Cell biology IV - Nucleic acids

1. [A]: DNA and RNA are acidic in nature

    [R]: They have pentose sugars

    1) Both A and R are true and R is the correct explanation of A

    2) Both A and R are true but R is not the correct explanation of A

     3) A is true but R is false 4) A is false but R is true

2. The nitrogen base Cytosine is

    1) Monocyclic, Homocyclic                                2) Dicyclic, Heterocyclic

    3) Monocyclic, Heterocyclic                               4) Dicyclic, Homocyclic

3. In a given nucleotide

    1) Phosphate is attached to 1st position of Nitrogen base and Nitrogen base is attached       to 1st carbon of sugar

    2) Phosphate is attached to 2rd Carbon and Nitrogen base to the 1st carbon of the pentose sugar

   3) Uracil is attached to 1st Carbon of Deoxyribose and phosphate to the 5th carbon of the sugar

   4) Phosphate is attached to 5th carbon and Nitrogen base to the 1st carbon of Pentose sugar

4. These components of DNA are 5-Carbon substances

     I. Sugar        II. Adenine        III. Guanine       IV. Cytosine         V. Thymine

     1) All except V      2) All except II        3) All except IV          4) All except III

5. DNA replication is initiated with the catalytic activity of

   1) DNA polymerase      2) DNA ligase      3) Topoisomerase      4) Helicase

6. A given DNA has 4 spirals with the following condition in its different spirals

      I. A spiral with 28 hydrogen bonds         II. A spiral with 6 Guanine bases

     III. Spiral with 25 hydrogen bonds          IV. Spiral with 6 Adenine bases

  Arrange the above 4 different spirals in a sequence of gradual increase in the number of    methylated nitrogen bases

     1) I, II, III, IV      2) I, III, II, IV      3) IV, II, III, I        4) III, II, IV, I

7. In a B-DNA molecule, there are 300 hydrogen bonds, These hydrogen bonds are formed in 3:2 ratio between GC and AT. Then the ratio between number of Adenine and Cytosine bases in the DNA is

      1) 3:2           2) 2:3         3) 3:4             4) 1:1

8. The most common nitrogen base seen in various non-sense codons and initiating codons is

    1) Adenine   2) Guanine        3) Uracil                 4) Cytosine

9. Match the following

List – I                                                                                   List – II                                A B C D

A) Trasfer of genetic material from parents to offspring    I) Watson                        1) V I IV III

B) DNA as double stranded structure                                     II) E. Chargaff               2) V II III IV

C) Amount of Adenine is equal to the amount of Thymine in DNA III) L. Pauling     3) V I II III

D) Presence of 3 hydrogen bonds between Guanine and Cytosine IV) Avery etal 4) IV I II III

                                                                                                                 V) Hershey



10. Study the following table and choose the correct combination

Nucleic acid              Character I                                                           Character II

I) mRNA         Has intra-strand hydrogen bonds                                   Has codons

II) tRNA           Has intra-strand hydrogen bonds                          Anticodon can be UAA

III) DNA          Has inter strand hydrogen bonds            Every helix has 10 dicyclic nitrogen bases

IV) rRNA            Has inter strand hydrogen bonds                  synthesised on DNA stand

1) I and II               2) II and III                     3) III and IV                      4) I and IV

11. Guanine and Cytosine exist in 1:1 ratio but not Adenine and Thymine in

         1) M 13 virus        2) mRNA             3) tRNA                    4) Reovirus

12. The following nucleic acid always ends with Adenine nucleotide

                 1) mRNA                 2) tRNA                3) rRNA              4) DNA

13. rRNA is mainly transcribed on the DNA of chromosomes which must have

           1) Secondary constriction II                             2) Secondary constriction I

           3) Telocentric condition                                       4) Isobrachial chromosomes