2.2 Cell Division and Stem Cells Flashcards
Chromosome defintion
Linear arrangements of genes found in pairs in body cells
How many chromosomes does the human body have (+how many from mother & father)
46 - 23 from mother, 23 from father
Purpose of (mitosis) cell division
Growth, repair, replacement of damage
Mitosis summary
- occurs in all body cells except those forming gametes
- 2 daughter cells formed
- daughter cells are genetically identical
- daughter cells have a full set of chromosomes
Meiosis summary
- occurs only in gamete-forming cells
- 4 daughter cells are formed
- daughter cells are genetically different
- daughter cells have half a set of chromosomes (half number as mother cell)
How do meiosis cells end up genetically different
When DNA replicates some genes are swapped between chromosome pairs (crossing-over)
A special gene does what - mitosis
Regulates the speed of mitosis, allowing cells to mature before dividing again
What happens of the speed of mitosis is unregualted
Uncontrolled growth - leads to cancer - cells can grow into a tumour, damaging the organ it’s in
Differentiate definition
Become specialised
Where are stem cells found and what can they become
Embryo, bone marrow, umbilical cord
Any cell at all
Uses of stem cells
- Scientists can take stem cells and grow them into any type of cells
- this can repair/replace damaged tissue
- this could treat cancer, diabetes, injuries…………
Ethical issues with the use of embryonic stem cells
A potential life is destroyed
