Stem cells are unspecialized cells with the unique ability to develop into any type of cell in the body.
Embryonic and Adult Stem Cells
Embryonic stem cells are pluripotent and found in the inner cell mass of the blastocyst. Embryonic stem cells are able to replicate indefinitely. Currently, embryonic stem cells are the only known pluripotent cell. However, it is possible multipotent cells can de-differentiate into a pluripotent cell type. Adult stem cells are found in various tissues and are multipotent. They perform tissue repair and regeneration. Adult stems cells are tissue-specific and differentiate into slightly more differentiated progenitor cells before they completely differentiate.
Application of Stem Cells
Many diseases could be treated with stem cells including blood and immune disorders, cancer, spinal cord injuries, Parkinson’s disease, juvenile diabetes and blindness. Since stem cells are pluripotent, they have the ability to be manipulated to become other types of cells to help with these specific complications. Harvesting stem cells is controversial since many are embryonic and come from the blastocyst that was created for in vitro fertilization. It’s controversial because the blastocyst is destroyed in the process.
Practice Questions
Khan Academy
MCAT Official Prep (AAMC)
Official Guide B/B Section Passage 3 Question 10
Key Points
• Stem cells are undifferentiated cells that have the ability to specialize into any type of cell
• Stem cells self-replicate by mitosis
• Embryonic stem cells are pluripotent and adult stem cells are multipotent
• Embryonic stem cells are found in the inner cell mass of a blastocyst and adult stem cells are found in specific tissues
• Many diseases can be treated using stem cells such as blood and immune disorders, cancer, spinal cord injuries, Parkinson’s disease, juvenile diabetes and blindness
Practice Questions
Khan Academy
Chronic myelogenous leukemia and the Philadelphia chromosome
MCAT Official Prep (AAMC)
Official Guide B/B Section Passage 3 Question 10
Key Terms
Pluripotent: cells that can develop into many different types of cells in the body
Multipotent: cells that can develop into more than one cell type, but are more limited than pluripotent cells
Progenitor cell: are early descendants of stem cells that can differentiate to form one or more kinds of cells, but cannot divide and reproduce indefinitely
Pseudopregnant: the female is bred by an infertile male, resulting in sterile mating
Blastocyst: is a structure formed in the early development of mammals