Which sequence best describes the fertilization and early growth of stem cells in a culture setting?

Which sequence best describes the fertilization and early growth of stem cells in a culture setting?

• A. A sperm fertilizes an egg, which then forms a zygote and is cultured to develop tissue.
• B. An egg is fertilized and implanted into a uterus to grow into tissue.
• C. An egg is fertilized, grows into a blastocyst, placed in a culture dish, and develops into needed tissue types.
• D. A single cell line is cloned and expanded in vivo.

Answer: (C)

Embryonic stem cell culture begins with fertilization and follows a blastocyst stage before cells are grown in a dish to differentiate into various tissues. After fertilization, the egg becomes a zygote and divides until it forms a blastocyst. The inner cell mass of that blastocyst provides the embryonic stem cells, which are then cultured in the lab to proliferate and be directed to form different tissue types. This sequence—fertilization, blastocyst formation, placing the cells in a culture dish, and differentiation into needed tissues—is exactly what the option describes. The other scenarios alter the process: fertilization with direct development into tissue in a non-culture context skips the critical blastocyst stage and in vitro culture; implanting into a uterus describes in vivo development rather than in vitro culture of stem cells; and cloning with in vivo expansion doesn’t reflect the standard in vitro culture and differentiation of embryonic stem cells.

Embryonic stem cell culture begins with fertilization and follows a blastocyst stage before cells are grown in a dish to differentiate into various tissues. After fertilization, the egg becomes a zygote and divides until it forms a blastocyst. The inner cell mass of that blastocyst provides the embryonic stem cells, which are then cultured in the lab to proliferate and be directed to form different tissue types. This sequence—fertilization, blastocyst formation, placing the cells in a culture dish, and differentiation into needed tissues—is exactly what the option describes.

The other scenarios alter the process: fertilization with direct development into tissue in a non-culture context skips the critical blastocyst stage and in vitro culture; implanting into a uterus describes in vivo development rather than in vitro culture of stem cells; and cloning with in vivo expansion doesn’t reflect the standard in vitro culture and differentiation of embryonic stem cells.