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+--- Thread: bichem q - drdi (/showthread.php?tid=464737)
bichem q - drdi - ArchivalUser - 11-17-2009
Endonuclerase activation and chromatin formation are characteristic features of eukaryotic cell death by apoptosis. Which of the fallowing chromosome structure would most likely be degraded first in an apoptotic cell?
a.barr body
b. 10nm fiber
c. 30 nm fiber
d. centromere
e. heterochromatin
0 - ArchivalUser - 11-17-2009
bbbbbb
0 - ArchivalUser - 11-17-2009
yess agree B 10nm fiber is in relaxed state=euchromatin=where apoptosis occurs
0 - ArchivalUser - 11-17-2009
That is great guys since b is the answer. But can someone explian me what is the diff in between a and b?
Thx!
0 - ArchivalUser - 11-17-2009
i also found in kaplan bichem pag 12 that euchromatin has 30 nm fb...
0 - ArchivalUser - 11-17-2009
barr body is the inactive X chromosome that is present in females (or males with 2 X chromosomes) it is transcriptionally inactive and is thus heterochromatin
0 - ArchivalUser - 11-17-2009
Heterochramatin, Barr body, are 30nm and transcriptionally inactive wheras euchromatin is 10nm and transcriptionally active and apoptosis occurs in euchromatin
0 - ArchivalUser - 02-21-2019
my understanding for the question:
Apoptosis is induced by apoptotic stimuli and endonucleases. The more opened the DNA, the more sensitive it is to enzyme endonucleases attack.
The 10nm fiber is the most open structure listed without the H1. The endonuclease would attack the region of unprotected DNA between the nucleosomes.