Stem Cells Flashcards
What is a stem cell?
A cell that has not yet become a specialised cell (undifferentiated)
What are the four different potencies of stem cells?
Unipotent, multipotent, pluripotent, totipotent
What is a unipotent stem cell?
A stem cell that can not differentiate but are capable of self renewal (e.g. progenitor cells, muscle stem cells)
What is a multipotent stem cell?
A stem cell that can differentiate into a number of closely related cell types within a certain type of tissue.
What is a pluripotent stem cell?
A stem cell that can differentiate into any cell type found in an embryo (but not cells that make up the placenta).
What are totipotent stem cells?
Stem cells that are able to differentiate into any type of cell found in the body (including extra embryonic cells).
What is the term for the production of red blood cells?
Erythropoiesis
What are the changes that occur during erythropoiesis?
• Changing of shape into a biconcave disc (larger SA -> more oxygen absorbed)
• Build up of haemoglobin in the cytoplasm
• Ejection of the nucleus and other organelles (more space for oxygen)
• An elastic membrane (allows it to change shape and squeeze through narrow capillaries
What are the adaptations neutrophils (a white blood cell type) undergo when differentiating?
• A flexible shape and nuclear membrane (fits between capillary wall cells to form pseudpodia that engulf foreign bodies during phagocytosis)
• Containing many lysosomes (containing digestive enzyme to destroy invading cells)
Where are plant stem cells found?
In the meristems
What are xylem and phloem formed from?
Stem cells found in the tissue between them, known as the cambium (the term given to any undifferentiated tissue in a plant that has the ability to give rise to new cells).
What can stem cells be used for?
• Nerve cells - Parkinson’s and paralysis
• Bone marrow - Leukemia
• Skin cells - burn victims
• Islet cells - diabetes
• Myocardium - heart disease
• Retinal cells - blindness
