CBSE
DNA replicates semi-conservatively was first shown in
Vicia faba
E. coli
Streptococcus pneumoniae
Drosophila
Drosophila
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
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
The enzyme that catalyses transcription of RNA in bacteria
DNA dependent RNA polymerase
RNA polymerase I
DNA polymerase
RNA polymerase II
RNA polymerase II
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%
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
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