7.1 Life Is Cellular

Understand Key Concepts

1. In many cells, the structure that controls the cell's activities is the

   1. cell membrane.

   2. organelle.

   3. nucleolus.

   4. nucleus.

2. Despite differences in size and shape, at some point all cells have DNA and a

   1. cell wall.

   2. cell membrane.

   3. mitochondrion.

   4. nucleus.

3. What distinguishes a eukaryotic cell from a prokaryotic cell is the presence of

   1. a cell wall.

   2. a nucleus.

   3. DNA.

   4. ribosomes.

4. Create a table that summarizes the contributions made to the cell theory by Robert Hooke, Matthias Schleiden, Theodor Schwann, and Rudolf Virchow.

Think Critically

5. Apply Concepts If you wanted to observe a living organism—an amoeba, for example—which type of microscope would you use?

6. Compare and Contrast How are prokaryotic and eukaryotic cells alike? How do they differ?

7.2 Cell Structure

Understand Key Concepts

7. In eukaryotic cells, chromosomes carrying genetic information are found in the

   1. ribosomes.

   2. lysosomes.

   3. nucleus.

   4. cell membrane.

8. The organelles that break down lipids, carbohydrates, and proteins into small molecules that can be used by the cell are called

   1. vacuoles.

   2. lysosomes.

   3. ribosomes.

   4. microfilaments.

9. Cell membranes consist mainly of

   1. lipid bilayers.

   2. protein pumps.

   3. carbohydrates.

   4. proteins.

10. Draw a cell nucleus. Label and give the function of the following structures: chromatin, nucleolus, and nuclear envelope.

11. What is the function of a ribosome?

12. Describe the role of the Golgi apparatus.

Think Critically

13. Infer The pancreas, an organ present in certain animals, produces enzymes used elsewhere in the animals' digestive systems. Which type of cell structure(s) might produce those enzymes? Explain your answer.

14. Classify For each of the following, indicate if the structure is found only in eukaryotes, or if it is found in eukaryotes and prokaryotes: cell membrane, mitochondria, ribosome, Golgi apparatus, nucleus, cytoplasm, and DNA.

7.3 Cell Transport

Understand Key Concepts

15. The movement of water molecules across a selectively permeable membrane is known as

    1. exocytosis.

    2. phagocytosis.

    3. endocytosis.

    4. osmosis.

16. A substance that moves by passive transport tends to move

    1. away from the area of equilibrium.

    2. away from the area where it is less concentrated.

    3. away from the area where it is more concentrated.

    4. toward the area where it is more concentrated.

17. Describe the process of diffusion, including a detailed explanation of equilibrium.

18. What is the relationship between diffusion and osmosis? By definition, what's the only substance that undergoes osmosis?

19. What is the difference between passive transport and active transport?