Table of Contents

1. Chapter 4 Cell Structure and Function Table of Contents Section 1 The History of Cell Biology Section 2 Introduction to Cells Section 3 Cell Organelles and Features Section 4 Unique Features of Plant Cells

2. Section 1 The History of Cell Biology Chapter 4 Objectives • Namethe scientists who first observed living and nonliving cells. • Summarizethe research that led to the development of the cell theory. • Statethe three principles of the cell theory. • Explainwhy the cell is considered to be the basic unit of life.

3. Introduction to the Cell • Definition – A cell is the smallest unit of structure and function of living things that carries on life processes.

4. A. Discovery of the Cell • Robert Hooke ( 1665) – 1st to see cells; • looked at cork (dead plant cell); • box-shaped structures looked like monk’s rooms called ‘cells’.

5. A. Discovery of the Cell • Anton Van Leeuwenhoek (1673) – 1st to see living cells. • Scraped mouth:bacteria, yeast. • Water:Protozoans, “Animalcules”.

6. A. Discovery of the Cell • Matthias Schleiden (1838) – Botanist, • concluded all plants are made of cells.

7. A. Discovery of the Cell • Theodor Schwann (1839) – Zoologist, • concluded all animals are made of cells

8. A. Discovery of the Cell • Rudolf Virchow (1855) – Physician, • concluded cells come only from other living cells.

9. Section 1 The History of Cell Biology Chapter 4 Cell Theory

10. A. Discovery of the Cell • This information gave evidence for the Cell Theory: • Cells are the basic unit of structure and function in all living things. • All living things are made of cells. • Cells come only from the reproduction of other living cells.

11. Section 1 The History of Cell Biology Chapter 4 The Cell Theory, continued Think & Discuss: • Cellular Basis of Life • All living things are made of organized parts, obtain energy from their surroundings, perform chemical reactions, change with time, respond to their environment, and reproduce.

12. Section 2 Introduction to Cells Chapter 4 Objectives • Explain the relationship between cell shape and cell function. • Identify the factor that limits cell size. • Describethe three basic parts of a cell. • Compareprokaryotic cells and eukaryotic cells. • Analyzethe relationship among cells, tissues, organs, organ systems, and organisms.

13. B. Cell Diversity • Cell Size • Most cells are only visible with microscope. • Cell size varies from 2 m to .2m (.2 x 10-6) • Examples: • Bacteria - 0.2 m (.000008 in. or 8 millioneth in.) • Giraffe leg nerve – 2 m (6 ½ ft.) • Eggs • Most body and plant cells – 10 to 50 m (.002 in.)

14. Section 2 Introduction to Cells Chapter 4 • Think & Discuss: • Cell Size • Cell size is limited by a cell’s surface area–to-volume ratio.

15. B. Cell Diversity • Why are Cells so Small? • Diffusion is too slow to move nutrients & wastes through cell. • As cell size increases, volume increases at faster rate than surface area. Surface area becomes too small to allow materials to enter cell quickly enough to meet its needs.

16. B. Cell Diversity • Cell Shape • The shape of a cell helps it to perform its function. • Examples: a. RBCs – concave, flexible – squeeze thru vessels b. WBCs – change shape – engulf particles c. Nerves – long, threadlike, branched – receive & send messages d. Epithelial tissue – flat, packed – protection e. Muscles – long, rod-like, contract – pull parts together

17. Section 2 Introduction to Cells Chapter 4 Cell Diversity • Cell Shape • A cell’s shape reflects its function.

18. Section 2 Introduction to Cells Chapter 4 Cellular Organization • Think & Discuss: • In multicellular eukaryotes, cells organize into tissues, organs, organ systems, and finally organisms.

19. How are organelles like organs? • Organelles perform specific functions to keep a cell healthy and alive. • Organs perform specific functions to keep an organism healthy and alive.

20. Section 2 Introduction to Cells Chapter 4 Two Basic Types of Cells Think & Discuss: • Prokaryotes • Prokaryote cellslack a nucleus and membrane-bound organelles.

21. B. Cell Diversity • Eukaryotes – cells that have a nucleus and membrane-bound organelles. • Prokaryotes – cells that lack a nucleus and have no membrane-bound organelles. (bacteria)

22. Section 2 Introduction to Cells Chapter 4 Comparing Prokaryotes and Eukaryotes

23. Section 2 Introduction to Cells Chapter 4 Basic Parts of a Cell Think & Discuss: • The three basic parts of a cell are the plasma membrane, the cytoplasm, and the nucleus.

24. B. Cell Diversity • Internal Organization a. Organelles – cell components that perform specific functions to maintain the life of the cell. b. Cell Membrane – Thin membrane surrounding cell. c. Nucleus – large organelle near center of cell; contains genetic information; directs cell activities.

25. Section 3 Cell Organelles and Features Chapter 4 Objectives • Describethe structure and function of a cell’s plasma membrane. • Summarize the role of the nucleus. • Listthe major organelles found in the cytosol, and describe their roles. • Identifythe characteristics of mitochondria. • Describe the structure and function of the cytoskeleton.

26. Section 2 Introduction to Cells Chapter 4 Internal Organization of a Cell

27. Section 2 Introduction to Cells Chapter 4 Basic Parts of a Cell, continued • Cytoplasm - (Cytosol) • a. Located between cell membrane & nucleus • b. Contains gel-like fluid called Cytosol and organelles. • c. Helps give shape to cell.

28. B. Organelles: a. Organelles – cell components that perform specific functions to maintain the life of the cell.

29. Section 3 Cell Organelles and Features Chapter 4 Endoplasmic Reticulum (“E.R.”) a. Intracellular “Highway” b. Membranous tubes used to transport molecules c. Rough ER – has ribosomes; transports proteins d. Smooth ER – no ribosomes; makes lipids

30. Section 3 Cell Organelles and Features Chapter 4 Endoplasmic Reticulum, continued • The smooth ER builds lipids and participates in detoxification of toxins.

31. Section 3 Cell Organelles and Features Chapter 4 Endoplasmic Reticulum (ER) and Ribosomes

32. Section 3 Cell Organelles and Features Chapter 4 Ribosomes • Ribosomes • a. site of protein synthesis • b. Located on rough E.R. and scattered throughout cytoplasm

33. Section 3 Cell Organelles and Features Chapter 4 Ribosomes

34. Section 3 Cell Organelles and Features Chapter 4 Golgi Apparatus (“Packing & Shipping”) a. Stack of flat membranous sacs. b. Packages proteins from the ER c. Secretes (‘ships’) them to other parts

35. Section 3 Cell Organelles and Features Chapter 4 Mitochondria • Mitochondria(“Powerhouse”) • a. site of cellular respiration- make ATP energy from glucose • b. inner membrane has many folds (Cristae) to increase surface area • c. large numbers found in muscle cells

36. Section 3 Cell Organelles and Features Chapter 4 Mitochondria • Mitochondriaharvest energy from organic compounds and transfer it to ATP.

37. Section 3 Cell Organelles and Features Chapter 4 Mitochondrion

38. Section 3 Cell Organelles and Features Chapter 4 Vesicles • (Vesicles, including lysosomes (digestive enzymes) and peroxisomes (detoxification enzymes), are classified by their contents.) • Lysosomes (“Cleaning Crew”) • a. Sac of digestive enzymes • b. Break down nutrients, invaders, debris

39. Section 3 Cell Organelles and Features Chapter 4 Processing of Proteins

40. Section 3 Cell Organelles and Features Chapter 4 Cytoskeleton • (The cytoskeleton is made of protein fibers that help cells move and maintain their shape.) • Cytoskeleton • a. Microfilaments – fine protein threads • Ex: Actin – cause muscles to contract • b. Microtubules – hollow protein tubes • Ex: Spindle Fibers – move chromosomes

41. Section 3 Cell Organelles and Features Chapter 4 Cytoskeleton

42. Section 3 Cell Organelles and Features Chapter 4 Cytoskeleton, continued Think & Discuss: • Cilia and Flagella • (Cilia and flagella are hairlike structures that extend from the surface of the cell, where they assist in movement.)

43. Section 3 Cell Organelles and Features Chapter 4 Cytoskeleton, continued • Cilia • a. Tiny hair-like projections on cell membrane packed in rows • b. Wave, move mucus, catch debris • Flagella • a. Long, whip-like, on cell surface • b. Allow sperm cells to swim

44. Section 3 Cell Organelles and Features Chapter 4 Structure of Cilia and Flagella

45. Section 3 Cell Organelles and Features Chapter 4 Cytoskeleton, continued • Centrioles • A. two short cylinders of microtubules at right angles to each other • B. involved in cell division.

46. Section 3 Cell Organelles and Features Chapter 4 Nucleus • Nucleus • a. Contains DNA (genetic info) – directs cell’s activities • b. Located near center of cell • c. Nuclear Envelope – porous, double membrane • d. Nucleolus – produces ribosomes • e. Chromatin – “thread-like” DNA

47. Section 3 Cell Organelles and Features Chapter 4 Nucleus of a Cell

48. Section 2 Introduction to Cells Chapter 4 Parts of the Eukaryotic CellA. Cell Membrane Next, we’ll discuss: • Plasma Membrane • (The cell’s outer boundary, called the plasma membrane (or the cell membrane), covers a cell’s surface and acts as a barrier between the inside and the outside of a cell. )

49. Section 3 Cell Organelles and Features Chapter 4 Plasma Membrane, continued Think & Discuss: • Membrane Proteins • Cell membranes often contain proteins embedded within the phospholipid bilayer.

50. Section 2 Introduction to Cells Chapter 4 Parts of the Eukaryotic CellA. Cell Membrane • Selectively Permeable – controls which substances pass into and out of cell.