human bio 1.1

Somatic Cell

Any cell in the body other than the cells involved in reproduction

Somatic Cells divide by ...

mitosis to form more somatic cells

Germline Cell

Cells involved in reproduction

Germline Cells divide by ...

mitosis to produce more germline cells andmeiosis to produce haploid gametes

Mitosis produces...

2 genetically identical diploid cells

Mitosis occurs in ...

all body cells except gamete forming cells

Meiosis produces ...

4 genetically varied haploid cells.

Meiosis occurs in ...

gamete forming cells

Stem Cells are ...

unspecialised cells that have the ability to divide and differentiate into a diverse range of specialised cells.

How do specialised cells arise ?

Specialised cells arise from the differentiation of unspecialised cells during embryological development

What is differentiation ?

Cellular differentiation is process by which a cell expresses certain genes to produce protein characteristics for that type of cell.

What does differentiation allow the cell to do ?

Carry out specialised functions

Pluripotent Cells

they can differentiate into any cell type e.g embryonic

Multipotent cells

can differentiate into multiple types of cells within a particular tissue e.g blood stem cells

Genes in an embryonic stem cell can ...

be switched on so that these cells can differentiate into any cell type.

Therapeutic uses of stem cells

repair of damaged or diseased tissues or organs:- corneal repair- regeneration of damaged skin

Stem Cells in research

- To study how diseases develop - For drug testing - To provide info on cell processes such as differentiation, cell growth and gene regulation

Ethical Issues

destroys embryos

Why do cancer cells divide excessively ?

they do not respond to regulatory signals


mass of abnormal cells. Caused by cancer cells diving excessively and them not responding to regulatory signals.

What causes tumours to spread ?

Cells failing to attach to each other, means that they travel through the body where they may form secondary tumours.