Prob 1. Peptide linkage is





Sol. (D). Peptide linkage is formed when two amino acid combine with elimination of water.

Prob 2.  If one strand of a DNA has the sequence AATCGTAGGCAC.What is the sequence of complementary strand.

                  (A)  TTAGCATCCGTG                                 (B)  TTAGCATCCGTG

                  (C)  UUTCGTAGGCAC                                 (D)  UUAGCAUCCGUG

Sol.  DNA is AATCGTAGGCAC its complementary strand will be TTAGCATCCGTG.  Hence (B) is correct answer.

Prob 3. Structure of DNA molecule is

                  (A)  single stranded                                      (B)  linear

                  (C)  branched                                               (D)  double strand                     

 Sol. DNA always exists as double stranded, only at the time of replication or transcription it acts as template (single strand) for synthesis of new strand.

Prob 4. Which amino acid is achiral? 

                  (A)  Alanine                                                 (B)  Valine

                  (C)  Proline                                                  (D)  Histidine

                  (E)  None of these

 Sol.  All amino acid except glycine have asymmetric carbon atom so answer is (E).

 Prob 5.  Match items in list –I with those in the list – II form the combinations shown. 

List – I

List – II

(i) Pepsin (A) Genetic material
(ii) Nucleic acid (B) Digestive enzyme
(iii) Ascorbic acid (C) Antibiotic
(iv) Testosterone (D) Sex hormone
  (E) Vitamin

A)               I – B; II – A ; III – C ; IV – E                         (B)  I – A ; II – B ; III – E ; IV – C

                  (C)  I – B ; II – A ; III – E ; IV – D                  (D)  I – C ; II – A ; III – A ; IV – D

 Sol.    Answer is (B), pepsin is a diagestic enzyme, nucleic acid is genetic material, ascorbic acid is vitamin C and testosterone is sex hormone.

Prob 6. Which substance is not present in nucleic acids?

                  (A)  cytosine                                                (B)  adenine

                  (C)  thymine                                                 (D)  guanidine

 Sol.  Nitrogenous base in nucleic acids are

Purine – Adenine and guanine

Pyrimidine – Cytosine and Thymine or uracil

So answer (D) is correct.

 Prob 7.  Nylon-66 is a polyamide of

 (A)  Vinylchloride and formaldehyde              

 (B)  Adipic acid and methyl amine

(C)  Adipic acid and hexamethylene diamine  

 (D)  Formaldehyde and melamine


∴ (C)

Prob 8.  Which of the following is not a condensation polymer?

                  (A)  Glyptal                                                  (B)  Nylon-66

                  (C)  Dacron                                                  (D)  PTFE


Sol. Others are condensed polymer


Prob 9. Which of the following is an example of basic dye?

                  (A)  Alizarine                                                (B)  Indigo

                  (C)  Malachite                                              (D)  Orange – I



Prob 10. Which one of the following is a copolymer?

                  (A)  Buna-S                                                 (B)  Polyvinyl chloride

                  (C)  Polypropylene                                        (D)  Poly-cis-isoprene

Sol. (A). Polymers whose repeating units are derived from two or more types of monomers units, are called copolymer. Only Buna-S is obtained by the copolymerization of butadiene and styrene monomers. Other polymers (B), (C) and (D) are homopolymers, because they consists of only one type of monomers.

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