Learn: Cell Structure and Function: Key Concepts for Biology Students

1. When viewing a specimen through a light microscope, scientists use ______ to distinguish the individual components of cells.

Special stains

2. The ______ is the basic unit of life.

Cell

3. Prokaryotes depend on ______ to obtain some materials and to get rid of wastes.

Diffusion

4. Bacteria that lack fimbriae are less likely to ______.

Adhere to cell surfaces

5. Which of the following organisms is a prokaryote?

E. coli

6. Which of the following is surrounded by two phospholipid bilayers?

the nucleoplasm

7. Peroxisomes got their name because hydrogen peroxide is:

Produced during their oxidation reactions

8. In plant cells, the function of the lysosomes is carried out by:

Vacuoles

9. Which of the following is both in eukaryotic and prokaryotic cells?

Ribosomes

10. Tay-Sachs disease is a genetic disorder that results in the destruction of neurons due to a buildup of sphingolipids in the cells. Which organelle is malfunctioning in Tay-Sachs?

Lysosome

11. Which of the following is not a component of the endomembrane system?

Mitochondrion

12. The process by which a cell engulfs a foreign particle is known as:

Phagocytosis

13. Which of the following is most likely to have the greatest concentration of smooth endoplasmic reticulum?

A cell that makes steroid hormones

14. Which of the following sequences correctly lists in order the steps involved in the incorporation of a proteinaceous molecule within a cell?

Synthesis of the protein on the ribosome; modification in the endoplasmic reticulum; tagging in the Golgi; distribution via the vesicle

15. Congenital disorders of glycosylation are a growing class of rare diseases. Which organelle would be most commonly involved in the glycoprotein disorder portion of the group?

Golgi apparatus

16. Which of the following have the ability to disassemble and reform quickly?

Microfilaments and microtubules

17. Which of the following do not play a role in intracellular movement?

Intermediate filaments

18. In humans, ______ are used to move a cell within its environment while ______ are used to move the environment relative to the cell.

Flagella; cilia

19. Which of the following are only in plant cells?

Plasmodesmata

20. The key components of desmosomes are cadherins and ______.

Intermediate filaments

21. Diseased animal cells may produce molecules that activate death cascades to kill the cells in a controlled manner. Why would neighboring healthy cells also die?

The death molecule passes through gap junctions.

22. Which plasma membrane component can be either found on its surface or embedded in the membrane structure?

Protein

23. Which characteristic of a phospholipid contributes to the fluidity of the membrane?

Double bonds in the fatty acid tail

24. What is the primary function of carbohydrates attached to the exterior of cell membranes?

Identification of the cell

25. A scientist compares the plasma membrane composition of an animal from the Mediterranean coast with one from the Mojave Desert. Which hypothesis is most likely to be correct?

The cells from the Mediterranean coast animal will have more fluid plasma membranes.

26. Water moves via osmosis ______.

From an area with a high concentration of water to one of lower concentration

27. The principal force driving movement in diffusion is the ______.

Concentration gradient

28. What problem is faced by organisms that live in fresh water?

Their bodies tend to take in too much water.

29. In which situation would passive transport not use a transport protein for entry into a cell?

Oxygen moving into a cell after oxygen deprivation

30. Active transport must function continuously because ______.

Diffusion is constantly moving solutes in opposite directions

31. How does the sodium-potassium pump make the interior of the cell negatively charged?

By expelling more cations than are taken in

32. What is the combination of an electrical gradient and a concentration gradient called?

Electrochemical gradient

33. What happens to the membrane of a vesicle after exocytosis?

It fuses with and becomes part of the plasma membrane.

34. Which transport mechanism can bring whole cells into a cell?

Phagocytosis

35. In what important way does receptor-mediated endocytosis differ from phagocytosis?

It brings in only a specifically targeted substance.

36. Many viruses enter host cells through receptor-mediated endocytosis. What is an advantage of this entry strategy?

The virus only enters its target host cell type.

37. Which of the following organelles relies on exocytosis to complete its function?

Golgi apparatus

38. Imagine a cell can perform exocytosis, but only minimal endocytosis. What would happen to the cell?

The plasma membrane would increase in size over time.

39. Energy is stored long-term in the bonds of ______ and used short-term to perform work from an ______ molecule.

Glucose; ATP

40. DNA replication involves unwinding two strands of parent DNA, copying each strand to synthesize complementary strands, and releasing the parent and daughter DNA. Which of the following accurately describes this process?

This is an anabolic process.

41. Consider a pendulum swinging. Which type(s) of energy is/are associated with the pendulum in the following instances: i. the moment at which it completes one cycle, just before it begins to fall back towards the other end, ii. the moment that it is in the middle between the two ends, and iii. just before it reaches the end of one cycle (just before instant i.).

i. potential, ii. potential and kinetic, iii. potential and kinetic

42. Which of the following comparisons or contrasts between endergonic and exergonic reactions is false?

Endergonic reactions consume energy and exergonic reactions release energy.

43. Which of the following is the best way to judge the relative activation energies between two given chemical reactions?

Compare their reaction rates.

44. Which of the following is not an example of an energy transformation?

None of the above

45. In each of the three systems, determine the state of entropy (low or high) when comparing the first and second: i. the instant that a perfume bottle is sprayed compared with 30 seconds later, ii. an old 1950s car compared with a brand new car, and iii. a living cell compared with a dead cell.

i. low, ii. high, iii. high

46. The energy released by the hydrolysis of ATP ______.

Provides energy to coupled reactions

47. Which of the following molecules is likely to have the most potential energy?

Sucrose

48. Which of the following is not true about enzymes:

They increase ΔG of reactions.

49. An allosteric inhibitor does which of the following?

Binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate.

50. Which of the following analogies best describes the induced-fit model of enzyme-substrate binding?

A hug between two people

51. Which statement best describes a virus?

A noncellular infectious agent that requires a host cell to reproduce

52. Why are viruses generally considered nonliving?

They cannot reproduce independently outside of a host cell

53. What is the genetic material found in viruses?

Either DNA or RNA

54. What is the protein coat surrounding a viral genome called?

Capsid

55. What is the primary function of a viral capsid?

To protect the viral genetic material

56. Some viruses have an additional membrane surrounding their capsid. What is this structure called?

Envelope

57. Which structure is found in all viruses?

A capsid

58. Why is viral classification difficult?

Viruses have very simple structures and do not fit easily into traditional biological classification systems

59. Which of the following is an example of a virus with an RNA genome?

Influenza virus

60. Which statement best explains why viruses are considered obligate intracellular parasites?

They can reproduce only inside living host cells