Molecular Basis of Inheritance

Which of the following statements are correct with reference to packaging of DNA helix ? Choose the correct answer from the options given below :

1. B, D and E only
2. A, B and D only
3. C, D and E only
4. A, C and E only

Histones are enriched with -

1. Phenylalanine & Leucine
2. Phenylalanine & Arginine
3. Lysine & Arginine
4. Leucine & Lysine

Given below are two statements: In the light of the above statements, choose the correct answer from the options given below:

1. Both Statement I and Statement II are false.
2. Statement I is correct but Statement II is false.
3. Statement I is incorrect but Statement II is true.
4. Both Statement I and Statement II are true.

Read the following statements and choose the set of correct statements: Choose the correct answer from the options given below :

1. (B), (D), (E) only
2. (A), (C), (D) only
3. (B), (E) only
4. (A), (C), (E) only

If the length of a DNA molecule is 1.1 metres, what will be the approximate number of base pairs?

1. 3.3 109 bp
2. 6.6 109 bp
3. 3.3 106 bp
4. 6.6 106 bp

If A and C make 30% and 20% of DNA, respectively, what will be the percentage composition of T and G?

1. T : 20%, G : 20%
2. T : 20%, G : 30%
3. T : 30%, G : 20%
4. T : 30%, G : 30%

If Adenine makes 30% of the DNA molecule, what will be the percentage of Thymine, Guanine and Cytosine in it?

1. T : 20 ; G : 25 ; C : 25
2. T : 20 ; G : 30 ; C : 20
3. T : 20 ; G : 20 ; C : 30
4. T : 30 ; G : 20 ; C : 20

Which one of the following statements about histones is wrong?

1. Histones carry positive charge in the side chain
2. Histones are organized to form a unit of 8 molecules
3. The pH of histones is slightly acidic
4. Histones are rich in amino acids - Lysine and Arginine

If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6 109 bp, then the length of the DNA is approximately

1. 2.7 meters
2. 2.0 meters
3. 2.5 meters
4. 2.2 meters

Which of the following statements is correct?

1. Adenine does not pair with thymine
2. Adenine pairs with thymine through one H-bond
3. Adenine pairs with thymine through two H-bonds
4. Adenine pairs with thymine through three H-bonds

Purines found both in DNA and RNA are:

1. Guanine and cytosine
2. Cytosine and thymine
3. Adenine and thymine
4. Adenine and guanine

The association of histone H1 with a nucleosome indicates :

1. DNA replication is occurring
2. Transcription is occurring
3. The DNA is condensed into a Chromatin Fibre
4. The DNA double helix is exposed

Which one of the following is not applicable to RNA?

1. Complementary base pairing
2. 5' phosphoryl and 3' hydroxyl ends
3. Heterocyclic nitrogenous bases
4. Chargaff's rule

Identify the correct order of organisation of genetic material from largest to smallest :

1. Chromosome, genome, nucleotide, gene
2. Genome, chromosome, nucleotide, gene
3. Genome, chromosome, gene, nucleotide
4. Chromosome, gene, genome, nucleotide

In sea urchin DNA, which is double stranded, 17% of the bases were shown to be cytosine. The percentages of the other three bases expected to be present in this DNA are

1. G 17%, A 16.5%, T 32.5%
2. G 17%, A 33%, T 33%
3. G 8.5%, A 50%, T 24.5%
4. G 34%, A 24.5%, T 24.5%

The diagram shows an important concept in the genetic implication of DNA. Fill in the blanks A to C. [figure]

1. A-translation B-extension C-Rosalind Franklin
2. A-translation B-transcription C-Erwin Chargaff
3. A-transcription B-translation C-Francis Crick
4. A-transcription B-replication C-James Watson

[figure] The figure gives an important concept in the genetic implication of DNA. Fill the blanks A, B and C.

1. A - Erwin Chargaff B - translation C - replication
2. A - Maurice Wilkins B - transcription C - translation
3. A - Francis Crick B - translation C - transcription
4. A - James Watson B - replication C - extension

What are those structures that appear as 'beads-on-string' in the chromosomes when viewed under electron microscope ?

1. Nucleosomes
2. Genes
3. Nucleotides
4. Base pairs

The 3'-5' phosphodiester linkages inside a polynucleotide chain serve to join -

1. One nucleotide with another nucleotide
2. One nitrogenous base with pentose sugar
3. One nucleoside with another nucleoside
4. One DNA strand with the other DNA strand

Which one of the following statements about the particular entity is true?

1. Nucleosome is formed of nucleotides
2. Centromere is found in animal cells, which produces aster during cell division
3. The gene for producing insulin is present in every body cell
4. DNA consists of a core of eight histones

Which one of the following does not follow the central dogma of molecular biology ?

1. Mucor
2. HIV
3. Chlamydomonas
4. Pea

In the DNA molecule:

1. the total amount of purine nucleotides and pyrimidine nucleotides is not always equal
2. there are two strands which run antiparallel one in 5' 3' direction and other in 3' 5'
3. there are two strands which run parallel in the 5' 3' direction
4. the proportion of adenine in relation to thymine varies with the organism

Which one of the following pairs of nitrogenous bases of nucleic acids is wrongly matched with the category mentioned against it?

1. Thymine, Uracil — Pyrimidines
2. Guanine, Adenine — Purines
3. Uracil, Cytosine — Pyrimidines
4. Adenine, Thymine — Purines

One turn of the helix in a B-form DNA is approximately -

1. 20 nm
2. 3.4 nm
3. 2 nm
4. 0.34 nm

Antiparallel strands of a DNA molecule means that-

1. The phosphate groups at the start of two DNA strands are in opposite position (pole)
2. One strand turns anti-clockwise
3. One strand turns clockwise
4. The phosphate groups of two DNA strands, at their ends, share the same position

Which one of the following makes use of RNA as a template to synthesize DNA -

1. Reverse transcriptase
2. DNA dependent RNA polymerase
3. RNA polymerase
4. DNA polymerase

The following ratio is generally constant for a given species :-

1. A+CT+G
2. G+CA+T
3. A+GC+T
4. T+CG+A

The telomeres of eukaryotic chromosomes consist of short sequences of

1. Adenine rich repeats
2. Cytosine rich repeats
3. Thymine rich repeats
4. Guanine rich repeats

In a DNA percentage of thymine is 20% then what is the percentage of guanine : -

1. 40%
2. 20%
3. 30%
4. 60%

Length of one loop of B-DNA:

1. 20 nm.
2. 10 nm.
3. 3.4 nm.
4. 0.34 nm.