Higher Human | Division and Differentiation in Human Cells

The following links offer some useful revision on Cell Structure to support your learning:

At Higher, you will need to know the following:

Somatic cells divide by mitosis to form more somatic cells.
Cellular differentiation is the process by which a cell develops more specialised functions by expressing the genes characteristic for that type of cell.
Once a cell becomes differentiated it only expresses the genes that produce the proteins characteristic for that type of cell.
Stem cells are unspecialised somatic cells that can divide to make copies of themselves (self-renew) and/or differentiate into specialised cells.
Tissue (adult) stem cells are involved in the growth, repair and renewal of the cells found in that tissue. They are multipotent.
Tissue stem cells are multipotent as they can make all of the cell types found in a particular tissue type. For example, blood (haematopoietic) stem cells can make all of the cell types in the blood.
The main body tissue types are epithelial, connective, muscle and nerve tissue. The body organs are formed from a variety of these tissues.
Development of tissue (adult) stem cells in bone marrow into red blood cells, platelets and the various forms of phagocytes and lymphocytes.
Epithelial cells cover the body surface and line body cavities, connective tissue includes blood, bone and cartilage cells, muscle cells form muscle tissue and nerve cells form nervous tissue.
The cells of the early embryo can make all of the differentiated cell types of the body. They are pluripotent.
The inner cell mass cells of an early embryo (blastocyst stage) are pluripotent as they can make nearly all of the cell types in the body.
When grown in the lab scientists call these embryonic stem cells.
These cells can self-renew, under the right conditions, in the lab. It is then they are termed embryonic stem cells.
Germline cells divide by mitosis to produce more germline cells or by meiosis to produce haploid gametes.
Mutations in germline cells are passed to offspring.
During cell division the nucleus of a somatic cell divides by mitosis to maintain the diploid chromosome number.
Diploid cells have 23 pairs of homologous chromosomes.
Research and therapeutic uses of stem cells by reference to the repair of damaged or diseased organs or tissues
Stem cells can also be used as model cells to study how diseases develop or for drug testing.
The ethical issues of stem cell use and the regulation of their use.
Stem cell research provides information on how cell processes such as cell growth, differentiation and gene regulation work
The therapeutic uses of stem cells should be exemplified by reference to the repair of diseased or damaged organs, eg corneal transplants and skin grafts for burns.
Cancer cells divide excessively to produce a mass of abnormal cells (called a tumour).
These cells do not respond to regulatory signals and may fail to attach to each other. If the cancer cells fail to attach to each other they can spread through the body to form secondary tumours.