2.7 (P1) Cell Division Flashcards
Are chromosomes normally in pairs or not?
In pairs
What are chromosomes made from?
DNA
What are genes?
Short sections of DNA
Why do cells divide?
To repair and grow
What has to happen before the cell can divide?
Copies of genetic material has to be made
What are the two types of cell division?
Mitosis
Meiosis
Describe mitosis
Copies of the genetic material are made
The cell divides once to form two genetically identical body cells
What are the properties of mitosis?
One cellular division
Produces diploid body cells (homologous - in pairs)
Produces genetically identical daughter cells
Describe meiosis
Copies of the genetic material are made
Then the cell divides twice to form 4 gametes, each with a single set of chromosomes
What are the properties of meiosis?
Two cellular division
Produces gametes (haploid)
Leads to variation
Only has one chromosome from the original pair
What happens at fertilisation?
Gametes join to make a single body cell with new pairs of chromosomes
What are cells called that are undifferentiated?
Stem cells
When do most animal cells differentiate?
At an early stage in development
Where can you get stem cells from?
Bone marrow
Embryonic stem cells
What are the benefits of using embryos as stem cells?
Prevent children transferring disease
Cure diseases
Help conditions like paralysis
Grow organs instead of donors
