Embryonic development is orchestrated by a cascading series of genes, the expression of many of which are controlled in time and space by transcription factors and effector molecules of various kinds
But what controls the expression of the first regulatory genes to be transcribed in the newly fertilized zygote?
The egg contains stored mRNAs as well as transcription factors derived from the mother, and both of these orchestrate the expression of the first regulatory genes.
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Seedless vascular plants include all of the following EXCEPT
A. Psilotum-Pteridophytes. B. Sphagnum-Bryophyta. C. whisk ferns-Psilotophyta. D. horsetails-Sphenophyta.
Which of the following is the best explanation for the inability of a specific animal cell to reduce the Ca2+ concentration in its cytosol compared with the extracellular fluid?
A) blockage of the synaptic signal B) loss of transcription factors C) insufficient ATP levels in the cytosol D) low levels of protein kinase in the cell
The larval stage is a(n) _______ stage.
A. sessile B. reproductive C. haploid D. immature
What trait is exhibited only in Homo sapiens and not in other primates in existence today?
A. symbolic language B. opposable thumb C. tool use D. bipedalism