A researcher is investigating compounds that modulate the cell cycle as possible chemotherapeutic agents against peripheral T-cell lymphoma. The researcher discovers a group of natural compounds with inhibitory activity against histone deacetylases, a class of enzymes that remove acetyl groups from the lysine residues of histones. A histone deacetylase inhibitor most likely causes which of the following?
APrevention of DNA strand reannealing
BIncreased heterochromatin formation
CSuppression of gene transcription
DRelaxation of DNA coiling
ETighter coiling of DNA
An investigator is studying the biology of human sperm cells. She isolates spermatogonia obtained on a testicular biopsy from a group of healthy male volunteers. She finds that the DNA of spermatogonia obtained from these men show a large number of TTAGGG sequence repeats. This finding can best be explained by increased activity of an enzyme with which of the following functions?
ALigation of Okazaki fragments
BProofreading of synthesized daughter strands
CRNA-dependent synthesis of DNA
DProduction of short RNA sequences
EHemimethylation of DNA strand
A group of scientists developed a mouse model to study nondisjunction in meiosis. Their mouse model produced gametes in the following ratio: 2 gametes with 24 chromosomes each and 2 gametes with 22 chromosomes each. In which of the following steps of meiosis did the nondisjunction occur?
ATelophase I
BMetaphase II
CAnaphase I
DAnaphase II
EMetaphase I
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