8 The Control of Gene Expression- Gene Expression Flashcards
What are stem cells and what are they capable?
Unspecialised cells; capable of dividing & differentiating into any type of cell
Types of stem cells; what are totipotent cells and their function?
-Exist only for a very limited time during embryonic development in mammals (first few cell divisions)
-During development, totipotent cells translate only part of their DNA—> cells remain unspecialised
-Are able to produce any type of body cell, cells of supportive structures like the placenta
-Are the most unspecialised stem cell, specialise into many different cell types
Types of stem cells; what are pluripotent cells and their function?
-Totipotent cells develop into pluripotent cells in embryos
-Are able to divide in unlimited numbers & produce any type of cell that makes up body
-Can be used to treat human disorders
Types of stem cells; what are multipotent cells and their function?
-Found in mature mammals
-Can develop into a limited number of cell types
Types of stem cells; what are unipotent cells and their function?
-Found in mature mammals
-Can divide to produce new cells but can only produce one type of cell
What is the process of stem cells becoming specialised?
-Totipotent cells become specialised in embryonic development
-When become specialised—> only some genes in cell are activated; those are expressed
-If gene is expressed—> transcribed into mRNA & translated into a protein
-Differentiation happens as certain proteins are made
-Presence of certain proteins= cell has become specialised
What are the 3 main sources of stem cells?
-Adult stem cells (taken from adult body tissues)
-Embryonic stem cells (taken from embryos)
-Induced pluripotent stem cells (iPS)
What are the benefits of using stem cells in disease?
-Can be used to reduce preventable deaths
-Can be used to treat conditions decreasing quality of life
What are the disadvantages of using stem cells?
-Obtaining them from embryos is controversial for ethical reasons; some think it is depriving an embryo of life
What are Induced Pluripotent Stem Cells (iPS) produced from?
-From a specialised adult somatic (body) cell
-Somatic cells → specialised, can’t be used to treat disease
How are iPS cells produced?
-Somatic cells are converted → iPS cells by activating genes using appropriate protein transcription factors
-Makes somatic cells unspecialised, so can treat disease
-Can be made from patient’s own body cells → decreases chance of rejection during transplants
How are stem cells used in bone marrow transplants?
-Transplants are used to treat blood & immune disorders
-Bone marrow has multipotent stem cells → can produce all types of blood cell
How are stem cells used in drug research?
-Stem cells are used to grow artificial tissues
-Drugs can be tested on the tissues before on humans
How can stem cells be used in developmental biology?
-Stem cells used to learn more about how an embryo develops & organs are formed
-Learning about developmental biology can help improve medicine by informing us why organs fail/have abnormalities
How can stem cells be used in potential future research?
-Stem cells can be used to make new organs/tissue from transplants
-Can also be used to treat irreversible diseases (eg paralysis)
-Could be injected at site of disorder/ problem & encouraged to differentiate → required specialised cell
