DNA replication and transcription occurs in which direction -
Ans. is 'a' i.e., 51 - 31 Elongation in DNA synthesiso Once the RNA primer has been synthesized at each of the replicating forks, a DNA polymerase III initiates the synthesis of new DNA strand by adding deoxyribonucleotides to the 31 end of RNA primer. Thus, both new strands are synthesized always in 51- 31 direction. Both the DNA strands are synthesized simultaneously, but in opposite direction.o During synthesis of RNA primer and synthesis of DNA strands, the nucleotides are added according to the sequence of base in the template strand, i.e. 'base pairing rule'. For example, an adenine nucleotide would enter at a thymine nucleotide.Elongation in transcriptiono The process of elongation proceeds after the formation of the first phosphodiester bond. After formation of approximately 10 phosphadiester bonds of new RNA, sigma (a) factor dissociates from the core enzyme. RNA polymerase utilize ribnucleotide triphosphate (ATP, GTP, CTP and UTP) for the formation of RNA.o RNA synthesis occurs in 51-3' direction (similar to DNA synthesis), i.e. genetic information is read in 31-51direction on template DNA and complementary base sequence is synthesized in 51-31 direction for RNA strand.o The selection of nucleotide is according to base-pairing rule, (e.g. U opposite to A and G opposite to C)o The process of elongation continues until a termiantion point is reached.
51-31
5l-51
31 -51
31 -31
DNA Replication 