MCQ Questions for Class 12 Biology: Ch 6 Molecular Basis of Inheritance
1. 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
► (b) Viral DNA
2. Commonly used vectors for human genome sequencing are:
(a) T-DNA
(b) BAC and YAC
(c) Expression Vectors
(d) T/A Cloning Vectors
► (b) BAC and YAC
3. Signaling between cells usually results in the activation of protein_______.
(a) Kinases
(b) Nucleases
(c) Lipases
(d) Proteases
► (a) Kinases
4. Which of the following important biochemical reactions in living systems is catalyzed by a ribozyme?
(a) Formation of peptide bond
(b) Repair of DNA
(c) Electron transfer chain
(d) Organization of MTOC during cell division
► (a) Formation of peptide bond
5. The portion of DNA which contains information for an entire polypeptide is called
(a) Operon
(b) Recon
(c) Muton
(d) Cistron
► (d) Cistron
6. Nitrogenous bases present in DNA:
(a) Adenine, guanine, cytosine, thymine
(b) Guanine, uracil
(c) Adenine, guanine, cytosine, uracil
(d) Adenine, thymine, uracil
► (a) Adenine, guanine, cytosine, thymine
7. During translation initiation in prokaryotes, a GTP molecule is needed in
(a) association of 50 S subunit of ribosome with initiation complex
(b) formation of formyl-met-tRNA
(c) binding of 30 S subunit of ribosome with mRNA
(d) association of 30 S-mRNA with formylmet-tRNA
► (d) association of 30 S-mRNA with formylmet-tRNA
8. Genetic information is carried out by long chain molecule made up of
(a) Nucleotides
(b) Enzymes
(c) Histone proteins
(d) Amino acids
► (a) Nucleotides
9. Manoj and Pramod studied lactose metabolism in E.coli and proposed operon concept. Operon concept is applicable for
(a) all prokaryotes
(b) all prokaryotes and some eukaryotes
(c) all prokaryotes and all eukaryotes
(d) all prokaryotes and some protozoans
► (b) all prokaryotes and some eukaryotes
10. The chromosomes in which centromere is situated close to one end are:
(a) Acrocentric
(b) Telocentric
(c) Sub-metacentric
(d) Metacentric
► (a) Acrocentric
11. Enzymes called ______ add complementary nucleotides, floating inside the nucleus.
(a) DNA polymerase
(b) Lipoprotein lipase
(c) DNA synthetase
(d) None of the above
► (a) DNA polymerase
12. The strand of DNA that forms mRNA is called?
(a) Lagging strand
(b) Coding strand
(c) Antisense strand
(d) Template strand
► (d) Template strand
13. A man with blood group 'A' marries a woman with blood group 'B'. What are all the possible blood groups of their offsprings?
(a) A,B and AB only
(b) A,B,AB and O
(c) O only
(d) A and B only
► (b) A,B,AB and O
14. DNA fingerprinting refers to
(a) molecular analysis of profiles of DNA samples
(b) analysis of DNA samples using imprinting devices
(c) techniques used for molecular analysis of different specimens of DNA
(d) techniques used for identification of fingerprints of individuals
► (a) molecular analysis of profiles of DNA samples
15. By which bonds the purine & pyrimidine pairs of Complementary Strands of DNA held together?
(a) N – bonds
(b) H – bonds
(c) O - bonds
(d) C - bonds
► (b) H – bonds
16. A typical nucleosome contains
(a) 100 bp of DNA helix
(b) 400 bp of DNA helix
(c) 200 bp of DNA helix
(d) 300 bp of DNA helix
► (c) 200 bp of DNA helix
17. At time of organogenesis genes regulate the process at different levels and at different time due to
(a) Promoter
(b) Exon
(c) Intron
(d) Regulator
► (b) Exon
18. Which of the following are the functions of RNA?
(a) It is a carrier of genetic information from DNA to ribosomes synthesising polypeptides.
(b) It carries amino acids to ribosomes.
(c) It is a constituent component of ribosomes.
(d) All of the above.
► (d) All of the above.
19. DNA is made of two chains that twist about one another in the shape of a _______.
(a) Broken ladder
(b) Straight ladder
(c) Straight spiral
(d) Double helix
► (d) Double helix
20. In a DNA percentage of thymine is 20% then what will be the percentage of guanine?
(a) 20%
(b) 40%
(c) 30%
(d) 60%
► (c) 30%
21. During transcription, the DNA site at which RNA polymerase binds is called
(a) Enhancer
(b) Receptor
(c) Promoter
(d) Regulator
► (c) Promoter
22. Which one of the following is the starter codon?
(a) AUG
(b) UGA
(c) UAA
(d) UAG
► (a) AUG
23. DNA elements, which can switch their positions, are called
(a) Cistron
(b) Intron
(c) Recon
(d) Transposon
► (d) Transposon
24. In the genetic code dictionary, how many codons are used to code for all the 20 essential amino acids ?
(a) 60
(b) 20
(c) 64
(d) 61
► (d) 61
25. Out of 64 codons, 61 codons code for 20 types of amino acid. It is called
(a) degeneracy of genetic code
(b) overlapping of gene
(c) wobbling of codon
(d) universality of codons
► (a) degeneracy of genetic code
26. Name the conjugated protein used as genetic material in living cells?
(a) Metalloprotein
(b) Lipoprotein
(c) Glycoprotein
(d) Nucleoprotein
► (d) Nucleoprotein
27. During transcription, RNA polymerase holoenzyme binds to a gene promoter and assumes a saddle-like structure. What is its DNA-binding sequence?
(a) CACC
(b) TATA
(c) AATT
(d) TTAA
► (b) TATA
28. State the use of molecular medicine?
(a) Used to understand several diseases like Alzheimer’s Parkinsons diseases, etc.
(b) Used as gene therapy
(c) Improves diagnosis of diseases
(d) All of the above
► (d) All of the above
29. DNA has genetic properties was revealed for the first time by
(a) Chargaff
(b) Griffith
(c) Avery
(d) Wilkins
► (c) Avery
30. Degeneration of a genetic code is attributed to the
(a) third member of a codon
(b) first member of a codon
(c) second member of a codon
(d) entire codon
► (a) third member of a codon
31. Repressor proteins are coded for by ______ genes.
(a) Promoter
(b) Structural
(c) Regulator
(d) Operator
► (c) Regulator
32. In sea urchin DNA, which is double stranded, 17% of the bases were shown to be cytosine. The percentages of the other three bases expected to be present in this DNA are :
(a) G 17%, A 16.5%, T 32.5%
(b) G 17%, A 33%, T 33%
(c) G 8.5%, A 50%, T 24.5%
(d) G 34%, A 24.5%, T 24.5%
► (b) G 17%, A 33%, T 33%
33. When a cluster of genes show linkage behaviour they
(a) induce cell division
(b) do not show a chromosome map
(c) show recombination during meiosis
(d) do not show independent assortment
► (d) do not show independent assortment
34. Human genome project was closely associated with the rapid development of a new area in biology called as
(a) Genomics
(b) Genetic engineering
(c) Bioinformatics
(d) Biotechnology
► (c) Bioinformatics