Stem cell

A group of cells with a simular structure and function. Different tissues are grouped into organs.

Multicellular organisms are made of lots of cells.

Differentiation is when a cell changes to become specialised for a particular job. It occurs as cells divide. Most animals cells differentiate at an early stage. Many types of plant cells keep the abiltity to differentiate throughout life.

Xylem cells transport water and minerals from the roots around the plant.

Phloem cells are involved in transaction which means the transport off dissolved sugars made in the leaves around the plant.

- They can grow into any type of cell found in the body. - All tissues and organs can be grown. - They could be used to replace cells that have been damaged or destroyed.

- Embryos specifically made and then discarded. - It can be difficult to obtain/store embryonic stem cells. - Patients could be exploited. - Transplant issues and organs may be rejected by the immune system.

- As the cells are from the same body they would not reject their own cells.

- Can only differentiate into cells from the type of tissue where they are found. - Some human stem cells growing in labs that researches have used in experiments to treat serious diseases contain serious cancer-causing mutations.

- Only a small chance the cells will be rejected. - Organs have an exact match of DNA. - Help create vital organs. - Prevents diseases.

- Embryos are specifically made and then discarded. - Ethical issues - Viruses can be transferred. - Cost is high. - Extracting eggs from a female is costly and painful.

- Rich source of stem cells. - Possible use in the future for the child. - No rejection. - No ethical issues. - They could be used to replace blood cells that have been destroyed or damaged.

- Have to pay to store the blood.