Gr.10 Bio(Stem Cells)

Stem cells

• Animal cells

• Self-renewal: make copies of themselves.

  • Without this, you would run out. Your body needs to maintain a pool of stem cells to use throughout your life.

• Differentiation: make other types of cells that become the specialized cells of the body.

  • Specialized cells are used up/damaged/die and cannot divide or make copies of themselves.

Differentiation

Every cell’s nuclei has the SAME DNA. However, certain genes(segments of DNA) are expressed and others are “turned off”.

This expression is influenced by

• internal/external signals

• environmental conditions

  • Scientists are still trying to figure out under which conditions stem cells differentiate into diff cell types.

Stem cells(in animals)

• Embryonic stem cells

  • Found in a blastocyst(very early embryo)

  • Pluripotent - can make all of the diff types of cells

• Tissue stem cell

  • Found in fetus, baby, and throughout life

  • Multipotent - can only make the specialized cells found in the tissue they belong to.

  • Body parts: surface of eye, brain, skin, breasts, testicles, intestines(gut), bone marrow, muscles

• Induced pluripotent Stem Cells

  • Adult cells that are made by adding specific genes to reprogram them, allowing them to behave like embryonic stem cells.

Stem cells(in plants)

Found in places where the plant grows:

• tips of stems, leaves, roots

Meristematic

• Stem cells in plants.

• Found in the place where the plant grows: tips of stems, leaves, roots.

Potency

Measure of how many types of specialized cells a stem cell can make.

Pluripotent

Can make almost all types of specialized cells in the body.

Eg. embryonic stem cells (after the embryo develops)

Multipotent

Can make multiple types of specialized cells but not all types.

Eg. tissue stem cells ()

Totipotent

Can differentiate into all types of specialized cells in the body + cells that are needed during development of the embryo(placenta, yolk sac, umbilical cord).

Unipotent

Can differentiate into one type of specialized cell.

Eg. spermatogonia stem cells —> can only form sperm cells

Clone

lineage of genetically identical individuals or cells.

Cloning

• process of forming identical offspring from a single cell/tissue.

• type of asexual reproduction.

Cell specialization

the process by which cells develop from similar cells into cells that have specific functions within a multicellular organism.

Cell differentiation

A stage of development of a living organism during which specialized cells form.