KA1 - Division And Differentiation In Human Cells Flashcards
Define somatic cells
Somatic cells are any cell in the body other than the cells involved in reproduction
Define germline cells
Germline cells involve the gametes and the stem cells that divide to produce the gametes
How do somatic cells divide?
Somatic cells divide by mitosis to form more somatic cells.
What does mitosis maintain?
The diploid chromosome number
How many chromosomes do diploid cells have?
Diploid cells have 23 pairs of homologous chromosomes
How to germline cells divide?
The nucleus of a germline cell can divide by mitosis to produce more germline cells
How do germline stem cells divide?
Germline stem cells can divide by meiosis to produce haploid gametes
What 2 divisions does germline cells undergo to produce haploid gametes?
Separating homologous chromosomes
Separating chromotides
How many chromosomes do haploid gametes contain?
Haploid gametes contain 23 single chromosomes
Define cellular differentiation
Cellular differentiation is the process by which a cell becomes specialised
How do unspecialised cells develop a specialised function?
The cell expresses certain genes to produce proteins characteristics for that type of cell
What are stem cells?
Stem cells are unspecialised somatic cells that have the ability to differentiate into a diverse range of specialised cells
What are the 2 types of stem cell?
Embryonic
Tissue
Why are embryonic stem cells described as pluripotent?
Cells in the very early embryo can differentiate into all of the cell types that make up that individual
What allows embryonic stem cells to differentiate into any type of cell?
All the genes in embryonic stem cells can be switched on so these cells can differentiate into any type of cell
Why are tissue stem cells described as multipotent?
Tissue stem cells can differentiate into all of the cell types found in a particular tissue type and are said to be multipotent
Give an example of the differenciation of tissue stem cells
For example, blood stem cells located in bone marrow can give rise to red blood cells, platelets, phagocytes and lymphocytes.
Give examples of research involving stem cells
How cell processes work such as cell growth, differentiation and gene regulation work.
The study of diseases and their development.
Drug testing.
Give examples of therapeutic uses of stem cells
Treatment of disease e.g. heart disease
Regeneration of damaged skin for burns patients
Cornea repair
How are stem cells used outside the body?
Stem cells from the embryo can self renew, under the right conditions in the lab
Give an ethical issue for the use of stem cells
Embryonic stem cells have the potential to discover cures for diseases for which there are currently none and can be used in the treatment of injury
Give an ethical issue against the use of stem cells
Destruction of an embryo which could be a potential life
How do tumours form?
Cancer cells divide excessively because they do not respond to regulatory signals. This results in a mass of abnormal cells called a tumour.
How to secondary tumours form?
Cells within a tumour may fail to attach to each other, spreading through the body where they may form secondary tumours
