KA1: Producing New cells Flashcards
What is mitosis
The process of cell division
How are new cells produced in the body
Mitosis
What does mitosis involve
The doubking of chromosomes to produce new cells
Where are chromosomes found
The nucleus
How many chromosomes are in a diploid human cell
46
What do diploids contain
2 matching sets of chromosomes which are replicated during mitosis
What are the stages of mitosis
1: Interphase - The cell is a resting phase before mitosis. Individual chromosomes cannot be identified
2: Prophase - Chromosomes doublr to form chromatids held together by a centromere. They shorten and become visible
3: Metaphase - Chromosomes line up along the equator and are attached to spindle fibres
4: Anaphase - Spindle fibres shorten and pull the chromatids to opposite poles
5: Telophase - Nucleus and cell membrane divided forming 2 new cells with the sane chromosome complement
What do sex cells have?
Half of an organisms DNA (1 set of chromosomes)
What cells are haploid?
Sex cells (egg and sperm)
How do parent cells divide?
Produce 2 new cells with the same number of chromosomes
What is a parent cell?
A cell that is copied during mitosis
What is in the centre of a chromsome
A centromere
Why is it important that the cells produced during mitosis have the same number of chromosomes?
It allows cells to work and function correctly and to make sure no genetic information is lost
What is mitosis used for?
Growth
Repair
Maintain diploids chromosome complement
What is a stem cell?
Unspecialised (spare) cells
What can stem cells divide to do
Self-renew to make copies of themselves
Differentiate to make different types of cells
What is a feature of a stem cell
It is unspecialised
What are stem cells involved in
Growth abd repair of damaged tissue or to replace dead cells
Where are embyonic stem cells from
Human embryos
What can embryonic stem cells do
Become all different types of cells in the body
Where are tissue stem cells found
Various tissues around the body
What can tissue stem cells not do
Differentiate into every type of cell
What do tissue stem cells do
Replenish the supply of one or more types of specialised cell closely to the tissue they are found in
