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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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