cell differentiation Flashcards
What is differentiation?
It is the process during development whereby cells become more specialized and distinct from one another as they mature?
What do all cells in the organism share?
An identical genome, each cell contains all genetic information for the organism.
What causes differentiation?
The activation of different instructions (genes) within a given cell by chemical signals. (e.g. an expression neuron-specific gene will cause the cell to differentiate into a neuron)
What is the DNA packaged in?
In proteins in order to form chromatin.
What are the two types of chromatin and where can they appear in the nucleus?
Euchromatin (more broadly present in the nucleus) and heterochromatin ( mainly closer to the nucleus).
What is packaged in euchromatin (looser)?
Active genes
Where are inactive genes packed?
In heterochromatin (more condensed, saves space, is not transcribed)
What is the slightly dangerous feature of heterochromatin?
It can spread into the neighbouring euchromatic region and repress gene expression. That is why it’s important to set boundaries between them.
Heterochromatin divides into:
facultative and constitutive chromatin
What is constitutive chromatin?
It’s the kind that contains highly repetitive sequences that are not transcribed. It plays the role in chromosome structure.
What is facultative chromatin?
This one has the potential for gene expression, can be condensed or decondensed depending on the cell type. Is only found at some stages of development.
