![]() ![]() ![]() The flow of genetic information from DNA to RNA (transcription) and from RNA to protein (translation) occurs in all living cells Transcription and translation are the means by which cells read out, or express, the genetic instructions in their genes. This primer is erased by a special DNA repair enzyme (an RNAse H) that recognizes an RNA strand in an RNA/DNA helix and fragments it this leaves gaps that are filled in by DNA polymerase and DNA liqaseħ FROM DNA TO RNA The pathway from DNA to protein. In eucaryotes, RNA primers are made at intervals spaced by about 200 nucleotides on the lagging strand, and each RNA primer is approximately 10 nucleotides long. ![]() The synthesis of one of many DNA fragments on the lagging strand. On the lagging strand, the Okazaki fragments are synthesized sequentially, with those nearest the fork being the most recently made.Ħ The synthesis of one of many DNA fragments on the lagging strand Because both daughter DNA strands are polymerized in the 5’ to 3'direction, the DNA synthesized on the lagging strand must be made initially as a series of short DNA molecules, called Okazaki fragments. The original strands therefore remain intact through many cell generationsĥ The structure of a DNA replication fork In a round of replication, each of the two strands of DNA is used as a template for the formation of a complementary DNA strand. ![]() As shown, base-pairing between an incoming deoxyribonucleoside triphosphate and an existing strand of DNA (the template strand) guides the formation of the new strand of DNA and causes it to have a complementary nucleotide sequence.Ĥ Review : Replication The semiconservative nature of DNA replication. The addition of a deoxyribonucleotide to the 3' end of a polynucleotide chain (the primer strand) is the fundamental reaction by which DNA is synthesized. In this way, a double-helical DNA molecule can be copied preciseģ Review : Replication The chemistry of DNA synthesis. Because the nucleotide A will pair successfully only with I and G only with C, each strand of DNA can serve as a template to specify the sequence of nucleotides in its complementary strand by DNA basepairing. 2 Review : Replication The DNA double helix acts as a template for its own duplication. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |