WEEK 3 Flashcards
LOOK OVER NOTES ON:
Metabolism and its control (2) and Structure and Function of connective tissue (+histology)
What are the key cellular processes in making a human?
Cell division (expansion) Cell death (elimination) Cell differentiation (specialisation)
What is cell differentiation?
What proteins a cell expresses and how cells interact with the outside world as a result
What is cell potency?
The ability of a cell to differentiate into different cell types (more cell types=greater potency)
Different types of stem cells written in order of decreasing potency
Totipotent (zygote)->Pluripotent (embryonic stem cell)->Multipotent (bone marrow stem cell)->Unipotent (tissue)
What happens to stem cells when they are not differentiating?
Self-renewal (maintenance)
What is a progenitor?
Intermediate cells of cell differentiation from stem cells which undergo expansion and form terminally differentiated cells
How is cell differentiation controlled?
Gene expression control, some activated/some inhibited
Give the control of RBC and platelet differentiation
stem cell->erythroblast->reticulocyte->RBC w/ cell specific proteins (alpha/beta globulins/spectrin/carbonic anhydrase)
stem cell->megakaryoblast->megakaryocyte->platelet w/ cell specific proteins (thrombin/collagen/fibrinogen receptors)
What factors control gene expression?
Transcription factors
What do transcription factors bind to on the DNA sequence?
Gene regulatory sequences-enhancer and promoter regions
What effect does binding of TF to gene regulatory sequences cause?
RNA polymerase transcribes DNA, forming mRNA
What two domains do TFs have?
DNA-binding domain (binds to enhancer/promoter regions) Activation domain (interacts with RNA polymerase resulting in gene transcription)
How are different steps of differentiation controlled?
By different transcription factors
How are transcription factors controlled?
Extracellular signals
