Animal Development

Stem cells are

• cells that grow uncontrollably
• undifferentiated and can be any type of cell
• never go through cell division
• only found in embryos

Stem cells can be obtained from

• embryos
• some adult tissues
• umbilical cord blood
• all of the above

What does "pluripotent" mean?

• able to divide and make many different types of cells
• not able to divide
• can only divide and make one cell type 
• if it divides, it will make a cancerous tumor

What process best explains how muscle cells and nerve cells can develop from the same fertilized egg?

• genetic engineering
• survival of the fittest
• differentiation
• selective breeding

Which best explains why muscle cells are different from blood cells?

• Muscle cells are produced by the brain, but blood cells are produced by the heart. 
• Different genes are activated in muscle cells than in blood cells. 
• Muscles cells experience different environmental influences than blood cells. 
• A mutation occurs during the development of muscle cells but not in blood cells. 

What is the difference between embryonic stem cells and adult stem cells?

• Embryonic stem cells can differentiate into more cell types than adult stem cells
• Adult stem cells are pluripotent, just like embryonic stem cells
• Adult stem cells can differentiate into more cell types than embryonic stem cells
• Adult stem cells grow bigger than embryonic stem cells

Which is true about embryonic stem cells?

• They no longer divide, their cell type is set and cannot change.
• They can develop into only one type of cell.
• They can become any cell type in the body.
• They are found in adults.

How do stem cells know what type of cells to differentiate into?

• The nucleus has instructions to turn some genes on and some genes off.
• Signals from chemicals in the organism or from the environment determine which genes will be turned on and off.
• Genes turn on and off randomly.
• The cell has unique DNA that determines what the cell will become.

what is the role of stem cells in the body 

• fight against infection 
• provide specialized roles in the body 
• used for fertility treatment 
• they produce new specialized cells in the body to replace old cells that are used up 

The animal's digestive tract forms from the _______.

• endoderm

• mesoderm

• ecotoderm

• protostome