1.2 Flashcards
Chromosomes
Made of DNA molecules that carry large number of genes, found in the nucleus.
Number of chromosomes in body cells.
46 - 23 pairs.
Stages of cell cycle.
- DNA duplicates, sub-cellular organelles replicate, cell increases in size.
- Each set of chromosomes are pulled to each end of cell; nucleus divides.
- Cell membrane and cytoplasm divide to form two new identical daughter cells.
Importance of mitosis.
Growth and development of multicellular organisms.
Stem cell
Unspecialised cell of an organism which is capable of differentiating into other cell types, and of self-renewal.
Embryonic stem cell function.
Can be cloned and made to differentiate into most (if not any) different types of human cells.
Adult bone marrow stem cell function.
Can form into related types of cells, such as blood cells and cells of the immune system.
Meristem tissue function.
Can differentiate into any type of plant cell, throughout the life of the plant.
Stem cell treatment
May be able to help conditions such as diabetes and paralysis.
Therapeutic cloning
When stem cells from an embryo produced with the same genes as a patient is used for their medical treatment as there is a lower risk of rejection.
Benefits of using meristem tissue for cloning.
- Rare species can be cloned to protect them from extinction.
- Plants with favourable characteristics can be cloned into large numbers and used for agriculture/horticulture.
- Plants can be cloned quickly and economically.
Benefits of using stem cells in medical treatment.
- Find treatment for currently untreatable conditions.
- Enable growth of organs for transplants.
- Aids in medical research.
Issues associated with using stem cells in medical treatment.
- Risk of transferring viral infections.
- Stem cells sometimes come from unused embryos - IVF.
- Development of stem cells is slow, expensive and difficult.
- Donor stem cells that don’t have similar genetic makeup will cause an immune response.
- There is no guarantee that it will work.
