Cmmb403 midterm exam with 100% correct answers

Cmmb403 midterm exam with 100% correct answers Holt-Oram - answer____ syndrome is a human disease w a developmental basis that causes forelimb and heart defects where radius is missing and theres a hole btw ventricles so oxygenated and deoxygenated blood mixes. It is caused by a mutation of ONE copy of the TBX5 gene that codes for a transcription factor TBX5 - answerthe transcription factor that is mutated in Holt-Oram syndrome - is expressed in the forelimb and the heart (NOT the hind limb) one (haploinsufficient) - answerone/two copy/copies oft he TBX5 transcription factor minimum must be mutated for Holt-Oram syndrome to occur in babies haploinsufficiency - answerwhen on functional copy of a gene is not enough to provide sufficient protein for normal function- heterozygote loss of function mutations cause an abnormal phenotype when a gene is____. for example, TBX5 transcription factor gene is ____ or holt Oram syndrome is caused by this of TBX5 whole-mount in situ hybridization (WISH) - answermethod used to tell where in an embryo a given gene is transcribed c - answerwhy is there never human patients w a homozygous loss of function mutation of TBX5? a) mutations of it are so rare that its v unlikely that 2 holt-roam patients would ever have a baby together b) there is only one copy of the TBX5 gene in the human genome c) like in mice, homozygous mutations of TBX5 are likely lethal in humans so homozygous mutant embryos die long before birth d) its impossible to say since TBX5 probably has a very diff function in mice than humans e) humans cannot survive without forelimbs fertilization - answerstage of embryogenesis where sperm and egg use to produce a zygote cleavage - answerstage of embryogenesis where rapid mitotic divisions occur and the zygote is cleaved into a variety of cell numbers - cell sizes get smaller but more numerous, begins as a synchronous division but becomes asynchronous during MBT - rapid cell divisions divide the zygote cytoplasm into man progressively smaller cells w no increase in total volum