Cell differentiation Flashcards
What are the key processes that occur in a multicellular organism
Cell division
Cell death
Cell differentiation
What are the defined stages of cell differentiation
1- stem cell
2- progenitor cell
3- terminal functional cells
Are the steps reversible or irreversible in cell differentiation
irreversible, once the cell has made a decision it cannot go back
Describe the stages of cell differentiation in detail
Stem cells- these cells are pluripotent (have the ability to differentiate into any cell), they also carry out maintainance by self renewal so there are stem cells for future use and so that stem cells do not run out. They undergo COMMITMENT and move to progenitor cells
Progenitor cells- these cells are multi potent (can only differentiate into a few cells)
Terminated functional cells- these cells are unipotent (cannot differentiate into another type of but only its own)
Describe the stages in blood differentiation
Stem cells- this is from the bone marrow, stem cells commit to progenitor cells
Progenitor cells- these cells are known as common myeloid, common lymphoid, common erythromegakaryoctic
Terminated functional cells- common myeloid gives T and B cells, common lymphoid differentiates to monocytes, common erythromegakaryoctic differentiate to platelets or erythrocytes
What makes the cells different from one another when they specialise
Proteins inside them
What are the 4 main proteins inside a cell that determines the function of the cell
1- proteins depending cell type features
2- metabolic proteins
3- structural proteins
4- regulatory proteins
In a red blood cell what are the example of the proteins that determine the function
1- proteins depending cell type feature: haemoglobin
2- metabolic protein: carbonic anhydrase
3- structural proteins: spectrins
4- regulatory proteins: GATA-1
How are proteins regulated
By gene expression through gene regulation and transcriptional factors
How do transcriptional factors work
Transcriptional factors are modular (they have 2 parts)
DNA BINDING DOMAIN- when the transcriptional factor bind to the enhancer/promoter region the dna binding domain is activated which recognises the DNA sequence
ACTIVATION DOMAIN- this domain interacts with the DNA polymerase so it can make the RNA
Does every protein have the same transcriptional factor
There are different transcriptional factors that make different proteins. It is not the same for each protein.
What other signals may allow differentiation
Extracellular signals (signals from the environment)
Give an example of an extracellular signal in cells and describe it
EPO is an example of a cell that regulates with extracellular signals:
1- low oxygen levels in the body are detected by the proximal convoluted tubules in the kidney
2- this release EPO
3- EPO interacts with the bone marrow of the body so it can make stem cells
3- the stem cells differentiate into erythrocytes
4- oxygen levels raise
5- the system is inhibited by negative feedback
What are the clinical implications of cell differentiation
Leukaemia- this is a disease when the body has many white blood cells caused by precursors not differentiating into B cells
Cell based therapy- we can use cell differentiation to replace cells in a patient.
