Lect2. Structure and Function of Eukaryotes and Prokaryotes Cell.pptx
- 1. 1 Cellular Level of Organization • Detailed study of the cell began in the 1830s • A unifying concept in biology • Originated from the work of biologists Schleiden and Schwann in 1838-9 • Cell Theory: – All organisms are composed of cells • German botanist Matthais Schleiden (1804-1881) • German zoologist Theodor Schwann (1810-1882) – All cells come only from preexisting cells • German physician Rudolph Virchow (1821-1902) – Cells are the smallest structural and functional unit of organisms
- 2. 2 Organisms and Cells d. c. b. a. 50 m 140 m Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Geoff Bryant/Photo Researchers, Inc.; b: Courtesy Ray F. Evert/University of Wisconsin Madison; c: © Barbara J. Miller/Biological Photo Service; d: Courtesy O. Sabatakou and E. Xylouri-Frangiadak
- 3. 3 Sizes of Living Things 10 m 1 m 0.1 m 1 cm 1 mm 100 nm 10 nm 1 nm 0.1 nm mouse frog egg human egg most bacteria virus protein atom ant electron microscope light microscope human eye human blue whale chloroplast rose 1 km 100 m 100 m 10 m 1 m plant and animal cells amino acid ostrich egg Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 4. 4 Microscopy Today: Compound Light Microscope • Light passed through specimen • Focused by glass lenses • Image formed on human retina • Max magnification about 1000X • Resolves objects separated by 0.2 mm, 500X better than human eye
- 5. 5 Compound Light Microscope eye amoeba, light micrograph light rays ocular lens objective lens specimen condenser lens light source a. Compound light microscope 85 µm © Robert Brons/Biological Photo Service Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 6. 6 Microscopy Today: Transmission Electron Microscope • Abbreviated T.E.M. • Electrons passed through specimen • Focused by magnetic lenses • Image formed on fluorescent screen – Similar to TV screen – Image is then photographed • Greater magnification than Compound Light Microscope • Resolves objects separated by 0.0002 mm, 100,000X better than human eye
- 7. 7 Transmission Electron Microscope electron source electron beam b. Transmission electron microscope specimen 200 nm pseudopod segment, transmission electron micrograph observation screen or photographic plate electromagnetic objective lens electromagnetic condenser lens electromagnetic projector lens © M. Schliwa/Visuals Unlimited Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 8. 8 Microscopy Today: Scanning Electron Microscope • Abbreviated S.E.M. • Specimen sprayed with thin coat of metal – Electron beam scanned across surface of specimen – Metal emits secondary electrons • Emitted electrons focused by magnetic lenses • Image formed on fluorescent screen – Similar to TV screen – Image is then photographed
- 9. 9 Scanning Electron Microscope amoeba, scanning electron micrograph electron gun electron beam electromagnetic condenser lenses scanning coil final condenser lens secondary electrons specimen electron detector c. Scanning electron microscope 500 m TV viewing screen © Kessel/Shih/Peter Arnold, Inc. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. µ
- 10. 10 Microscopy and Amoeba proteus eye amoeba, light micrograph amoeba, scanning electron micrograph light rays ocular lens objective lens specimen condenser lens light source a. Compound light microscope electron gun electron beam scanning coil specimen c. Scanning electron microscope electron source electron beam b. Transmission electron microscope specimen 85 µm 200 nm 500 µm pseudopod segment, transmission electron micrograph electromagnetic condenserl enses final Condenser lens secondary electrons observation screen or photographic plate electromagnetic objective lens electromagnetic condenser lens electromagnetic projector lens electron detector TV Viewing screen a: © Robert Brons/Biological Photo Service; b: © M. Schliwa/Visuals Unlimited; c: © Kessel/Shih/Peter Arnold, Inc. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 11. 11 Immunofluorescence Light Microscope • Antibodies developed against a specific protein – Fluorescent dye molecule attached to antibody molecules – Specimen exposed to fluorescent antibodies • Ultra-violet light (black light) passed through specimen – Fluorescent dye glows in color where antigen is located – Emitted light is focused by glass lenses onto human retina • Allows mapping distribution of a specific protein in cell
- 12. 12 Confocal Microscopy • Narrow laser beam scanned across transparent specimen • Beam is focused at a very thin plane • Allows microscopist to optically section a specimen – Sections made at different levels – Allows assembly of three-dimensional image on computer screen that can be rotated
- 13. 13 Microscopy and Cheek Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bright-field. Light passing through the specimen is brought directly into focus. Usually, the low level of contrast within the specimen interferes with viewing but its largest component Bright-field (stained). dyes are used to stain the specimen. Certain components take up the dye more than other components, and therefore contrast is enhanced. Differential interference contrast. Optical methods are used to enhance density differences within the specimen so that certain regions appear brighter than others. This technique is used to view living cells, chromosomes, and organelle masses. Phase contrast. Density differences in the specimen cause light rays to come out of “phase.” The microscope enhances these phase differences so that some regions of the specimen appear brighter or darker than others. The technique is widely used to observe living cells and organelles. Dark-field. Light is passed through the specimen at an oblique angle so that the objective lens receives only light diffracted and scattered by the object. This technique is used to view organelles, which appear quite bright against a dark field. 30 µm 30 µm 25 µm 25 µm 25 µm Left: © Ed Reschke; Left middle: © Biophoto Associates/Photo Researchers, Inc.; Middle: © David M. Phillips/Visuals Unlimited; Right middle: © David M.Phillips/Visuals Unlimited; Right: © David M. Phillips/Visuals Unlimited
- 14. Lect2. Structure and Function of Eukaryotes and Prokaryotes Cells
- 15. 15 Two Cell Types 1. Prokaryotic Cells 2. Eukaryotic Cells • Recall Three Domains • Defined by cell type 1.Eukarya • Plantae • Fungi • Animlia • Protista 2.Bacteria 3.Archaea Eukaryotic Prokaryotic
- 16. 16 1. Prokaryotic Cells Prokaryotic Cells • Origin: ‘pro’-before; ‘karyote’ - nut • Lack a membrane-bound nucleus. - genetic material is present in the nucleoid ((Inti sel pada sel prokariot)) • Two types of prokaryotes: 1. Archaea 2. Bacteria
- 17. 17 1. Prokaryotic Cells • Prokaryotic Cell Characteristics: • Simplest organisms - simple internal organization • Very small (1 to 10 microns across) • Genetic material in the nucleoid • No membrane-bound organelles • Capsules • Cytoplasm
- 18. Nukleus VS Nukleoid • Nukleus adalah struktur di mana Eukariota menyimpan materi genetik, sementara Nukleoid adalah tempat di mana Prokariota menyimpan materi genetik. • Nukleus berukuran besar dan terorganisasi dengan baik, sedangkan Nukleoid berukuran kecil dan tidak terorganisir • Nukleus dikelilingi oleh membran berlapis ganda yang disebut “membran nuklir” dan memisahkan dari organel sel lainnya. Membran tersebut tidak dapat ditemukan dalam Nukleoid. • Nukleus mengandung banyak kromosom sementara Nukleoid umumnya hanya memiliki satu molekul DNA melingkar. • Nukleolus dan nukloeplasm terdapat di dalam nukleus, dan tidak terdapat di nukleiod.
- 19. 19 1. Prokaryotic Cell Structure
- 20. 20 Prokaryotic Cell Structure • Prokaryotic cell walls – Surround and protect cell and maintain cell shape – Composed of polysaccharides (sugar coated) • Bacterial cell walls composed of peptidoglycan (polisakarida penyusun dinding sel bakteri) • Archaean cell walls lack peptidoglycan.
- 21. 22 Recall Ch. 3 Polysaccharides b. Function 1. Structural Molecules Cellulose - plant cell walls Chitin – Fungi cell walls Peptidoglycan - Bacterial cell walls
- 22. 22 Prokaryotic Cell Structure Bacterial cell walls composed of peptidoglycan • Two Types of Bacterial Cell Walls 1. Gram Positive 2. Gram Negative • Gram Positive/Gram Negative type is determined by cell cell wall structure and the Gram Stain Reaction • Gram Positive Bacteria Stain Purple • Gram Negative Bacteria Stain Pink
- 23. Gram + vs. Gram - • Gram + Bacteria stain Purple • Gram – Bacteria stain Pink Courtesy: Dr. O’Steen
- 24. 24 The Structure of Prokaryotes • Extremely small: 1–1.5 μm wide and 2–6 μm long • Occur in three basic shapes: – Spherical coccus, – Rod-shaped bacillus, – Spiral spirillum (if rigid) or spirochete (if flexible). • Cell Envelope includes: – Plasma membrane - lipid bilayer with imbedded and peripheral protein • Form internal pouches (mesosomes) – Cell wall - maintains the shape of the cell and is strengthened by peptidoglycan – Capsul/ Glycocalyx - layer of polysaccharides on the outside of the cell wall • Well organized and resistant to removal (capsule)
- 25. 25 The Structure of Prokaryotes spirillum coccus bacillus spirochete Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 26. 26 The Structure of Prokaryotes phospholipid bilayer protein molecules Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 27. 27 Prokaryotic Cytoplasm and Appendages • Cytoplasm – Semifluid solution • Bounded by plasma membrane • Contains water, inorganic and organic molecules, and enzymes – Nucleoid is a region that contains the single, circular DNA molecule – Plasmids are small accessory (extrachromosomal) rings of DNA • Appendages – Flagella – provide motility – Fimbriae – small, bristle-like fibers that sprout from the cell surface – Conjugation pili – rigid tubular structures used to pass DNA from cell to cell
- 28. 28 Prokaryotic Cell Structure Flagella (singular, flagellum) • Whip-like proteins attached to cell wall used for locomotion • Present in some prokaryotic cells - one to several flagella on a single cell • Rotary motion of flagellum propels the cell through fluid environment • Flagella powered by protein motors - uses energy of a proton gradient
- 30. 30 The Structure of Prokaryotes Inclusion body: stored nutrients for later use Mesosome: plasma membrane that folds into the cytoplasm and increases surface area Ribosome: site of protein synthesis Nucleoid: location of the bacterial chromosome Plasma membrane: sheath around cytoplasm that regulates entrance and exit of molecules Cell wall: covering that supports, shapes, and protects cell Glycocalyx: gel-like coating outside cell wall; if compact, called a capsule; if diffuse, called a slime layer Conjugation pilus: elongated, hollow appendage used for DNA transfer to other bacterial cells Fimbriae: hairlike bristles that allow adhesion to the surfaces Flagellum: rotating filament present in some bacteria that pushes the cell forward Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Howard Sochurek/The Medical File/Peter Arnold, Inc. Escherichia coli
- 31. 31 2. Eukaryotic Cells Eukaryotic Cells • Origin: ‘eu’ - true, good; ‘karyote’ - nut • Possess a membrane-bound nucleus. - genetic material is highly organized within double- layer nuclear envelope - DNA never leaves the nuclear envelope • Types of eukaryotes divided into 4 kingdoms: 1. Plantae 2. Fungi 3. Animalia 4. Protista
- 32. 32 4.3 Introducing Eukaryotic Cells • Cells contain: –Membrane-bound nucleus that houses DNA –Specialized organelles –Plasma membrane • Much larger than prokaryotic cells 2. Eukaryotic Cells
- 33. 33 Origin of Organelles Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Original prokaryotic cell DNA 1. Cell gains a nucleus by the plasma membrane invaginating and surrounding the DNA with a double membrane. Nucleus allows specific functions to be assigned, freeing up cellular resources for other work. 2. Cell gains an endomembrane system by proliferation of membrane. Increased surface area allows higher rate of transport of materials within a cell. aerobic bacterium mitochondrion Animal cell has mitochondria, but not chloroplasts. photosynthetic bacterium 3. Cell gains mitochondria. Ability to metabolize sugars in the presence of oxygen enables greater function and success. 4. Cell gains chloroplasts. Ability to produce sugars from sunlight enables greater function and success. chloroplast Plant cell has both mitochondria and chloroplasts.
- 34. 34 2. Eukaryotic Cells • Eukaryotic Cell Characteristics: • More complex organisms • highly organized structure (compartmentalization) known as endomembrane system • Typically larger than prokaryote (10-100 microns) • Genetic material in the membrane-bound nucleus • Many membrane-bound organelles • Cytoplasm • Cytoskeleton
- 35. 35 2. Eukaryotic Cells • Eukaryotic and Prokaryotic Characteristics: • DNA, RNA • Ribosomes • Plasma membrane • Cytoplasm • Cell walls (plantae, fungi, protista, not present in animal cells) • Flagella
- 36. 36 Eukaryotic Cells: Organelles • Eukaryotic cells are compartmentalized – They contain small structures called organelles • Perform specific functions • Isolates reactions from others • Two classes of organelles: – Endomembrane system • Organelles that communicate with one another – Via membrane channels – Via small vesicles – Energy related organelles • Mitochondria and chloroplasts • Independent and self-sufficient
- 37. 37 Animal Cell Anatomy Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 2.5 µm Plasma membrane: outer surface that regulates entrance and exit of molecules protein phospholipid mitochondrion chromatin nucleolus nuclear envelope endoplasmic reticulum Cytoskeleton: maintains cell shape and assists movement of cell parts: Nucleus: command center of cell • Nuclear envelope: double membrane with nuclear pores that encloses nucleus • Chromatin: diffuse threads containing DNA and protein • Microtubules: protein cylinders that move organelles • Intermediate filaments: protein fibers that provide stability of shape • Nucleolus: region that produces subunits of ribosomes Endoplasmic reticulum: protein and lipid metabolism • Rough ER: studded with ribosomes that synthesize proteins • Smooth ER: lacks ribosomes, synthesizes lipid molecules Peroxisome: vesicle that is involved in fattyacid metabolism Ribosomes: particles that carry out protein synthesis Polyribosome: string of ribosomes simultaneously synthesizing same protein Mitochondrion: organelle that carries out cellular respiration, producing ATP molecules Golgi apparatus: processes, packages, and secretes modified proteins *not in plant cells Cytoplasm: semifluid matrix outside nucleus that contains organelles Vesicle: small membrane- bounded sac that stores and transports substances Centrioles*: short cylinders of microtubules Centrosome: microtubule organizing center that contains a pair of centrioles Lysosome*: vesicle that digests macromolecules and even cell parts © Dr. Dennis Kunkel/Visuals Unlimited • Actin filaments: protein fibers that play a role in cell division and shape
- 38. 38 Plant Cell Anatomy Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. peroxisome mitochondrion nucleus ribosomes central vacuole plasma membrane cell wall chloroplast Central vacuole*: large, fluid-filled sac that stores metabolites and helps maintain turgor pressure 1 µm Nucleus: command center of cell • Nuclear envelope: double membrane with nuclear pores that encloses nucleus • Nucleolus: produces subunits of ribosomes • Chromatin: diffuse threads containing DNA and protein • Nuclear pore: permits passage of proteins into nucleus and ribosomal subunits out of nucleus Ribosomes: carry out protein synthesis Endoplasmic reticulum : protein and lipid metabolism Centrosome: microtubule organizing center (lacks centrioles) • Rough ER: studded with ribosomes that synthesize proteins • Smooth ER: lacks ribosomes, synthesizes lipid molecules Peroxisome: vesicle that is involved in fatty acid metabolism Golgi apparatus: processes, packages, and secretes modified proteins Cytoplasm: semifluid matrix outside nucleus that contains organelles Cell wall of adjacent cell Middle lamella: cements together the primary cell walls of adjacent plant cells Chloroplast*: carries out photosynthesis, producing sugars Granum*: a stack of chlorophyll- containing thylakoids in a chloroplast Mitochondrion: organelle that carries out cellular respiration, producing ATP molecules Microtubules: protein cylinders that aid movement of organelles Actin filaments: proteinfibers that play a role in cell division and shape Plasma membrane: surrounds cytoplasm, and regulates entrance and exit of molecules Cell wall*: outer surface that shapes, supports, and protects cell *not in animal cells © Newcomb/Wergin/Biological Photo Service (FIRST USE)
- 39. 39 Eukaryotic Cells Nucleus • Largest most definitive organelle in the cytoplasm • Surrounded by a nuclear envelope composed of 2 phospholipid bilayers • Stores the genetic material of the cell as long separate chains of DNA known as chromosomes • Cell DNA is organized with proteins to form chromatin
- 40. 40 Eukaryotic Cells Nucleus • Cell DNA is organized with proteins to form chromatin - Chromosomes are tightly packed (condensed) with proteins inside the nucleus into nucleosomes - DNA is wound around histone proteins to resembles beads on a string
- 41. Fig. 4.9
- 42. 42 Eukaryotic Cells Nucleolus (plural, nucleoli) • Dark staining zone within the nucleus • Composed of RNA • Synthesis of ribosomal RNA (rRNA) occurs here - rRNA is involved in the translation of DNA into protein
- 43. 43 Eukaryotic Cells Nuclear Envelope • Composed of an inner and outer phospholipid bilayer - the outer layer is continuous with the membrane of the endoplasmic reticulum - an organelle for protein synthesis • Nuclear pores provide passage for proteins and rRNA into and out of the nucleus - DNA never leaves the nucleus
- 45. 45 Eukaryotic Cells Ribosomes • Present in prokaryotic and eukaryotic cells • Composed of ribosomal RNA and proteins • Found in the cytoplasm and attached to internal membranes of the endoplasmic reticulum • Important protein function in protein synthesis in the cell - Translate the DNA code into RNA
- 46. 46 Eukaryotic Cells Ribosomes • Composed of 2 subunits of ribosomal RNA (rRNA) and protein • The two subunits associate to form complete Ribosomes • Other types of RNA assist with protein synthesis: - mRNA - tRNA
- 47. Fig. 4.10
- 48. LDM • Berdasarkan uraian tentang struktur dan fungsi sel eukariot dan prokariot, analisislah: 1. Struktur dan fungsi yang berbeda dari sel eukariot dan prokariot 2. Struktur dan fungsi yang sama dari sel eukariot dan prokariot 3. Bagian bagian dari sel prokariot dan eukariot Note: Buat dalam bentuk tabel
- 49. 49 Comparison of Prokaryotic and Eukaryotic Cells
Editor's Notes
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