BIO 310: Week One Notes
BIO 310: Week One Notes BIO 310
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This 6 page Class Notes was uploaded by Madison Notetaker on Monday February 1, 2016. The Class Notes belongs to BIO 310 at Missouri State University taught by Dr. Schweiger in Spring 2016. Since its upload, it has received 22 views. For similar materials see Microbiology in Biology at Missouri State University.
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Date Created: 02/01/16
Micro 1-11-16 Cyanobacteria: developed oxygen for eukaryotes Conquest of incas – cortes: smallpox, etc Potato famine : fungal infection of potatoes Robert Hooke First to describe fungus Leeuwenhoek First to describe bacteria 1-13-16 Jenner First vaccination effort Giving cow pox to prevent smallpox [Vaccinated an 8-year old boy with fluid from cow-pox blisters challenged with fluid from small pox blister] Cohn Discovered endospores (endospores: very tough to kill) Pasteur Living organisms discriminate between optical isomers - Molecules are particular about left/right, form [Aspergillus only metabolizes in D-tartrate form] Discovered that Alcoholic fermentation was a biologically mediated process (thought before to be chemical) Developed vaccines for anthrax, cholera, and rabies Disproved theory of spontaneous generation (living things come from living things, they do not spontaneously generate) Koch Demonstrated that microbes cause disease [Bacillus anthracis cause anthrax] [Mycobacterium tuberculosis causes TB] - Cultures M. tuberculosis from lung tissue - Before this people didn’t really know how to isolate organisms in culture - He used gelatin - Developed techniques for pure cultures of microbes (solid media) - Pitri dishes named after the researcher working with Koch Won Nobel Prize (1905) Koch’s Postulates - Diseased animal; you have a suspected pathogen that is absent in the healthy animal; isolating bacteria; insert into animal again; isolate bacteria again after it has caused disease Beijerinck Developed enrichment culture techniques - Take a complicated environment like soil and in order to get a specific type of bacteria you need these techniques - Highly selective culturing - Isolation of nitrogen- fixing bacteria Winogradsky Proposed concept of chemolithotrophy [oxidation of inorganic compounds] Linked microbes with cycling of carbon, nitrogen, sulfur, and oxygen - Linked microorganisms to the cycling of elements in the environment Carl Woese Uses small subunit RNA (SSU rRNA) sequence to establish the phylogenic relationship between organisms (three domains of life) - Determining relationships between types of organisms - Developed theory of archaea Before Woese, all microbes were divided into prokaryotes or eukaryotes He said that: Prokaryotes: lack a true nucleus Eukaryotes: contain a nucleus All bacteria are either prokaryotes or archaea Nomenclature Genus species G. species Cannot use species name without the genus Strains All cells are descendants from a single isolated organisms (not a formal taxonomic unit) PROKARYOTIC STRUCTURE AND FUNCTION: BACTERIA AND ARCHAEA Shapes: Spherical: coccus (single coccus, diplococci, streptococci, tetrad, sarcinae, staphylococci) Rod: Bacillus (single bacillus, diplobacilli, streptobacilli, coccobacillus) Curved Rod: Vibrio Spiral: Spirillum Spirochetes Stalks Hypha Filamentous Square Triangles Stella Star-shaped Appendages Network Structure Pleomorphic (same prokaryote but has many shapes) Size Prokaryotes are 0.2-700 microns long Average bacterium is 0.5-5 microns long Eukaryotes are 1000x larger than bacteria Epulopiscium: 600 microns x 75 microns Largest bacterium: Thiomargarita namibiensis [750 microns] Nanoarchaeum equitans (400nm) (one of the smallest prokaryotes) - Completely dependent on another archaea, needs a host cell Advantages to being small: - More surface area relative to volume - Higher surface to volume ratio - Volume increases more rapidly than surface area as a cell grows - Faster diffusion/uptake of nutrients - Tend to grow faster than larger cells Bacterial Cell Structure: Cytoplasm - DNA nucleoid: usually a single circular chromosome - Chromosome-packaging-proteins – Topoisomerases – coil the DNA - Enzymes: biosynthesis, catabolism, replication, transcription, etc. - Ribosomes : translation - Plasmids - Inclusion bodies : energy storage, carbon, phosphorous, sulfur - Gas vesicles : buoyancy - Magnetosomes : orienting cell during movement - Endospores : dormant stage resistance to harsh conditions - Cytoskeletal structures : cell wall synthesis, cell division, chromosome partitioning 1-15-16 Inclusion Bodies Ex: 1. Polyphosphates : strings of phosphates ; storage of phosphates 2. Storage of carbon (starch, glycogen) 3. Sulfur globules: stores sulfur and energy 4. Polyhydroxy butyric acid (PHB): store carbon and energy; can make biodegradable plastics (bioplastics) from them Gas Vesicles Composed of protein; filled with gas; used by microbes to position themselves in a water column; do not have a lipid membrane; membranes made with protein; this is for permeability; lipid membranes aren’t gas tight but protein membranes are Magetosomes Membrane enclosed organelle; Fe3O4 (Magnetite) aligns to the magnetic field (magnetotaxis); align bacterium in a water column Endospores - Highly differentiated cells that can be resistant to heat, harsh chemicals, and radiation - NOT REPRODUCTIVE - Dormant stage of life brought on by nutrient limitation; can live for thousands and thousands of years in the dormant stage They produce a developing spore inside the mother cells; when the spore is mature it pops up and lyses the mother cell; then it germinates into a vegetative cell again; not reproductive because you’re going from one cell to one cell, technically a dormant stage of life - Dipicolinic acid dehydrates the spore and gives heat resistance; tend to have very low water activity and water content - Small acid-soluble proteins (SASPs): bind DNA and help protect the spore against UV light Prokaryotic Membranes Cell envelope: layers that define the cell, which include the cytoplasmic membrane, cell wall, and outer membrane. Cytoplasmic membrane: (plasma or cell membrane) all cells contain a cytoplasmic membrane; membrane comprised of a phospholipid bilayer, proteins, and sometimes hopanoids (related to steroids) - Separates cytoplasm from environment - Highly selective permeable barrier; enables concentration of specific metabolites and excretion of waste products that would otherwise be toxic - LIPID BILAYER: basic structure element of membranes Lipids and Membranes The lipids are phospholipids composed of fatty acid esters of glycerol - The third –OH of the glycerol is linked to a phosphate forming a phosphoester bond Lipids are amphipathic Differences found in Archaeal Membranes - Bacteria and Eukarya both have ester linkages in phospholipids - Archaeal membranes have all of the same characteristics (chemically, physical properties) - Difference: R-groups are made of isoprenes (not a fatty acid); they link isoprenes over and over to make long chains - Isoprenes are linked by ether linkage - Archael lipids lack fatty acids; have isoprenes instead - Ether bunny: make the bunny ears on the oxygen with two lone pairs, cannot be made with ester - Archaeal membranes can be monolayers Hopanoids Lipids found in some bacteria and archaea; their function is similar to cholesterol in stabilizing the membrane - Very similar to steroids (steroids stabilize the membrane and play a role in signaling) - Hopanoids are only used for stabilizing the membrane Fluid Mosaic Model Phospholipids and sterols form a lipid bilayer in which the non-polar regions of the lipid molecules face each other at the core of the bilayer and their polar head groups face outward. - Proteins are embedded at irregular intervals - Individual lipids and proteins form a mosaic which is free to change constantly - Moving system; not static - Cytoplasmic membrane is stabilized by hydrogen bonds and hydrophobic interactions Functions of the Plasma Membrane 1. Permeability barrier - polar and charged molecules must be transported - transport proteins accumulate solutes against the concentration gradient 2. Protein anchor - holds transport and sensor proteins in place - responsible for reacting to things in the environment 3. Energy Conservation - establish proton motive force (PMF) by pumping protons out of the membrane Nutrient Transport Facilitated diffusion: requires a transport protein Active transport : requires energy (typically PMF or ATP) - Three types of transport events 1. uniport (trasnports in one direction across the membrane) 2. symport ( 3. antiport Three major classes of active transport systems: a. Simple Transport single protein needed; transport with co-transport (H+); driven by a proton gradient b. Group Translocation a series of proteins needed; transport by conversion of energy rich compound (ex: phosphotransferase system); transferring a phosphate group - glucose is transported across the membrane and phosphorylated once inside the cytoplasm - multiple proteins required in a phosphor-transfer chain - energy derive from phosphoeonolpyruvate (the phosphate is used to drive glucose) c. ABC system requires 3 proteins (A, B, C) substrate binding, transporter, ATP hydrolase; can work against gradients by using a binding protein and ATP
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