MCQ Questions for Class 12 Biology Chapter 6 Molecular Basis of Inheritance with Answers

We have compiled the NCERT MCQ Questions for Class 12 Biology Chapter 6 Molecular Basis of Inheritance with Answers Pdf free download covering the entire syllabus. Practice MCQ Questions for Class 12 Biology with Answers on a daily basis and score well in exams. Refer to the Molecular Basis of Inheritance Class 12 MCQs Questions with Answers here along with a detailed explanation.

Molecular Basis of Inheritance Class 12 MCQs Questions with Answers

Multiple Choice Type Questions

Question 1.
Nucleic acids are polymer of
(a) Nucleosides
(b) Proteins
(c) Glycoproteins
(d) Nucleotides

Answer

Answer: (d) Nucleotides


Question 2.
DNA structure was discovered by
(a) Weismann
(b) Watson and Crick
(c) Har Gobind Khorana
(d) Sutton

Answer

Answer: (b) Watson and Crick


Question 3.
Enzyme responsible for DNA replication
(a) Polymerase
(b) Proteolytic
(c) Ligase
(d) Carboxylase

Answer

Answer: (a) Polymerase


Question 4.
Cistron is
(a) Functional unit of RNA
(b) Non-functional unit of RNA
(c) Functional unit of DNa that specifies a polypeptide chain
(d) Non-functional unit of DNA

Answer

Answer: (c) Functional unit of DNa that specifies a polypeptide chain


Question 5.
Transcription is the formation of
(a) mRNA
(b) tRNA
(c) rRNA
(d) Protein

Answer

Answer: (a) mRNA


Question 6.
Which of the RNA is smallest and used in feeding of amino acid to a ribosome?
(a) hnRNA
(b) tRNA
(c) mRNA
(d) rRNA

Answer

Answer: (b) tRNA


Question 7.
Initiation codon in higher plants is
(a) UAG
(b) AUG
(c) AGU
(d) GAU

Answer

Answer: (b) AUG


Question 8.
Synthesis of any protein in a cell is determined by
(a) Types of ribosomes
(b) Mitochondria
(c) Sequence of nucleotides in DNA
(d) Sugar and phosphate of DNA

Answer

Answer: (c) Sequence of nucleotides in DNA


Question 9.
The element required for the activation of DNA and DNA polymerase is
(a) Ca2+
(b) Mg2+
(c) K+
(d) Cu2+

Answer

Answer: (b) Mg2+


Question 10.
The first gene isolated by shapiroet-al in 1969 was the gene of
(a) Insulin gene of .mouse
(b) Nitrogenase of cynobacteria
(c) Alamine of tRNA of yeast
(d) Lac operon of E.Coli

Answer

Answer: (d) Lac operon of E.Coli


Question 11.
Regulated unit of genetic material is called
(a) Operon
(b) Operater gene
(c) Regulator gene
(d) Promoter gene

Answer

Answer: (a) Operon


Question 12.
Sickle cell anaemia is caused by change in
(a) A single base
(b) a chain of haemoglobin
(c) Frame shift mutation
(d) Whole ß chain of haemoglobin

Answer

Answer: (a) A single base


Question 13.
The mitochondrial DNA differs from nuclear DNA in
(а) Being linear
(b) Having A = T and C = G
(c) Being highly twisted
(d) Lacking binding of histones.

Answer

Answer: (d) Lacking binding of histones.


Question 14.
Which is required for protein synthesis?
(a) Initiation codon
(b) Peptidyl transferase
(c) GTP
(d) All the above

Answer

Answer: (d) All the above


Question 15.
Haploid represents
(a) Haploid chromosome set
(b) Complete chromosome set
(c) Diploid chromosome set
(d) AH the genes present in a population set

Answer

Answer: (a) Haploid chromosome set


Question 16.
As per template theory, amino acid first combines with
(a) tRNA
(b) mRNA
(c) rRNA
(d) DNA

Answer

Answer: (a) tRNA


Question 17.
In DNa replication, the primer is
(a) A small deoxyribonucleotide polymer
(b) Small ribonucleotide polymer
(c) Helix destabilising protein
(d) Enzyme taking part in joining nucleotides to their complementary template bases.

Answer

Answer: (b) Small ribonucleotide polymer


Question 18.
The experimental system used in studies of discovery of replication of DNA has been
(a) Drosophila melanogaster
(b) Pneumococcus
(c) Escherichia Coli
(d) Neurospora crassa

Answer

Answer: (c) Escherichia Coli


Question 19.
The approximate life span of mRNA is
(a) 2 hours
(b) 2 minutes
(c) 2 seconds
(d) None of the above

Answer

Answer: (b) 2 minutes


Question 20.
Topoisomerase is involved in
(a) Producing RNA primer
(b) Joining of DNA segment
(c) Producing nick in DNA
(d) Separation of DNA strands

Answer

Answer: (c) Producing nick in DNA


Fill in the Blanks

Question 1.
The DNA molecule takes a complete turn after every ……………….. base pairs.

Answer

Answer: 10


Question 2.
Genes that shuffle from one location to another are called ………………..

Answer

Answer: jumping genes


Question 3.
The formation of a peptide bond is catalysed by the enzyme ………………..

Answer

Answer: peptidy, transferase


Question 4.
……………….. is the technique by which the three dimensional structures of macromolecules can be studied.

Answer

Answer: X-ray analysis


Question 5
……………….. has the shape of clover-leaf.

Answer

Answer: tRNA


Question 6
……………….. is the process in which information is carried from RNA to DNA in some viruses.

Answer

Answer: Reverse transcription


Question 7.
New strands of DNA are formed only in the ……………….. direction.

Answer

Answer: 5′ → 3′ direction


Question 8.
One gene-one enzyme concept is now more accurately referred to as one ……………….. one ……………….. concept.

Answer

Answer: gene, polypeptide


Question 9.
……………….. are enzymes that unwind DNA helices while ……………….. break and reseal the strands.

Answer

Answer: Helicases, topoisomerases


Question 10.
The unidirectional flow of genetic information from DNA → RNA → protein is referred to as the ……………….. in molecular biology.

Answer

Answer: central dogma.


Write True or False

Question 1.
Genetic code is ambiguous.

Answer

Answer: False


Question 2.
RNA also serves catalytic functions.

Answer

Answer: True


Question 3.
Phosphodiester linkage is present in DNA.

Answer

Answer: True


Question 4.
DNA is basic in nature.

Answer

Answer: False


Question 5.
Histones are rich in lysines and arginines.

Answer

Answer: True


Question 6.
RNA being unstable, mutate at a faster rate.

Answer

Answer: True


Question 7.
In Eukaryotes, the DNA replication occurs at S-phase of cell cycle.

Answer

Answer: True


Question 8.
Cycloheximide prevent polypeptide chain elongation in eukaryotes but not in bacteria.

Answer

Answer: True


Question 9.
Extra nuclear DNA is found in Endoplasmic reticulum.

Answer

Answer: False


Question 10.
Genes are inert and can act in isolation.

Answer

Answer: False


One Word Questions

Question 1.
Who coined the word gene?

Answer

Answer: Johannsen.


Question 2.
Write any two non-sense codons.

Answer

Answer: UGA, UAA.


Question 3.
How many bases code for one amino acid?

Answer

Answer: Three.


Question 4.
Name any organism where RNA acts as genetic material.

Answer

Answer: TMV.


Question 5.
Who first deciphered the genetic code?

Answer

Answer: Nirenberg Ochoa, Hargobind Khorana and Francis Crick.


Question 6.
A nucleosome contains how many base pairs of DNA helix?

Answer

Answer: 200 base pairs.


Question 7.
What is genetic material?

Answer

Answer: DNA.


Question 8.
Who suggested inborn errors in metabolism?

Answer

Answer: Archibold Garrod.


Question 9.
mRNA of eukaryotes is synthesized with the help of what?

Answer

Answer: RNA polymerase II.


Question 10.
Who proved experimentally that DNA replication is semi conservative?

Answer

Answer: Nesselson and Stahl.


Match the Following

Column I Column II
1. A retrovirus A. One gene – one enzyme hypothesis
2. Splicing B. Initiation codon
3. Beadle and Tatum C. TMV
4. AUG D. Non-sense codon
5. UAA E. processing of mRNA molecules
Answer

Answer:

Column I Column II
1. A retrovirus C. TMV
2. Splicing E. processing of mRNA molecules
3. Beadle and Tatum A. One gene – one enzyme hypothesis
4. AUG B. Initiation codon
5. UAA D. Non-sense codon

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