B2 Cell Divison Flashcards
In body cells, chromosomes are found in…
Pairs
Stage 1 of the cell cycle
Replication of DNA to form two copies of each chromosome and synthesis of new sub-cellular structures
Stage 2 of the cell cycle
Mitosis-one set of chromosomes is pulled to each end of the dividing cell and the nucleus divides
Stage 3 of the cell cycle
Cytoplasm and the cell membrane also divide to form two identical daughter cells
Mitotic division is important for the…
Growth, repair and development of multicelluler organisms
Most specialised cells can divide by mitosis but…
They can only form the same sort of cell
Some differentiated cells such as red blood cells and skin cells cannot…
Divide at all and so adult stem cells replace dead or damage cells
Nerve cells cannot…
Divide once they have differentiated and they are not usually replaced by stem cells
In animals, many types of cells become specialised…
Very early in life
In contrast to animal cells, most plant cells are able to differentiate…
All their lives
Meristems
Active regions of the stems and roots where undifferentiated cells are formed and where mitosis takes place almost continuously
Many types of plant cells retain the ability to differentiate…
Throughout life
Zygote
A single new cell formed when an egg and sperm cell fuse
Embryonic stem cells
Undifferentiated cells that can differentiate into any type of cell
Adult stem cells
Undifferentiated cell of an organism which can give rise to many more cells of the same type
