Molecular Basis of Inheritance - NCERT Based MCQ Questions

This article contains NCERT based 45 MCQ questions test on Biology chapter "Molecular Basis of Inheritance". You can attempt these questions in the form of an interactive quiz and calculate your score. Read the below quiz rules carefully before you start

General Instructions

• Quiz contains 45 questions of 4 marks each.
• Correct answer (✔) will award you +4 marks and Incorrect answer (✘) will give you -1 mark.
• Total test is of 180 marks.
• Tap on box in order to select any option that you think is correct.
• Press the Submit button given in the end of quiz to calculate your score.
• There is a PDF file attached in the end of quiz. You can see detailed solutions to all questions and do self analysis from that file as well.

Question 1. In a DNA strand the nucleotides are linked together by:

(1) glycosidic bonds

(2) phosphodiester bonds

(3) peptide bonds

(4) hydrogen bonds

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Question 2. A nucleoside differs from a nucleotide. It lacks the:

(1) base

(2) sugar

(3) phosphate group

(4) hydroxyl group

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Question 3. Aminoacylation of t-RNA is essential for –

(1) replication of RNA

(2) formation of peptide bond

(3) splicing

(4) initiation of transcription

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Question 4. The fact that a purine base always paired through hydrogen bonds with a pyrimidine base leads to, in the DNA double helix:

(1) the antiparallel nature

(2) the semiconservative nature

(3) uniform width throughout DNA

(4) uniform length in all DNA

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Question 5. The net electric charge on DNA and histones is:

(1) both positive

(2) both negative

(3) negative and positive, respectively

(4) zero

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Question 6. Which codon is not an indicator of completion of protein synthesis?

(1) UAG

(2) AUG

(3) UAA

(4) UGA

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Question 7. Which of the following statements is the most appropriate for sickle cell anaemia?

(1) It cannot be treated with iron supplements

(2) It is a molecular disease

(3) It confers resistance to acquiring malaria

(4) All of the above

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Question 8. If the sequence of bases in the coding strand of a double-stranded DNA is 5'-GTTCGAGTC-3' the sequence of bases in its transcript will be –

(1) 5'-GACUCGAAC-3'

(2) 5'-CAAGCUCAG-3'

(3) 5'-GUUCGAGUC-3'

(4) 5'-CUGAGCUUG-3'

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Question 9. The first genetic material could be:

(1) protein

(2) carbohydrates

(3) DNA

(4) RNA

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Question 10. With regard to mature m-RNA in eukaryotes:

(1) exons and introns do not appear in the mature RNA.

(2) exons appear but introns do not appear in the mature RNA.

(3) introns appear but exons do not appear in the mature RNA.

(4) both exons and introns appear in the mature RNA.

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

(1) Chromosome 21 and Y

(2) Chromosome 1 and X

(3) Chromosome 1 and Y

(4) Chromosome X and Y

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Question 12. Which of the following processes was discovered by Lederberg and Tatum (1946)?

(1) Transduction

(2) Transformation

(3) Asexual reproduction

(4) Conjugation

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Question 13. DNA is a polymer of nucleotides which are linked to each other by 3'-5' phosphodiester bond. To prevent polymerization of nucleotides, which of the following modifications would you choose?

(1) Replace purine with pyrimidines

(2) Remove/Replace 3' OH group in deoxy ribose

(3) Remove/Replace 2' OH group with some other group in deoxy ribose

(4) Both ‘B’ and ‘C’

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Question 14. Discontinuous synthesis of DNA occurs in one strand, because:

(1) DNA molecule being synthesized is very long.

(2) DNA dependent DNA polymerase catalyzes polymerization only in one direction (5’ → 3’)

(3) it is a more efficient process

(4) DNA ligase has to have a role

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Question 15. Which of the following steps in transcription is catalyzed by RNA polymerase?

(1) Initiation

(2) Elongation

(3) Termination

(4) All of the above

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Question 16. Control of gene expression takes place at the level of:

(1) DNA-replication

(2) Transcription

(3) Translation

(4) Both (2) and (3)

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Question 17. Regulatory proteins are the accessory proteins that interact with RNA polymerase and affect its role in transcription. Which of the following statements is correct about regulatory protein?

(1) They only increase expression

(2) They only decrease expression

(3) They interact with RNA polymerase but do not affect the expression

(4) They can act both as activators and as repressors

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Question 18. Which was the last human chromosome to be completely sequenced:

(1) Chromosome 1

(2) Chromosome 11

(3) Chromosome 21

(4) Chromosome x

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Question 19. Which of the following are the functions of RNA?

(1) It is a carrier of genetic information from DNA to ribosomes synthesizing polypeptides.

(2) It carries amino acids to ribosomes.

(3) It is a constituent component of ribosomes.

(4) All of the above.

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Question 20. While analyzing the DNA of an organism a total number of 5386 nucleotides were found out of which the proportion of different bases were: Adenine=29%, Guanine=17%, Cytosine=32%, Thymine=17%. Considering the Chargaff’s rule it can be concluded that:

(1) it is a double stranded circular DNA

(2) It is single stranded DNA

(3) It is a double stranded linear DNA

(4) No conclusion can be drawn

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Question 21. In some viruses, DNA is synthesized by using RNA as template. Such a DNA is called:

(1) A-DNA

(2) B-DNA

(3) c DNA

(4) r DNA

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Question 22. If Meselson and Stahl's experiment is continued for four generations in bacteria, the ratio of ¹⁵N/¹⁵N:¹⁵N/¹⁴N:¹⁴N/¹⁴N containing DNA in the fourth generation would be:

(1) 1 : 1 : 0

(2) 1 : 4 : 0

(3) 0 : 1 : 3

(4) 0 : 1 : 7

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Question 23. If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is: 5' - A T G A A T G - 3', the sequence of bases in its RNA transcript would be –

(1) 5' - A U G A A U G - 3'

(2) 5' - U A C U U A C - 3'

(3) 5' - C A U U C A U - 3'

(4) 5' - G U A A G U A - 3'

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Question 24. The RNA polymerase holoenzyme transcribes:

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

(2) the promoter, and the

(3) the structural gene and the terminator regions

(4) the structural gene only.

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Question 25. If the base sequence of a codon in m-RNA is 5'-AUG-3', the sequence of t-RNA pairing with it must be:

(1) 5' - UAC - 3'

(2) 5' - CAU - 3'

(3) 5' - AUG - 3'

(4) 5' - GUA - 3'

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Question 26. The amino acid attaches to the t-RNA at its:

(1) 5' - end

(2) 3' - end

(3) Anti codon site

(4) DHU loop

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Question 27. To initiate translation, the m-RNA first binds to:

(1) The smaller ribosomal sub-unit

(2) The larger ribosomal sub-unit

(3) The whole ribosome

(4) No such specificity exists

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Question 28. In E.coli, the lac operon gets switched on when:

(1) lactose is present and it binds to the repressor

(2) repressor binds to operator

(3) RNA polymerase binds to the operator

(4) lactose is present and it binds to RNA polymerase

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Question 29. What are a group of chemicals that cut DNA by recognizing and cleaving it at specific nucleotide sequences?

(1) restriction enzymes

(2) polymerases

(3) functional genomics

(4) restriction fragments

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Question 30. What is the study of DNA sequence information to help explain cell functions?

(1) gel electrophoresis

(2) functional genomics

(3) polymerase chain reaction

(4) restriction enzymes

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Question 31. What is an international project that studies the genomes of humans and other organisms?

(1) National Health Initiative

(2) Human Genome Project

(3) International Energy Project

(4) International Genome Project

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Question 32. What organism contributed the DNA polymerase that is used in polymerase chain reactions?

(1) Saccharomyces cerevisiae

(2) Escherichia coli

(3) Thermus aquaticus

(4) Caenorhabditis elegans

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Question 33. What is the process that results in the reproduction or growth of genetically identical cells or organisms?

(1) recombination

(2) polymerase chain reaction

(3) cloning

(4) genomics

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Question 34. Why do restriction enzymes cut the DNA of individuals of the same species in different places?

(1) because of recombinant DNA

(2) because of genetic engineering

(3) because males and females have different types of DNA

(4) because of genetic variation

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Question 35. What was one of the first bacterial genomes to be sequenced?

(1) that of Caenorhabditis elegans

(2) that of Escherichia coli

(3) that of Staphylococci

(4) that of Streptococci

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Question 36. When will be the number of histone molecules in a chromatin fibre having 50 nucleosomes?

(1) 400

(2) 459

(3) 500

(4) 1000

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Question 37. The sequence of nucleotides AUG CUU CUC indicates that it is a segment of –

(1) sense strand of DNA

(2) anti sense strand of DNA

(3) RNA

(4) polypeptide chain

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Question 38. Match the following columns.

Column I Chemical Compounds	Column II Example
A. Nitrogen base	i. RNA
B. Nucleoside	ii. Thymidylic acid
C. Nucleotide	iii. Cytidine
D. Nucleic acid	iv. Uracil

Codes

(1) A-i, B-iv, C-v, D-iii, E-ii

(2) A-ii, B-i, C-iv, D-iii, E-v

(3) A-ii, B-iv, C-iii, D-v, E-i

(4) A-i, B-iv, C-iii, D-ii, E-v

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Question 39. In eukaryotic genes, coding sequences are called –

(1) introns

(2) exons

(3) regulatory sequence

(4) repetitive DNA

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Question 40. Which site of the t-RNA pairs through hydrogen bonding with the triplet codes on m-RNA?

(1) Codon

(2) 5' end t-RNA

(3) 3' end of t-RNA

(4) Anticodon

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Question 41. Find the wrongly matched pair –

(1) Har Govind Khorana – Synthesised RNA molecules chemically

(2) George Gamow – Codon is triplet

(3) Meselson and Stahl – Regulation of gene expression

(4) Alec Jeffreys – DNA fingerprinting

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Question 42. If an inheritable mutation is observed in a population at high frequency, it is referred as –

(1) DNA polymorphism

(2) expressed sequence tag

(3) sequence annotation

(4) linkage

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Question 43. In eukaryotes, RNA polymerase II transcribe

(1) Hn-RNA

(2) 18S r-RNA

(3) 28s r-RNA

(4) t-RNA

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Question 44. Identify the wrong statement about DNA.

(1) The length of DNA is defined as the nwnber of base pairs present in it.

(2) Cytosine is common to both DNA and RNA

(3) In a nucleotide, the nitrogenous base is linked to a phosphate group.

(4) Thymine is chemically 5-methyl uracil.

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Question 45. Which property among these listed below is not a criteria for a molecule to act as a genetic material?

(1) Generate its replica.

(2) Chemically and structurally stable.

(3) Mutate slowly to facilitate evolution.

(5) Destroy itself after every cell cycle.

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Detailed Solutions

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