DNA replicates semi-conservatively was first shown in

• Vicia faba

• E. coli

• Streptococcus pneumoniae

• Drosophila

• Drosophila

The enzyme that catalyses transcription of RNA in bacteria

• DNA dependent RNA polymerase

• RNA polymerase I

• DNA polymerase

• RNA polymerase II

• RNA polymerase II

A molecule to act as a genetic material has the following properties

(i) should be able to replicate

(ii) should be structurally more stable

(iii) should be more reactive and labile

(iv) should provide scope for slow changes

Choose the correct option

• (i), (ii) and (iii) are correct

• (iii) alone is correct

• (iii) and (iv) are correct

• (i), (ii) and (iv) are correct

• (i), (ii) and (iv) are correct

Choose the correct statement among the following

• Taylor and his colleagues used E.coli to prove semi-conservative replication of DNA

• In Griffith's experiment the mice infected with R-strain of Streptococcus pneumoniae died due to pneumonia. 

• Hershey and Chase proved the transforming principle experimentally

• Meselson and Stahl grew staphylococcus in a medium containing cesium chloride to prove DNA is the genetic material

• Meselson and Stahl grew staphylococcus in a medium containing cesium chloride to prove DNA is the genetic material

A nanometre is

• 10^–9m

• 10^–4m

• 10^–6m

• 10^–12m

• 10^–12m

The precursor of eukaryotic mRNA is

• 5srRNA

• tRNA

• rRNA

• snRNA

• snRNA

In a polynucleotide chain of a DNA molecule, the two nucleotides are linked through

• hydrogen bonds

• 5' – 3' phosphoester linkage

• 3' – 5' phosphodiester linkage

• N-glycosidic linkage

• N-glycosidic linkage

278.

Find the correctly matched enzyme with the rRNAs they transcribe

I. RNA polymerase    —   I 28S, 18S and 5.85 rRNAs

II. RNA polymerase   — III 28 S, 18S and 5.85 rRNAs

III. RNA polymerase  — II tRNA, 5srRNA and Sn(1c)RNAs

IV. RNA polymerase   — II hnRNA

• I and II only

• III and III only

• II only

• III and IV only

• III and IV only

If the total amount of adenine and thymine in a double stranded DNA is 55%, the amount of guanine in this DNA will be

• 45%

• 27.5%

• 25%

• 22.5%

• 22.5%

Structure of a polynucleotide chain of DNA is given below. Identify the locations (numbered 1 to 5) that show errors in the structure

• 1 and 3

• 1 and 4

• 3 and 5

• 2 and 4

• 2 and 4