Question

vocabulary
fill in the blank with the term that best completes the following sentences.

1. the functional and structural unit of all living things.
2. all cells are surrounded by a(n)
3. a living thing is called a(n)

key concepts

1. describe discuss two ways that all cells are alike.
2. list what are the main ideas of the cell theory?
3. compare how do prokaryotes differ from eukaryotes? how are they similar?

critical thinking

1. apply what is the surface - area - to - volume ratio of this cube?
2. apply cells are not as large as this cube. explain why in terms of the surface - area - to - volume ratio.
3. compare how is the structure of a unicellular organism different than the structure of a multicellular organism? how does this affect function?

Explanation:

1. The cell is the basic functional and structural unit of all living things.
2. All cells are surrounded by a cell - membrane.
3. A living thing is called an organism.
4. All cells have a cell - membrane that controls what enters and leaves the cell, and all cells contain genetic material (DNA or RNA).
5. The main ideas of cell theory are: all living things are made of cells; cells are the basic unit of life; new cells come from pre - existing cells.
6. Prokaryotes lack a nucleus and membrane - bound organelles while eukaryotes have them. Both have genetic material, a cell membrane, and ribosomes.
7. For a cube with side length \(s = 5\ cm\), the surface area \(SA=6s^{2}=6\times5^{2}=150\ cm^{2}\), the volume \(V = s^{3}=5^{3}=125\ cm^{3}\), and the surface - area - to - volume ratio is \(\frac{SA}{V}=\frac{150}{125}=\frac{6}{5}=1.2\).
8. As cells grow larger, their volume increases faster than their surface area. A large volume requires more nutrients and produces more waste, but a relatively small surface area may not be sufficient for efficient exchange of materials, so cells stay small to maintain a favorable surface - area - to - volume ratio.
9. A unicellular organism has all life processes occurring within one cell. A multicellular organism has cells specialized for different functions and organized into tissues, organs, and organ systems. Functionally, unicellular organisms are self - sufficient while multicellular organisms rely on cell cooperation.

Answer:

1. Cell
2. Cell - membrane
3. Organism
4. All cells have a cell - membrane and genetic material.
5. All living things are made of cells; cells are the basic unit of life; new cells come from pre - existing cells.
6. Prokaryotes lack a nucleus and membrane - bound organelles; both have genetic material, a cell membrane, and ribosomes.
7. 1.2
8. As cells grow, volume increases faster than surface area, and a large surface - area - to - volume ratio is needed for efficient material exchange.
9. Unicellular organisms have all life processes in one cell; multicellular organisms have specialized cells and cell cooperation.