The nucleus must be taken from the blastula and gastrula stages of frog embryos. |
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Gastrulation in its broadest sense is the reorganization of the cells of the blastula to form a multilayered embryo, the gastrula. |
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After the blastula develops, it undergoes transition to the gastrula, a process called gastrulation. |
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This conclusion is supported by a shift in mitochondrial enzymes toward aerobic metabolism at the gastrula stage. |
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Use an open paper clip to cut through the center of the gastrula to show the three different layers. |
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In starfishes and other echinoderms, the deep part of the endomesodermal invagination forms two thin-walled sacs, one on each side of the gastrula. |
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The embryo showed embryonic ectoderm and endoderm, it now had reached the gastrula stage. |
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In this process, a piece of chordamesoderm from an embryo at the gastrula stage, when transplanted, induces a secondary embryo in a competent host embryo. |
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