Human Cells: Division and Differentiation of Human Cells Flashcards
What is a somatic cell?
Any cell in the body other than cells involved in reproduction
What type of cells are somatic cells?
They are diploid and contain two sets of homologous chromosomes
What do diploid cells in humans have?
23 pairs of homologous chromosomes
Somatic cells divide by what to form what?
Mitosis
More somatic cells
What are germline cells?
Gametes (sperm and ova) and the stem cells that divide to form gametes
Germline stem cells divide by what?
Mitosis and meiosis
Germline cells divide by mitosis and meiosis to produce what?
Divide by mitosis to produce more germline cells.
Divide by meiosis to produce haploid gametes.
The nucleus of a germline stem cell can do what?
Divide by mitosis to maintain the diploid chromosome number
The nucleus of a germline stem cell can divide by meiosis. What two divisions does it undergo?
Firstly separating homologous pairs of chromosomes.
Secondly separating pairs of chromatids.
Haploid gametes in humans contain what?
23 single chromosomes
What is cellular differentiation?
The process by which a cell expresses certain genes to produce proteins characteristic for that type of cell
Cellular differentiation allows a cell to do what?
Carry out specialised functions
What are stem cells?
Unspecialised somatic cells that can divide to make copies of themselves (self-renew) and to make cells that differentiate into specialised cells of one or more types
What are the two types of stem cells in mammals?
Embryonic stem cells and tissue stem cells
Embryonic stem cells are what? Meaning they can do what?
Pluripotent stem cells.
They can differentiate into all the cell types that make up the individual.
What happens to all the genes in embryonic stem cells?
They can be switched on so these cells can differentiate into any type of cell
What are tissue stem cells involved in?
The growth, repair and renewal of the cells found in that tissue
Tissue stem cells are what? Meaning they can do what?
Multipotent stem cells.
They can differentiate into all of the types of cell found in a particular tissue type e.g. blood stem cells located in bone marrow can give rise to red blood cells, platelets, phagocytes and lymphocytes.
What are the two types of uses of stem cells?
Therapeutic and research
What do therapeutic uses of stem cells involve?
The repair of damaged or diseased organs or tissues
What are therapeutic stem cells used in?
Corneal repair and the regeneration of damaged skin
What can be done to embryonic stem cells?
They can be cultured in a laboratory to self-renew and provide a supply of embryonic stem cells
What does the research use of stem cells involve?
Stem cells being used as model cells to study how diseases develop or being used for drug testing
What does stem cell research provide?
Information on how cell processes such as cell growth, differentiation and gene regulation work
Use of embryonic stem cells can offer effective treatments for diseases and injury; however it raises what?
Ethical issues because it involves the destruction of an early embryo
Cancer cells divide excessively because they do not respond to what?
Regulatory signals
The uncontrolled cell division of cancer cells results in what?
A mass of abnormal cells called a tumour
Cells of the tumour may fail to attach to each other causing them to what?
Spread through the body where they may form secondary tumours
