Question:
Thanks for the info. Steve! Your explanation made sense to me. However
I am still confused as to when telomerase acts on "normal" cells. At what
point in the development of the cell (or chromosome) is the telomere added?
It would seem that telomerase must add the telomere and then shut off in
a normal cell. Would the inhibition of telomerase interfere with this
"split second" addition of the telomere?
Replies:
I'm glad we can keep this conversation going. Let's see if I can
adequately address your next questions.
The telomere DNA is a long stretch of repetitive sequence that is
present from the "beginning" of the individual organism (conception)
because the sperm and egg cells have active telomerase. For most
"normal" cells, telomerase is not needed at all!. Without telomerase,
the telomere DNA (repetitive sequence) gets a little bit shorter every
time the DNA (chromosome) is replicated - that is, each time the cell
divides. But for most cells, they don't divide often enough to lose
so much sequence that bad things happen -- like the leader or trailer
on a movie or a tape; as long as the music or story is not disrupted, the
length of the leader or trailer is really irrelevant. Therefore, for most
normal cells the inhibition of telomerase is a moot issue - because
telomerase is not active anyway! More questions? keep 'em coming, and
I'll check back with Newton in a week or so.
NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.