In a sequence of experiments, genes which code for mutant forms of a receptor tyrosine kinase are introduced into the cells. The cells as well express their own normal form of the receptor from their normal gene, though the mutant genes are constructed so that they are expressed at considerably higher concentrations than the normal gene. What would be the effects of introducing mutant genes which code for a receptor tyrosine kinase which:

a) Lacks its extracellular domain.

b) Lacks its intracellular domain.