NEET Biology Chapter Wise Mock Test – Molecules Basis of Inheritance
1. Antiparallel strands of a DNA molecule means that/
(a) one strand turns anticlockwise
(b) the phosphate groups of two DNA strands at their ends, share the same position
(c) the phosphate groups at the start of two DNA strands are in opposite position (pole)
(d) one strand turns clockwise
2.In AGCT bases of DNA, hydrogen bonds and base pairing occur between
(a) A=T, G=C
(b)A = T, G=C
(c) A =G, T=C
(d) A=G, T=C
3.The enzyme, which helps to cut one strand of DNA duplex to release tension of coiling of two strands is
(a) DNA ligase
(b) DNA polymerase-l
(d) swielases (helicase or unwindases)
4. RNA and DNA were artificially synthesised in vitro by/
(a) Ochoa and Nirenberg
(b) Ochoa and Kornberg
(c) Kornberg and Nirenberg
(d) Nirenberg and Khorana
5. After a mutation at a genetic locus the character of an organism changes due to the change in
(a) protein structure
(b) DNA replication
(c) protein synthesis pattern
(d) RNA transcription pattern
6. The following ratio is generally constant for a given species/
(a) A + G /C + T
(b)T + C/G + A
(c) G+C/A + T
(d) A + C / T + G
7. Which of the following is capable of self replication?
(b) Amino acid
8. The DNA in nucleolar organiser region codes for /RNA is called
(d) All of these
9. Polypeptide chain is initiated by
10. Ligase is an enzyme responsible for
(a) renaturation of DNA
(b) proof reading
(c) joining of DNA bits
(d) breaking of DNA
11. Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?
12. Semiconservative model of DNA replication was first demonstrated by
(a) Watson and Crick
(b) Meselson and Stahl
(c) Herbert Taylor
(d) Har Govind Khorana
13. The net electric charge on DNA and histones is
(a) both positive
(b) both negative
(c) negative and positive, respectively
14. The fact that a purine base always paired through hydrogen bonds with a pyrimidine base leads to, in the DNA double helix
(a) the antiparallel nature
(b) the semiconservative nature
(c) uniform width throughout DNA
(d) uniform length in all DNA
15. The sequence of bases that orient RNA polymerase, so that synthesis proceeds in left to right direction is called
(a) pribnow box
(b) promoter box
(c) regulator box
(d) operator box
16. Hogness box or TATA box has base sequences
(b) TATA AA
17. A nucleoside differs from a nucleotide. It lacks the
(c) phosphate group
(d) hydroxyl group
18. E. coli about to replicate was placed in a medium containing radioactive thymidine for five minutes. Then it was made to replicate in a normal medium. Which of the following observations will be correct?
(a) Both the strands of DNA will be radioactive
(b) One strand will be radioactive
(c) Each strand will be half radioactive
(d) None of the strands will be radioactive
19. First code of every mRNA is
(a) either AUG or GUG
(b) either AUG or UAG
(c) either GUG or UAA
(d) either UGA or UAA
20. Wobble hypothesis establishes
(a) peptide chain formation
(b) initiation of peptide chain
(c) termination of peptide chain
(d) economy in tRNA molecules
21. One gene-one enzyme hypothesis was postulated by
(a) R Franklin
(b) Hershey and Chase
(d) Beadle and Tatum
22. Reverse transcription is the process of formation of DNA from RNA. It was discovered by
(a) Watson and Crick
(c) Temin and Baltimore
(d) Beadle and Tatum
23. Genetic code is said to be degenerate because
(a) codons degenerate very quickly
(b) one amino acid is coded by more than one codon
(c) one codon codes for more than one amino acids
(d) None of the above
24. Which one of the following makes use of RNA as a template to synthesise DNA?
(a) Reverse transcriptase
(b) DNA dependant RNA polymerase
(c) DNA polymerase
(d) RNA polymerase
25. During transcription, the nucleotide sequence of the DNA strand that is being coded is ATACG, then the nucleotide sequence in the mRNA would be
26. Discontinuous synthesis of DNA occurs in one strand, because
(a) DNA molecule being synthesised is very long
(b) DNA dependent DNA polymerase catalyses polymerisation only in one direction (5’->3’)
(c) It is a more efficient process
(d) DNA ligase has to have a role
27. DNA is a polymer of nucleotides which are linked to each other by 3′ -5′ phosphodiester bond. To prevent polymerisation of nucleotides, which of the following modifications would you choose?
(a) Replace purine with pyrimidines
(b) Remove/replace 3’OH group in deoxyribose
(c) Remove/replace 2’OH group with some other group in deoxyribose
(d) Both (b) and (c)
29. One gene-one enzyme relationship was established for the first time in
(a) Neurospora crassa
(b) Salmonella typhimurium
(c) Escherichia coli
(d) Diplococcus pneumoniae
30. Anticodon is present on
31. In silent mutation, there is
(a) no change in base sequence
(b) no change in protein type
(c) change in chromosomal segment
(d) change in amino acid sequence of protein
32. Artificial gene for alanine tRNA with 77 base pairs was first synthesised by
(a) Khorana et. al (1968)
(b) Nirenberg and Mathaei (1967)
(c) Beadle and Tatum (1966)
(d) Watson and Crick (1958)
33. Process of protein synthesis in a cell is called
34. Central dogma of modern biology is
(a) DNA -> RNA-> Proteins
(b) RNA -> DNA-> Proteins
(c) DNA-> RNA-> Protein
(d) RNA -> Proteins -> DNA
35. Non-sense codon takes part in
(a) terminating message of gene controlled protein synthesis
(b) formation of unspecified amino acids
(c) conversion of sense DNA into non-sense one
(d) releasing tRNA from polypeptide chain
36. What are proteosomes?
(a) Complexes of snRNA and proteins that excise introns
(b) Small, positively charged proteins that form the core of nucleosomes
(c) Enormous protein complexes that degrade unneeded proteins in the cell
(d) Complexes of transcription factors, whose protein-protein interaction are required for enhancing gene transcription
37. A DNA strand is directly involved in the synthesis of all the following except
(a) tRNA molecule
(b) mRNA molecule
(c) another DNA strand
(d) protein synthesis
38. Reverse transcriptase is
(a) RNA dependent RNA polymerase
(b) DNA dependent RNA polymerase
(c) DNA dependent DNA polymerase
(d) RNA dependent DNA polymerase
39. Genes, which are inactive for long periods, hayq the tendency to be bound to
(a) each other
(b) methyl groups
(c) actin and myosin
40. Which one of the following pairs is correctly matched with regard to the codon and the amino acid coded by it?
(b) AAA-lysine .
41. With regard to mature mRNA in eukaryotes
(a) exons and introns do not appear in the mature RNA
(b) exons appear but introns do not appear in the mature RNA
(c) introns appear but exons do not appear in the mature RNA
(d) both exons and introns appear in the mature RNA
42. An eukaryotic cell, post transcription prepares itself for synthesis of proteins, so as to meet its metabolic needs. The modified mRNA translates into proteins through a sequential stepwise process. Identify the correct sequence of steps in translation and select the correct option.
I. Amino acylation of fRNA
II. Attachment of larger subunit of ribosome to mRNA- fRNA met complex.
III. Linking of adjacent amino acids to form a polypeptide.
IV. Codon anticodon reaction between RNA and amino acyl fRNA complex.
V. Attachment of mRNA with smaller subunit of ribosome.
(a) l->ll->V —>IV->lll
(b) II —>lll ->l —>IV —>V
(c) I -> V —>IV —> II —> III
(d) II —>IV —>V —>I -> III
43. In an animal cell, protein synthesis takes place
(a) only on the ribosomes protein in the cytosol
(b) only on the ribosomes attached to nuclear envelope and endoplasmic reticulum
(c) on ribosomes present in the nucleolus as well as in cytoplasm
(d) on ribosomes present in the cytosol as well as in the mitochondria
44. In translocation on ribosome, the amino acid shifts from
(a) A site to P site
(b) P site to A site
(c) tRNA to A site
(d) tRNA to P site
45. During translation initiation in prokaryotes, a GTP molecule is needed in
(a) association of 30 S, mRNA with formyl-met-tRNA
(b) association of 50 S subunit of ribosome with initiation complex ,
(c) formation of formyl-met-tRNA
(d) binding of 30 subunit of ribosome with mRNA\
46. Which antibiotic inhibits interaction between fRNA and mRNA during bacterial protein synthesis?
47. Amino acid sequence in protein synthesis is decided by the sequence of
48. In E. coli, an operator gene combines with
(a) inducer gene to switch on structural gene action
(b) inducer gene to switch off structural gene action
(c) regulator protein (repressor) to switch off structural gene action
(d) regulator protein to switch on gene action
49. A prokaryotic bacterial cell, regulates the expression of genes and switches on the lac operon in the presence of inducer, i.e. lactose. Identify the components in its functioning and select the correct codes.
(a) A-Promoter B-ln, active repressor, C-p-galactosidase, D-Transacetylase
(b) A-Transacetylase, B-Inducer, C-lnactive repressor, D-|3-galactosidase
(c) A-Inducer, B-lnactive repressor, C-p-galactosidase, D-Transacetylase
(d) A-lnactive repressor, B-Transacetylase, C-Promoter, D-p-galactosidase
50. 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?
(a) They only increase expression
(b) They only decrease expression
(c) They interact with RNA polymerase but do not affect the expression
(d) They can act both as activators and as repressors
51. The term ‘gene’ was introduced by
52. E. coli cells with a mutated Z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because
(a) in the presence of glucose, £. coli cells do not utilise lactose
(b) they cannot transport lactose from the medium into the cells
(c) the lac operon is constitutively active in these cells
(d) they cannot synthesise functional p-galactosidase
53. Genetic code was discovered by
(a) Holley and Ochoa
(b) Watson and Crick
(c) Nirenberg and Matthaei
(d) Holley, Nirenberg and Khorana
54. A functional unit of gene, which specifies the synthesis of one polypeptide is known ag
55. Which was the last human chromosome to be completely sequenced?
(a) Chromosome 1
(b) Chromosome 11
(c) Chromosome 21
56. The human chromosome with the highest and least number of genes in them atd respectively
(a) chromosome 21 and Y
(b) chromosome 1 and X
(c) chromosome 1 and Y
(d) chromosome X and Y
57. In E. coli, lac operon is induced by
(c) structural gene
(d) promoter gene
58. An environmental agent that triggers transcription from an operon is
(d) controlling element
59. Catabolite Activator Protein (CAP) and repressor protein control the
(c) lac operon
(d) trp operon
60. When genes resemble functional genes but do not produce functional substance are called
(a) jumping genes
(b) overlapping genes
(d) non-functional genes
61. Cistron was called as functional gene in 1955 by
62. Non-constitutive genes express themselves only when needed are also called as
(a) structural genes
(b) promoter genes
(c) house-keeping genes
(d) luxury genes
63. If the base sequence on template strand is ACTGCTA then, the complementary strand will have
64. The mRNA sequences in eukaryotes, which do not code for anything are called
65. During transcription, RNA polymerase holoenzyme binds to a gene promotor and assumes a saddle-like structure. What is it’s DNA-binding sequence?
66. Molecular basis of organ differentiation depends on the modulation in transcription by
(a) RNA polymerase
(c) transcription facto
67. The unwinding of DNA helix is carried out by the enzyme
(a) DNA ligase
(b) DNA helicase
(c) DNA polymerase
68. The strand synthesised continuously and discontinuously are called
(a) leading strand and lagging strand respectively
(b) lagging strand and leading strand respectively
(c) template strand and leading strand respectively
(d) non-template strand and lagging strand respectively
Direction (Q. Nos. 69-75) In each of the following questions a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements, mark the correct answer as
(a) If both Assertion and Reason are true and Reason is the correct explanation of the Assertion.
(b) If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
(c) If Assertion is true, but Reason is false.
(d) If both Assertion and Reason are false.
69. Assertion Gene expression is a molecular mechanism by which a gene express a phenotype.
Reason Structural genes are controlled by control genes.
70. Assertion Lac operon is seen in E. coli.
Reason E. coli lacks a definite nucleus.
71. Assertion Amber codon is a termination codon.
Reason If a termination codon is present in mRNA, then protein synthesis stops abruptly whether, the protein synthesis is complete or not.
72. Assertion Corepressor is a metabolite.
Reason Corepressor has the affinity for repressor.
73. Assertion Polytene chromosomes have a high amount of DNA.
Reason Polytene chromosomes are formed by repeated replication of chromosomal DNA without separation of chromatids.
74. Assertion Replication and transcription occur in the nucleus but translation occurs in the cytoplasm.
Reason mRNA is transferred from the nucleus into the cytoplasm, where ribosomes and amino acids are available for protein synthesis.
75. Assertiohe genetic code is polar.
Reason Each codon has its specific 5′-end and 3′- end.
76. Match the following columns.
ABC D A B C D
(a) 4 5 1 2 (b)1 2 3 4
(c) 2 1 3 5 (d) 5 2 4 2
77.Match the following columns.
ABC D A B C D
(a) 2 1 3 5 (b) 5 2 4 1
(c) 3 4 1 2 (d) 1 2 3 4
78. Gene regulation governing lactose operon of E. coli that involves the lac I gene products is
(a) positive and inducible because it can be induced by lactose
(b) negative and inducible because repress or protein prevents transcription
(c) negative and repressible because repress or protein prevents transcription
(d) feedback inhibition because excess of p-galactosidase can.switch off transcription
79. Identify the correct order of organisation of genetic material from largest to smallest
(a) Chromosome, gene, genome, nucleotide
(b) Genome, chromosome, nucleotide, gene
(c) Genome, chromosome, gene, nucleotide
(d) Chromosome, genome, nucleotide, gene
80. Which one of the following is wrongly matched?
(a) Transcription-Writing information from DNA to fRNA
(b) Translation-Using information in mRNA to make protein
(c) Repressor protein-Binds to operator to stop enzyme synthesis
(d) Operon-Structural genes, operator and promoter
81. The diagram shows an important concept in the genetic implication of DNA. Fill in the blanks A to C.
(a) A-Translation, B-Transcription, C-Erevin Chargaff
(b) A-Transcription, B-Translation, C-Francis Crick
(c) A-Translation, B-Extension, C-Rosalind Franklin
(d) A-Transcription, B-Replication, C-James Watson
82. Removal of RNA polymerase-lll from nucleoplasm will affect the synthesis of
83. Which one of the following is not a part of a transcription unit in DNA?
(a) The inducer
(b) A terminator
(c) A promoter
(d) The structural gene
84. Removal of introns and joining of exons in a defined order during transcription is called
85. Ribosomal RNA is actively synthesised in
86. If one strand of DNA has the nitrogenous base sequence as ATCTG, what would be the complementary RNA strand sequence?
87. Given below is a sample of portion of DNA strand giving the base sequence on the opposite strands. What is so, special shown in it?
(a) Deletion mutation
(b) Start codon at the 5’end
(c) Palindromic sequence of base pairs
(d) Replication completed ,
88. What are those structures that appear as beads-on-string’ in the chromosomes, when viewed under electron microscope?
(c) Base pairs
89. Translocase is an enzyme required for
(a) DNA replication .
(b) RNA synthesis
(c) initiation of protein synthesis
(d) protein synthesis chain elongation
90. Select the two correct statements out of the four (l-IV) , given below about lac operon.
I. Glucose or’galactose may bind with the repressor and inactivate it.
II. In the absence of lactose the repressor binds with the operator region.
III. The z-gene codes for permease.
IV. This was elucidated by Francois Jacob and Jacques Monod
The correct statements are
(a) II and III
(b) I and III
(c) II and IV
(d) I and II