1. In DNA , the nitrogenous bases are :
( A ) ATUC
( B ) AUGC
( C ) UTGC
( D ) ATGC
Answer-( D )
2. Pyrimidines in DNA are :
( A ) thymine and cytosine
( B ) cytosine and guanine
( C ) adenine and uracil
( D ) adenine and thymine
Answer-( A )
3. Anticodon is associated with :
( A ) TRNA
( B ) mRNA
( C ) rRNA
( D ) genetic RNA
Answer-( A )
4. In double helix of DNA , the two DNA strands are :
( A ) coiled upon itself around a common axis
( B ) coiled around each other
( C ) coiled differently
( D ) coiled over protein sheath
Answer-( A )
5. Most abundant RNA of the cell is :
( A ) TRNA
( B ) rRNA
( C ) mRNA
( D ) tRNA threonini
Answer-( B )
6. DNA strand are antiparallel because of :
( A ) H-bonds
( B ) phospho-diester bonds
( C ) disulphide (S-S bonds)
( D ) none of the above
Answer-( B )
7. In double helix model of DNA how far is each base pair from the next ?
( A ) 34nm
( B ) 3.4 nm
( C ) 2 nm
( D ) 0.34 nm
Answer-( D )
8 How many nucleotides are found in one spiral of B DNA ?
( A ) 5
( B ) 10
( C ) 20
( D ) 25
Answer-( C )
9. If DNA has 10 spirals, the length of DNA will be :
( A ) 34 Å
( B ) 340 Å
( C ) 640 Å
( D ) 64 Å
Answer-( B )
10. The basic unit (monomer) of a nucleic acid molecule is :
( A ) nucleoside
( B ) nucleotide
( C ) nitrogenous base
( D ) pentose sugar
Answer-( B )
11. RNA differs from DNA in nature of :
( A ) sugar and purines
( B ) sugar and pyrimidines
( C ) purines and phosphate
( D.) sugar and phosphate
Answer-( B )
12. Nitrogen base is attached to pentose sugar in a nucleoside at carbon atom :
( A )1
( B ) 2
( C ) 3
( D ) 5
Answer-( A )
13. Which one is a nucleotide ?
( A ) Uridylic acid
( B ) Thymidine
( C ) Cytosine
( D ) Glutamic acid
Answer-( A )
14. Which RNA is short lived :
( A ) mRNA
( B ) TRNA
( C.) rRNA
( D ) SnRNA
Answer-( A )
15. Hydrogen bonds present between cytosine and guanosine are :
( A ) 2
( B ) 3
( C ) 1
( D ) 4
Answer-( B )
16. The terminal (stop) condon is :
( A )UAG (Amber)
( B )UAA (Ochre)
( C )UGA (Opal)
( D ) All of these
Answer-( D )
17. There are 100 amino acids. How many types of proteins can be formed by triplet genetic code ?
( A ) 20¹⁰⁰
( B ) (100)²⁰
( C )100 x 20 x 3
( D )100 x 3
Answer-( A )
18. Of 64 codons in a genetic code,how many codons are responsible for specifying 20 types of amino acids :
( A ) 61
( B ) 64
( C ) 20
( D ) 59
Answer-( A )
19. The initiation codon in protein synthesis is :
( A ) AUG
( B ) GUG
( C )met
( D ) AUG and GUG
Answer-( B )
20. The genetic code occurs in :
( A ) rRNA
( B ) TRNA
( C ) rDNA
( D ) mRNA
Answer-( D )
