Stem cells

stem cells

undifferentiated cells which have the ability to develop into various kinds of cells. Able to undergo cell division.

potency

ability to differentiate

Totipotent

• can differentiate into any cells.

• found in umbilical cord and uses fertilised eggs.

Multipotent

• adult stem cells that can differentiate into specific cells in same tissue.

• Found in bone marrow

• form red blood cells (erythrocytes)

Pluripotent

• can form tissue but not whole organisms.

• Found in meristem and can form xylem and phloem tissue

Stem cells in planta

• stem cells found in meristem. contain cambium (pluripotent.)

• Inner cambium forms xylem tissues. Deposits lignin and loses end cell walls.

• Outer cambium forms phloem tissues. Develops sieve tubes.

STIMULATED BY HORMONES

stem cell replacement therapy

cures diseases.

controversial as it uses embryonic/adult stem cells

Neurological conditions

Parkinsons disease: caused by destruction of dopamine so stimulating stem cells to differentiate into dopamine

e into iPSCs

induced pluripotent stem cells: derived from somatic (any normal cell) cells and are genetically modified to pluripotent state.

Benefits: genes can be edited.

Advantage of stem cells

• iPSCs dont require embryos.

• can get consent for adult stem cells.

• able to cure diseases

Arguments against stem cells

• iPSCs are expensive and difficult to control.

• embryonic cant give consent

• unethical - religious views