B4 Stem Cells Flashcards
To start all the cells in an embryo are all the same. What are they called?
Embryonic stem cells
Embryonic cells are unspecialised. What does this means?
They are able to divide to produce any type of specialised cell.
In humans, what stage are the cells in the embryo unspecialised to?
Stage 8
What is the process of a stem cell becoming specialised called?
Differentiation.
What happens after stage 8 in a human embryo?
Most stem cells start to differentiate.
This allows the embryo to grow and develop tissues. These groups of specialised cells work together with a particular function.
Adults have stem cells, where can they be found?
Bone marrow.
What is the role of stem cells found in adult bone marrow?
They are important in replacing dead cells eg. making new red blood cells.
What is special about the genes contained in stem cells?
All body cells contain the same genes, but in specialised cells most of the genes are not active.
Stem cells can switch any gene on or off during their development.
Why are most genes not active in specialised cells?
So the cells only produce the specific proteins they need.
What are meristems?
Plant tissue.
In plants, the only cells that divide by mitosis are found in plant tissue called meristems.
Where are meristems found?
In areas of the plant that are growing eg. the tips of the roots and shoots.
What type of cells do meristems produce?
Unspecified cells.
What is the difference between the unspecialised cells that meristems produce and human stem cells?
The cells can differentiate to generate any type of cell for as long as the plant lives.
What is the role of unspecialised cells?
They are able to divide and from any cell type in the plant.
They go on to form specialised tissues like xylem and phloem.
What experiments have scientists done with stem cells?
They have extracted stem cells from very early human embryos and grown them.
Under certain conditions the stem cells can be stimulated to differentiate into specialised cells.
