Which one of the following makes use of RNA as a template to synthesize DNA?
Reverse transcriptase
DNA dependant RNA polymerase
DNA polymerase
RNA polymerase
During transcription holoenzyme RNA polymerase binds to a DNA sequence and the DNA assumes a saddle like structure at that point. What is that sequence called?
CAAT box
GGTT box
AAAT box
TATA box
D.
TATA box
TATA box is present in eukaryotic promoter region. It has a resemblance with pribnow box of prokaryotes. TATA box was identified by Dr. Hogness and so, it is also called as Hogness box. It is a 7 bp long region located 20 bp upstream to the start point. During the process of transcription, the RNA polymerase (a holoenzyme which has a core unit and a sigma factor for proper initiation of transcription) binds to TATA box due to which DNA assumes a saddle like structure at this place.
Which one of the following hydrolysis internal phosphodiester bonds in a polynucleotide chain?
Lipase
Exonuclease
Endonuclease
Protease
E. coli cells with a mutated Z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because
in the presence of glucose, E. coli cells do not utilize lactose
they cannot transport lactose from the medium into the cell
the lac operon is constitutevely active in these cells
they cannot synthesize functional - galactosidase
DNA replication generally proceeds in a
5 3 direction
3 5 direction
3 3 direction
5 5 direction
DNA polymerase enzyme is required for synthesis of
DNA from RNA
RNA from DNA
DNA from DNA
RNA from RNA