E the organizer secretes factors that activate

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: r. e) The organizer secretes factors that activate formation of the Nieuwkoop center. Understanding embryonic development In general, cells become more restricted in their developmental potential as embryonic development proceeds. This progessive determination involves first combinatorial control by transcription factors, but later gene silencing by epigenetic changes in DNA and chromatin. 3 12/2/12 Understanding embryonic development Sheets of cells (epithelia) can rearrange to change shape and move e.g. convergent extension Cells in an epithelium can leave it and become mesenchymal. Mesenchymal cells can join an epithelium. e.g. during gastrulation. Which of the following is NOT true of the organizer? a.  Induces gastrulation b.  Inhibits ventral ectoderm c.  Converts ventral mesoderm to intermediate mesoderm d.  Involutes through the dorsal lip of the blastopore e.  Becomes intermediate mesoderm Transplant purple cells Patterns of cells with different fates and behaviors can arise in response to gradients of diffusible signaling factors (morphogens), and then be maintained by local cell interactions. Morphogens can be intracellular (e.g. transcription factors in the Drosophila syncytial blastoderm embryo), but are usually extracellular. Again, signaling pathways, for both pattern determination and maintenance. These cells are purple What can you conclude about the purple...
View Full Document

This note was uploaded on 01/22/2014 for the course MCB 305 taught by Professor Schroeder during the Fall '11 term at University of Arizona- Tucson.

Ask a homework question - tutors are online