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Read the following statements and choose...

Read the following statements and choose the correct option.
A. Nitrogenous base is linked to the pentose sugar through a N- glycosidic linkage.
B. Phosphate group is linked to 5'-OH of a nucleoside through phosphoester linkage.
C. Two nucleosides are linked through 3'-5' N- glycosidic linkage.
D. Negatively charged DNA is wrapped around positively charged histone octamer to form nucleosome.

A

i and ii are wrong

B

iv along is wrong

C

iii and v are wrong

D

i along is wrong

Text Solution

Verified by Experts

The correct Answer is:
C
Chromatin that is more densely packed and stains dark is called heterochromatin.
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Read the following statements and choose the correct option. A. Nitrogenous base is linked to the pentose sugar through a N-glycosidic linkage. B. Phosphate group is linked to 5'-OH of a nucleoside through phosphoester linkage. C. Two nucleosides are linked through 3'-5' N-glycosidic linkage. Negatively charged DNA is wrapped around positively charged histone octamer to form nucleosome. E. The chromatin that is more densely packed and stains dark is called euchromatin.

Go through the following statements: (i) In RNA the uracil is found in place of 5-methyl uracil (ii) A nitrogenous base is linked to the pentose sugar through an N-glycosidic linkage to form a nucleoside (iii) Two nucleotides are linked through 3'-5' phosphodiester linkage to form a dinucleotide. (iv). The length of double DNA helix in a typical mammalian cell is approximately 3.2 metres. find out the correct statement

Read the following statements and find out the incorrect statements. a. The length of DNA is usually defined as number of nucleotides or base pairs present in it. b. In DNA, every nucleotide residue has an additional -OH group present at 2' -position in the deoxyribose. c. Nuclein was discovered and named by Friedrich Meisher in 1969. d. Adenine pair with Thymine and Guanine with Cytosine through H-bonds. This makes one strand complementary to the other. e. the proposition of double helical model of DNA was also based on the observation of Erwin Chargaff.

Read the passage given below and answer the question: EVIDENCE FOR THE FIBROUS NATURE OF DNA The basic chemical formula of DNA is now well established. As shown in Figure 1 it consists of a very long chain, the backbone of which is made up of alternate sugar and phosphate groups, joined together in regular 3' 5' phosphate di-ester linkages. To each sugar is attached a nitrogenous base, only four different kinds of which are commonly found in DNA. Two of these---adenine and guanine--- are purines, and the other two thymine and cytosine-are pyrimidines. A fifth base, 5-methyl cytosine, occurs in smaller amounts in certain organisms, and a sixth, 5-hydroxy-methyl-cytosine, is found instead of cytosine in the T even phages. It should be noted that the chain is unbranched, a consequence of the regular internucleotide linkage. On the other hand the sequence of the different nucleotides is, as far as can be ascertained, completely irregular. Thus, DNA has some features which are regular, and some which are irregular. A similar conception of the DNA molecule as a long thin fiber is obtained from physicochemical analysis involving sedimentation, diffusion, light scattering, and viscosity measurements. These techniques indicate that DNA is a very asymmetrical structure approximately 20 A wide and many thousands of angstroms long. Estimates of its molecular weight currently center between 5 xx 10^6 and 10^7 (approximately 3 xx10^4 nucleotides). Surprisingly each of these measurements tend to suggest that the DNA is relatively rigid, a puzzling finding in view of the large number of single bonds (5 per nucleotide) in the phosphate-sugar back bone. Recently these indirect inferences have been confirmed by electron microscopy. (source: Watson, J. D., & Crick, F.H. (1953, January). The structure of DNA. In Cold Spring Harbor symposia on quantitative biology (Vol. 18, pp. 123-131). Cold Spring Harbor Laboratory Press.) DNA molecule has _______ internucleotide linkage and ______ sequence of the different nucleotides

Read the passage given below and answer the question: EVIDENCE FOR THE FIBROUS NATURE OF DNA The basic chemical formula of DNA is now well established. As shown in Figure 1 it consists of a very long chain, the backbone of which is made up of alternate sugar and phosphate groups, joined together in regular 3' 5' phosphate di-ester linkages. To each sugar is attached a nitrogenous base, only four different kinds of which are commonly found in DNA. Two of these---adenine and guanine--- are purines, and the other two thymine and cytosine-are pyrimidines. A fifth base, 5-methyl cytosine, occurs in smaller amounts in certain organisms, and a sixth, 5-hydroxy-methyl-cytosine, is found instead of cytosine in the T even phages. It should be noted that the chain is unbranched, a consequence of the regular internucleotide linkage. On the other hand the sequence of the different nucleotides is, as far as can be ascertained, completely irregular. Thus, DNA has some features which are regular, and some which are irregular. A similar conception of the DNA molecule as a long thin fiber is obtained from physicochemical analysis involving sedimentation, diffusion, light scattering, and viscosity measurements. These techniques indicate that DNA is a very asymmetrical structure approximately 20 A wide and many thousands of angstroms long. Estimates of its molecular weight currently center between 5 xx 10^6 and 10^7 (approximately 3 xx10^4 nucleotides). Surprisingly each of these measurements tend to suggest that the DNA is relatively rigid, a puzzling finding in view of the large number of single bonds (5 per nucleotide) in the phosphate-sugar back bone. Recently these indirect inferences have been confirmed by electron microscopy. (source: Watson, J. D., & Crick, F.H. (1953, January). The structure of DNA. In Cold Spring Harbor symposia on quantitative biology (Vol. 18, pp. 123-131). Cold Spring Harbor Laboratory Press.) Out of the four different kinds of nitrogenous bases which are commonly found in DNA, _______ has been replaced in some organisms.

Read the passage given below and answer the question: EVIDENCE FOR THE FIBROUS NATURE OF DNA The basic chemical formula of DNA is now well established. As shown in Figure 1 it consists of a very long chain, the backbone of which is made up of alternate sugar and phosphate groups, joined together in regular 3' 5' phosphate di-ester linkages. To each sugar is attached a nitrogenous base, only four different kinds of which are commonly found in DNA. Two of these---adenine and guanine--- are purines, and the other two thymine and cytosine-are pyrimidines. A fifth base, 5-methyl cytosine, occurs in smaller amounts in certain organisms, and a sixth, 5-hydroxy-methyl-cytosine, is found instead of cytosine in the T even phages. It should be noted that the chain is unbranched, a consequence of the regular internucleotide linkage. On the other hand the sequence of the different nucleotides is, as far as can be ascertained, completely irregular. Thus, DNA has some features which are regular, and some which are irregular. A similar conception of the DNA molecule as a long thin fiber is obtained from physicochemical analysis involving sedimentation, diffusion, light scattering, and viscosity measurements. These techniques indicate that DNA is a very asymmetrical structure approximately 20 A wide and many thousands of angstroms long. Estimates of its molecular weight currently center between 5 xx 10^6 and 10^7 (approximately 3 xx10^4 nucleotides). Surprisingly each of these measurements tend to suggest that the DNA is relatively rigid, a puzzling finding in view of the large number of single bonds (5 per nucleotide) in the phosphate-sugar back bone. Recently these indirect inferences have been confirmed by electron microscopy. (source: Watson, J. D., & Crick, F.H. (1953, January). The structure of DNA. In Cold Spring Harbor symposia on quantitative biology (Vol. 18, pp. 123-131). Cold Spring Harbor Laboratory Press.) Purines present in DNA are:

A2Z-MOLECULAR BASIS OF INHERITANCE-Section D: Chapter -end Test
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  2. Wobble hypothesis establishes :

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  3. DNA replication in eukaryotes commences :

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  4. An anticodon of t-RNA can recognize more than one codon of m-RNA . It ...

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  5. Who proposed that genes control production of enzymes ?

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  6. Nobel Prize for one gene one enzyme hypothesis was given to

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  7. The number of base substitution possible in amino acid codons is

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  8. Find out the correct answers out of the following discoveries. 1. Gr...

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  9. Protein helping in opening of DNA double helix in front of replication...

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  10. Lac operon is

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  11. Who synthesised the first artificial gene ?

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  12. tRNA recognises ribosome by

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  13. A mutation at one base of the first codon of a gene produces a non-fun...

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  14. Jacob and Monod won Nobel Prize for their work on

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  15. Temin worked on virus

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  16. Reverse transcription was discovered by

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  17. Transition mutation is due to replacement of

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  18. Which organism was used by Beasdle and Tatum to proposed one gene one ...

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  19. Which one is involved in DNA repair ?

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  20. H.G. Khorana was awarded the Nobal Prize for :

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  21. Telomere of eukaryotic chromosome possess short segments

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