Chapter 21

cell division morphogenesis cell differentiation

all cells have the same DNA, so they have the same genes

gene expression differences arise during development by regulatory mechanisms

gene is expressed through a physical trait

different cells have different genes that are active heart cells and eye cells have same DNA, but different genes are expressed to give the cells different function

a cell that can generate a completely new organism

using one or more somatic cells from a multicellular organism makes a genetically identical individual

nucleus of an unfertilized egg cell or zygote is replaced from a nucleus from a differentiated cell

nuclear transportation is from a nucleus of a less differentiated cell instead of a fully developed cell

• mammary cell from donor taken, egg cell from donor taken • nucleus removed from egg cell, mammary cells are cultured to cause differentiation • cells fused • grown in culture • implanted in uterus of a different sheep • clone is identical to mammary cell donor

creates a random phenotype in offspring, even if a clone is genetically identical to the mother

relatively unspecialized cell that can reproduce itself indefinitely and differentiate into specialized cells of any type

separated at the blastocyst stage totipotent taken from an unconsenting fetus

they are pluripotent

cell determination- precedes differentiation involves expression of genes for tissue-specific proteins

generic cell becomes a specialized cell

maternal substances in the cell influence early development regulate expression of genes that affect cell’s developmental rate

development of a spatial organization of tissues and organs occurs continually in plants

molecular cues that control pattern formation tells a cell its location relative to the body sent by chemicals

establish the axes of the body control orientation of the egg and eventually the fly

affects front half of the body

an individual will lack the front half of its body and has a duplicate posterior structure at both ends

at the egg’s anterior high to low concentration

produce proteins that produce the formation of segments after axes information