Cell Biology ppt

Chapter 4 Cell Biology

1. Cell Structure and Function Chapter 4 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 Name the scientists who first observed living and nonliving cells. Summarize the research that led to the development of the cell theory. State the three principles of the cell theory. Explain why the cell is considered to be the basic unit of life.

3. Section 1 The History of Cell Biology Chapter 4 The Discovery of Cells All living things are made up of one or more cells. A cell is the smallest unit that can carry on all of the processes of life.

4. Section 1 The History of Cell Biology Chapter 4 The Discovery of Cells, continued Hooke In 1665, Robert Hooke discovered cells in slices of cork. Leeuwenhoek In 1673, Anton van Leeuwenhoek was the first to observe living cells in microorganisms; Leeuwenhoek called these organism animalcules ~ we now call them protists.

5. Section 1 The History of Cell Biology Chapter 4 The Cell Theory The cell theory states that all living organisms are made of one or more cells, cells are the basic units of structure and function, and cells come only from pre-existing cells. In 1838, the German botanist Matthias Schleiden concluded that all plants were composed of cells In 1839, Theodor Schwann concluded the same thing for animals In 1855, Rudolf Virchow noted that all cells come from other cells

6. Chapter 4 Click below to watch the Visual Concept. Visual Concept Cell Theory Section 1 The History of Cell Biology

7. Section 1 The History of Cell Biology Chapter 4 The Cell Theory, continued 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.

8. Section 2 Introduction to Cells Chapter 4 Objectives Explain the relationship between cell shape and cell function. Identify the factor that limits cell size. Describe the three basic parts of a cell. Compare prokaryotic cells and eukaryotic cells. Analyze the relationship among cells, tissues, organs, organ systems, and organisms.

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

10. Section 2 Introduction to Cells Chapter 4 Cell Diversity, Continued Cell Size Cell size is limited by a cell’s surface area–to-volume ratio.

11. Cell size differs amongst species Chapter 4 Section 2 Introduction to Cells

12. Cell Size Unicellular organisms are made up of one cell Multicellular organisms are made up of many cells that often specialize according to function - differentiation Section 2 Introduction to Cells Chapter 4

13. Specialized Animal Cells Section 2 Introduction to Cells Chapter 4 Bone Cells Cheek Cells Red Blood Cells

14. Prokaryotic Cells Chapter 4 -Cells lack a nucleus and membrane-bound organelles -Includes bacteria -Single, circular chromosome in nucleoid region -Surrounded by cell membrane and a cell wall made up of peptidoglycan Section 2 Introduction to Cells -Divided into two domains, I.e., Archaea and Bacteria

15. Eukaryotic Cells Section 2 Introduction to Cells Chapter 4 - Cells have a nucleus and membrane-bound organelles -Incudes protists, fungi, plants, and animals

16. Chapter 4 Click below to watch the Visual Concept. Visual Concept Comparing Prokaryotes and Eukaryotes Section 2 Introduction to Cells

17. Section 2 Introduction to Cells Chapter 4 Basic Parts of a Eukaryotic Cell The three basic parts of a cell are the plasma membrane, the cytoplasm, and the nucleus.

18. Chapter 4 Click below to watch the Visual Concept. Visual Concept Internal Organization of a Cell Section 2 Introduction to Cells

19. Section 2 Introduction to Cells Chapter 4 Basic Parts of a Cell, continued 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.

20. Section 2 Introduction to Cells Chapter 4 Basic Parts of a Cell, continued Cytoplasm The region of the cell that is within the plasma membrane and that includes the fluid, the cytoskeleton, and all of the organelles except the nucleus is called the cytoplasm . The part of the cytoplasm that includes molecules and small particles, such as ribosomes, but not membrane bound organelles is the cytosol About 20% of the cytosol is made up of protein

21. Section 2 Introduction to Cells Chapter 4 Basic Parts of a Cell, continued Nucleus The nucleus is a membrane-bound organelle that contains a cell’s DNA.

22. Section 2 Introduction to Cells Chapter 4 Cellular Organization In multicellular eukaryotes, cells organize into tissues, organs, organ systems, and finally organisms.

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

24. Chapter 4 Plasma Membrane Selectively permeable, separates internal metabolic reactions from the external environment, and allows cell to excrete waste Membrane Lipids Cell membranes consist of a phospholipid bilayer . Phospholipids have a polar, hydrophilic (“water-loving”) phosphate head and two nonpolar, hydrophobic (“water-fearing”) fatty acid tails Cholesterol gives membrane firmness and prevents freezing in low temperatures Section 3 Cell Organelles and Features

25. Chapter 4 Structure of Lipid Bilayer Section 3 Cell Organelles and Features

26. Chapter 4 Plasma Membrane, continued Membrane Proteins Cell membranes often contain proteins embedded within the phospholipid bilayer. Proteins help move large molecules or aid in cell recognition (peripheral and integral) Section 3 Cell Organelles and Features

27. Chapter 4 Plasma Membrane, continued Fluid Mosaic Model The fluid mosaic model states that the phospholipid bilayer behaves like a fluid more than it behaves like a solid. As a result of such lateral movement, the pattern, or “mosaic,” of lipids and proteins in the cellmembrane constantly changes Section 3 Cell Organelles and Features

28. Chapter 4 Nucleus The nucleus directs the cell’s activities and stores DNA. When a cell is not dividing, the DNA is in the form of a threadlike material called chromatin When a cell is about to divide, the chromatin condenses to form chromosomes Nuclear Envelope The nucleus is surrounded by a double membrane called the nuclear envelope. Nucleolus The nucleolus is the place where DNA is concentrated when it is in the process of making ribosomal RNA. Section 3 Cell Organelles and Features

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

30. Chapter 4 Mitochondria Mitochondria harvest energy from organic compounds and transfer it to ATP. Mitochondrial DNA – endosymbiotic origin Section 3 Cell Organelles and Features

31. Chapter 4 Ribosomes Ribosomes are either free or attached to the rough ER and play a role in protein synthesis. Made of protein an RNA molecules Ribosome assembly begins in the nucleolus and is completed in the cytoplasm Section 3 Cell Organelles and Features

32. Chapter 4 Click below to watch the Visual Concept. Visual Concept Ribosomes Section 3 Cell Organelles and Features

33. Chapter 4 Endoplasmic Reticulum – intracellular highway The rough ER prepares proteins for export or insertion into the cell membrane. Most abundant in cells that produce large amounts of protein for export, such as digestive glands and antibody-producing cells The smooth ER builds lipids, like cholesterol, and participates in detoxification of toxins. In ovaries and testes, smooth ER produces estrogen and testosterone, respectively In skeletal and heart muscle cells, smooth ER releases calcium, which stimulates contraction Abundant in liver and kidneys for detoxification Section 3 Cell Organelles and Features

34. Chapter 4 Click below to watch the Visual Concept. Visual Concept Endoplasmic Reticulum (ER) and Ribosomes Section 3 Cell Organelles and Features

35. Chapter 4 Golgi Apparatus The Golgi apparatus processes and packages proteins; proteins get address labels that direct them to other parts of the cell Section 3 Cell Organelles and Features

36. Chapter 4 Vesicles Vesicles, including lysosomes (digestive enzymes) and peroxisomes (detoxification enzymes – liver and kidneys), are classified by their contents. Lysosomes digest worn-out organelles in a process called autophagy; digestion of damaged or extra cells by the enzymes of their own lysosomes is called autolysis Section 3 Cell Organelles and Features Protein Synthesis The rough ER, Golgi apparatus, and vesicles work together to transport proteins to their destinations inside and outside the cell.

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

38. Chapter 4 Cytoskeleton The cytoskeleton is made of protein fibers that help cells move and maintain their shape. The cytoskeleton includes microtubules , microfilaments , and intermediate filaments . Section 3 Cell Organelles and Features

39. Chapter 4 Click below to watch the Visual Concept. Visual Concept Cytoskeleton Section 3 Cell Organelles and Features

40. Chapter 4 Cytoskeleton, continued Cilia and Flagella Cilia and flagella are hairlike structures that extend from the surface of the cell, where they assist in movement. Section 3 Cell Organelles and Features

41. Chapter 4 Click below to watch the Visual Concept. Visual Concept Structure of Cilia and Flagella Section 3 Cell Organelles and Features

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

43. Chapter 4 Objectives List three structures that are present in plant cells but not in animal cells. Compare the plasma membrane,the primary cell wall, and the secondary cell wall. Explain the role of the central vacuole. Describe the roles of plastids in the life of a plant. Identify features that distinguish prokaryotes, eukaryotes, plant cells, and animal cells. Section 4 Unique Features of Plant Cells

44. Chapter 4 Plant Cells Plant cells have cell walls, central vacuoles, and plastids. Section 4 Unique Features of Plant Cells

45. Chapter 4 Cell Wall In plant cells, a rigid cell wall covers the cell membrane and provides support and protection. Section 4 Unique Features of Plant Cells

46. Chapter 4 Click below to watch the Visual Concept. Visual Concept Parts of a Cell Wall Section 4 Unique Features of Plant Cells

47. Chapter 4 Central Vacuole Large central vacuoles store water, enzymes, and waste products and provide support for plant tissue. Section 4 Unique Features of Plant Cells

48. Chapter 4 Plastids Plastids store starch and pigments. Chloroplasts – use light energy to make carbohydrates from carbon dioxide and water; thylakoids contain green pigment chlorophyll that absorbs light energy Chromoplasts – contain colorful pigments Amyloplasts – store starch Section 4 Unique Features of Plant Cells

49. Chapter 4 Comparing Cells Prokaryotes, animal cells, and plant cells can be distinguished from each other by their unique features. Section 4 Unique Features of Plant Cells

50. Chapter 4 Comparing Plant and Animal Cells Section 4 Unique Features of Plant Cells