Chapter 13.3.3 (Exam 3) Telomeres Flashcards
DNA Is Replicated Semiconservatively
What are telomeres?
Eukaryote chromosomes have repetitive sequences at the ends called telomeres
What is the telomere sequence in humans?
In humans, the sequence is TTAGGG, repeated about 2,500 times
What is the function of telomeres?
The repeats bind proteins that prevent the DNA repair system from recognizing chromosome ends as breaks
How come genes may be lost and cells die after many divisions?
On lagging strands, when the terminal Okazaki primer is removed, no DNA can be synthesized to replace it (no 3’ end)
The short piece of single stranded DNA is removed, and the chromosome becomes shorter with each replication
What is the role of telomerase, and what cells is it present in?
Continuously dividing cells, such as bone marrow stem cells, have telomerase, which catalyzes addition of lost telomeres
