form a D-loop. After telomerase adds telomere sequences, chromosomal replication proceeds in the usual way. Any shortening of the chromosome ends is compensated for by the addition of the telomere repeats. Telomere length may vary, but organisms and cell have characteristic telomere lengths, resulting from many levels of regulation of telomerase. Mutants affecting telomere length have been identified, and data shortening of telomeres eventually leads to cell death. Loss of telomerase activity results in limited rounds of cell division before the cell death. Telomerase, an enzyme containing both protein and RNA, includes an 11-bp RNA sequence used to synthesize the new telomere repeat DNA. Using an RNA template to make DNA, telomerase functions as a In cells the genetic information carried in the DNA reverse transcriptase called TERT (telomerase reverse nucleotide sequence becomes functional information transcriptase). The 3’-end of the telomerase RNA that gives characteristics to cells ultimately specifying contains the sequence 3’-CAUC, which binds the traits. This conversion of DNA sequence information overhang on the chromosome, positioning into functional information begins with the creation of telomerase to complete its synthesis of the GGGTTAG cellular RNAs from one of the two strands of DNA telomere repeat. Additional rounds of telomerase sequence. This process is called transcription. The activity lengthen the chromosome by adding telomere mechanism by which these cellular RNAs are transcribed repeats. Ends of telomere DNA usually loop back to
Telomerase, an enzyme containing both protein and RNA, includes an 11-bp RNA sequence used to synthesize the new telomere repeat DNA. Using an RNA template to make DNA, telomerase functions as a reverse transcriptase called TERT (telomerase reverse transcriptase). The 3’-end of the telomerase RNA contains the sequence 3’-CAUC, which binds the overhang on the chromosome, positioning telomerase to complete its synthesis of the GGGTTAG telomere repeat. Additional rounds of telomerase activity lengthen the chromosome by adding telomere repeats. Ends of telomere DNA usually loop back to form a D-loop. After telomerase adds telomere sequences, chromosomal replication proceeds in the usual way. Any shortening of the chromosome ends is compensated for by the addition of the telomere repeats. Telomere length may vary, but organisms and cell have characteristic telomere lengths, resulting from many levels of regulation of telomerase. Mutants affecting telomere length have been identified, and data shortening of telomeres eventually leads to cell death. Loss of telomerase activity results in limited rounds of cell division before the cell death. In cells the genetic information carried in the DNA nucleotide sequence becomes functional information that gives characteristics to cells ultimately specifying traits. This conversion of DNA sequence information into functional information begins with the creation of cellular RNAs from one of the two strands of DNA sequence. This process is called transcription. The mechanism by which these cellular RNAs are transcribed
ch3-MolecularGenetics_1.2.docx