Stem Cell Potency and Differentiation

Study Notes

Stem Cell Potency

Potency: A cell's ability to differentiate into other cell types. The more types, the greater its potency.
Totipotent Stem Cells: Found from zygote to the morula stage (16 cells), capable of becoming any cell type, including placental cells.
Pluripotent Stem Cells: Present in blastocysts, can develop into any cell type within the body, but not placental cells.
Multipotent Stem Cells: Found in adult tissues, can differentiate into a limited number of cell types within their tissue of origin.
Unipotent Stem Cells: Can only differentiate into one specific cell type.

Cellular Differentiation

Multicellular organisms begin with a single cell, the zygote, which divides and differentiates into trillions of specialized cells through mitosis.
Cellular differentiation involves changes in gene expression within stem cells, leading them to become specialized.
Stem cells are found in embryos, specific adult tissues, and meristem tissue in plants.
Stem cells can divide indefinitely, while specialized cells have reduced or arrested division.
Specialized cells can resume division to repair injuries or replace dead cells.

Cell Hierarchy

Cellular differentiation allows multicellular organisms to function through a hierarchical organization.
Specialized Cells: Individual cells with specific functions.
Tissues: Groups of specialized cells working together to form a functional unit.
Organs: Groups of two or more tissues working together for a common purpose.
Systems: Groups of organs working together to perform a vital task.
This hierarchical organization enables multicellular organisms to:
- Obtain nutrients
- Exchange gases
- Remove wastes

Stem Cells

Two main types:
- Embryonic stem cells: Undifferentiated cells in embryos that can replicate indefinitely.
- Adult stem cells: Found in small numbers in adult tissues, have limited potential and cannot replicate indefinitely.

Specialised Cell Examples

Root Hair Cell:
- Function: Absorb water and nutrients from the soil, increase surface area for absorption.
- Specializations: Long, thin shape, large surface area for increased absorption.
Nerve Cell:
- Function: Transmit information in the nervous system.
- Specializations: Receive and send electrical signals, release neurotransmitters, respond to neurotransmitters, process and store information.
Sperm Cell:
- Function: Responsible for fertilizing an egg cell during reproduction.
- Specializations: Head carries genetic material and helps break down the egg during fertilization, tail propels itself.
Plant Leaf Cell:
- Function: Photosynthesis and light absorption.
- Specializations: Numerous chloroplasts for high chlorophyll concentration, large surface area to absorb water and minerals.

Description

Explore the fascinating world of stem cells and their differentiation capabilities. This quiz covers the different types of stem cells, including totipotent, pluripotent, multipotent, and unipotent, as well as the process of cellular differentiation. Test your knowledge on how these cells contribute to the development of multicellular organisms.