20. GENE EXPRESSION Flashcards
What is the single cell produced from fertilisation called?
Zygote
How does a zygote produce more cells to become an embryo and then a foetus?
Mitosis
What causes cells to become differentiated?
Certain genes stay switched on, and certain genes are switched off
Which proteins do the genes that are switched on in a cell code for?
The proteins that are required to carry out the cell’s specialised function
Which proteins do the genes that are switched off in a cell code for?
The proteins that are not required to carry out the cell’s specialised function
Which genes are usually always switched on in most cells?
The genes that code for respiratory enzymes
Define what stem cells are
Stem cells are undifferentiated cells that have the ability to keep dividing
Define what cell potency is
Cell potency is the varying ability of stem cells to differentiate into different specialised cells
What happens to the potency of most cells as they become more specialised?
Cells gradually lose potency as they become more specialised
Name the types of potency a cell can have, from the highest to the lowest potency
Totipotent, Pluripotent, Multipotent and Unipotent
How many types of cells can multipotent cells differentiate into?
Multipotent cells can differentiate into any cell type
Give an example of totipotent stem cells
Embryonic stem cells
How many types of cells can pluripotent cells differentiate into?
Pluripotent cells can differentiate into almost any cell type
Give an example of pluripotent stem cells
Embryonic and foetal stem cells
How many types of cells can multipotent cells differentiate into?
Multipotent cells can differentiate into a limited number of cell types
Give an example of multipotent stem cells
Adult and umbilical stem cell
How many types of cells can unipotent cells differentiate into?
Unipotent cells can only differentiate into one cell type
Give an example of unipotent cell
Differentiated adult somatic cells
Which potency of cell are the only ones that can rise to a whole new organism?
Totipotent (stem) cells
Why are pluripotent stem cells useful for treating certain conditions of organs?
Because they can differentiate into and therefore replace the many different cell types within an organ
Describe the two disadvantages of using pluripotent stem cells to treat conditions of organs
The might differentiate into the wrong cell type, or divide uncontrollably to form a tumour
Which potency of cell are useful for treating conditions caused by non-functioning blood cells?
Multipotent (adult) stem cell
Define what iPS cells are
iPS (induced pluripotent stem) cells are a type of pluripotent stem cell produced from unipotent stem cells
Describe how iPS cells are produced from unipotent cells
Unipotent cells are genetically altered by using transcription factors to switch genes on