MICRO-s10_08 - 2/15/2010 BIOL 240: General Microbiology...

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Unformatted text preview: 2/15/2010 BIOL 240: General Microbiology General Spring 2010 Rm. 22-116 T, Feb. 16, 2010 http://www.smccd.edu/accounts/staplesn/biol240/ 1. Pre-Lab Writeups: Be sure to prepare before each Lab W riteups Be Monday’s labs (for BOTH Mon. & Wed.)!! Monday – (What? Why? How? are we doing in the lab??) 2. Pre-llecture slides and study guides available on ecture course website by the night before. • (Print WISELY!! If you choose to do so..) 3. Midterm 1 study guides ARE updated!!! • Review session in LAB ROOM THIS Thurs. at 12:45 pm!!! 4. Quiz #2 due THUR. night!!!! REVIEW: REVIEW: 1. Compare and contrast 5 structural characteristics of the gram positive and gram 1. Compare negative cell walls. Include illustrations. negative 2. Describe the prevailing model of cell membrane structure and how the Describe model and macromolecules that form them exemplify structure determining function. structure 3. Compare and contrast the transported molecules, energy balances and membrane Compare molecules required for 2 types each of passive & active transport. passive TODAY’s Objectives: Students should be able to….. 1. Compare and contrast 8 differences between “prokaryotic” and Compare and eukaryotic cells. W hat structures do they share in common? eukaryotic What 2. Recognize and describe the properties and functions of the various 2. us Eukaryotic Organelles. Eukaryotic 3. Illustrate and explain the evidence supporting the predominant Theory heory on the origin of energetic organelles in Eukaryotes. origin 4. Describe how enzymes speed up chemical reactions, and how they Describe how and affect the energy and equilibrium of a reaction. affect 1 2/15/2010 K. Endospores K. Endospores • Resting / dormant cells • Resistant to desiccation, heat, chemicals – Dipicolinic acid + Calcium in spore coat • Bacillus, Clostridium • Sporulation: Endospore formation Endospore • Germination: Return to vegetative state Figure 4.21 2 2/15/2010 4.2) Eukaryotic Cells • Comparing Prokaryotic & Eukaryotic Cells – Prokaryote comes from the Greek words for Prokaryote pre-nucleus. pre – Eukaryote comes from the Greek words for Eukaryote true nucleus. true Plant Figure 4.22 Alga Plasma Plasma B-Cell Animal Prokaryotic vs. Eukaryotic Cells vs. Eukaryotic 1. No true nucleus 2. No memb.-bound No memb bound organelles organelles 3. Single, circular chromosome Single, chromosome 4. 70S ribosomes 70S ribosomes 5. Unique cell wall (PG) 6. Unique flagella 7. Outer Membrane (gram -) Outer 8. Only unicellular 9. Small (1-5 m diameter) 10.Bacteria: no histones Bacteria: histones 1. True Nucleus 2. Memb.-bound nucleus and bound other organelles 3. Many, linear chromosomes 3. 4. 80S ribosomes 80S ribosomes 5. Plants and Fungi CW ’s Plants CW 6. Microtubule flagella 7. No O.M. 8. Many spp. Multicellular Many Multicellular 9. Larger (10-100 m diameter) 100 10.Histone-bound chromosomes bound chromosomes 3 2/15/2010 A. Flagella and Cilia Figure 4.23 • Microtubules + motor proteins – Tubulin • 9 pairs + 2 -- arrangements pairs -- B. Euk. Cell Wall B. Euk • Cell wall – Plants, algae, fungi – Carbohydrates • Cellulose, chitin, glucan, Cellulose, glucan mannan, pectins mannan pectins • Glycocalyx jjejunum, glycocalyx and enteroendocrine cell ejunum, glycocalyx and enteroendocrine cell – Carbohydrates extending from animal plasma Carbohydrates membrane membrane – Bonded to proteins and lipids in membrane 4 2/15/2010 C. Euk. Plasma Membrane C. Euk 1. Phospholipid bilayer 2. Peripheral proteins 3. Integral proteins 4. Transmembrane proteins 5. Sterols (animal cells, [mycoplasmas]],, Sterols (animal fungi, plants) fungi, 6. Glycocalyx carbohydrates Euk. Plasma Membrane • Selective permeability allows passage of Selective some molecules some 1. 2. 3. 4. 5. Simple diffusion Facilitated diffusion Osmosis Active transport Endocytosis • Phagocytosis: Pseudopods extend and engulf Pseudopods extend particles particles • Pinocytosis: Membrane folds inward bringing in Membrane fluid and dissolved substances fluid 5 2/15/2010 Eukaryotic Cell Cytoplasm Substance inside plasma membrane Substance & outside nucleus outside Cytosol Fluid portion of cytoplasm Cytoskeleton Microfilaments, intermediate Microfilaments, filaments, microtubules filaments, Cytoplasmic Movement of cytoplasm throughout Movement streaming cells cells Figure 4.22b D. Eukaryotic Organelles: NOT membrane-Bound 1. Ribosome = Protein synthesis 2. Centrosome = Consists of protein fibers Consists and centrioles centrioles 3. Centriole = Mitotic spindle formation Figure 4.22a 6 2/15/2010 E. Eukaryotic Organelles: Membrane-Bound 1. Nucleus = Contains chromosomes. 2. ER = Synthesis & transport network. 3. Golgi complex = Membrane Membrane formation and secretion. formation 4. Lysosome = Digestive enzymes 5. Vacuole = Brings food into cells and Vacuole provides support. provides 6. Mitochondrion = Cellular respiration Mitochondrion Cellular 7. Chloroplast = Photosynthesis 8. Peroxisome = Oxidation of fatty Oxidation acids; destroys H2O2. acids; (E.) Memb. Bound Organelles: (E.) Memb 1. Nucleus **** 1. Nucleus 1. Nuclear Pores 2. Chromatin – Complex of DNA Complex and protein and – Histones; nonhistones nonhistones 3. Nucleolus – Site of Ribosome Site synthesis synthesis Figure 4.24 7 2/15/2010 2. Endoplasmic Reticulum Figure 4.25 a) Smooth ER – llipid ipid synthesis; detoxification synthesis; b) Rough ER – protein protein synthesis for export – secretion or PM; secretion protein modification protein – Lipoproteins, Lipoproteins, glycoproteins glycoproteins 3. Ribosomes 3. Ribosomes • = Protein factories!!! • 80S – Membrane-bound = attached to ER – Free – in cytoplasm Free • 70S – In chloroplasts and mitochondria 8 2/15/2010 4. Golgi Complex • Cisterns – stacks of membrane “pita pocket” bread stacks • Vesicles transport proteins and lipids from ER to Vesicles Golgi for modification and sorting Golgi – “Post Office” of the Cell – package & transport prot & lipid of package prot Figure 4.26 5. Vacuoles; 6. Lysosomes Lysosomes • For storage; tonicity For (firmness of cell) (firmness • For endocytosis For endocytosis In plant/algae cells: • Storage (food, minerals, wastes); Storage • osmotic pressure -supports cell!! osmotic Figure 4.22b Hydrolytic enzymes: • fuse with endocytic vesicles; fuse endocytic vesicles; • intracellular digestion 9 2/15/2010 7. Mitochondrion Figure 4.27 • Powerhouse of the of cell! cell! – O2 usage – ATP & CO2 production! • Oxidative respiratory Oxidative enzymes in inner membrane of mitoch. membrane of mitoch – Cristae – Double membrane!! 8. Chloroplast • Site of photosynthesis: Convert Site light energy to bio-chemical energy light –ATP, Sugars “Solar Solar Panel !” Panel • Photosynthesis = source of source organic carbon and energy for ALL living things!! ALL • Chlorophyll & other pigments Chlorophyll (carotenoids…) • Thylakoid membranes = site of site energy conversion energy –Grana = stacks of thylakoid sacs stacks thylakoid –Stroma = fluid matrix –Double membrane Figure 4.28 10 2/15/2010 Mitochondria and Chloroplasts: Mitochondria …some early observations… 1. Have Double-membranes 2. Contain their own DNA and ribosomes Contain ribosomes 3. Can make some of their own proteins • Possible scientific explanation??…. F. Endo-sym-biosis Theory 1. The evolution of mitochondria and chloroplasts: The • llarge prokaryotes engulfed (by “endocytosis”), but did not digest, arge ), smaller ones DOUBLE MEMBRANE (from host & endosymbiont) (from endosymbiont 2. Mutual benefits permitted this symbiotic relationship to permitted evolve into eukaryotic organelles of today evolve • Home & protection for small cell; food & mineral sources (gatherer) • New, powerful energy source for larger cell (anaerobic?) (aerobic or (aerobic photosynthetic) photosynthetic) (Purves et al, 2001) 11 2/15/2010 Endosymbiotic Theory EVIDENCE: 1. Approximately the same size Approximately and shape of known prokaryotes and of (“bacteria”) 2. Double Membranes 3. Bacteria-llike genetic information ike (chromosomal DNA): (chromosomal a) Closed, circular DNA (not linear, (not like Euk.). Euk b) Encode own: metabolic proteins, Encode prok.-type ribosomes (70S!!) prok type ribosomes Endocytosis w/out digestion 4. Prok.-like division mechanisms. 5. Other very intimate/intracellular Other symbioses between free-lliving iving symbioses organisms exist now!! organisms Figure 10.2 Chapter 5 Microbial Microbial Metabolism Metabolism 12 2/15/2010 Microbial Metabolism 1. Metabolism iis the sum of the chemical s reactions in an organism. reactions 2. Catabolism is the breaking-down complex down molecules; energy-releasing processes. molecules; 3. Anabolism iis building up complex s molecules from simpler subunits; energymolecules using processes. Microbial Metabolism • Catabolism provides the building blocks and provides energy for anabolism. anabolism “Energetic Coupling!!” “Energetic Coupling!!” Figure 5.1 13 2/15/2010 Metabolism • A metabolic pathway iis a sequence of s metabolic enzymatically catalyzed chemical enzymatically catalyzed reactions in a cell. reactions 1. Metabolic pathways are determined by Metabolic enzymes. enzymes. 2. Enzymes are encoded by genes……. Therefore: Therefore: Genes drive metabolism!!! • The Collision Theory: chemical reactions The Collision chemical can occur when atoms, ions, and molecules collide – allowing exchange of electrons. allowing exchange • **Activation energy iis needed to disrupt s electronic configurations.** electronic • Reaction rate iis the frequency of collisions s with enough energy to bring about a reaction. • Reaction rate can be increased by enzymes Reaction enzymes or by increasing temperature or pressure. or temperature or pressure 14 2/15/2010 5.1) Enzymes Figure 5.2 Enzymes • Biological catalysts – Specific for a chemical reaction; not used up in Specific that reaction; usually protein that • Holoenzyme: Apoenzyme + cofactor Apoenzyme – Apoenzyme: protein – Cofactor: Nonprotein component • Coenzyme: Organic cofactor ***************************** • RIBOZYMES: = Catalytic RNA’s!! – RNA that cuts and splices RNA; in peptide RNA synthesis (ribosome)….. synthesis 15 2/15/2010 Enzymes & Important Coenzymes • • • • NAD+ NADP+ electron carriers FAD Coenzyme A – carries 2C units. Coenzyme Figure 5.3 • The turnover number is generally 1-10,000 10,000 molecules per second. molecules Enzymes Figure 5.4 http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html http://www.stolaf.edu/people/giannini/flashanimat/enzymes/prox-orien.swf 16 ...
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This note was uploaded on 03/18/2010 for the course BIOL 240 taught by Professor Staples during the Spring '09 term at Canada College.

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