cell division Flashcards
What does the nucleus of a cell contain?
chromosomes and DNA
What does each chromosome contain?
hundreds to thousands of genes
What is mitosis?
The division of two parental cells into 2 genetically identical daughters
What is the cell cycle?
parent cell with 2 pairs of chromosomes ➡️ each chromosome replicated (copies) itself➡️ chromosomes line up along the centre of the cell, divide and the copies move to the opposite poles➡️each ‘daughter’ cell has the same number of chromosomes and contains the same genes as the parent cell
Why is cell division by mitosis is important?
It makes new cells for growth and development, repairing damaged tissues, asexual reproduction.
What are stem cells?
Some cells are undifferentiated (not yet specialised). This means that they can divide to make different types of cells.
Where are stem cells found?
In human embryos, the umbilical cord of a baby and some organs and tissues.
What are stem cells for human embryos called?
Embryonic stem cells.
Where are adult stem cells found?
In some organs and tissues e.g bone marrow.
What is stem cells useful for?
Treating conditions- where cells are damaged they can replace them, could be through cloning embryos (therapeutic cloning)
What are risks of cloned embryos?
Transfers of viral infection, ethical or religious objections.
Where are stem cells found in plants?
Meristems
What are meristems useful for?
rare species can be cloned to protect form extinction, large numbers of identical crop plants with special features can be made.
How many chromosomes are there in each human body cell?
23 pairs, 42 together.
