

Question 17: Cistron is

(a) Functional unit of RNA
(b) Non-functional unit of RNA
(c) Functional unit of DNa that specifies a polypeptide chain
(d) Non-functional unit of DNA

Answer: (c) Functional unit of DNa that specifies a polypeptide chain

Question 18: Transcription is the formation of

(a) mRNA
(b) tRNA
(c) rRNA
(d) Protein

Answer: (a) mRNA

Question 19: The RNA polymerase holoenzyme transcribes:

(a) the structural gene and the terminator regions

(b) the structural gene only

(c) the promoter, and the

(d) the promoter, structural gene and the terminator region

Answer: (a) the structural gene and the terminator regions

Question 20: If the base sequence of a codon in mRNA is 5′-AUG-3′, the sequence of tRNA pairing with it must be

(a) 5′ – CAU – 3′

(b) 5′ – AUG – 3′

(c) 5′ – GUA – 3′

(d) 5′ – UAC – 3′

Answer: (a) 5′ – CAU – 3′

Question 21: The amino acid attaches to the tRNA at its:

(a) 3′ – end

(b) 5′ – end

(c) Anti codon site

(d) DHU loop

Answer: (a) 3′ – end

Question 22: To initiate translation, the mRNA first binds to

(a) The smaller ribosomal sub-unit

(b) The larger ribosomal sub-unit

(c) The whole ribosome

(d) No such specificity exists

Answer: (a) The smaller ribosomal sub-unit

Question 23: Which of the following steps in transcription is catalysed by RNA polymerase ?

(a) Initiation
(b) Elongation
(c) Termination
(d) All of the above

Answer: (d) All of the above

Question 24: Control of gene expression takes place at the level of

(a) DNA-replication
(b) transcription
(c) translation
(d) none of the above.

Answer: (b) transcription

Question 25: If the sequence of initrogen bases of the coding strand of DNA in a transcription unit is: 5’ – ATGAATG – 3’, the sequence of bases in its RNA transcript would be

(a) 5’ – AUG A AUG – 3’
(b) 5’ – UACUU AC – 3’
(c) 5’ – CAUUCAU – 3’
(d) 5’ – GUAAGUA – 3’.

Answer: (d) 5’ – GUAAGUA – 3’.

Question 26: The RNA polymerase holocnzyme transcribes

(a) the promoter, structural gene and the terminator region.
(b) the promoter and the terminator region
(c) the structural gene and the terminator region
(d) the structural gene only.

Answer: (b) the promoter and the terminator region

Question 27: The amino acid attaches to the tRNA at its

(a) 5’- end
(b) 3’ – end
(c) anticodon site
(d) DHUloop.

Answer: (b) 3’ – end

Question 28: To initiate translation, the wiRNA first bind to

(a) the smaller ribosomal sub-unit
(b) the larger ribosomal sub-unit
(c) the whole ribosome
(d) no such specificity exists.

Answer: (a) the smaller ribosomal sub-unit

Question 29: In DNA helix:

(a) Quadrate structure
(b) Polarity
(c) Antiparallel Polarity
(d) Disuiphide bond

Answer: (c) Antiparallel Polarity

Question 30: During splicing axon attached and inducer enzyme for reaction:

(a) RNA Ligase
(b) RNA Catalase
(c) RNA permease
(d) RNA poloymerase

Answer: (b) RNA Catalase

Question 31: In prokaryotes, the predominant site for control of gene expression is the  :

(a) transcription initiation

(b) processing level

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