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CBSE Questions for Class 12 Medical Biology Molecular Basis Of Inheritance Quiz 11 - MCQExams.com
CBSE
Class 12 Medical Biology
Molecular Basis Of Inheritance
Quiz 11
Which is not true about the genetic code?
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It is exactly the same in all organisms
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It is composed of a tripletcode of three bases per codon
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It produces 64 different possibilities of base sequences
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It contains start and stop codons as instructions
Explanation
The genetic code is the coding sequence which constitutes three base pairs called as codons.
These codons are responsible for the formation of specific proteins.
There are 64 different codons that were introduced to produce different amino acids.
These codons are different for the different organism, no two organisms have the same codons as they may be deleterious.
These codes help in the transformation of genetic information from one generation to another by the process of translation (Protein synthesis).
Start codons are the initiation site of translation where protein synthesis occurs while stop codons are those bases which stops the process of formation of proteins and are called as termination codons.
So, the correct option is 'It is exactly the same in all organisms'.
Choose the correct answers from the alternatives given :
The creation of an RNA molecule from a section of DNA is known as
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replication
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RNA splicing
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transcription
0%
translation
Explanation
Transcription is also called DNA dependent RNA synthesis where DNA acts as the template catalysed by the RNA polymerase enzyme. This enzyme adds complementary bases to the DNA sequences and finally produces mRNA as the product.
So, the correct option is 'transcription'.
Choose the correct answers from the alternatives given :
Which of the following is not true of a codon?
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It extends from one end of a tRNA molecule
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It never codes for more than one amino acid
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It may code for the same amino acid as another codon does
0%
It consists of three nucleotides
Explanation
A codon is the shortest sequence that consists of only three nucleotide bases. Each codon codes for only one amino acid. This means codons are universal in nature and will code for the same amino acid in all organisms.
A particular amino acid can be coded by more than one codon. Example: Arginine is coded by six codons CGU, CGC, CGA, CGG, AGA, and AGG.
The codons are continuous and commaless in nature.
So, the correct option is 'It extends from one end of a tRNA molecule'.
In a dsDNA number of phosphodiester bonds are $$3250$$, then find the number of base pairs.
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$$1625$$
0%
$$1626$$
0%
$$3252$$
0%
$$3250$$
Explanation
If the number of base pairs in a DNA is n, then the number of phosphodiester bonds will be 2x(n-1), now according to the formula the number of base pairs will be 2x(n-1)=3250, the value of n will be 1626.
So, the correct option is '
1626'.
'
Purines have nitrogen atoms at ______ positions.
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1',3',7',9'
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1',5',7',9'
0%
1',3'
0%
1',9'
Explanation
The purine bases have a 9‐membered double‐ring system with four nitrogens and five carbons. The two-carbon nitrogen ring bases (adenine and guanine) are examples of purines.
So, the correct option is '1',3',7',9'.
In a DNA molecule, the phosphate group is attached
to ____carbon of the sugar residue of its own
nucleotide and _____ carbon of the sugar residue
of the next nucleotide by ____bonds.
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5', 3', phosphodiester
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5', 3', glycosidic
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3', 5', phosphodiester
0%
3', 5', glycosidic
Explanation
A deoxyribonucleotide of DNA is formed by cross- linking of three chemicals - deoxyribose sugar $$(C_5H_{10}O_4)$$,a nitrogen base and phosphoric acid $$(H_3PO_4)$$. The backbone of a DNA strand is build up of alternate deoxyribose and phosphoric acid groups. The phosphate group is connected to carbon $$5'$$ of the sugar residue of its own nucleotide and carbon $$3'$$ of the sugar residue of the next nucleotide by phosphodiester bonds.
So, the correct answer is '5', 3', phosphodiester'.
Choose the correct answer from the alternatives given, Human genome consists of approximately
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$$3 \, \times \, 10^9$$ bp
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$$6 \, \times \, 10^9$$ bp
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20,000 + 25,000 bp
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$$2.2 \, \times \, 10^4$$ bp
Explanation
The human genome contains 23 chromosomes. The DNA in the haploid set contains 3 billion base pairs.
So, the correct answer is '($$3\, \times \,10^9$$ bp)'
Choose the correct answer from the alternatives given :
An organism uses 20 amino acids while its DNA is made up of 6 types of nitrogenous bases. What would be the minimum size of a codon?
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6
0%
4
0%
3
0%
2
Explanation
As there are 20 amino acids thus there must be at least 20 unique combinations of the bases. If the code is singlet i.e., consists of only one base then possible codons can be (6)1=6, which is far less than the required number i.e., 20. If the code is doublet (made up of combination of two bases) then the possible codons can be (6)2=36. 36 is sufficient (even more) than the required number. Here some amino acid could be coded by more than one codon and some codons will function as start and stop codons.
So, the correct answer is ''2'.
Which bonds are indicated by X and Y in the given diagram?
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X - Glycosidic bond
Y - Hydrogen bond
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X - Phosphodiester bond
Y - Hydrogen bond
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X - Glycosidic bond
Y - Phosphodiester bond
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X - Phosphodiester bond
Y - Glycosidic bond
Explanation
A phosphodiester bond occurs when exactly two of the hydroxyl groups in phosphoric acid react with hydroxyl groups on other molecules to form two ester bonds.
Guanine and cytosine make up a nitrogenous base pair because their available hydrogen bond donors and hydrogen bond acceptors pair with each other in space. Guanine and cytosine are said to be complementary to each other.
So, the correct answer is 'B'.
B-DNA which is right-handed double helix contains ______ base pairs per turn of the helix and each turn is _______ long.
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10, 3.4 $$\mathring {A} $$
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10, 34 $$\mathring {A}$$
0%
11, 20 $$\mathring {A}$$
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11, 34 $$\mathring {A}$$
Explanation
B-DNA is the most commonly found form of DNA in nature. This form of DNA is very narrow and elongated.
B-DNA contains 10 base pairs per turn and each turn is about 34
Å long.
So, the correct answer is '10, 34
Å'
Choose the correct answer from the alternatives given :
In a DNA strand the nucleotides are linked together by
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Glycosidic bonds
0%
Phosphodiester bonds
0%
Peptide bonds
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Hydrogen bonds
Explanation
A nucleotide has three components - nitrogenous base, a pentose sugar ribose in case of RNA and deoxyribose for DNA) and a phosphate group. There are two types of nitrogenous bases - Purines (Adenine and Guanine) and Pyrimidines (Cytosine and Thymine). A nitrogenous base is linked to the pentose sugar through a N-glycosidic linkage to form a nucleoside. When a phosphate group is linked to 5 -OH of a nucleoside through phosphodiester linkage, a corresponding nucleotide is formed. The nucleotides are linked through 3-5 phosphodiester linkage to form a dinucleotide.
So, the correct answer is 'Phosphodiester bonds'.
Fill up the blanks and select the correct option.
(i) EcoRI cuts the DNA between bases ___ and ____ when the sequence _____ is present in the DNA.
(ii) Disruption of the cell membranes can be achieved by treating the bacterial cells, plant cells and fungal cells with enzymes respectively ____, ____ and ___.
(iii) Since DNA has a ____ charge, it moves towards the ____ of the electrophoretic chamber.
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(i) G, A, GAATTC (ii) endonuclease, cellulase, chitinase (iii) negative, anode
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(i) G, A, GAATTC (ii) lysozyme, cellulase, chitinase (iii) positive, cathode
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(i) G, A, GAATTC (ii) lysozyme, cellulase, chitinase (iii) negative/anode
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(i) G, A, GAAATC (ii) lysozyme, cellulase, chitinase (iii) positive, cathode
Explanation
EcoRI cuts the DNA between bases G and A only when the sequence GAATTC is present in the DNA.
Disruption of the cell membranes can be achieved by treating the bacterial cells, plant cells and fungal cells with enzymes lysozyme, cellulase and chitinases respectively.
Since DNA has a negative charge , it moves towards the anode of the electrophoretic chamber.
So, the correct option is 'Option C' .
Pyrimidines have nitrogen atoms at ____positions.
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1',3',7',9'
0%
1',5',7',9'
0%
1',3'
0%
1',9'
Explanation
The pyrimidine bases have a 6‐membered ring with two nitrogens and four carbons. As
it can be seen in the structure, pyrimidine have nitrogen atoms at 1', 3' positions.
So, the correct option is '
1',3'.
Which out of the following statements is incorrect?
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Genetic code is ambiguous.
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Genetic code is degenerate.
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Genetic code is universal.
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Genetic code is non-overlapping.
Explanation
Since there are 64 triplet codons and only 20 amino acids, genetic code is non-ambiguous. Non-ambiguous code means that there is no ambiguity about a particular code. One codon specifies only one amino acid and not any other except GUG which normally codes for valine but in certain conditions it also codes for N-formyl methionine as initiation codon.
Choose the correct answer from the alternatives given :
The semi-conservative nature of DNA replication was established by Meselson and Stahl in their classic experiment with bacteria They grew bacteria in $$N^{15} \, - \, NH_4Cl$$ containing medium, washed and then incubated in fresh medium with $$N^{14}$$ - containing compounds and allowed to grow for three generations. $$C_5Cl$$ density gradient centrifugation of isolated DNA established the nature of semiconservative DNA Replication. The pictorial representation below shows the position of differentially labeled DNA in $$C_5Cl$$ density gradient. Had the DNA replication been conservative, what would have been the pattern?
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0%
0%
0%
Explanation
Correct option: C
Explanation:
If the replication had been conservative then the two strands of DNA would have been preserved in one daughter cell and in other an entirely new DNA would have been formed. Hence no hybrid N14/N15 DNA would have been observed.
As the bacteria are grown for one generation in N15 medium and then for three generations in N14 medium, therefore, the amount of N14 DNA will be more than that of N15 DNA.
So, the correct answer is 'C'.
The amino acid attaches to the tRNA at its
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5' - end
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3' - end
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Anticodon site
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DHU loop
Explanation
tRNA has anticodon loop that has bases complementary to the code, it also has an amino acid acceptor end by which it binds to amino acids. The site lies at the 3' end opposite the anticodon in tRNAs are specific for each amino acid.
Which of the following Is correct regarding genetic code?
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UUU is the initiation codon which also codes for phenylalanine.
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There are 64 triplet codons and only 20 amino adds.
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Three random nitrogen bases specify the placement of one amino acid.
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UAA is the nonsense codon which also codes for methionine.
Explanation
Once transcription and processing of rRNAs, tRNAs and snRNAs are completed, the RNAs are ready to be used in the cell ‑ assembled into ribosomes or snRNPs and used in splicing and protein synthesis. But the mature mRNA is not yet functional to the cell. It must be translated into the encoded protein. The nucleotide triplet that encodes an amino acid is called a codon. Each group of three nucleotides encodes one amino acid. Since there are 64 combinations of 4 nucleotides taken three at a time and only 20 amino acids, the code is degenerate (more than one codon per amino acid, in most cases). The adaptor molecule for translation is tRNA. A charged tRNA has an amino acid at one end, and at the other end it has an anticodon for matching a codon in the mRNA. The machinery for synthesizing proteins under the direction of template mRNA is the ribosome.
So the correct option is 'there are 64 triple codons and only 20 amino adds'.
The sequencing of the entire genome (the totality of all genes) of an organism was completed inThe organism was
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Human being
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Yeast
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Albino mouse
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Plasmodium vivax
Explanation
The sequencing of the entire genome of an organism was completed in 1996 and the organism was yeast.
So, the correct option is '
Yeast'.
Find the sequence of binding of the following amino acyl-tRNA complexes during translation of an mRNA transcribed by a DNA segment having the base sequence 3'TACATGGGTCCG5'. Choose the answer showing the correct order of alphabets.
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P, Q, S, R
0%
Q, P, S, R
0%
P, Q, R, S
0%
Q, P, R, S
Which of the following biologists has been dubbed as the architect of molecular biology?
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Francis Crick
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Frederick Sanger
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Jacques Lucien Monod
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James Watson
Explanation
The advent of molecular biology and the discovery of DNA (Watson and Crick, 1953) provided techniques.
So, the correct option is 'Francis Crick'.
One of the following is true with respect to AUG
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it codes for methionine only
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it is also an initiation codon
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it codes for methionine in both prokaryotes and eukaryotes
0%
all of the above
Explanation
AUG one of the codes in the genetic code is the initiation code which means that it
is the first
codon
of a messenger RNA (mRNA) transcript translated by a ribosome. The
start codon
always codes for methionine an amino acid and is universal and codes for the same in both the prokaryotes and eukaryotes.
SO, the correct answer is 'All of the above'.
Which of the following option shows correct matching of Column - I and Column - II.
Column - I
Column - II
(i) Degeneration codon
(a) AUG
(ii) Initiation codon
(b) UAG
(iii) Non - sense codons
(c) AGU
(iv) Anti codon (UCA)
(d) AGA
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(i - c) (ii - b) (iii - a) (iv - d)
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(i - d) (ii - a) (iii - b) (iv - c)
0%
(i - b) (ii - d) (iii - a) (iv - c)
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(i - d) (ii - c) (iii - b) (iv - a)
Explanation
Degeneration codon is a codon which along with other codon/s specify for a single amino acid. AGA codes for arginine amino acid. The same amino acid is encoded by AGG, CGA, CGC, CGG, CGT codons. Initiation codon is the first codon of the mRNA. AUG is an initiation codon that codes for methionine. Non-sense codons causes termination of translation. There are 3 non-sense codons, namely UAG, UAA and UGA. Anti codon is a region present on tRNA that is complementary to a codon in the mRNA. Anti codon for TCA is AGU.
Thus, the correct answer is '(i - d) (ii - a) (iii - b) (iv - c).'
The technique of DNA finger printing was initially developed by
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lan wilmut
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Hargobind Khorana
0%
Jacque Monod
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Alec Jeffreys
0%
Francois Jacob
Explanation
DNA profiling is the process of determining an individual's DNA characteristics, which are as unique as fingerprints. The technique was developed in 1984 by British geneticist Alec Jeffreys.
So, the correct option is D, 'Alec Jeffreys'.
Basis of DNA fingerprinting is
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relative proportion of purines and pyrimidines
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relative difference in DNA occurrence in blood, skin and saliva
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relative amounts of DNA in ridges and groves of fingerprints
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satellite DNA occuring as highly short DNA segments.
Explanation
By cutting a sample of DNA into fragments and comparing it with other samples it's possible to work out if the DNA has come from the same person. This technique is called DNA fingerprinting, and is a technique used to help solve crimes where the suspect may have left a sample of body tissue at the crime scene. Satellite DNA consists of very large arrays of tandemly repeating, non-coding DNA. Satellite DNA is the main component of functional centromeres, and form the main structural constituent of heterochromatin. The term satellite is used to describe DNA sequences that comprise short head-to-tail tandem repeats incorporating specific motifs. So, the correct option is "Satellite DNA occurring as highly short DNA segments."
The toxin produced by the bacteria that is responsible for the development of diarrhea is produced by a section of DNA that has the code CCT TAT CAG. The sequence of amino acids produced by this sequence is ____________.
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Glycine - isoleucine - aspartic acid
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Glycine - isoleucine - valine
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Glycine - tyrosine - valine
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Glycine - tyrosine - isoleucine
Explanation
$$\begin{array}{l}CCT\,GGU \to Giu\\TAT\,AUA \to Iso\\CAG\,GUC \to Val\end{array}$$
Select the correct one in reference to Wobble hypothesis.
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Third base of codon lacks vibrating capacity.
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Third base can establish H-bonds even with the non-complementary anticodon.
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Specificity of a anticodon is particularly determined by first two codon.
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Major cause of degeneracy is the first two N-bases of codon.
Explanation
The wobble hypothesis explains the degeneracy of codon (one amino acid can be coded by more than one codon). It explains that t-RNA containing one amino acid can bind to more than one codon which depends on the nonprecise base pairing between the third base of the codon and the first base of anticodon this explains that the third base can establish H-bonds even with the non-complementary anticodon.
So, the correct answer is 'Third base can establish H-bonds even with the non-complementary anticodonn'.
Teminism is same as _____.
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Transcription
0%
Translation
0%
Reverse transcription
0%
DNA synthesis
Explanation
Teminism is a theory. It is popularly known as reverse transcription.
It is discovered by Temin and Baltimore in 1978. In molecular biology, Teminism theory explains that RNA can act as a template for the DNA formation, that is, DNA can be synthesized from RNA.
Thus teminism is same as reverse transcription.
So, the correct answer is 'Reverse transcription'.
1.38 milimeter DNA is present in E. coli. How many base pair will be present in it?
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$$4 \times 10^6 bp$$
0%
$$4 \times 10^7 bp$$
0%
$$4 \times 10^8 bp$$
0%
$$4 \times 10^5 bp$$
Explanation
The distance between two base pairs is 0.34 X 10$$^{-9}$$ m.
The total length of DNA in
E. coli
is 1.38 millimeter.
Total length of DNA = the total number of base pairs x distance between two consecutive base pairs
Hence, total number of base pairs = total length of DNA / distance between two consecutive base pairs
= 1.38 /
0.34 X
10$$^{-9}$$ =
4 X 10$$^6$$ base pairs.
Thus, the correct answer is '4 x 10$$^6$$ bp'.
Name the enzyme which removes the non coding split genes
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Ribosome
0%
Lysozyme
0%
Ribozyme
0%
Helicase
Explanation
Ribozymes (ribonucleic acid enzymes) are RNA molecules that are capable of catalyzing specific biochemical reactions, similar to the action of protein enzymes.
They also participate in a variety of RNA processing reactions, including RNA splicing, viral replication, and transfer RNA biosynthesis.
Hence. Ribozyme removes the non-coding split genes.
So, the correct answer is 'Ribozyme'.
Transfer of information from molecule of DNA to mRNA is called as
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Transcription
0%
Translation
0%
Replication
0%
None of the above
Explanation
Transfer of information from molecule of DNA to mRNA is called as transcription. Translation of mRNA into amino acid sequence of protein is called as translation. The process of producing two identical copies of DNA from one original double stranded DNA molecule is called as replication.
Thus, the correct answer is 'Transcription.'
Replication in prokaryotes differ from replication in eukaryotes for which of the following reasons?
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Prokaryotes have telomeres but eukaryotes do not
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Prokaryotes produces Okazaki fragments but eukaryotes do not
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The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes
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Prokaryotes have a single origin of replication (ori -site) whereas eukaryotes have many ori -sites
Explanation
A. The telomeres are structures at the end of linear chromosomes to keep the chromosome from being degraded by particular molecules in the cell. But in case of prokaryotes have circular chromosomes, there is no need for them. So the telomeres only found in the eukaryotes, linear chromosomes.
B. A building block for DNA synthesis of the lagging strand.
C. The rates are not comparable, as elongation only occurs in prokaryotes.
D. Ori is the DNA sequence that signals for the origin of replication, sometimes referred to simply as the origin. Prokaryotes have a single ori-site and eukaryotes have many ori-sites.
So the correct answer is "D".
Calculate the number of nitrogen bases in E.coli, if the length of E.coli DNA is 1.36 mm.
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$$4 \times 10^6$$
0%
$$8 \times 10^6$$
0%
$$2 \times 10^6$$
0%
$$16 \times 10^6$$
Explanation
The distance between two base pairs is 0.34 X 10$$^{-9}$$ m.
The total length of DNA in
E. coli
is 1.36 mm.
Total length of DNA = the total number of base pairs x distance between two consecutive base pairs
Hence, total number of base pairs = total length of DNA / distance between two consecutive base pairs
= 1.36 /
0.34 X
10$$^{-9}$$ =
4 X 10$$^6$$ base pairs.
Thus, the correct answer is '4 x 10$$^6$$.'
Light DNA ($$14_N$$) transferred to $$15_N$$ labelled culture medium for replication. The ratio of the total number of $$15_N$$ and $$14_N$$ labeled strands of DNA extracted from the culture after three generations is
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0%
1 : 3
0%
7 : 1
0%
1 : 15
0%
15 : 1
Explanation
According to the figure, after three generations hybrid strands(N$$^(14$$, N$$^{15)$$) and light strands (
N$$^(14$$,
N$$^(14$$) is in the ratio 1:3
So, the correct answer is "1:3".
If a triplet on template DNA is AAA, what will be the anticodon on tRNA
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UUU
0%
AAA
0%
TTT
0%
AUG
Explanation
Correct option: B
Explanation:
The template strand of DNA has AAA sequence, which will be transcribed to mRNA as UUU. Then. the anticodon on tRNA to this mRNA would have
AAA
sequence.
Thus, the correct answer is 'AAA'. Option B is correct.
All living organisms of the present,past and future are
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Not linked to any extent
0%
Linked to one another in their cell membrane
0%
Linked to one another by the sharing of the common genetic materials ,but to varying degrees
0%
Linked to another by the sharing of the common genetic material to $$100\%$$ extent
Explanation
All living organisms—present, past and future are linked to one another by the sharing of the common genetic material, but to varying degrees.
The genetic material of living organisms undergoes mutations and reshuffling of genes. This causes variations in the genetic material. Variations are so abundant that no two individuals of the same race are exactly similar.
So the answer is 'Linked to one another by the sharing of the common genetic materials, but to varying degrees'.
Maximum possible transversion, which may take place in genetic code
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$$366$$
0%
$$183$$
0%
$$549$$
0%
In each coden $$9$$ only
Explanation
Transversion is a type of gene mutation in which single purine is changed into pyrimidine. The process may be transversion. It explains the distributation of gene coding.
So, the correct option is '366'.
By using only one of the two strands of DNA, mRNA is produced this process is called as _____
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Transcription
0%
Translation
0%
Translocation
0%
Replacement
Explanation
Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA.
So, the correct option is, 'Transcription'.
Purine base of DNA molecule has
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A and C
0%
C and T
0%
A and G
0%
None of the above
Explanation
Purine base of DNA molecule has Adenine(A) and Guanine(G) which bond with their complimentary pyrimidines, Thymine(T) and Cytosine(C) respectively.
A purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring.
So, the correct answer is 'A and G'.
The ratio of $$H_1$$ and $$H_3$$ proteins in chromatin is
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0%
$$1:2$$
0%
$$2:1$$
0%
$$1:1$$
0%
$$1:4$$
Explanation
The chromatin structure of DNA is formed by folding or wraping of DNA around the nucleosome
The nucleosome is made up of an octamer of 4 histone proteins in dimeric condition
So, $$H_3$$ protein which also forms the nucleosome exists in dimeric state or two units
For every nucleosome there exists only one $$H_1$$ protein present on the exterior clamping the nucleosome structure
Therefore, the ratio of $$H_1$$ to $$H_3$$ is 1:2
So, the correct answer is '1:2'
Sequencing of genomic DNA is included under
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Structural genomics
0%
Functional genomics
0%
Proteomics
0%
Transgenesis
Explanation
Structural genomics refers to the process of studying and characterizing the genes in the genome of organisms. It involves sequencing of genomic DNA because the nucleotides are studied and arranged in order as they appear in DNA. Functional genomics refers to the use of the information gathered in structural genomics such as gene therapy.
Hence, the correct answer is 'Structural genomics'.
Read the statements given below.
I. Thiamine and Uracil are pyrimidines found in DNA & RNA respectively.
II. Number of base pairs per turn in B - DNA helix is 10.
Choose the correct option.
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Both statements I & II are correct
0%
Only statement II is correct
0%
Both statement I & II are incorrect
0%
Only statement I is correct.
Explanation
Thymine and uracil are pyrimidines (nitrogenous bases) found in DNA & RNA respectively.
It is a characteristic feature of both these nucleic acids. On the other hand, B-DNA, the most common double-helical structure found in nature, has a double helix which is right-handed with about 10–10.5 base pairs per turn.
So, the correct option is 'both the statements I & II are correct'.
No. of of phosphoester bonds found in one turn of DNA is ____________.
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0%
$$18$$
0%
$$10$$
0%
$$40$$
0%
$$38$$
Explanation
There are 10 base pair in one turn of DNA and two phosphodiester bonds are present between two adjacent base pairs,therefore there must be 9 phosphodiester bonds in one side of the 10 base pair and 9 phosphodiester bond on the other side.so the total number of phosphodiester bonds found in one turn of DNA is 18. so, 'the correct option is 18'.
Sometimes the starting codon is GUG in place of AUG, GUG normally stands for ___________.
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0%
Valine
0%
Glycine
0%
Methionine
0%
Tyrosine
Explanation
In, DNA the start codon initiates the translation of the first amino acid in the polypeptide chain. The most common
start codon
is AUG and codes for
methionine.
GUG
is an efficient
initiation codon or start codon and codes for Valine. AUG is the start codon
83% of the time and GUG 14% of the time
So, the correct answer is "A Valine".
Which enzyme polymerizes RNA with defined sequence in a template independent manner?
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Peptidyl transferase
0%
RNA Polymerase
0%
Reverse transcription
0%
Polynucleotide phosphorylase
Explanation
Polynucleotide phosphorylase polymerizes RNA with defined sequence in a template independent manner. PNPase is a bifunctional enzyme with a phosphorolytic 3' to 5' exoribonuclease activity and a 3'-terminal oligonucleotide polymerase activity.
So, the correct option is '
Polynucleotide phosphorylase'.
How many among the following organisms hve linear ds DNA as their genetic material?
Homo sapiens, Escherichia coil, Drosophila, $$\phi \times 174$$ bacteriophage
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0%
$$1$$
0%
$$4$$
0%
$$3$$
0%
$$2$$
Explanation
All eukaryotes have double-stranded DNA which is linear.
Also, Bacteriophage and E. coli have ds DNA.
So, the correct option is '4'.
Complete the steps for the separation and isolation of $$DNA$$ fragments.
(i) $$DNA$$ fragment separates in matrix of________.
(ii) $$DNA$$ fragments are stained with______
(iii) $$DNA$$ fragments are viewed under_________
(iv) Fragments are extruded from gel piece. This is called________
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Agarose gels,ethidium bromide, UV light, elution
0%
Polyacrylamide gels, ethidium bromide, UV light, elution
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Polyacrylamide gels, ethidium bromide, X-ray light, elution
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Agarose gels,ethidium bromide, X- ray light, extraction
Explanation
A. DNA fragment separates in the matrix of agarose.
B. DNA fragments are stained with ethidium bromide.
C. DNA fragments are viewed under UV light.
D. DNA fragments are extruded from a gel piece. This is called elution.
If heat killed S-III and live R-II are mixed then?
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Something from S-III enters into R-II
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Something from R-II enters into S-III
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R-II receives material its nature changes
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A and C both
The following picture depicts the DNA .What is the structure of DNA ?
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Spherical
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Double Helix
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Dumbell
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Renal and longitudinal
Explanation
DNA is a long polymer of deoxyribonucleotides that has a double helical structure with a sugar-phosphate backbone where nitrogenous bases project inside and are paired together with the help of hydrogen bonds, that forms the double stranded structure of the DNA.
So, the correct option is 'Double helix'
In bacteria, DNA has no free ends and is not associated with
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Polyamines
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Histone
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RNA
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More than one option is correct
Read the given statement and statements and select the correct option.
Statement 1: The alien DNA is cloned in the host organism by integrating it in host DNA.
statement II: The alien DNA has specific DNA sequence called origin of replication, which help it join to host genome.
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statement I is correct, statement II is incorrect.
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statement i is incorrect, statement II is correct.
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Both statements I and II are correct
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Both statements I and II are incorrect
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Practice Class 12 Medical Biology Quiz Questions and Answers
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