Stem Cell Functions and Differentiation

Multicellular organisms start as a single cell that divides to form an embryo. Initially, cells are unspecialized stem cells, which later differentiate to perform specific functions. Despite having identical DNA, cells express different genes, leading to varied functions and structures. Stem cells reside in niches, responding to environmental signals to either remain undifferentiated or become specialized. Chemical signals from surrounding cells guide gene expression, resulting in the formation of specialized cells.

What is the initial form of a multicellular organism?

• A single cell

• A fully formed embryo

• A group of specialized cells

• A cluster of tissues

What are unspecialized cells in an embryo called?

• Nerve cells

• Muscle cells

• Stem cells

• Differentiated cells

What is the process called when stem cells become specialized?

• Gene expression

• DNA replication

• Cell differentiation

• Protein synthesis

How can cells with the same DNA have different functions?

• They have different DNA sequences

• They express different genes

• They are located in different organs

• They have different sizes

What do different types of cells produce due to gene expression?

• Identical DNA

• Identical proteins

• Different proteins

• The same RNA

What are stem cell niches?

• Parts of the digestive system

• Regions in the brain

• Types of specialized cells

• Micro environments for stem cells

What role do signals from surrounding cells play in stem cell niches?

• They destroy stem cells

• They create new DNA

• They cause cell death

• They prevent or start differentiation

What happens when new cells are needed for tissue repair?

• Stem cells are destroyed

• Stem cells remain unchanged

• Stem cells become unspecialized

• Stem cells differentiate into specialized cells

How do chemical signals affect stem cells in tissues?

• They guide stem cells to differentiate

• They make stem cells identical

• They prevent stem cell division

• They cause stem cells to die

What is the result of stem cells expressing specific genes?

• They stop dividing

• They differentiate into specialized cells

• They become unspecialized

• They lose their DNA