1. Treatment of a… Show more Answer True or False Which of the following are true about embryonic…

1. Treatment of a… Show more Answer True or False Which of the following are true about embryonic development? 1. Treatment of an embryo undergoing gastrulation with cytochalasin (a drug that destabilizes microfilaments) would have minimal effect on this developmental stage because the focus of this stage is cellular differentiation and formation of the three germline layers (ectoderm, mesoderm, and endoderm), not cell division. 2. Cells in a developing embryo exist in a three-dimensional gradient of extracellular signals that help establish its identity based on its spatial localization. 3. This is true: once a cell has fully differentiated, it can be reprogrammed into a pluripotent stem cell by altering the expression of several key transcription factors. Is this true: This suggests that the process of differentiation and the diminution of potency is not the result of a loss of DNA. 4. Many regulatory genes – such as the Bicoid and Hox (homeotic) genes – that are involved in development encode transcriptional regulatory proteins (e.g. enhancer/suppressors) that in turn affect the expression of further regulatory genes, creating a temporal and spatial regulatory cascade. • Show less