Unit 1 KA1 - Division and Differentiation in Human Cells
What are body cells called?
Somatic Cells
Whatis a somatic cell?
Any cell in the body other than those involved in reproduction.
How do somatic cells divide?
By mitosis to form more somatic cells
What are germline cells?
Gametes (sperm and ova) and the stem cells that divide to form gametes
What type of division produces more germlins stem cells?
Mitosis
What happens when the nucleus of a germline stem cell divides by mitosis
It maintains the diploid chromosome number
How many pairs of homologous chromosomes are found in diploid cells?
23 pairs.
What happens when the nucleus of a germline stem cell divides by meiosis?
It produces haploid gametes.
What happens during the first division of meiosis?
The homologous chromosomes are seperated.
What happens during the second division of meiosis?
The chromatids are seperated.
What is the chromsone content of haploid gametes?
23 single chromosomes.
What is cellular differentiation?
The process by which a cell expresses certain genes to produce proteins characteristic of that type of cell
How does a cell become specialised?
By expressing specific genes and producing certain proteins that allow it to carry out specialised functions
Why are genes switched on and off in cells?
To prevent the body wasting energy producing proteins that are not needed in certain cells.
What type of cells in the early embryo can differentiate into all cell types?
Pluripotent cells
Why are embryonic stem cells considered pluripotent?
Because they can differentiate into any cell type in the organism
What does it mean for all genes in embryonic stem cells to be switched on?
It means these cells can potentially become any type of cell since they express all genes.
Whatare tissue stem cells involved in?
The growth renewal and repair of the cells found in that tissue.
An example of a multipotent tissue stem cell is...
Blood stem cells
What are a therapeutic use of stem cells?
Corneal repair and regeneration of damaged skin.
Under what conditions can embryonic stem cells self-renew in the lab?
Under the right conditions provided in a labatory setting.
How are stem cells used in research?
As model cells to study how diseases develop and for drug testing.
What kind of information does stem cell research provide?
Information on how cell processes such as growth, differentiation, and gene regulation work.
What ethical concern is there with the use of embryonic stem cells?
It involves the destruction of embryos
Why do cancer cells divide excessively?
They do not respond to regulatory signals?
What is the result of uncontrolled cell division in cancer?
A mass of abnormal cells called a tumour.
What can happen when cells in a tunour fail to attach to each other?
They can spread throughout the body and form secondary tumours.