Question

a view of the cell, continued
section 7.3 eukaryotic cell structure
in your textbook, read about structures for support and locomotion.
determine if the statement is true. if it is not, rewrite the italicized part to make it true.

1. cells have a support structure within the cytoplasm called the cytoskeleton.
2. the exoskeleton is composed of thin, fibrous elements that form a framework for the cell.
3. microtubules of the cytoskeleton are thin, hollow cylinders made of protein.
4. cilia and flagella are cell surface structures that are adapted for respiration.
5. flagella are short, numerous, hairlike projections from the plasma membrane.
6. flagella are longer and more numerous than cilia.
7. in multicellular organisms, cilia and flagella are the major means of locomotion.
8. in prokaryotic cells, both cilia and flagella are composed of microtubules.

Explanation:

1. The statement is true. The cytoskeleton is indeed a support structure within the cytoplasm of cells.
2. The correct term is "cytoskeleton" instead of "exoskeleton". The cytoskeleton is composed of thin, fibrous elements that form a framework for the cell.
3. The statement is true. Microtubules of the cytoskeleton are thin, hollow cylinders made of protein.
4. Cilia and flagella are adapted for "locomotion" not "respiration".
5. "Cilia" are short, numerous, hairlike projections from the plasma membrane. Flagella are longer and fewer in number.
6. Flagella are longer but "less" numerous than cilia.
7. In "unicellular" organisms, cilia and flagella are the major means of locomotion. In multicellular organisms, they have other functions like moving substances along surfaces.
8. In "eukaryotic" cells, both cilia and flagella are composed of microtubules. Prokaryotic flagella have a different structure.

Answer:

1. True
2. The cytoskeleton is composed of thin, fibrous elements that form a framework for the cell.
3. True
4. Cilia and flagella are cell surface structures that are adapted for locomotion.
5. Cilia are short, numerous, hairlike projections from the plasma membrane.
6. Flagella are longer and less numerous than cilia.
7. In unicellular organisms, cilia and flagella are the major means of locomotion.
8. In eukaryotic cells, both cilia and flagella are composed of microtubules.