1.3 Cell physiology Flashcards
Genotype
The same exact chromosomal DNA that every somatic cell in the body has
Phenotype
Form and function of a cell, determined by the types of proteins expressed in cells, separates a brain cell from a pancreatic cell, etc.
The proteins expressed in a cell depends on…
The genes that are transcribed from DNA to RNA
What selects the genes from the genome to differentiate the cells?
Transcription factors
Tissues
Groups of similarly oriented cells working together
How do you ensure a constant supply of differentiated cells?
Tissue stem cells
What does it take to be a stem cell?
They have to engage in a rare form of cellular mitosis that enables
- Self- Renewal
- Ability to remain undifferentiated
Self-renewal
Ability to make an exact copy of the original stem cell
Ability to remain undifferentiated
Since they stay uncommitted, they have the unique ability to give rise to numerous other cell types (from one to many)
Totipotent cell
“Unlimited potential,” can create any type of tissue known- even placental tissue
Pluripotent cell
“many potential” any adult tissue (not placental)
Multipotent cell
Stem cell capable of self-renewal, but committed to forming a “lineage” of tissue
Differentiated cell
Committed to a single, specialized function in the body; limited capacity to reproduce itself (dead end)
Bone marrow transplants are…
Stem cell transplants
Bone marrow is lethally irradiated (leukemia patients)
3 types of stem cells with therapeutic potential
- Adult stem cells
- Embryonic stem cells
- Reprogrammed adult cells
Adult stem cells
MULTIPOTENT, undifferentiated cells that are capable of self renewal, don’t yet know how to identify and isolate them
Embryonic stem cells
Totipotent and pluripotent cells, easy to expand and grow but are controversial
Alternatives to ES cells
Possibly could use umbilical cords to extract pluripotent stem cells
Reprogrammed adult cells (types)
Somatic cell nuclear transfer and iPS cells
Somatic cell nuclear transfer
Used to make ES cells, same technique used to clone Dolly the sheep, involves transferring an adult cell’s nucleus into an oocyte that has had its DNA removed
Steps of somatic cell nuclear transfer
Electric shock starts division, develops into an embryo, derive embryonic stem cells, grow new organ or clone
iPS
Induced pluripotent stem cells, took differentiated adult cells and introduced 4 proteins, differentiated adult stem cells were reprogrammed back to embryonic stem cell state
Who was the man responsible for iPS and when?
Shinya Yamanaka 2006
What are 4 big issues with creating new organs?
1) Directing differentiating process is extremely challenging
2) Building an organ…
3) Host rejection (not iPS)
4) Moral issues((not iPS)
