Cell Differentiation Flashcards
What is cell differentiation?
The production of different cell types within an organism and this process is stable.
How are cells or tissues that are used to damage and wear able to be maintained/replaced?
They are maintained by the differentiation of immature stem cells.
What is determination?
The stability of cell differentiation even after the end of any inducing signal. It is transmitted to the daughter cells after division. E.g. different blood cells are all in the same enviroment, but they will ‘remember’ what cell type they are.
What is cell lineage?
The series of cell types leading from the zygote to a particular cell type.
Differentiation in the embryo occurs in a series of steps from one immature or precursor cell type to another more mature cell (may still be some kind of precursor).
How are skeletal muscles created?
Skeletal muscles comes from cells in the somite. Parts of the somite differentiates into the myotome which differentiate into a type of migrating cell, which migrates through the embryo to all the places where we want the skeletal muscle to be.
What are myoblasts?
Myoblasts are precursors for muscle and when they get to the place they need to be, they start fusing together to start producing skeletal muscle.
What does the suffix ‘-blast’ mean?
It means that the cell is a precursor cell type.
Why do cell lineages often branch off?
The branches indicate that a particular kind of precursor cell is able to produce more than one kind of daughter cell given the right signals. For example there are several kinds of red and white blood cells from bone marrow stem cells during postnatal life.
What are pluripotent stem cells?
A cell that is able to differentiate into all types of cells, an example of this is embryonic cells.
How can cell types become different?
Different cell types express different sets of genes.
What does gene expression mean?
The whole process leading to synthesis of the final product of a given gene; either a protein or a functional RNA like tRNA. Includes transcription and translation.
Is a change in gene expression always differentiation?
No, there is also modulation.
What is modulation?
- Gene expression is the synthesis of the product of a given gene – a protein or a functional RNAs like tRNA. It includes both transcription and (for proteins) translation.
- Differentiation involves an altered pattern of gene expression. But not all altered gene expression is differentiation. Cells can also undergo small, simple changes in gene expression in response to a specific stimulus, which are reversed when the stimulus is removed.
- This kind of change is called modulation (of gene expression).
- This is a transcriptional change that is reversible, and dependent on a continuing external stimulus. This can also be called adaptation.
What is an example of modulation?
An example is the upregulation of alcohol dehydrogenase enzyme expression in hepatocytes (liver cells) in response to a rise in blood alcohol. The enzyme breaks down alcohol. So as the alcohol level falls again the enzyme switches off, not being made anymore
What is the difference between differentiation and modulation?
-In comparison, both differentiation and modulation involve changes in gene expression but differentiation is a stable, complex change in gene expression, while modulation is a reversible (temporary), simple change.