Week 5 - Cell differentiation Flashcards
Where is the euchromatin on this high power transmission electron micrograph?
the lighter area
euchromatin is unwound and active DNA
What does this image tell you about the transcriptional activity of the cell?
This cell is very metabolically active and has a high transcriptional activity. Most of the nucleus of the cell is a light colour indicating the presence of euchromatin (unravelled DNA). The darker areas are heterochromatin which is the condensed and tightly packed form of DNA. There are lots of mitochondria around the nucleus.
What does DNA methylation do to cytosine?
reduces gene expression
What is totipotency?
a cell that is capable of forming all differentiated cells of an adult
What is pluripotency?
capable of forming more than 1 differentiated cell type
What is a hemopoietic stem cell?
blood cells that give rise to all other blood cells (pluripotent)
What are the two types of cloning?
reproductive and therapeutic
What is the purpose of telomeres?
to protect the end of the chromosone and stop the genes from being trunkated
What happens to telomeres over time?
they shorten and eventualy cell division stops
What are ‘housekeeping genes’?
genes that are required for the maintenence of basic cellular function
Give examples of housekeeping gene products
metabolic enzymes, ribosomal proteins, RNA polymerase
Luke has been diagnosed with a rare condition called Hutchinson-Gilford progeria, where he is 20 years old, however appears 160 years old. What is the genetic basis of this condition?
mutation in LMNA gene
The LMNA gene provides instructions for making a protein called lamin A. This protein is an essential supporting component of the nuclear envelope. Mutations that cause Hutchinson-Gilford progeria syndrome result in the production of an abnormal version of the lamin A protein. The altered protein makes the nuclear envelope unstable and progressively damages the nucleus, making cells more likely to die prematurely
What are the three stages of cell differentiation?
Specification - fate is not absolute, cell identity is still subject to change
Determination - fate is fixed and cannot be changed in response to the environment
Differentiation - change in cell structure and function - expression of genetic coding
What are the three stages to cell differentiation?
specification- fate is not absolute and cell identity’s can change in response to external environment
determination- fate is fixed and canno change in response to environment
differentiation- changes in cell structure and function occur
