CBSE Questions for Class 12 Medical Biology Molecular Basis Of Inheritance Quiz 10 - MCQExams.com

The codons UUU and UUC codes for phenylalanine only. This feature of genetic code is called
  • Commaless
  • Nonoverlapping
  • Degenerate
  • Nonambiguous
Escherichia coli in which both the strands are labelled with $$^{15}N$$ is transferred to $$^{14}N$$ medium and allowed to replicate for two generations. Find the number of hybrid DNA molecules in the second generation
  • Four
  • Eight
  • One
  • Two
Which Indian molecular biologist was awarded Noble Prize for the discovery of genetic code 
  • Khorana
  • Ramakrishnan
  • Kashyap
  • Raman
A molecule that acts as a genetic material must fulfill the traits given, except
  • It should provide the scope for slow changes that are required for evolution
  • It should be able to generate its replica
  • It should be able to express itself in the form of Mendelian characters
  • It should be unstable structurally and chemically
Which statement is wrong
  • F. Conrat established that RNA is also genetic material
  • DNA acts as template for synthesis of both DNA and RNA
  • DNA polymerase I is the main polymerising enzyme
  • DNA forms mRNA using RNA polymerase II
Read the following statements carefully and choose the correct ones
a) In a transcription unit, the promoter located at the 5 end of coding strand
b) The single strand DNA having the polarity 5 3 is the template strand
c) RNA polymerase binds to the operator during transcription
d) Single base DNA difference occuring in humans are called Single Nucleotide Polymorphism (SNP)
  • Statements a and b
  • Statements b and c
  • Statements b and d
  • Statements a and d
Whose experiments cracked the genetic code and discovered unequivocally that genetic code is triplet
  • Nirenberg and Mathaei
  • Hershey and Chase
  • Morganand Sturtevant
  • Beadle and Tatum
What is first step in Southern blot techinique
  • Denaturation of DNA on gel for hybridization with specific probe
  • Digestion of DNA by restriction endonuclease
  • Production of a group of genetically identical cells
  • Isolation of DNA from a nucleated cell such as the one from the scene of crime
Haploid content of human DNA is
  • $$3.3\times 10^6$$ bp
  • $$3.3\times 10^9$$ bp
  • $$4.6\times 10^6$$ bp
  • $$6.6\times 10^9$$ bp
  • $$48502$$bp
Nucleotide pairs present in human genes vary between
  • 100 - 1000
  • 500 - 5000
  • 2000 - 2,000,000
  • 10,000 - 10,000,000
The number of DNA coils present over a nu body is?
  • $$1.75$$
  • $$17.5$$
  • $$75$$
  • $$5$$.
In one polynucleotide strand of a DNA molecule, the ratio of $$A+T/G+C$$ is $$0.3$$. What is the $$A+G/T+C$$ ratio of the entire DNA molecule?
  • $$0.3$$
  • $$0.6$$
  • $$1.2$$
  • $$1$$
During replication, DNA gyrases takes part in 
  • Nicking DNA in eucaryotes
  • Nicking DNA in procaryotes
  • Synthesis of prier in eucaryotes
  • Synthesis of primer in procaryotes
As per latest information human genome has
  • $$3,00,000$$ genes
  • $$20,000$$ genes
  • $$3,000$$ genes
  • $$300$$ genes
Human genome project was started in
  • $$1989$$
  • $$1990$$
  • $$1992$$
  • $$1995$$
Number of genes believed to be present in a human being is
  • 1000
  • 10,000
  • 100,000
  • 1,000,000
Total number of base pairs found in human genome is?
  • $$3.5$$ million
  • $$35000$$
  • $$35$$ billion
  • $$3.1$$ billion
Consider the following codons:
UAA          
UAC
UAG      
Which of these are considered to be the termination codons codons in protein synthesis?
  • 1, 2 and 3
  • 1 and 2
  • 2 and 3
  • 1 and 3
If there are 10,000 nitrogenous base pairs in a DNA then how many nucleotides are there?
  • 500
  • 10,000
  • 20,000
  • 40,000
Replication of DNA on its lagging strand is initiated by.
  • DNA polymerase III
  • RNA primer
  • DNA polymerase I
  • DNA ligase
The number of ribosomal binding sites used by tRNAs during protein elongation are ______________.
  • $$2$$
  • $$4$$
  • $$6$$
  • $$8$$
The distance between two nitrogen bases in a polynucleotide of DNA is?
  • $$34.00$$A'
  • $$10.4$$A'
  • $$6.4$$A'
  • $$3.4$$A'
In yeast mitochondria UGA codes for:
  • Termination codon
  • Initiation codon
  • Tryptophan
  • Tyrosine glycerate concentration
Beside direct chemical analysis DNA and RNA can be detected by which of the following method?
a. Photometric procedures
b. Staining reactions
c. Enzyme digestion
Select the correct answer using the codes given.
  • $$1, 2$$ and $$3$$
  • $$1$$ and $$2$$
  • $$2$$ and $$3$$
  • $$1$$ and $$3$$
Which one of the following is a terminator codon?
  • AUG
  • UGA
  • UUU
  • UGG
'DNA fingerprinting' has proved to be useful in forensic science. It involves the use of _______________.
  • Minisatellites
  • Ribosomal RNA
  • cDNA
  • Bacterial DNA
A bacterium with completely non-radioactive DNA was allowed to replicate in radioactive medium for three generation what $$ \%$$ of the bacteria should contain radioactive DNA:
  • $$ 25\%$$
  • $$ 75\%$$
  • $$ 0\%$$
  • $$ 100\%$$
Which of the following pairs of lectin source and the name of the lection are correctly matched?
a. Canacalia ensiformis-Con A
b. Abrus precatorius - Abrin
c. Dolichos biflorus - Dolin
d. Ricinus communis- Ricinin
Select the correct answer using the codes given.
  • $$1, 2$$ and $$3$$
  • $$1, 3$$ and $$4$$
  • $$1, 2$$ and $$4$$
  • $$2, 3$$ and $$4$$
Codon degeneracy means that
  • Several of the amino acids are coded by more than one codon.
  • One codon can code for many amino acids.
  • One amino acid can be coded by only one codon.
  • The codons are triplet nucleotide sequences.
Match List I(Enzyme) with List II(Function) and select the correct answer using the codes given the lists.
List-IList-II
a. DNA Ligase$$1$$. Catalyses the covalent union of segments of an interrupted sugarphosphate strand in double-stranded DNA
b. DNA polymerase$$2$$. End nuclease that digests either single stranded or double stranded DNA
c. DNase I$$3$$. Produces single or double stranded breaks in DNA during replication to release tension brought about by the separation of double strands
d. DNA topoisomerase$$4$$. Catalyses the formation of DNA worn deoxyribonucleotides using one strand of DNA as template
  • A-$$1$$, B-$$4$$, C-$$3$$, D-$$2$$
  • A-$$4$$, B-$$1$$, C-$$2$$, D-$$3$$
  • A-$$1$$, B-$$4$$, C-$$2$$, D-$$3$$
  • A-$$4$$, B-$$1$$, C-$$3$$, D-$$2$$
The state in which the viral genome gets integrated with the bacterial genome is called.
  • Prophage
  • Prophase
  • Adsorption
  • Lysogeny
Consider the following statements.
The genetic code is said to be degenerate and universal which means that.
a. Amino acids may have more than one codon.
b. All Amino acids have the one codon.
c. Codons are common for higher and lower organisms.
Of these statements.
  • $$2$$ and $$3$$ are correct
  • $$1$$ and $$3$$ are correct
  • $$3$$ alone is correct
  • $$1$$ alone is correct
Which one of the following statements is incorrect for translation in the cytoplasm?
  • One codon codes for only one amino acid.
  • One amino acid may be coded by many codons.
  • More than one amino acids are coded by one specific codon.
  • There are some codons that do not code for any amino acid.
According to Watson-Crick model, hydrogen bonding in a double-stranded DNA occurs between.
  • Adenine and guanine.
  • Adenine and thymine.
  • Cytosine and adenine.
  • Guanine and thymine.
Which of the following bonds are formed by action of DNA ligase?
  • Sugar-phosphate bond
  • Phosphodiester bond
  • Phosphate-phoshpate bond
  • Both (1) and (2)
The helical structure of DNA was discovered by
  • Sanger
  • Bloor
  • L.Pauling
  • Watson and Crick
What is the length of human DNA containing $$6.6\times10^9$$ bp nitrogen bases?
  • $$22$$nm
  • $$0.22$$mm
  • $$2.2$$m
  • $$22$$m
Genetic information in a DNA molecule is coded by the
  • Sequence of nucleotides
  • Base pairing
  • Turning pattern of the helix
  • Proportion of each base present
Watson and Crick are credited for the discovery that DNA
  • Is a double stranded helix
  • Is responsible for the synthesis of tRNA
  • Is a carrier of genetic information
  • Provides proof for the X-Y chromosomal theory of sex determination
The two strands of double helix of DNA are linked together by hydrogen bonds between
  • Bases
  • Deoxysugars
  • Phosphates
  • Ribose sugars
In the double helix model of DNA as proposed by Watson and Crick, each base pair is how far from the next base pair?
  • 0.034 nm
  • 0.34 nm
  • 3.4 nm
  • 34 nm
Choose the correct answers from the alternatives given :
Which enzyme catalyzes the synthesis of a new strand for a DNA molecule by linking nucleotides to the developing strand?
  • DNA ligase
  • DNA polymerase
  • Single-strand binding proteins
  • Topoisomerase
Choose the correct answers from the alternatives given :
Which of the following is not a chemical component of deoxyribonucleic acid?
  • Thymine
  • A phosphate group
  • A pentose sugar
  • Uracil
All of the following except are sources of change in the genome
  • Nondisjunction during meiosis
  • Gene mutations
  • Crossing over
  • Amniocentesis
Choose the correct answers from the alternatives given :
Transcription is the transfer of genetic code from a DNA molecule to a
  • RNA molecule
  • Second DNA molecule
  • Ribosomal subunit
  • Sequence of amino acids in a protein molecule
Choose the correct answers from the alternatives given :
In DNA replication, the Okazaki fragments on the lagging strand are joined together by
  • DNA ligase
  • DNA polymerase
  • Primase
  • Helicase
Choose the correct answers from the alternatives given :
Each codon calls for a specific
  • carbohydrate
  • polypeptide
  • amino acid
  • protein
Choose the correct answers from the alternatives given :
Transcription involves
  • synthesizing the protein on the ribosome
  • transferring information contained in the DNA to mRNA
  • joining amino acids by peptide bonds
  • transferring information from the mRNA to tRNA
Choose the correct answer from the alternatives given.
A restriction enzyme breaks bonds between the
  • base pairs of a DNA molecule
  • sugar and phosphate components of a nucleic acid molecule
  • base pairs of a DNA-RNA hybrid molecule.
  • exons and introns of a DNA molecule
Codons are
  • triplets coding for a single amino acid
  • alphabet of the genetic language
  • redundant in their coding for various amino acids
  • all of the above
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