Chapter 3

The Cellular Level of Organization

Outline and Objectives

INTRODUCTION

1.   Define a cell

2.   Describe the connection between the chemical level of organization and cellular components.

3.   Relate the essential importance of the cellular level of organization to all life forms.

A GENERALIZED VIEW OF THE CELL

4.   Describe the three principal parts of a cell.

The Plasma Membrane

5.   Describe how the “fluid mosaic model” concept appropriately describes the nature and structure of the plasma membrane.

The Lipid Bilayer

6.   Explain how the chemical nature of the distinct regions of phospholipids

automatically produces a lipid bilayer in a water solution, with a range of

properties.

7.   Describe the function of cholesterol and glycolipids in membranes.

Arrangement of Membrane Proteins

8.   Distinguish between integral and peripheral proteins in cell membranes.

Functions of Membrane Proteins

9.   Describe the chemistry and function of membrane proteins.

Membrane Fluidity

10. Discuss the fluidity of membranes and the mobility of membrane lipids and proteins.

11. Explain how cholesterol modifies membrane fluidity.

Membrane Permeability

12. Explain the mechanisms and factors involved in the selective movement of

materials across the cell membrane.

Gradients Across the Plasma Membrane

13. Define a chemical and electrical gradient and the predominant ions involved on opposite sides of the plasma membrane.

14. Explain how an electrical gradient leads to the membrane potential that exists

in cells of the body.

Transport Across the Plasma Membrane

15. Distinguish between passive and active transport, including direction of particle

movement and energy requirements.

16. Distinguish between nonmediated and mediated transport.

17. Discuss the role of transporter proteins in mediated transport.

18. Discuss the basis of vesicular transport.

Principles of Diffusion

19. Explain the concept of diffusion based on the kinetic energy of random motion in terms of concentration differences, net movement, and the properties of substances and conditions.

20. List and explain the factors that influence the diffusion rate of substances in solution.

Osmosis

21. Explain the process of osmosis as the net movement of a solvent through a

selectively permeable membrane.

22. Discuss the roles of hydrostatic pressure and osmotic pressure in regulating osmosis.

23. Show the relation of osmotic pressure to tonicity by the effect on red blood

cells of different concentrations of solute in a surrounding solution.

Diffusion Through the Lipid Bilayer

24. Describe the movement and importance of nonpolar, hydrophobic molecules

through the lipid bilayer of the plasma membrane.

Diffusion Through Membrane Channels

25. Describe the process of small, inorganic ion movement across the plasma membrane.

Facilitated Diffusion

26. Detail the facilitated diffusion characteristics and process where transporter

proteins move glucose molecules along their concentration gradients.

Active Transport

27. Define active transport and list two energy sources used to drive the process.

Primary Active Transport

28. Describe the process of primary active transport and relate it to the sodium pump.

Secondary Active Transport

29. Describe the process of secondary active transport and the role of symporters and antiporters.

30. Discuss the effect of digitalis on the sodium pump.

Vesicular Transport

31. Describe the two main types of vesicular transport between a cell and its

extracellular fluid.

Endocytosis

32. Describe the process of endocytosis.

Receptor-Mediated Endocytosis

33. Define ligand and discuss the function of ligands.

34. List and explain the steps involved in receptor-mediated endocytosis.

35. Describe how some viruses can use receptor-mediated endocytosis to infect body cells.

Phagocytosis

36. Define phagocytosis and explain its importance.

Pinocytosis

37. Define pinocytosis and explain its importance.

Exocytosis

38. Describe the process of exocytosis.

CYTOPLASM

39. List the two components of the cytoplasm.

Cytosol

40. Describe the elements of the cytosol and how it is different from the plasma membrane.

ORGANELLES

41. Describe the basic structural features and functions of organelles.

42. Distinguish between membranous and nonmembranous organelles.

The Cytoskeleton

43. Distinguish the characteristics and functions of microfilaments, microtubules, and intermediate filaments.

Centrosome

44. Show the relationship of cytoskeletal elements to centrioles and the

centrosome and note their purpose in dividing and nondividing cells.

Cilia and Flagella

45. Describe the arrangement of microtubules in flagella and cilia that allow these

projections to perform the different types of transport movements.

Ribosomes

46. Indicate the origin and components of ribosomes that allow them to produce

proteins, and their association with other organelles in this process.

Endoplasmic Reticulum

47. Specify how the interconnected form of the ER membranous labyrinth is

related to its various synthetic purposes and molecular distribution within the

cell.

Golgi Complex

48. Describe how the Golgi apparatus conducts the processing and directing of

newly synthesized molecules.

49. Convey how the faulty operation of the Golgi complex is related to cystic fibrosis.

Lysosomes

50. Delineate the role of lysosomal enzymes in protection, digestion, and recycling

of external and internal substances.

51. Describe how faulty lysosomes are related to Tay-Sachs disease.

Peroxisomes

52. Describe the enzymes and reactants peroxisomes use to deactivate potentially

toxic molecules.

Mitochondria

53. Indicate how the two membrane layers of the mitochondrion are associated

with the enzymes that produce the energy-storage molecule ATP.

54. Describe the role of DNA in mitochondrial replication.

Nucleus

55. Discuss the morphology and function of the nuclear envelope, nucleoli, and

hierarchical levels of chromatin.

Protein Synthesis

56. Accentuate that DNA acts by coding for structural and functional (enzyme)

proteins,and those proteins form all the structures and perform almost all the

metabolic reactions to generate and maintain an organism.

Transcription

57. Describe the steps of transcription and nucleotides of the DNA sequence that

are used to synthesize complementary sequences of RNA nucleotides of three

types.

58. Define the process and functions of the gene splicing of mRNA.

Translation

59. Provide the identity and function of all the molecules involved in the

translation process.

60. Illustrate the relation between the codes of the DNA nucleotide triplet, the

mRNA codon, and the rRNA anticodon that specifies an amino acid in the

protein sequence.

61. Go through the steps in which the molecular components of this process

interact to translate the mRNA sequence into a successive coupling of amino

acids in a protein.

62. Discuss the techniques of genetic engineering and recombinant DNA.

Normal Cell Division

63. Define cell division

64. Distinguish between somatic and reproductive cell division.

The Cell Cycle in Somatic Cells

65. Describe the purpose and activities of the DNA and cell components in each

phase of the interphase cell cycle.

Interphase

66. Indicate the objectives and activities of the DNA and cell components in each

phase of the interphase cell cycle.

Mitotic Phase

67. List the events of mitosis.

Nuclear Division: Mitosis

68. Describe the physical events of each phase occurring with the chromatids/

centromeres in relation to the spindle apparatus, and show the concomitant

development of other cell parts that allow the process.

Cytoplasmic Division: Cytokinesis

69. Explain what is happening to the cytoplasm, organelles, and plasma membrane

during cytokinesis, and why.

Control of Cell Destiny

70. List and describe the three possible destinies of a cell.

71. Describe the role of tumor-suppressor genes in the cell cycle.

Cells and Aging

72. Explain how the three main theories of aging (genetic programming, free

radical reactions, and excess immune response) lead to the signs of aging.

Cellular Diversity

73. Discuss the concept of cellular diversity.

Disorders: Homeostatic Imbalances

74. Describe cancer (CA) as a homeostatic imbalance of cells with different

characteristics for benign versus malignant tumors.

Types of Cancer

75. Distinguish the origins and properties of the different types of tumors.

Growth and Spread of Cancer

76. Describe the effects of hyperplasia, metastasis, and secondary site development

on normal tissue.

Causes of Cancer

77. Explain the nature of the numerous carcinogens and viruses and with which

cell growth control genes they may interact.

Carcinogenesis: A Multistep Process

78. Describe the features and progression of steps that lead a normal cell to

develop into a malignancy.

Treatment of Cancer

79. Discuss how it is that the multiple personalities of the cells within a tumor

make the differing drug therapies difficult or ineffective.

Medical Terminology

80. Define medical terminology associated with cells.