Chapter 19 Flashcards
What is a stem cell?
An unspecialised cell that can both reproduce itself indefinitely and, under appropriate conditions, differentiate into specialised cells of one or more types. Stem cells have great potential for regenerating damaged tissues.
The successful cloning of whole plants from single differentiated cells was accomplished when?
The 1950s by F.C Stewart and his students at Cornell University.
What are totipotent cells?
The cells potential to dedifferentiate and then give rise to all the specialised cell types of the organism
What is somatic cell nuclear transfer?
The nucleus of the somatic cell is then inserted into the enucleated egg cell. After being inserted into the egg, the somatic cell nucleus is reprogrammed by the host cell.
Can the nucleus from a differentiated animal cell direct development of an organism?
Not successfully. In an experiment, the nucleus from a differentiated frog cell caused direct development of a tadpole. However, its ability to do so decreases as the donor cell becomes more differentiated, presumably because of changes in the nucleus.
Why have researchers been trying to clone human embryos?
Not for reproduction but for the production of stem cells that treat human diseases
What is the blastocyst stage?
In humans, blastocyst formation begins about 5 days after fertilization when a fluid-filled cavity opens up in the morula, the early embryonic stage of a ball of 16 cells.
What is a progenitor cell?
A progenitor cell is a biological cell that, like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its “target” cell.
What are adult stem cells?
They erve to replace nonreproducing specialized cells as needed. These cells that generate a limited number of cell types
What are Embryonic stem cells?
Cells that generate all embryonic cell types.
What are ES cells?
Embryonic stem cells (ESCs) are stem cells derived from the undifferentiated inner mass cells of a human embryo.
Why do ES cells hold more of a promise than adult stem cells for most medical applications?
Because ES cells are Pluripotent.
What does pluripotent mean?
(of an immature cell or stem cell) capable of giving rise to several different cell types.
What is therapeutic cloning?
The production of embryonic stem cells for use in replacing or repairing damaged tissues or organs.
What is a retrovirus?
A retrovirus is a type of RNA virus that inserts a copy of its genome into the DNA of a host cell that it invades, thus changing the genome of that cell
