(1) Division and differentiation in human cells (F) Cancer Cells (A) Somatic cells Human Cells (E) Uses of stem cells (B) Differentiation in cells (D) Germline cells (C) Stem cells

Division and differentiation in human cells (C) State the 2 types of stem cells Define what a stem cell is Define the terms ‘multipotent’ and ‘pluripotent’ State which type of stem cell is ‘multipotent’ and which is ‘pluripotent’ State 3 things adult stem cells are involved in State what is meant by a ‘blastocyst’

Think / pair / share What do you already know about stem cells? Re-cap Think / pair / share What do you already know about stem cells? What is a stem cell? What are some different types of stem cells? What is the purpose of stem cell research? What are some ways that stem cells have been successfully used in medicine? What are some of the issues in stem cell research? What are some of the misconceptions that people have about stem cell research?

Watch me  animation of blood cell differentiation detailed intro to stem cells (4 mins) basic intro to stem cells (4 mins)

Stem Cells EMBRYONIC TISSUE (ADULT) Stem cells are unspecialised somatic cells that can divide to make copies of themselves (self-renew) and/or differentiate into specialised cells. The 2 types of stem cells are: EMBRYONIC TISSUE (ADULT)

Tissue (Adult) stem cells Adult or tissue stem cells are found in small numbers in the tissues and organs of adults and children, including the brain, bone marrow, skeletal muscle and skin. These cells give rise to a much more limited range of cell types and will tend to develop into cell types that are closely related to the tissue in which they are found. These cells replenish differentiated cells that need replaced in the tissues in which they are found.

Tissue (Adult) stem 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.

Development of tissue (adult) stem cells in bone marrow into red blood cells, platelets and the various forms of phagocytes and lymphocytes. (see figure 1.4 on page 4)

Embryonic stem cells Embryonic stem cells are derived from an embryo about 4–5 days old (bastocyst). These cells have the ability to differentiate into all of the cell types that make up an organism.

Embryonic stem cells The cells of the early embryo can make all of the differentiated cell types of the body. When grown in the lab scientists call these embryonic stem cells. 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. These cells can self-renew, under the right conditions, in the lab. It is then, they are termed embryonic stem cells.

Embryonic stem cells

Other types of stem cells Stem cells can also be taken from the umbilical cord of new babies. Like adult stem cells, these cells can differentiate into a limited range of specialised cells.

Incredible research… Induced pluripotent stem cells Induced pluripotent stem cells are adult cells that have been genetically reprogrammed to an embryonic stem cell-like state. First video is method used by Gurdon and Yamanaka Second Video is an interview with Gurdon http://www.bbc.co.uk/news/science-environment-19878542 http://www.bbc.co.uk/news/science-environment-19872346

Extended Answer Question! Give an account of cell differentiation under the following headings. (i) Stem cells; 4marks (ii) Somatic cells; 4marks

Give an account of cell differentiation under the following headings: Give an account of cell differentiation under the following headings: (i) Stem cells 1. Differentiation occurs when unspecialised cells become specialised (to perform a specific function) 2 Stem cells are unspecialised cells that can (divide to) form more stem cells 3 Embryonic stem cells can differentiate / develop into all / any cell types 4 Tissue / adult stem cells give rise to a more limited range of / fewer cell types Example given such as stem cells in the (red) bone marrow only produce blood cells / named blood cells 6 A differentiated cell only has a few genes switched on / produces specific proteins. 4marks

(ii) Somatic cells 7 Somatic cells form different types of body tissues 8 One example of a somatic cell and the tissue formed from it 9 Two more examples of somatic cells or two more of the tissues formed Examples include – a. epithelial cells form lining tissue of body cavities / surface b. blood/bone/cartilage cells forming connective tissue c. muscle cells forming muscle tissue d. nerve cells forming nervous tissue 10 Body organs are formed from a variety/mixture of these tissues 11 (The nucleus of a) somatic cell divides by mitosis (to maintain the diploid chromosome number) 4marks