AP BIOLOGY

Detailed explanation-1: -Consistent with the definition, the zygote is totipotent, meaning that this single cell has the potential to develop into an embryo with all the specialized cells that make up a living being, as well as into the placental support structure necessary for fetal development.

Detailed explanation-2: -Embryonic stem (ES) cells are totipotent stem cells, able to differentiate into all types of somatic and germ-line tissues in vitro (61).

Detailed explanation-3: -Embryonic stem cells. These stem cells come from embryos that are 3 to 5 days old. At this stage, an embryo is called a blastocyst and has about 150 cells. These are pluripotent (ploo-RIP-uh-tunt) stem cells, meaning they can divide into more stem cells or can become any type of cell in the body.

Detailed explanation-4: -The only human cells that have so far been shown to possess a totipotent character are blastomeres from early cleavage stages of an embryo [2]. Single blastomeres can be used for the derivation of pluripotent human embryonic stem cell lines (hu-man ESC lines).

Detailed explanation-5: -The best-known example of a totipotent cell is a fertilized egg (formed when a sperm and egg unite to form a zygote). It is at or around four days post-fertilization that these cells begin to specialize into pluripotent cells, which as described below are flexible cell types, but cannot produce an entire organism.