Humans Who Have Mutations in the Presenilin Genes Are at a Higher

Multiple Choice

Humans who have mutations in the presenilin genes are at a higher risk for developing early-onset Alzheimer's disease. The human presenilin proteins that are made from these genes are responsible for altering other proteins by cleaving (cutting) them at specific positions. Presenilin proteins that are highly similar to the human ones have been identified in C. elegans, a microscopic nematode worm. These nematodes do not get Alzheimer's disease, as they do not have a brain. What would you expect the function of nematode presenilins to be?

A) They are responsible for the development of the central nervous system.
B) They are responsible for altering other proteins by cleaving them.
C) They are responsible for altering other proteins by transporting them to a new location within cells.
D) They are responsible for the synthesis of new proteins.