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NEET ]1[ Contd...

NEET UG Molecular Basis

Duration: 180 minutesTotal Marks: 600Questions: 150Negative Marking: -1

Instructions:

  1. Each question has four options (1), (2), (3), (4). Choose the most correct answer.
  2. Each correct answer carries 4 marks.
  3. Each wrong answer will deduct 1 marks.
  4. Unanswered questions will not be penalised.
1.DNA length is usually defined in NCERT as the number of:
(1)
(2)
(3)
(4)
2.Which set correctly matches the approximate genome size values given in the chapter?
(1)
(2)
(3)
(4)
3.A nucleotide differs from a nucleoside because the nucleotide has:
(1)
(2)
(3)
(4)
4.Which statement is correct regarding bases in nucleic acids?
(1)
(2)
(3)
(4)
5.The linkage between a nitrogenous base and the 1′ carbon of pentose sugar is:
(1)
(2)
(3)
(4)
6.Two nucleotides in a polynucleotide chain are joined through:
(1)
(2)
(3)
(4)
7.At the 5′ end of a polynucleotide chain, the free group is generally:
(1)
(2)
(3)
(4)
8.Which combination is true for RNA but not for DNA?
(1)
(2)
(3)
(4)
9.Who first identified DNA as an acidic substance present in the nucleus and named it nuclein?
(1)
(2)
(3)
(4)
10.Which pair received the Nobel Prize in 1962 for the DNA double helix work mentioned in NCERT?
(1)
(2)
(3)
(4)
11.Chargaff’s rule, as used in Watson-Crick model, states that in double-stranded DNA:
(1)
(2)
(3)
(4)
12.If one strand of DNA has the sequence 5′-ATGCC-3′, the complementary strand will be:
(1)
(2)
(3)
(4)
13.Which feature of the DNA double helix is correctly stated?
(1)
(2)
(3)
(4)
14.Select the correct pairing and hydrogen-bond count:
(1)
(2)
(3)
(4)
15.In the Watson-Crick model, purine always pairs with pyrimidine mainly to maintain:
(1)
(2)
(3)
(4)
16.The pitch of the DNA helix and the approximate distance between two consecutive base pairs are:
(1)
(2)
(3)
(4)
17.How many base pairs occur roughly in one complete turn of the DNA helix?
(1)
(2)
(3)
(4)
18.Assertion (A): DNA strands are complementary.

Reason (R): In dsDNA, specific base-pairing follows A–T and G–C pairing.
Choose the correct option.
(1)
(2)
(3)
(4)
19.The length of DNA in a typical mammalian cell is about 2.2 m because the calculation uses:
(1)
(2)
(3)
(4)
20.A typical nucleosome in NCERT contains approximately:
(1)
(2)
(3)
(4)
21.Histones are rich in which amino acid residues, according to the chapter?
(1)
(2)
(3)
(4)
22.In eukaryotic chromatin, negatively charged DNA wraps around:
(1)
(2)
(3)
(4)
23.The ‘beads-on-string’ appearance under electron microscope refers to:
(1)
(2)
(3)
(4)
24.Which statement about prokaryotic DNA packaging is correct?
(1)
(2)
(3)
(4)
25.Euchromatin is generally:
(1)
(2)
(3)
(4)
26.Heterochromatin is:
(1)
(2)
(3)
(4)
27.Which scientists proposed the central dogma in molecular biology as mentioned in the chapter?
(1)
(2)
(3)
(4)
28.In some viruses, the flow of genetic information is:
(1)
(2)
(3)
(4)
29.Griffith used which bacterial species for the transforming principle experiment?
(1)
(2)
(3)
(4)
30.In Griffith’s experiment, which injection killed the mice?
(1)
(2)
(3)
(4)
31.The biochemical nature of Griffith’s transforming principle was identified by:
(1)
(2)
(3)
(4)
32.Which enzyme treatment destroyed the transforming principle in Avery’s experiment?
(1)
(2)
(3)
(4)
33.Hershey and Chase labelled viral DNA and protein respectively with:
(1)
(2)
(3)
(4)
34.In the Hershey-Chase experiment, after blending and centrifugation, radioactive 32P was mainly found:
(1)
(2)
(3)
(4)
35.Which feature is not a required property of genetic material as listed in NCERT?
(1)
(2)
(3)
(4)
36.DNA is generally more stable than RNA because:
(1)
(2)
(3)
(4)
37.Which statement best explains why DNA is preferred over RNA as genetic material for long-term storage?
(1)
(2)
(3)
(4)
38.RNA is considered important in early life because RNA can:
(1)
(2)
(3)
(4)
39.Which is not an NCERT-supported role of RNA in living systems?
(1)
(2)
(3)
(4)
40.Watson and Crick’s semiconservative replication model means that after replication:
(1)
(2)
(3)
(4)
41.Meselson and Stahl used which isotope to label heavy DNA?
(1)
(2)
(3)
(4)
42.After one generation of E. coli growth in 14N medium following transfer from 15N medium, DNA density is:
(1)
(2)
(3)
(4)
43.After two generations in 14N medium in the Meselson-Stahl experiment, DNA consists of:
(1)
(2)
(3)
(4)
44.If E. coli divides every 20 minutes, after 80 minutes in 14N medium from 15N-labelled DNA, the expected hybrid:light DNA ratio is:
(1)
(2)
(3)
(4)
45.Very similar semiconservative replication evidence in higher organisms used radioactive:
(1)
(2)
(3)
(4)
46.During DNA replication, the enzyme that catalyses polymerisation of deoxyribonucleotides is:
(1)
(2)
(3)
(4)
47.DNA polymerase in E. coli must complete replication quickly because:
(1)
(2)
(3)
(4)
48.The replication fork is formed because:
(1)
(2)
(3)
(4)
49.Which statement about DNA replication is incorrect?
(1)
(2)
(3)
(4)
50.On the DNA template with polarity 5′→3′, synthesis of the new strand is:
(1)
(2)
(3)
(4)
51.The enzyme that joins discontinuously synthesized DNA fragments is:
(1)
(2)
(3)
(4)
52.Transcription is best defined as:
(1)
(2)
(3)
(4)
53.During transcription, adenine of DNA pairs with which base in RNA?
(1)
(2)
(3)
(4)
54.Unlike replication, transcription copies:
(1)
(2)
(3)
(4)
55.If both strands of a DNA segment code for RNA, the problem would be:
(1)
(2)
(3)
(4)
56.The strand whose sequence is same as RNA except T in place of U is:
(1)
(2)
(3)
(4)
57.The template strand has polarity:
(1)
(2)
(3)
(4)
58.A transcription unit contains all except:
(1)
(2)
(3)
(4)
59.The promoter in a transcription unit is located towards:
(1)
(2)
(3)
(4)
60.The terminator is generally located towards:
(1)
(2)
(3)
(4)
61.Regulatory sequences may be present:
(1)
(2)
(3)
(4)
62.A cistron is:
(1)
(2)
(3)
(4)
63.A structural gene in a transcription unit is monocistronic mainly in:
(1)
(2)
(3)
(4)
64.Split genes contain:
(1)
(2)
(3)
(4)
65.Exons are:
(1)
(2)
(3)
(4)
66.In bacteria, the three major types of RNA are:
(1)
(2)
(3)
(4)
67.Bacterial RNA polymerase catalyses transcription of:
(1)
(2)
(3)
(4)
68.In bacterial transcription, sigma factor is primarily associated with:
(1)
(2)
(3)
(4)
69.In bacterial transcription, rho factor is primarily associated with:
(1)
(2)
(3)
(4)
70.Why can translation begin before mRNA transcription is complete in bacteria?
(1)
(2)
(3)
(4)
71.Which eukaryotic RNA polymerase transcribes 28S, 18S and 5.8S rRNAs?
(1)
(2)
(3)
(4)
72.RNA polymerase III transcribes:
(1)
(2)
(3)
(4)
73.RNA polymerase II transcribes:
(1)
(2)
(3)
(4)
74.Which processing event adds methyl guanosine triphosphate to the 5′ end of hnRNA?
(1)
(2)
(3)
(4)
75.Tailing of hnRNA involves addition of:
(1)
(2)
(3)
(4)
76.Splicing removes:
(1)
(2)
(3)
(4)
77.Which sequence correctly represents eukaryotic mRNA processing?
(1)
(2)
(3)
(4)
78.The genetic code provides the relationship between:
(1)
(2)
(3)
(4)
79.George Gamow suggested that the genetic code should be made of:
(1)
(2)
(3)
(4)
80.Which experimental system helped decipher the codon for phenylalanine using poly-U RNA?
(1)
(2)
(3)
(4)
81.How many codons code for amino acids and how many function as stop codons?
(1)
(2)
(3)
(4)
82.The degeneracy of genetic code means:
(1)
(2)
(3)
(4)
83.The genetic code is read in a contiguous manner, meaning:
(1)
(2)
(3)
(4)
84.Which statement best describes universality of genetic code?
(1)
(2)
(3)
(4)
85.AUG has dual functions because it:
(1)
(2)
(3)
(4)
86.The stop codons are:
(1)
(2)
(3)
(4)
87.If mRNA sequence is 5′-AUG UUU UUC-3′, the peptide begins as:
(1)
(2)
(3)
(4)
88.Which property makes it difficult to predict a unique mRNA sequence from the amino acid sequence Met-Phe-Phe?
(1)
(2)
(3)
(4)
89.A single base insertion or deletion in a coding sequence can cause:
(1)
(2)
(3)
(4)
90.Insertion or deletion of three bases is generally less disruptive than one base because:
(1)
(2)
(3)
(4)
91.Sickle-cell anaemia is caused by substitution in the gene for:
(1)
(2)
(3)
(4)
92.In sickle-cell anaemia, the sixth amino acid of β-globin changes from:
(1)
(2)
(3)
(4)
93.The adapter molecule proposed by Crick was later found to be:
(1)
(2)
(3)
(4)
94.Which part of tRNA pairs with the codon on mRNA?
(1)
(2)
(3)
(4)
95.The amino acid attachment site of tRNA is located at:
(1)
(2)
(3)
(4)
96.There are no tRNAs for:
(1)
(2)
(3)
(4)
97.The secondary structure of tRNA is described in NCERT as:
(1)
(2)
(3)
(4)
98.The actual three-dimensional structure of tRNA is:
(1)
(2)
(3)
(4)
99.Assertion (A): There is a specific tRNA for initiation.

Reason (R): Stop codons have no tRNAs.
Choose the correct option.
(1)
(2)
(3)
(4)
100.Which option is the best long-combination answer?
Statements: I. Codon is triplet. II. UAA codes for methionine. III. Code is nearly universal. IV. AUG is both initiator and methionine codon.
(1)
(2)
(3)
(4)
101.Translation refers to:
(1)
(2)
(3)
(4)
102.The order of amino acids in a polypeptide is determined by:
(1)
(2)
(3)
(4)
103.Formation of a peptide bond requires:
(1)
(2)
(3)
(4)
104.The process of charging tRNA is:
(1)
(2)
(3)
(4)
105.The ribosome binds mRNA at the start codon recognized by:
(1)
(2)
(3)
(4)
106.In bacteria, the ribosome consists of:
(1)
(2)
(3)
(4)
107.Which bacterial rRNA acts as ribozyme for peptide bond formation?
(1)
(2)
(3)
(4)
108.A translational unit in mRNA is flanked by:
(1)
(2)
(3)
(4)
109.Untranslated regions (UTRs) are present:
(1)
(2)
(3)
(4)
110.Termination of translation occurs when:
(1)
(2)
(3)
(4)
111.Assertion (A): Ribosome is not merely a platform during translation.

Reason (R): 23S rRNA in bacterial ribosome acts as enzyme for peptide bond formation.
Choose the correct option.
(1)
(2)
(3)
(4)
112.Which is the correct flow during translation initiation?
(1)
(2)
(3)
(4)
113.Which statement about translation is incorrect?
(1)
(2)
(3)
(4)
114.AUG inside the translational unit is important because it:
(1)
(2)
(3)
(4)
115.Which long-combination set is correct for translation?

I. Amino acid activation uses ATP. II. tRNA carries amino acid to ribosome. III. 23S rRNA catalyses peptide bond formation in bacteria. IV. Stop codon has a corresponding tRNA.
(1)
(2)
(3)
(4)
116.Regulation of gene expression in eukaryotes can occur at:
(1)
(2)
(3)
(4)
117.In prokaryotes, gene expression is commonly regulated mainly at the level of:
(1)
(2)
(3)
(4)
118.The lac operon was elucidated by:
(1)
(2)
(3)
(4)
119.Which genes are structural genes of the lac operon?
(1)
(2)
(3)
(4)
120.The lac z gene codes for:
(1)
(2)
(3)
(4)
121.The lac y gene codes for:
(1)
(2)
(3)
(4)
122.The lac a gene codes for:
(1)
(2)
(3)
(4)
123.The lac i gene codes for:
(1)
(2)
(3)
(4)
124.In absence of inducer, the lac repressor binds to:
(1)
(2)
(3)
(4)
125.The inducer of lac operon as described in NCERT is:
(1)
(2)
(3)
(4)
126.Glucose or galactose cannot act as inducer for lac operon because:
(1)
(2)
(3)
(4)
127.Assertion (A): Lac operon regulation can be visualised as regulation of enzyme synthesis by its substrate.

Reason (R): Lactose induces transcription of genes required for its metabolism.
Choose the correct option.
(1)
(2)
(3)
(4)
128.Human Genome Project was formally launched in:
(1)
(2)
(3)
(4)
129.The Human Genome Project was completed in:
(1)
(2)
(3)
(4)
130.HGP was closely associated with a new area in biology called:
(1)
(2)
(3)
(4)
131.Which was not a goal of the Human Genome Project as per NCERT?
(1)
(2)
(3)
(4)
132.ELSI in the context of HGP stands for:
(1)
(2)
(3)
(4)
133.Which sequencing approach involves identifying all genes expressed as RNA?
(1)
(2)
(3)
(4)
134.Which sequencing approach in HGP involved sequencing the whole set of genome containing coding and non-coding sequences and later assigning functions?
(1)
(2)
(3)
(4)
135.The total length of the human genome reported in NCERT is approximately:
(1)
(2)
(3)
(4)
136.The average human gene consists of about:
(1)
(2)
(3)
(4)
137.The largest known human gene mentioned is:
(1)
(2)
(3)
(4)
138.Less than what percentage of human genome codes for proteins?
(1)
(2)
(3)
(4)
139.Which chromosome has most genes and which has fewest according to NCERT?
(1)
(2)
(3)
(4)
140.The proportion of human DNA sequence that is the same among humans is about:
(1)
(2)
(3)
(4)
141.DNA fingerprinting exploits mainly:
(1)
(2)
(3)
(4)
142.Polymorphism in DNA sequence arises due to:
(1)
(2)
(3)
(4)
143.A DNA polymorphism is useful for genetic mapping when it is:
(1)
(2)
(3)
(4)
144.DNA fingerprinting was initially developed by:
(1)
(2)
(3)
(4)
145.VNTR stands for:
(1)
(2)
(3)
(4)
146.VNTR belongs to which class of DNA?
(1)
(2)
(3)
(4)
147.The earlier DNA fingerprinting technique involved which correct sequence?
(1)
(2)
(3)
(4)
148.The membrane used for blotting in DNA fingerprinting may be:
(1)
(2)
(3)
(4)
149.DNA fingerprinting patterns are identical in:
(1)
(2)
(3)
(4)
150.Which long-combination set is correct for DNA fingerprinting?

I. VNTR copy number varies among individuals. II. VNTRs show high polymorphism. III. PCR increased sensitivity. IV. Only glucose can be used as a probe.
(1)
(2)
(3)
(4)
NEET ]150[ Contd...

Answer Key

12
22
33
42
53
61
72
81
92
102
112
122
133
142
151
162
172
181
192
202
212
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232
242
251
262
272
282
292
303
311
323
332
342
354
363
372
382
394
403
412
423
433
443
453
462
472
482
493
502
511
521
532
542
552
562
572
584
592
601
613
622
631
643
652
661
673
682
692
702
711
722
731
743
751
762
771
782
793
802
812
822
832
842
851
862
871
882
891
902
912
922
932
942
952
962
972
982
992
1002
1012
1021
1032
1041
1051
1062
1072
1082
1093
1101
1111
1122
1133
1142
1152
1163
1171
1181
1192
1203
1212
1221
1232
1242
1253
1261
1271
1282
1293
1302
1314
1322
1331
1342
1352
1363
1371
1381
1391
1403
1412
1421
1432
1441
1451
1461
1471
1481
1492
1502