| A | B |
|---|
| apical meristem | tissue in the tips of roots and in the buds of shoots that supplies cells for the plant to grow in length |
| apoptosis | changes that occur within a cell as it undergoes programmed cell death |
| cell differentiation | structural and functional divergence of cells as they become specialized |
| cell lineage | ancestry of a cell |
| chimera | organism with a mixture of genetically different cells |
| clone | lineage of genetically identical individuals or cells |
| cloning | Using a somatic cell from a multicellular organism to make one or more genetically identical individuals |
| cytoplasmic determinants | maternal substances in the egg that influence the course of early development |
| determination | progressive restriction of developmental potential |
| egg-polarity gene | gene that helps control the orientation (polarity) of the egg |
| embryonic lethal | mutation with a phenotype leading to death at the embryo or larval stage |
| homeobox | nucleotide sequence in homeotic genes that is the same in most animals |
| homeotic gene | genes that control the overall body plan of animals by controlling the fate of groups of cells |
| induction | group of embryonic cells to influence the development of another |
| maternal effect gene | when mutant in the mother |
| model organism | organism chosen to study broad biological principles |
| morphogen | provides positional information in the form of a concentration gradient along an embryonic axis |
| morphogenesis | development of body shape and organization |
| organ identity genes | homeotic plant genes that determine which leaf buds will form flowers |
| pattern formation | ordering of cells into specific three-dimensional structures |
| pluripotent | can give rise to multiple but not all differentiated cell types |
| positional information | indicating a cell’s location relative to other cells in an embryonic structure |
| segmentation gene | directs the actual formation of segments after the embryo’s axes are defined |
| stem cell | unspecialized cell that divides to form a specialized cell and an unspecialized cell |
| totipotent | cell that can give rise to all parts of an organism |
