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23 Cards in this Set
- Front
- Back
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What is cell differentiation? |
- process where cells develop into specialised structures suited for its role |
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Why do we need specialised cells? |
- functions need different cell structures/enzymes/proteins - no one cell provides best for all functions - some genes permanently on/off |
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What is the difference between specialisation and differentiation? |
Specialisaion: the function of a cell Differentiation: the process of the cell acquiring specialisation |
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What are totipotent cells? |
- cells that can differentiate into any body cell e.g early zygote cells |
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What happens to totipotent cells later on? |
- differentiate/specialise to particular function - some genes expressed=translated - conserve energy (other genes not expressed) |
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How do you prevent genes from being expressed? |
- prevent transcription (prevent producing mRNA) - prevent translation |
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What are stem cells? |
- undifferentiated dividing cells that occur in adult animal tissues and need to be constantly replaced - can self renew |
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What is self-renewal? |
- divide to form an identical stem cell and a differentiated cell |
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Why is it useful for stem cells to self renew and differentiate? |
- 1 stem cell can produce a stem cell and a specialised cell - self renewal: maintains the stem cell - differentiation: replaces dead/damaged cells throughout life |
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What are the different sources of stem cells? |
Embryonic: early development Umbilical cord blood: like adult stem cells Placental: differentiate to specific types of cells Adult: differentiate to specific tissue where produced |
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What are the characteristics of totipotent cells? |
Where: early stage embryo (blastocyst)
Uses: understand how body develops from zygote Clinic: early stage safety trails Pros: produce all cells;self renew Cons: can't fully control;ethical concerns |
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Where are embryonic stem cells located? |
- inner cell mass of blastocyst - outer layer=trophectoderm - stem cells taken and put in culture (fluid with nutrients) |
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What are pluripotent cells? |
- differentiate to almost any type of cell - e.g fetal stem cells |
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What are multipotent cells? |
- different to limited no. of specialised cells - e.g adult tissue stem cells |
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What are the characteristics of multipotent cells? |
Where: tissues of adult body What: only make cells that belong in own tissue Uses: understand how adult tissue made/maintained Clinic: skin stem cells for skin grafts Pros: partly specialised=easy to get cell Cons: tissues must be patient matched |
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What is the location of adult stem cells? |
- surface of eye/brain/bone marrow/skin - blood stem cell from bone marrow differentiates to specialised blood cells |
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What are unipotent cells? |
- only differentiate to one type of cell - from multipotent cells - made in adult tissue |
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What are induced pluripotent stem cells (iPS cells)? |
- type of pluripotent cell made from unipotent stem cells |
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How are induced pluripotent stem cells made? |
- take body cell/add genes (genetic programming)=embryonic stem cell traits - induce genes/transcription factors to express - adult cells keep genetic info like embryo - culture=differentiate to all cells - can self renew=limitless supply |
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What are the advantages of induced pluripotent stem cells? |
- could replace embryonic stem cells=bypass ethics
- iPS used to grow tissues that have been damaged |
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What can stem cells be used for? |
- create replacement organs for patients: - spare IVF embryos cultured;stem cells removed - stem cells used to see if tissues created - right type of tissue rejected=drugs/tissue typing |
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What is therapeutic cloning? |
- ovum nucleus removed=nucleus from patient cell - small electric shock=divides=blastocyst=stem cells removed/cultured - genetically identical tissue to patient |
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Who would benefit from stem cell research? |
- help people with faulty cell diseases: Parkinsons: replace faulty brain cells Diabetes: replace insulin producing tissue in pancreas Damaged nerves: replace spinal nerves=limbs work again Transplant organs: replace organs that don't work |
