Unit 2.2 - Cell Division and Stem Cells Flashcards
Describe the structure of chromosomes.
Chromosomes are linear arrangements of genes, found in pairs in the nucleus of cells.
What is the purpose of mitosis and meiosis?
Mitosis is required to grow, repair damaged tissue and replace worn out cells; meiosis is required to produce gametes (sex cells).
Compare mitosis and meiosis in terms of process and result.
Mitosis happens in all body cells, meiosis happens only in those where gametes are produced; mitosis is one division, producing two daughter cells, meiosis is two divisions, producing four daughter cells; mitosis produces genetically identical daughter cells with the same no. of chromosomes as the mother cell, meiosis produces genetically different daughter cells with half as many chromosomes as the mother cell.
Name the disease that can occur if mitosis is uncontrolled.
Cancer
Define stem cells.
Unspecialised cells which have not lost the ability to differentiate and thus have the capacity to develop into a variety of different types of cells.
What is the use of stem cells in medicine?
Stem cells are able to treat diseased or damaged tissue, and can be grown into a variety of cells, making them extremely useful as a medicinal tool.
Compare the use of adult and embryonic stem cells.
Adult stem cells are less versatile than embryonic stem cells, but the use of embryonic stem cells raises ethical issues as they have the potential to develop into a human being, so it is seen as taking life to harvest their stem cells.
What are the advantages of using your own stem cells?
No need to find a donor, no chance of rejection, no need for tissue typing.
What is the most common place where adult stem cells can be found?
Bone marrow.
Where can plant stem cells be found?
Meristems (in the tips of the roots and shoots)
How can cancer occur?
When cells change, causing uncontrolled mitosis (division), they form a tumor which can damage organs and stop them from functioning.
