![]() ![]() ![]() Sequence of bases in a gene does not, in itself, give any observable characteristic in an organism. Transcription is the synthesis of mRNA copied from the DNA base sequences by RNA polymerase. DNA polymerase continues to move along the template strand creating new strands with a base sequence complementary to the template strand – it does this with a very high degree of fidelity (very few mistakes made).Pentose sugar is 3 terminal and the phosphate is the 5 terminal, DNA polymerase adds on the 5 terminal of the free nucleotide to the 3 terminal of the existing.This is done with Covalent bonds between the phosphate group of the free nucleotide and the sugar of the nucleotide at the existing end of the new strand.Nucleotide is finally as the correct base and has been brought into position and hydrogen bonds have been formed between the two bases, DNA polymerase links it to the end of the new strand.DNA polymerase brings nucleotides into the position where hydrogen bonds could be formed but unless this happens and a complementary base pair is formed, the nucleotide break away again.Every time a nucleotide is added to the new strand only one of the four types of nucleotide has the base that can pair with the base at the position reached on the template strand.Free nucleotides with each of the four possible bases are available in the area where DNA is being replicated.DNA polymerase move along the template strand in the same direction, adding one nucleotide at a time.The creation of new strands is carried out by enzyme DNA polymerase Rule – one base always pairs with another is called complementary base pairing.This makes sure that the two DNA molecules that are created by DNA replication are identical in their base sequences to the parent molecule that was replicated. Since complementary bases form hydrogen bonds with each, stabilizing the structure, if a nucleotide with the wrong base started to be inserted, the hydrogen bond would not happen and the nucleotide would not be added to the chain The base sequence on the template strand determines the base sequence on the new strand, only a nucleotide carrying a base that is complementary to the next base on the template strand can successfully be added to the new strand. Therefore DNA replication is referred to as being semi-conservative.The results of this process is 2 DNA molecules, both made up of the original strand and a newly synthesized strand.New strands are formed by adding nucleotides, one by one, and linking them together.The new strands are used as a guide or template for the creation of a new strand. When a cell is preparing to divide, the two strands of the double helix separate.One strand will be from the original template molecule.DNA replication is a semi-conservative process, because when a new double-stranded DNA molecule is formed: ![]()
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