1. CAMPBELL BIOLOGY IN FOCUS © 2014 Pearson Education, Inc. Urry Cain Wasserman Minorsky Jackson Reece Lecture Presentations by Kathleen Fitzpatrick and Nicole Tunbridge 4 A Tour of the Cell

2. Do now:  What is a cell?  How are prokaryotic cells different from eukaryotic cells? Categorize the kingdoms into each  How are plant cells different from animal cells?  List as many organelles as you can and describe their functions

3. Overview: The Fundamental Units of Life  All organisms are made of one or more cells.  Smallest unit of life  All cells are related by their descent from earlier cells  Though cells can differ substantially from one another, they share common features © 2014 Pearson Education, Inc.

4. Why are cells small?  Metabolic requirements set upper limits on the size of cells  The ratio of surface area to volume of a cell is critical  As the surface area increases by a factor of n 2, the volume increases by a factor of n 3  Small cells have a greater surface area relative to volume © 2014 Pearson Education, Inc.

5. Figure 4.6 750 Surface area increases while total volume remains constant 125 150 125 6 1 6 1 6 1.2 5 1 Total surface area [sum of the surface areas (height  width) of all box sides  number of boxes] Total volume [height  width  length  number of boxes] Surface-to-volume ratio [surface area  volume]

6. Concept 4.1: Biologists use microscopes and the tools of biochemistry to study cells  Most cells are between 1 and 100  m in diameter, too small to be seen by the unaided eye © 2014 Pearson Education, Inc.

7. Figure 4.2 Most plant and animal cells Length of some nerve and muscle cells Viruses Smallest bacteria Human height Chicken egg Frog egg Human egg Nucleus Most bacteria Mitochondrion Super- resolution microscopy Atoms Small molecules Ribosomes Proteins Lipids Unaided eye LM 10 m EM 1 m 0.1 m 1 cm 1 mm 100  m 10 nm 1 nm 0.1 nm 100 nm 10  m 1  m

8.  Most subcellular structures, including organelles (membrane-enclosed compartments), are too small to be resolved by light microscopy © 2014 Pearson Education, Inc.

9.  Two basic types of electron microscopes (EMs) are used to study subcellular structures  Scanning electron microscopes (SEMs) focus a beam of electrons onto the surface of a specimen, providing images that look three-dimensional  Transmission electron microscopes (TEMs) focus a beam of electrons through a specimen  TEM is used mainly to study the internal structure of cells © 2014 Pearson Education, Inc.

10. Figure 4.3 Scanning electron microscopy (SEM) Transmission electron microscopy (TEM) Longitudinal section of cilium Cross section of cilium Cilia 2  m 50  m 10  m 50  m Brightfield (unstained specimen) Electron Microscopy (EM) Fluorescence Brightfield (stained specimen) Differential-interference contrast (Nomarski) Phase-contrast Confocal Light Microscopy (LM)

11. Do Now Q#1 categorize kingdoms  Prokaryotic  Bacteria  Archaea  Eukaryotic  Protists  Fungi  animals  plants © 2014 Pearson Education, Inc.

12. Do Now Q #1: differences between eukaryotic and prokaryotic Eukaryotic  DNA in a nucleus that is bounded by a membranous nuclear envelope  Membrane-bound organelles (ex: mitochondria, ER)  larger Prokaryotic  No nucleus  DNA in an unbound region called the nucleoid  No membrane-bound organelles

13. Comparing Prokaryotic and Eukaryotic Cells  Basic features of all cells  Plasma membrane  Semifluid substance called cytosol/cytoplasm  Chromosomes (carry genes- segments of DNA)  Ribosomes (make proteins) © 2014 Pearson Education, Inc.

14. Is this a prokayotic or eukaryotic cell? (a) A typical rod-shaped bacterium 0.5  m (b) A thin section through the bacterium Bacillus coagulans (TEM) chromosome Fimbriae Nucleoid Ribosomes Cell wall Plasma membrane Capsule Flagella

15. © 2014 Pearson Education, Inc. Review Of Organelles Organelle : cell :: organ system :: organism Structure enables function!

16. Cell/Plasma Membrane  Structure:  The general structure of a biological membrane is a double layer of phospholipids  Function  selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell © 2014 Pearson Education, Inc.

17. A Panoramic View of the Eukaryotic Cell  A eukaryotic cell has internal membranes that divide the cell into compartments—organelles  The plasma membrane and organelle membranes participate directly in the cell’s metabolism © 2014 Pearson Education, Inc. Animation: Tour of a Plant Cell Animation: Tour of an Animal Cell

18. © 2014 Pearson Education, Inc. Figure 4.7a E M A B C D E1 E2 F E3 H G J I L K M2 M1 M3

19. © 2014 Pearson Education, Inc. Figure 4.7a CYTOSKELETON: NUCLEUS ENDOPLASMIC RETICULUM (ER) Smooth ER Rough ER Flagellum Centrosome Microfilaments Intermediate filaments Microvilli Microtubules Mitochondrion Peroxisome Golgi apparatus Lysosome Plasma membrane Ribosomes Nucleolus Nuclear envelope Chromatin

20. © 2014 Pearson Education, Inc. Figure 4.7b I A L H J i1 i.2 F i.3 C D B G E K A2 A1 A3 M

21. © 2014 Pearson Education, Inc. Figure 4.7b CYTO- SKELETON NUCLEUS Smooth endoplasmic reticulum Chloroplast Central vacuole Microfilaments Intermediate filaments Cell wall Microtubules Mitochondrion Peroxisome Golgi apparatus Plasmodesmata Plasma membrane Ribosomes Nucleolus Nuclear envelope Chromatin Wall of adjacent cell Rough endoplasmic reticulum

22. © 2014 Pearson Education, Inc. Figure 4.8a Ribosome Chromatin Rough ER Nucleus Nucleolus Chromatin Nuclear envelope: Nuclear pore Inner membrane Outer membrane Pore complex Close-up of nuclear envelope

23. Nucleus Structure:  The nuclear envelope encloses the nucleus, separating it from the cytoplasm  The nuclear membrane is a double membrane; each membrane consists of a lipid bilayer Function:  The nucleus contains most of the DNA in a eukaryotic cell  DNA contains information on how to make proteins © 2014 Pearson Education, Inc.

24. Ribosomes: Protein Factories  Structure:  Made up of two parts, small  Function:  Ribosomes carry out protein synthesis  In the cytosol (free ribosomes)  On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes) © 2014 Pearson Education, Inc.

25. Endomembrane System- **important topic on the AP exam**  Components of the endomembrane system  Nuclear envelope  Endoplasmic reticulum  Golgi apparatus  Lysosomes  Vacuoles  Plasma membrane  These components are either continuous or connected through transfer by vesicles © 2014 Pearson Education, Inc.

26. The Endoplasmic Reticulum: Biosynthetic Factory  Structure:  The ER membrane is continuous with the nuclear envelope  There are two distinct regions of ER  Smooth ER: lacks ribosomes  Rough ER: surface is studded with ribosomes © 2014 Pearson Education, Inc. Video: Endoplasmic Reticulum Video: ER and Mitochondria

27. Functions of Smooth ER  The smooth ER  Synthesizes lipids  Metabolizes carbohydrates  Detoxifies drugs and poisons  Stores calcium ions © 2014 Pearson Education, Inc.

28. Functions of Rough ER  The rough ER  Has bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates)  Distributes transport vesicles, proteins surrounded by membranes  Is a membrane factory for the cell © 2014 Pearson Education, Inc.

29.  Structure:  The Golgi apparatus consists of flattened membranous sacs called cisternae  Functions  Modifies products of the ER  Manufactures certain macromolecules  Sorts and packages materials into transport vesicles The Golgi Apparatus: Shipping and Receiving Center © 2014 Pearson Education, Inc. Video: Golgi 3-D Video: Golgi Secretion Video: ER to Golgi Traffic

30. Lysosomes: Digestive Compartments  Structure:  membranous sac of hydrolytic enzymes  Function  Lysosomal enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids  Lysosomal enzymes work best in the acidic environment inside the lysosome  Also take part in phagocytosis © 2014 Pearson Education, Inc.

31. Vacuoles: Diverse Maintenance Compartments  Vacuoles are large vesicles derived from the endoplasmic reticulum and Golgi apparatus  Food vacuoles are formed by phagocytosis  Contractile vacuoles, found in many freshwater protists, pump excess water out of cells  Central vacuoles, found in many mature plant cells, hold organic compounds and water © 2014 Pearson Education, Inc.

32. Figure 4.14 Central vacuole Central vacuole Chloroplast Cytosol Cell wall Nucleus Plant cell vacuole 5  m

33. The Endomembrane System: A Review  The endomembrane system is a complex and dynamic player in the cell’s compartmental organization © 2014 Pearson Education, Inc.

34. Figure 4.15-1 Rough ER Nucleus Smooth ER Plasma membrane

35. © 2014 Pearson Education, Inc. Figure 4.15-2 Plasma membrane Rough ER cis Golgi Nucleus Smooth ER trans Golgi

36. © 2014 Pearson Education, Inc. Figure 4.15-3 Plasma membrane Rough ER cis Golgi Nucleus Smooth ER trans Golgi

37. Mitochondria and chloroplasts change energy from one form to another  Mitochondria are the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP  Chloroplasts, found in plants and algae, are the sites of photosynthesis  Peroxisomes are oxidative organelles © 2014 Pearson Education, Inc.

38. Figure 4.16 Mitochondrion Nonphotosynthetic eukaryote Photosynthetic eukaryote At least one cell Chloroplast Engulfing of photosynthetic prokaryote Nucleus Nuclear envelope Endoplasmic reticulum Ancestor of eukaryotic cells (host cell) Engulfing of oxygen- using nonphotosynthetic prokaryote, which becomes a mitochondrion

39.  The endosymbiont theory  An early ancestor of eukaryotic cells engulfed a nonphotosynthetic prokaryotic cell, which formed an endosymbiont relationship with its host  The host cell and endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion  At least one of these cells may have taken up a photosynthetic prokaryote, becoming the ancestor of cells that contain chloroplasts © 2014 Pearson Education, Inc. Video: ER and Mitochondria Video: Mitochondria 3-D

40.  Mitochondria and chloroplasts have similarities with bacteria  Enveloped by a double membrane  Contain free ribosomes and circular DNA molecules  Grow and reproduce somewhat independently in cells The Evolutionary Origins of Mitochondria and Chloroplasts © 2014 Pearson Education, Inc.

41. Figure 4.17 Free ribosomes in the mitochondrial matrix Mitochondrion Intermembrane space Matrix Cristae DNA Outer membrane Inner membrane 0.1  m

42. Mitochondria: Chemical Energy Conversion  Structure:  They have a smooth outer membrane and an inner membrane folded into cristae  The inner membrane creates two compartments: intermembrane space and mitochondrial matrix  Function:  Some metabolic steps of cellular respiration are catalyzed in the mitochondrial matrix  Cristae present a large surface area for enzymes that synthesize ATP © 2014 Pearson Education, Inc.

43. Figure 4.18a Intermembrane space Ribosomes Inner and outer membranes 1  m Stroma Granum DNA Thylakoid (a) Diagram and TEM of chloroplast

44. Chloroplasts: Capture of Light Energy  Structure: Chloroplast includes  Thylakoids, membranous sacs, stacked to form a granum  Stroma, the internal fluid  Chloroplasts contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis  Chloroplasts are found in leaves and other green organs of plants and in algae © 2014 Pearson Education, Inc.

45. Peroxisomes: Oxidation  Structure:  Peroxisomes are specialized metabolic compartments bounded by a single membrane  Function:  Peroxisomes produce hydrogen peroxide and convert it to water © 2014 Pearson Education, Inc. Video: Cytoskeleton in Neuron

46. Cytoskeleton  Structure:  The cytoskeleton is a network of fibers extending throughout the cytoplasm  Function:  It organizes the cell’s structures and activities, anchoring many organelles © 2014 Pearson Education, Inc. Video: Organelle Movement Video: Organelle Transport Video: Microtubule Transport

47. Components of the Cytoskeleton  Three main types of fibers make up the cytoskeleton  Microtubules are the thickest of the three components of the cytoskeleton  Microfilaments, also called actin filaments, are the thinnest components  Intermediate filaments are fibers with diameters in a middle range © 2014 Pearson Education, Inc.

48. Table 4.1

49. © 2014 Pearson Education, Inc. Figure 4.22 Microtubule Centrioles Centrosome

50. Cilia and Flagella  Microtubules control the beating of cilia and flagella, microtubule-containing extensions projecting from some cells  How are flagella and cilia different?  Flagella are limited to one or a few per cell, while cilia occur in large numbers on cell surfaces © 2014 Pearson Education, Inc.

51. Microfilaments (Actin Filaments)  Microfilaments are thin solid rods, built from molecules of globular actin subunits  Function:  Muscle: The structural role of microfilaments is to bear tension, resisting pulling forces within the cell  Bundles of microfilaments make up the core of microvilli of intestinal cells © 2014 Pearson Education, Inc.

52. Intermediate Filaments  Intermediate filaments are larger than microfilaments but smaller than microtubules  They support cell shape and fix organelles in place  Intermediate filaments are more permanent cytoskeleton elements than the other two classes © 2014 Pearson Education, Inc.

53. Concept 4.7: Extracellular components and connections between cells help coordinate cellular activities  Most cells synthesize and secrete materials that are external to the plasma membrane  These extracellular materials are involved in many cellular functions © 2014 Pearson Education, Inc.

54. Cell Walls of Plants  The cell wall is an extracellular structure that distinguishes plant cells from animal cells  Prokaryotes, fungi, and some protists also have cell walls  Structure:  Plant cell walls are made of cellulose fibers embedded in other polysaccharides and protein  Function:  The cell wall protects the plant cell, maintains its shape, and prevents excessive uptake of water © 2014 Pearson Education, Inc.

55.  Plasmodesmata are channels between adjacent plant cells  Through plasmodesmata, water and small solutes (and sometimes proteins and RNA) can pass from cell to cell © 2014 Pearson Education, Inc. Video: Extracellular Matrix Video: Fibronectin Video: Collagen Model

56. © 2014 Pearson Education, Inc. Figure 4.26a

57. The Extracellular Matrix (ECM) of Animal Cells  Animal cells lack cell walls but are covered by an elaborate extracellular matrix (ECM)  The ECM is made up of glycoproteins such as collagen, proteoglycans, and fibronectin  ECM proteins bind to receptor proteins in the plasma membrane called integrins © 2014 Pearson Education, Inc.

58. Cell Junctions  Neighboring cells in an animal or plant often adhere, interact, and communicate through direct physical contact  There are several types of intercellular junctions that facilitate this  Plasmodesmata  Tight junctions  Desmosomes  Gap junctions © 2014 Pearson Education, Inc.

59. Figure 4.27 1  m Intermediate filaments TEM 0.5  m TEM 0.1  m TEM Tight junction Tight junction Ions or small molecules Extracellular matrix Gap junction Desmosome Space between cells Plasma membranes of adjacent cells Tight junctions prevent fluid from moving across a layer of cells

60. Tight Junctions, Desmosomes, and Gap Junctions in Animal Cells  Animal cells have three main types of cell junctions  Tight junctions  Desmosomes  Gap junctions  All are especially common in epithelial tissue © 2014 Pearson Education, Inc. Animation: Gap Junctions Animation: Tight Junctions Animation: Desmosomes