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Botany

Molecular Basis of Inheritance

49 questions · Click an option and press Check Answer to reveal the result

Histones are enriched with -

Lysine & Arginine

Leucine & Lysine

Phenylalanine & Leucine

Phenylalanine & Arginine

According to the Watson-Crick model of DNA, the two polynucleotide chains have;

5'→3' polarity in same direction.

phosphate groups at the same end.

antiparallel polarity.

exactly same sequence of nitrogenous bases.

When DNA replication starts :

The leading strand produces Okazaki fragments.

The hydrogen bonds between the nucleotides of two strands break.

The phosphodiester bonds between the adjacent nucleotides break.

The bonds between the nitrogen base and deoxyribose sugar break.

DNA uniform diameter due to:

Double helix

Phosphate

Purine-pyrimidine pairing

Hydrogen bonds

Central dogma:

RNA → DNA → Protein

DNA → RNA → Protein

Protein → DNA → RNA

DNA → Protein → RNA

A genetic material must:

Be unstable

Replicate

Not mutate

Not express

Codon is:

Doublet

Triplet

Quartet

Single

Assertion (A): Unequivocal proof that DNA is the genetic material came from Griffith's transformation experiment.
Reason (R): The biochemical nature of genetic material was defined from transformation experiment.

Both (A) & (R) are true and the (R) is the correct explanation of the (A)

Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(A) is true but (R) is false

Both (A) and (R) are false

Pitch of DNA helix:

3.4 nm

34 nm

0.34 nm

10 nm

Ribosome is:

DNA unit

Protein factory

Lipid site

Enzyme

The DNA can be digested by the enzyme:

DNA polymerase.

DNA ligase.

RNase.

DNase.

Given below are some steps of transcription :
A. RNA Polymerase uses nucleotide triphosphates as substrate during elongation.
B. RNA Polymerase associates transiently with termination factor (ρ) to terminate the transcription.
C. DNA polymerase facilitates opening of the DNA helix.
D. Only a short stretch of RNA remains bound to the enzyme.
E. RNA polymerase binds to promoter by the help of sigma factor.
Choose the correct sequence of steps from the options given below:

E-C-D-A-B

E-D-B-E-A-C

B-D-E-A-C

E-C-A-D-B

Choose incorrect statement from given below options :-

DNA act as a genetic material in most of the organisms.

The back bone of DNA is constituted by sugar-phosphate, and bases are projected outside.

The principle of Complementarity governs the process of transcription.

Repeated DNA sequences makeup very large portion of the human genome.

Identify the correct statements from the following regarding Human Genome Project (HGP).
A. The total number of genes is estimated at 30,000.
B. More than 20% of the genome codes for proteins.
C. Chromosome 1 has the most genes (2968) and the X chromosome has the fewest (231).
D. The human genome contains 3164.7 million base pairs.
E. Snips are present at about 1.4 million locations.
Choose the correct option.

A, D and E

A, B and D

B, C and E

A, C and D

Statement-I : rRNA carries genetic information from DNA to ribosome.
Statement-II : One t-RNA can recognize more than one codon.

Statement I is correct but Statement II is incorrect.

Statement I is incorrect but Statement II is correct.

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect.

Assertion (A) : The t-RNA molecules possess anticodon.

Reason (R) : It needs the message in form of codon.

Both Assertion (A) and Reason (R) are true and Reason is the correct explanation of Assertion.

Both Assertion (A) and Reason (R) are true but Reason is not the correct explanation of Assertion.

Assertion (A) is true but Reason (R) is false.

Assertion (A) is false but Reason (R) is true.

Which histone protein is not present in the core of nucleosome:

H₂B

H₂A

H₃

H₁

In Hershey and Chase experiment, bacteriophage nucleic acid was labelled with:

32P

35S

14C

In Griffith experiment:

R → S transformation

S → R transformation

No transformation

Both die

5-methyl uracil is:

Cytosine

Adenine

Thymine

Guanine

A bacterium has 100% of its N₂ bases labelled with N¹⁵. If it is allowed to replicate in medium with N¹⁴bases for one cycle only, what will be the result?

All bacteria will be similar to parents but different among themselves

All bacteria will be N¹⁵N¹⁴

All bacteria will be like their parents only

100% bacteria will be with N¹⁴N¹⁴

Which of the following statements are correct ?
(A) In double helix model of DNA, two chains have parallel polarity.
(B) Pitch of helix in DNA is 3.4 nm.
(C) In structure of DNA if sequence of base in one strand is known then sequence in other can be predicted.
(D) In prokaryotes, DNA is scattered through the cell.

A and B only

A and D only

B and C only

C and D only

Match List I with List II :
Choose the correct answer from the options given below:

Column I	Column II
AGene ‘a’	iβ- galactosidase
BGene ‘y’	iiTransacetylase
CGene ‘i’	iiiPermease
DGene ‘z’	ivRepressor protein

A-ii, B-iii, C-iv, D-i

A-iii, B-iv, C-i, D-ii

A-ii, B-i, C-iv, D-iii

Match the following

(a) tRNA — (1) Linking of amino acids

(b) mRNA — (2) transfer of genetic information nucleolar organizing region

(d) Peptidyl — (4) Transfer of amino acid transferase from cytoplasm of ribosome

(a)-(4), (b)-(2), (c)-(3), (d)-(1)

(a)-(1), (b)-(4), (c)-(3), (d)-(2)

(a)-(1), (b)-(3), (c)-(2), (d)-(4)

(a)-(1), (b)-(2), (c)-(3), (d)-(4)

Read the following statements regarding the lac operon.
A. Lactose is the substrate for the enzyme beta- galactosidase and it regulates switching on and off of the operon.
B. The repressor of the operon is synthesised constitutively from the z gene.
C. In the presence of the inducer, the repressor is activated by interaction with it.
D. Regulation of lac operon by repressor is referred to as negative regulation.
E. The y gene codes for transacetylase.
In the light of above statements choose the correct answer from the options given below:

B and E are correct, A, C and D are incorrect

C and D are correct, A, B and E are incorrect

A and D are correct, B, C and E are incorrect

A, C and E are correct, B and D are incorrect

Nucleosome contains:

20 bp

200 bp

2000 bp

20 kb

Translation refers to:

DNA replication

RNA synthesis

Protein synthesis

Mutation

First genetic material:

DNA

RNA

Protein

Lipid

Which of the following RNA is not required for the synthesis of protein?

m-RNA

sn-RNA

t-RNA

r-RNA

Nucleosomes constitute the repeating unit of:

Histone octamer

Chromatin

Euchromatin

Heterochromatin

All are pyrimidines except:

Cytosine

Thymine

Guanine

Uracil

Okazaki fragments joined by:

DNA polymerase

DNA ligase

Helicase

Primase

Match the following:

Column I	Column II
APCR	iBinding site of repressor protein
BOperator	iiCatalytic activity in Ribosome
Cr-RNA	iiiRNA splicing
Dsn-RNA	ivDNA amplification

A-iv, B-iii, C-ii, D-i

A-iv, B-i, C-iii, D-ii

A-iv, B-i, C-ii, D-iii

A-i, B-ii, C-iii, D-iv

RNA polymerase:

Multiple types in bacteria

Single type in bacteria

Only in eukaryotes

Not needed

Match the columns I and II, and choose the correct combination from the options given.

Screenshot 2026-04-20 at 12.17.26 PM.png

a-ii, b-i, c-iii, d-iv

a-iii, b-iv, c-i, d-ii

a-ii, b-iv, c-iii, d-i

a-i, b-ii, c-iii, d-iv

In RNA, extra -OH group present at:

2’ position

3’ position

5’ position

1’ position

Meselson & Stahl experiment used:

Radioactive S

UV rays

CsCl gradient centrifugation

X-ray diffraction

Backbone of DNA:

Sugar only

Phosphate only

Sugar-phosphate

Bases

In the process of transcription, the strand of DNA with polarity ______ acts as a ______ strand:-

5' → 5', Coding strand

3' → 5', Template strand

3' → 3', Coding strand

5' → 5', Template strand

Assertion: During DNA replication, on one strand the replication is continuous while on the other strand it is discontinuous.
Reason : DNA polymerase can synthesize DNA only in the 5'→3' direction.

Both Assertion and Reason are true but Reason is NOT the correct explanation of Assertion.

Assertion is true but Reason is false.

Assertion is false but Reason is true.

Both Assertion and Reason are true and Reason is the correct explanation of Assertion.

DNA is a long polymer of:

Ribonucleosides

Deoxyribonucleotides

Deoxyribonucleosides

Ribonucleotides

DNA is a genetic material because of?

I. Its stability

II. Its replicability

III. Its slow mutability

IV. Its expressibility

Choose the correct combination:

I and II only

II and III only

III and IV only

I, II, III and IV

Base pairs per turn:

Given below are two statements:
Statement I: During transcription, adenosine complements forms base pair with thymine.
Statement II: In transcription, only a segment of DNA and only one of the strands is copied into RNA. Choose correct answer:

Both Statement I and Statement II are correct.

Both Statement I and Statement II are incorrect

Statement I is correct but Statement II is incorrect

Statement I is incorrect but Statement II is correct.

Which of the following is a primer dependent enzyme :-

DNA polymerase

RNA polymerase

Oligonucleotide

DNA ligase

If C = 20%, A = ?

20%

30%

40%

60%

Nuclein discovered by:

Watson

Crick

Meischer

Chargaff

Assertion: RNA can directly code for protein synthesis Reason: RNA cannot easily express characters

A true R false

A false R true

Both true correct

Both true wrong

Replication occurs at:

Nucleus only

Random site

Replication fork

Ribosome

Question Palette

Unattempted

Correct

Incorrect

Column I

Column II

AGene ‘a’

iβ- galactosidase

BGene ‘y’

iiTransacetylase

CGene ‘i’

iiiPermease

DGene ‘z’

ivRepressor protein

Column I

Column II

APCR

iBinding site of repressor protein

BOperator

iiCatalytic activity in Ribosome

Cr-RNA

iiiRNA splicing

Dsn-RNA

ivDNA amplification