Download Learning checkpoint p. 41 and p. 42

Learning Checkpoint ANSWERS TO QUESTIONS Learning checkpoint p. 41
1. A stem cell is an unspecialized cell. There are two types of stem
cells: embryonic and adult stem cells.
2. A stem cell becomes specialized when it is exposed to the proper
environmental conditions. Embryonic stem cells undergo
differentiation into cells that look different and perform different
functions.
3. Embryonic stem cells are able to differentiate into other cell types.
Adult stem cells have a limited ability to create a variety of cell
types and are involved in the replacement of damaged tissue.
4. Student answers may vary. One practical use of stem cell research
is for investigation into the replacement of damaged tissues and
organs, or into the treatment of various diseases, including cancer
and heart disease.
5. Meristematic cells are stem cells in plants. They are found where
growth takes place: root tips, stems, and the cambium.
Learning Checkpoint ANSWERS TO QUESTIONS Learning Checkpoint p. 42
1. The term “tissue” refers to groups of cells that function together to
perform specialized tasks.
2. The link between specialized cells and tissues is that tissues are
made of specialized cells that work together.
3. In animals, cells specialize to form epithelial tissue, which lines
body cavities and the outer surface of the body, protects structures,
and forms glands. Epithelial tissue is made of cells that are tightly
packed together and can be one cell thick or many layers thick. In
plants, cells specialize to form epidermal tissue, which forms the
protective outer coating of a plant. For example, epidermal tissue is
found on the top and bottom of a plant leaf. The tissue is clear and
very thin. Within the tissue are specialized openings called stomata
that allow for the exchange of gases and water.
4. Four types of animal tissues are epithelial tissue, connective tissue,
muscle tissue, and nervous tissue.
5. Four types of plant tissues are meristematic tissue, epidermal
tissue, ground tissue, and vascular tissue.