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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cell Architecture “Of the things of nature there are … two kinds: those which.

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Presentation on theme: "Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cell Architecture “Of the things of nature there are … two kinds: those which."— Presentation transcript:

1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cell Architecture “Of the things of nature there are … two kinds: those which are brought into being and perish, and those which are free from these processes throughout all ages. The latter are of the highest worth and are divine… Aristotle BC from Parts of Animals

2 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Techniques to view cells & fractionate cellular components -Microscopy - Differential Centrifugation

3 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-2 Measurements 1 centimeter (cm) = 10 –2 meter (m) = 0.4 inch 1 millimeter (mm) = 10 –3 m 1 micrometer (µm) = 10 –3 mm = 10 –6 m 1 nanometer (nm) = 10 –3 µm = 10 –9 m 10 m 1 m Human height Length of some nerve and muscle cells Chicken egg 0.1 m 1 cm Frog egg 1 mm 100 µm Most plant and animal cells 10 µm Nucleus 1 µm Most bacteria Mitochondrion Smallest bacteria Viruses 100 nm 10 nm Ribosomes Proteins Lipids 1 nm Small molecules Atoms 0.1 nm Unaided eye Light microscope Electron microscope When is magnification important? When is resolving power or resolution important? When object becomes too small to see by eye ~1 mm When details become blurry= the difference between two points is unclear What is the relationship between resolution and Wavelength  ) of light (electromagnetic spectrum)? Higher resolution (more details) at shorter

4 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6a Brightfield 50 µm Brightfield Phase-contrast Forms of Light Microscopy What is different about (a) vs (b)?

5 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-3b 50 µm Differential-interference-contrast (DIC) (Nomarski) Fluorescence (laser beam) Conventional fluorescence Confocal (Specific structures labeled with fluorescent tag) Any difference?

6 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE µm Scanning electron microscopy (SEM) Cilia Longitudinal section of cilium Transmission electron microscopy (TEM) Cross section of cilium Surface of rabbit tracheal cells Section of tracheal tissue (cilia)

7 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-7 Total surface area (height x width x number of sides x number of boxes) Total volume (height x width x length X number of boxes) Surface-to-volume ratio (surface area  volume) Surface area increases while Total volume remains constant Why do cells tend to be small?

8 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Isolating Organelles by Cell Fractionation

9 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-5a Homogenization Homogenate Tissue cells Differential centrifugation

10 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-5b Pellet rich in nuclei and cellular debris Pellet rich in mitochondria (and chloro- plasts if cells are from a plant) Pellet rich in “microsomes” (pieces of plasma membranes and cells’ internal membranes) Pellet rich in ribosomes 150,000 g 3 hr 80,000 g 60 min 20,000 g 20 min 1000 g (1000 times the force of gravity) 10 min Supernatant poured into next tube

11 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cells Exhibit Evolutionary Relatedness by their Similarities & Differences

12 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-6 A typical rod-shaped bacterium A thin section through the bacterium Bacillus coagulans (TEM) 0.5 µm Pili Nucleoid Ribosomes Plasma membrane Cell wall Capsule Flagella Bacterial chromosome Prokaryote

13 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-9a Flagellum Centrosome CYTOSKELETON Microfilaments Intermediate filaments Microtubules Peroxisome Microvilli ENDOPLASMIC RETICULUM (ER Rough ER Smooth ER Mitochondrion Lysosome Golgi apparatus Ribosomes: Plasma membrane Nuclear envelope NUCLEUS In animal cells but not plant cells: Lysosomes Centrioles Flagella (in some plant sperm) Nucleolus Chromatin Non-plant eukaryotic cell

14 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-9b Rough endoplasmic reticulum In plant cells but not animal cells: Chloroplasts Central vacuole and tonoplast Cell wall Plasmodesmata Smooth endoplasmic reticulum Ribosomes (small brown dots) Central vacuole Microfilaments Intermediate filaments Microtubules CYTOSKELETON Chloroplast Plasmodesmata Wall of adjacent cell Cell wall Nuclear envelope Nucleolus Chromatin NUCLEUS Centrosome Golgi apparatus Mitochondrion Peroxisome Plasma membrane Plant cell

15 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Basic features of ALL cells: – Plasma membrane – Semifluid substance called the cytosol – Chromosomes (carry genes) – Ribosomes (make proteins)

16 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-8 Hydrophilic region Hydrophobic region Carbohydrate side chain Structure of the plasma membrane Hydrophilic region Phospholipid Proteins Outside of cell Inside of cell 0.1 µm TEM of a plasma membrane Plasma membrane

17 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-10 Close-up of nuclear envelope Nucleus Nucleolus Chromatin Nuclear envelope: Inner membrane Outer membrane Nuclear pore Pore complex Ribosome Pore complexes (TEM)Nuclear lamina (TEM) 1 µm Rough ER Nucleus 1 µm 0.25 µm Surface of nuclear envelope

18 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-12 Ribosomes Smooth ER Rough ER ER lumen Cisternae Transport vesicle Smooth ER Rough ER Transitional ER 200 nm Nuclear envelope

19 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Functions of Smooth ER The smooth ER – Synthesizes lipids – Metabolizes carbohydrates – Stores calcium – Detoxifies poison

20 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Functions of Rough ER The rough ER – Has bound ribosomes that make proteins targeted for membranes or to be transported across membranes – Is a membrane factory for the cell

21 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-11 Ribosomes 0.5 µm ER Cytosol Endoplasmic reticulum (ER) Free ribosomes Bound ribosomes Large subunit Small subunit TEM showing ER and ribosomes RibosomePart of protein synthesis machinery

22 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-13 trans face (“shipping” side of Golgi apparatus) TEM of Golgi apparatus 0.1 µm Golgi apparatus cis face (“receiving” side of Golgi apparatus) Vesicles coalesce to form new cis Golgi cisternae Vesicles also transport certain proteins back to ER Vesicles move from ER to Golgi Vesicles transport specific proteins backward to newer Golgi cisternae Cisternal maturation: Golgi cisternae move in a cis- to-trans direction Vesicles form and leave Golgi, carrying specific proteins to other locations or to the plasma mem- brane for secretion Cisternae Golgi Apparatus

23 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lysosomes: Digestive Compartments Membranous sac of hydrolytic enzymes Hydrolyzes (breaks down) proteins, fats, polysaccharides, and nucleic acids Recycle organelles and macromolecules (autophagy) Hydrolyzes food taken up by the cell (phagocytosis)

24 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lysosomes: Digestive Compartments Animation: Lysosome Formation Animation: Lysosome Formation Formation of lysosomes with hydrolytic enzyme

25 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-14a Phagocytosis: lysosome digesting food 1 µm Plasma membrane Food vacuole Lysosome Nucleus Digestive enzymes Digestion Lysosome Lysosome contains active hydrolytic enzymes Food vacuole fuses with lysosome Hydrolytic enzymes digest food particles

26 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-14b Autophagy: lysosome breaking down damaged organelle 1 µm Vesicle containing damaged mitochondrion Mitochondrion fragment Lysosome containing two damaged organelles Digestion Lysosome Lysosome fuses with vesicle containing damaged organelle Peroxisome fragment Hydrolytic enzymes digest organelle components

27 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Vacuoles: Diverse Maintenance Compartments Vesicles and vacuoles (larger versions of vesicles) are membrane-bound sacs with varied functions A plant cell or fungal cell may have one or several vacuoles

28 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Food vacuoles: form by phagocytosis Contractile vacuoles: pump excess water out of cells (in many freshwater protists) Central vacuoles (plant cells): hold organic compounds and water, maintain turgor pressure Video: Paramecium Vacuole Video: Paramecium Vacuole

29 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE µm Central vacuole Cytosol Tonoplast Central vacuole Nucleus Cell wall Chloroplast

30 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Mitochondria and chloroplasts change energy from one form to another Mitochondria are the sites of cellular respiration Chloroplasts, found only in plants and algae, are the sites of photosynthesis Mitochondria and chloroplasts are not part of the endomembrane system Peroxisomes are oxidative organelles

31 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-17 Mitochondrion Intermembrane space Outer membrane Inner membrane Cristae Matrix 100 nm Mitochondrial DNA Free ribosomes in the mitochondrial matrix

32 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-18 Chloroplast DNA Ribosomes Stroma Inner and outer membranes Granum Thylakoid 1 µm Chloroplasts move with plant cells: cytoplasmic streaming video

33 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Peroxisomes: Oxidation Specialized metabolic compartments bounded by a single membrane Peroxisomes produce hydrogen peroxide and convert it to water How does the the cell protect itself from the toxic effects of hydrogen peroxide?

34 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-19 Chloroplast Peroxisome Mitochondrion 1 µm

35 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Summary -Microscopy and differential centrifugation are two powerful methods to examine cellular structure and function. -Optimal size for most cells is generally low to optimize surface area:volume ratio. -All cells have plasma membrane, cytosol, DNA and ribosomes. -Prokaryotic cells tend to be smaller than eukaryotic, and lack nuclei, cytoplasmic membranes systems and organelles. -Eukaryotic cells have evolved or acquired many membrane bound compartments for specialized functions.

36 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Please, ask questions.

37 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Eukaryotic Cell Structure: Part II

38 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Cytoskeleton -Intermediate Filaments -Microfilaments -Microtubules

39 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

40 Dynamic: shorten and lengthen

41 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-27b Cortex (outer cytoplasm): gel with actin network Amoeboid movement Inner cytoplasm: sol with actin subunits Extending pseudopodium Speculate on the how actin causes movement?

42 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings LE 6-26 Microfilaments (actin filaments) Microvillus Plasma membrane Intermediate filaments 0.25 µm Intestinal cell Function of MF?

43 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-27a Muscle cell Actin filament Myosin filament Myosin arm Myosin motors in muscle cell contraction

44 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-27c Nonmoving cytoplasm (gel) Cytoplasmic streaming in plant cells Chloroplast Streaming cytoplasm (sol) Cell wall Parallel actin filaments Vacuole

45 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Dynamic: shorten and lengthen

46 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-21b 0.25 µm Microtubule Vesicles

47 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-21a Vesicle Receptor for motor protein Microtubule of cytoskeleton Motor protein (ATP powered) ATP

48 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-23a Motile sperm 5 µm Direction of swimming Motion of flagella flagellum Undulating movement

49 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-23b 15 µm Direction of organism’s movement Motion of cilia Direction of active stroke Direction of recovery stroke protozoan

50 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Microtubules: Power Flagella & Cilia Movement

51 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-25a ATP Dynein “walking” Microtubule doublets Dynein arm ATP Molecular motor

52 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE 6-25b Wavelike motion Cross-linking proteins inside outer doublets ATP Anchorage in cell Effect of cross-linking proteins

53 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE µm Microtubules Plasma membrane Basal body Plasma membrane Outer microtubule doublet 0.1 µm Dynein arms Central microtubule Cross-linking proteins inside outer doublets Radial spoke MT organization in Flagella and Cilia 9+2

54 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Basal body Microtubule-containing structure at base of flagellum and cilium Organization: Nine triplets In contrast: MT organization in cilia and flagella is?_____________

55 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE µm Plasma membrane Basal body Cross section of basal body Triplet Basal body anchors each flagellum and cilium Basal Body Nine triplets 9 doublets+2

56 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Centrioles Occur in pairs oriented at right angle Similar nine triplet organization as basal body Present in animal cells Contained in centrosome:microtubule organizing center (MTOC) Note: plants cells have centrosomes but lack centrioles

57 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero LE µm Microtubule Centrosome Centrioles Longitudinal section of one centriole Microtubules Cross section of the other centriole

58 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Extracellular structures Secreted materials on the outside surface of plasma membrane: – Cell walls (cellulose) of plants – Extracellular matrix (ECM) of animal cells – Intercellular junctions

59 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cell Walls of Plants Mixture of cellulose fibers plus other polysaccharides and protein Distinctive to plants. Not present on animal cells Protection against physical stress, predators and disease Maintainance of cell shape Prevention of excessive water uptake

60 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings LE 6-28 Central vacuole of cell Plasma membrane Secondary cell wall Primary cell wall Middle lamella 1 µm Central vacuole of cell Central vacuole Cytosol Plasma membrane Plant cell walls Plasmodesmata

61 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Extracellular Matrix (ECM) of Animal Cells Proteoglycan complexes and other macromolecules Functions: – Support – Adhesion to other cells or surfaces – Movement – Regulation (influences binding of hormones or other factors to receptors on plasma membrane)

62 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings LE 6-29a EXTRACELLULAR FLUID Proteoglycan complex Collagen fiber Fibronectin Integrin Micro- filaments CYTOPLASM Plasma membrane

63 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings LE 6-29b Polysaccharide molecule Carbo- hydrates Core protein Proteoglycan molecule Proteoglycan complex

64 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Intercellular Junctions Between adjacent cells – Adhesion – Communication

65 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Plants: Plasmodesmata - Channels that perforate plant cell walls - Allow passage of water & small solutes between adjacent cells

66 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings LE 6-30 Interior of cell Interior of cell 0.5 µm Plasmodesmata Plasma membranes Cell walls

67 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animals: Tight Junctions, Desmosomes, and Gap Junctions Tight junctions: on membranes of neighboring cells prevent leakage of extracellular fluid between cells Desmosomes (anchoring junctions): fasten cells together into strong sheets Gap junctions (communicating junctions) provide cytoplasmic channels between adjacent cells Animation: Tight Junctions Animation: Tight Junctions Animation: Desmosomes Animation: Desmosomes Animation: Gap Junctions Animation: Gap Junctions

68 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings LE 6-31 Tight junctions prevent fluid from moving across a layer of cells Tight junction 0.5 µm 1 µm 0.1 µm Gap junction Extracellular matrix Space between cells Plasma membranes of adjacent cells Intermediate filaments Tight junction Desmosome Gap junctions

69 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Cell: A Living Unit Greater Than the Sum of Its Parts Cells rely on the integration of structures and organelles in order to function Think of the structures and organelles involved in the function of the following cell

70 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings LE µm Macrophage: patrols for & destroys foreign objects bacteria


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