Microbio Exam 1 Flashcards

Terms Definitions
Invented 1st microscopes. First to see microbes ("beasties"). Fungi, algae, protozoa, bacteria (later)
Developed taxonomic system for naming plants and animals (grouping similar organisms together). Animal & Plant Kingdoms: fungi, protozoa, algae, bacteria, archaea, & small multicellular animals (viruses too small)
Eukaryotic. Obtain food from other organisms (unlike plants) & have cell walls (unlike animals). Some molds and yeasts.
Multicellular and grow as long filaments. Reproduce by sexual and asexual spores
Unicellular and usually oval or round. Reproduce asexually by budding. Some produce sexual spores
Single-celled eukaryotes. Most are locomotive via flagella, cilia, or pseudopodia. Typically live in water (some in animal hosts where they may cause dz). Most asexual, some sexual.
Unicellular or multicellular photosynthetic organisms. Include seaweeds and kelps. Unicellular algae common in freshwater ponds, streams, lakes, and oceans. Provide most of the world's O2
Prokaryotic. Cell walls composed of peptidoglycan (some lack cell walls). Asexual. Most do not cause dz.
Prokaryotic. Archaea cell walls composed of different polymers than peptidoglycan. Asexual. Found in extreme environments (hot springs, Dead Sea, etc.) No known archaea cause dz.
Parasitic worms
Adults not microscopic, but early stages (eggs, larva) can be
invisible to Leeuwenhoek (too small). Discovered in 1932 (invention of electron microscope). Acellular obligatory parasites composed of small amounts of genetic material (DNA or RNA) surrounded by a protein coat.
Spontaneous generation. Promulgated by Aristotle
Francesco Redi
aimed to disprove spont gen with maggot/meat experiment. most scientists believed until Leeuwenhoek's microbes
John T. Needham
experiments with beef broth/plant infusions-->cloudy. Convinced scientists of spont gen of microbes
Lazarro Spallanzini
Boiled infusions for an hour and sealed vials by melting glass-->clear. Critics claimed air needed for microbes to thrive or heating destroyed "life force."
Louis Pasteur
Swan-necked flasks stayed clear for 18 months-->disproved spont gen. Broke necks-->cloudy; tipped over to touch dust-->cloudy. Instigated Scientific Method
Scientific Method
1. Group of observations leads to a question; 2. Generation hypothesis; 3. Design and conduct experiment to test hypothesis; 4. Based on results, accept, reject, or modify hypothesis
Pasteur: observed budding-->proved yeast arises from yeast. Sealed flasks of grape juice + yeast-->proved yeast reproduces w/o air. Bacteria + juice = acid. Yeast + juice = alcohol
heat enough to kill most bacteria w/o changing basic qualities
Eduard Buchner
Experiments demonstrated presence of enzymes. Began the field of biochemistry and study of metabolism
Germ Theory of Dz
Pasteur hypothesized that microbes cause dz
Robert Koch
Discovered rod-shaped bacterium that causes anthrax. Injected endospores into mice. Smeared specimens on slices of potato and gelatin media to observe colony growth and ID pathogens
Koch's Postulates
1. The suspected causative agent must be found in every case of dz and be absent from healthy hosts; 2. The agent must be isolated and grown outside host; 3. When the agent is introduced, the host must get the dz; 4. The same agent must be found in the diseased experimental host
Hans Christian Gram
Gram stain: positive = purple; negative = pink
Ignaz Semmelweis
Obstetrician that linked dirty med students to puerperal fever (strep). Made students wash hands in lime water, mortality dropped from 18% to 1%
Joseph Lister
Antisepsis: sprayed wounds/incisions with phenol and reduced death by 2/3 in his patients
Florence Nightingale
Statistically proved the benefit of sanitation. Helped form public health policies. Founded 1st nursing school.
John Snow
Mapped occurrence of cholera cases in London and showed it centered around public water supply. Foundation for infection control and epidemiology.
Edward Jenner
Cowpox to vaccinate against small pox. Pasteur built off his work to create vaccines for fowl cholera, anthrax, and rabies.
Paul Ehrlich
Chemotherapy: searched for chems that would selectively kill pathogens w/o harming human cells. Found chems against sleeping sickness and syphillis.
Anything that takes up space/has mass
Smallest chemical unit of matter
Matter composed of a single kind of atom
Atomic Number
# of protons
Atomic mass (atomic weight)
protons + neutrons (+electrons [negligible mass])
Atoms of a given element w/different #s of neutrons
Valence electrons
electrons in outermost shell
two or more atoms held together by a bond
molecule that contains atoms of greater than one element
Covalent bond
Sharing of a pair of electrons by two atoms
Nonpolar covalent bond
Shared electrons spend an equal amount of time around each nucleus; no poles exist (btwn atoms of similar electronegativities)
Polar covalent bond
unequal sharing of electrons; electrons hang out with more electronegative atom
Organic compound
contain carbon and hydrogen
positive ion
negative ion
Ionic bond
bond formed from opposing electrically charged ions to form salts
polar bonds of solvent interfere with ionic bonds of salt
Dissociated ions that can conduct electricity through solution
Hydrogen bond
electrical attraction btwn partially charged hydrogen ions and full or partial negative charge on either different region of same molecule or another molecule
Synthesis rxn
formation of larger, more complex molecules; reactant + reactant-->product(s)
Dehydration synthesis
2 smaller molecules join by covalent bond and water is also formed
Endothermic rxn
Requires energy
all the synth rxns of an organism
Decomposition rxns
break bonds w/in larger molecules to form smaller atoms, ions, and molecules; Reactant-->product + product
reverse of dehydration synth; covalent bond broken, H+ and OH- are products
all decomposition rxns of an organism
Exchange/Transfer rxns
break and form covalent bonds, endothermic and exothermic steps; A + BC-->AB + C
catabolic + anabolic + exchange rxns
Special properties of water
1. cohesive (surface tension); 2. excellent solvent; 3. remains liquid across with temp range; 4. can absorb significant amounts of heat w/o changing temp; evaporate taking energy with it; 5. participate in many cellular rxns as reactant and product
substance that dissociates into one or more hydrogen ions and one or more anions
molecule that binds with H+ when dissolved in water
substance that prevents drastic changes in internal pH
hydrophobic (insoluble in water). Composed almost entirely of C & H linked by nonpolar bonds
dehydration synth forms esters btwn 3 FA chains and glycerol (triglycerides)
Saturated FA
only single bonds btwn Cs and covalently linked to 2 Hs (except terminal Cs)
Unsaturated FA
contain at least one double bond btwn Cs
several double bonds
only 2 FA chains, glycerol linked to phosphate group; FA tail = nonpolar, hydrophobic; phospho head = polar, hydrophillic
one long-chain FA covalently linked to long-chain alcohol by ester bond; completely water insoluble
4 rings fused together and attached to various side chains and functional groups; add flexibility to cell walls
composed of C, H, N, O, and S
Special properties of proteins
1. structure; 2. enzymatic catalysis; 3. regulation; 4. transportation; 5. defense/offense
Amino Acids
H2N-CH^R-COOH; easily soluble in water
Peptide bonds
covalent bonds btwn AAs
Primary structure
sequence of AAs
Secondary structure
alpha helices and beta sheets
Tertiary structure
Quaternary structure
multiple chains fitting together
physical and chemical changes that disrupt 3D structure; temporary or permanent
Phosphate + pentose (deoxyribose or ribose) + cyclic nitrogenous base (adenine, guanine, cytosine, thymine, uracil)
genetic material, RNA synthesis
protein synthesis, structure of ribosomes, genome of viruses
Processes of Life
1. Growth; 2. Reproduction; 3. Responsiveness (to environment); 4. Metabolism
(Bacteria & Archaea) Lack nucleus; Lack membrane-bound organelles; Small (~1um in diameter); Simple structure
(Algae, Protozoa, Fungi, Animals, Plants) Have nucleus; Have membrane-bound organelles; Large (10-100um in diameter); More complex structure
Bacterial Glycocalyces
1. Capsule: organized repeating units of organic chems; firmly attached to cell surface; protect bacteria from phagocytosis. 2. Slime layer: loosely attached to cell surface; water soluble; sticky layer allows to attach to surfaces and each other
Bacterial Flagella
Movement; Long structures that extend beyond cell surface; Not present in all bacteria
Structure of bacterial flagella
Composed of filament, hook, and basal body (anchors filament and hook to cell wall by a rod and series of two or four rings of proteins)
Function of bacterial flagella
Rotation propels bacterium thru environment; Reversible (counterclockwise or clockwise); Move in response to stimuli; Tumbles and runs
Arrangement of bacterial flagella
1. Petrichous (cover the surface of the cell); 2. Polar (only at the ends); 3. Many polar (tuft of polar flagellum)
Flagella spiral around the cell; Endoflagella form an axial filament enabling a corkscrew movement
Gram positive
Relatively thick layer of peptidoglycan; Contain unique polyalcohols called teichoic acids; Up to 60% mycolic acid is acid-fast bacteria helps survive dessication; purple
Gram negative
Have additional basal bodies; Thin layer of peptidoglycan; Bilayer membrane outside peptidoglycan contains phospholipids, proteins, and lipopolysaccharide (LPS); May be impediment to treatment of dz; pink
Clockwise flagella movement
Counterclockwise flagella movement
Sticky, bristlelike projections; used by bacteria to adhere to one another, hosts, and the substances in environment; shorter than flagella; serve an important function in biofilms
Tubules composed of pilin; Longer than fimbriae but shorter than flagella; bacteria only have one or two per cell; Mediate transfer of DNA from one cell to another (conjugation)
Bacterial Cell Walls
1. Provide structure and shape and protect from osmotic forces; 2. Assist cells in attaching to other cells or in resisting antimicrobial drugs; 3. Can target cell wall with antibiotics; 4. Give cells characteristic shapes; 5. Most composed of peptidoglycan (NAG + NAM attached by tetropeptides [AAs])
Structure of Bacterial Cytoplasmic Membranes
Phospholipid bilayer (lipids and associated proteins); Fluid mosaic model (proteins arranged mosaically; proteins and lipids flow laterally w/in membrane)
Function of Bacterial Cytoplasmic Membranes
Energy storage; Harvest light energy (photosynthetic bacteria); Selectively permeable; Impermeable to most substances; Proteins allow substances to cross membranes; Maintain concentration and electrical gradient
Passive processes of Bac Cyto Membrane
Diffusion (net movement of a chem down its concentration gradient [high conc to low conc]); Facilitated diffusion (proteins facilitate pathway); Osmosis (diffusion of water)
higher concentration of solutes
Lower concentration of solutes
same concentration of solutes
Why bacteria have cell walls
Isotonic: no net movement of water; Hypertonic: cell shrinkage (w/ or w/o cell wall); Hypotonic: cells without walls burst while cells with walls are protected
Active processes of Bac Cyto Membranes
Active transport (utilizes transmembrane protein permeases but requires energy [gated channels or ports]; uniport = one substance at a time, antiport = simultaneous transport in opp directions, symport = 2 substances in same direction, coupled transport = energy provided from one port to power other); Group translocation (substance chemically modified in transport and can't go back)
Gelatinous material inside cell; Composed of: cytosol, inclusions, ribosomes, +/- cytoskeleton, +/- endospores
Liquid portion of cytoplasm; Mostly water; ions, carbs, proteins, lipids, and wastes; In prokaryotes contain the DNA in the nucleoid
May include reserve deposits of chemicals (lipids, starches, gas vesicles, etc.)
Unique structures produced by some bacteria as a copy of itself to survive harsh conditions (spore coat with several protein layers and layer of calcium)
Nonmembranous Organelles
Ribosomes (protein synth; 70S); Cytoskeleton (helps form cell's basic shape)
Archaeal Glycocalyces
Polysaccharides, polypeptides, or combo of both; Function in formation of biofilms; Adhere cells to one another and inanimate objects; Nonpathogenic
Archaeal Flagella
Consist of basal body, hook, and filament; Smaller; Not hollow; Powered by ATP
Archaeal Fimbriae
Many archaea have fimbriae; similar to bacterial
Archaeal Hami
Fimbriae-like structures; Attach archaea to surfaces; helical filament with tiny prickles like barbed wire
Archaeal Cell Walls
Most archaea have cell walls; do not have peptidoglycan; do not have phospholipid membranes; contain variety of specialized polysaccs and proteins
Archaeal Cytoplasmic Membranes
Maintain electrical and chemical gradients; control import/export of substances to/from cell
Archaeal Cytoplasm
Similar to bacterial: 70S ribosomes, fibrous cytoskeleton, circular DNA; Diff than bacterial: diff ribosomal proteins, diff metabolic enzymes to make RNA, genetic code more similar to eukaryotes
Eukaryotic Glycocalyces
Not present in cells with cell walls; Never as organized as prokaryotic capsules; Anchor animal cells to each other; Strengthen cell surface; Protect from dehydration; Cell-to-cell recognition and communication
Eukaryotic Cell Walls
Fungi, algae, plants, and some protozoa have cell walls; Composed of various polysaccs (plants = cellulose; fungi = cellulose, chitin, +/- glucomannan; algae = agar, carrageenan, algin, etc.)
Eukaryotic Cytoplasmic Membranes
All eukaryotic cells have cytoplasmic membranes; fluid mosaic model of phospholipid and proteins; contain steroids to help maintain fluidity; regions of lipids and proteins called membrane rafts; control movement in and out of cell
Eukaryotic methods of transport
Diffusion; Facilitated diffusion; Osmosis; Active transport (not group translocation); Endocytosis
Pseudopodia surrounds a substance and brings into cell (phagocytosis = solid; pinocytosis = liquid; exocytosis = reverse of endocytosis)
Eukaryotic Flagella
Within the cytoplasmic membrane; Shaft composed of tubulin arranged to form microtubules; Filaments anchored to cell by basal body (no hook); May be single or multiple (usually found at one pole); Do not rotate but undulate rhythmically
Eukaryotic Cilia
Shorter and more numerous than flagella; Coordinated beating propels cells thru environment; Move substances past surface of cell; Line endothelial cavities
Eukaryotic Nonmembranous Organelles
Ribosomes; Cytoskeleton; Centrioles and centrosome
Eukaryotic Ribosomes
Larger than prokaryotic ribosomes (80S); composed of 60S and 40S subunits
Eukaryotic Cytoskeleton
Extensive network of fibers and tubules; anchors organelles; produces basic shape of cell; made up of tubulin microtubules, actin microfilaments, and intermediate filaments
Centrioles and centrosome
Centrioles play a role in mitosis, cytokinesis, and formation of flagella and cilia; Centrosome is region of cytoplasm where centrioles are found
Eukaryotic Membranous Organelles
Nucleus; Endoplasmic reticulum; Golgi apparatus; Vesicles; Mitochondria; Chloroplasts
Often largest organelle in cell; Contains most of cell's DNA; Nucleoplasm (semi-liquid portion, contains chromatin); One or more nucleoli present in nucleoplasm (RNA synth); Surrounded by nuclear envelope (pores)
Endoplasmic Reticulum
Netlike arrangement of flattened, hollow tubules continuous w/nuclear envelope; Transport system; Smooth ER (lipid synth) and Rough ER (protein synth w/in membranous compartment)
Golgi apparatus
Receives, processes, and packages large molecules for export (in secretory vesicles that fuse with cyto mem); Flattened hollow sacs surrounded by phospholip bilayer; Not in all eukary cells
Store and txfer chems w/in cells; may store nutrients in cells; Lysosomes (contain catabolic enzymes useful for detroying cells), peroxisomes (contain enzymes that degrade poisonous wastes, found mostly in liver & kidney), vacuoles, and vesicles
Two membranes composed of phospholip bilayer; Produce most of cell's ATP; Interior matrix contains 70S ribosomes and circular molecule of DNA
Light-harvesting structures found in photosynth eukarys; 2 phospholip bilayer membranes and DNA; 70S ribosomes
Endosymbiotic Theory
Eurkarys formed from union of small aerobic prokarys w/larger anaerobic prakarys; not universally accepted
The distance btwn two corresponding parts of a wave
Apparent increase in size of an object
Resolution (resolving power)
Ability to distinguish btwn two objects that are close together
Numerical aperture
Ability of lens to gather light
Diff in intensity btwn two objects or object and background; Important in determining resolution; Increased by staining; Increased by use of light in phase
Bright-field, Compound Microscopes
Series of lenses. Light thru specimen into objective. Oil immersion lens increases resolution. One or two ocular lenses. Total mag = obj mag X ocular mag. Most have condenser lens (light thru specimen)
Immersion oil
Prevents light from refracting as it leaves specimen = more light to lens = better resolution
Dark Field Microscopes
Best for pale objects. Only light rays scattered by specimen enter objective. Specimen light against dark background. Increases contrast and enables observation of more details.
Altering phase
Used for organisms that are damaged or altered by staining or attaching to slides. Rays in phase = brighter, out of phase = darker. Contrast created b/c waves out of phase. (Phase-contrast microscope & differential interference microscope)
Fluorescent Microscope
Direct UV light source at specimen. Specimen radiates energy back as longer visible wavelength. Increases res and contrast. Some naturally fluorescent, some stained. Used in immunofluorescence to ID pathogens
Confocal Microscopy
Use fluorescent dyes. UV lasers to illuminate fluorescent chems in single plane. Increased res b/c emitted light passes thru pinhole aperture. Computer constructs 3D image
Electron Microscopy
Greater resolving power and mag compared to light (limit at 200 nm). Mag 10,000 - 100,000 X. (Transmission electron microscope and scanning electron microscope)
Transmission Electron Microscope
Generates beam of electrons that produces image on fluorescent screen. Beam thru mag fields not lenses. Use in vacuum with 100nm slices
Scanning Electron Microscope
Magnetic fields and vacuum tubes. Rapidly focuses electrons across the surface of specimen coated with platinum or gold. Whole specimens. 3D images
Probe Microscopy
Tunneling microscope and atomic force microscope
Scanning Tunneling Microscope
Metallic probe sharpened to end with an atom passes back and forth across and above the surface of specimen. Reveal surface details at the atomic level. Specimen must be electrically conductive.
Atomic Force Microscope
Probe traverses lightly on surface of specimen. Can magnify specimens that do not conduct electrons and living specimens.
Increases contrast and resolution. Smear made prior to staining. Microbiological stains contain chromophore
Acidic dye
Stains alkaline structures
Basic dyes
Stain acidic structures
Simple Stain
Soak smear in dye for 30-60 seconds and then rinse in water. Determine size, shape, and arrangement of cells.
Gram Stain
Gram negative bacteria have thicker cell walls with lipid A
Acid-Fast Stain
Stains mycobacterium and nocardia. These cells have large amounts of waxy lipid in their cell walls that resist water-based Gram staining.
Endospore Stain
steam used to drive stain into thick walls of endospores
Negative Stain
Acidic dyes that are repulsed by the negative charges on the surface of cells and do not stain them. Stain the background and leave cells colorless
Flagellar Stain
Flagella normally invisible with light microscopy. Flagellar stain binds to flagella nd increases contrast
Stains for EM
Chemicals containing atoms of heavy metals which absorb electrons. May bind molecules in specimens or the background.
Linnaean Taxonomy
Kingdom (Plantae and Animalia), Phyla, Class, Order, Family, Genera, Species
Whittaker Taxonomy
5 Kingdoms (Animalia, Plantae, Fungi, Protista, and Prakaryotae)
Carl Woese
Addition of Domain (Eurkarya, Bacteria, Archaea); determined by ribosomal nucleotide sequences
Characterizing Microbes
1. Physical characteristics; 2. Biochemical tests; 3. Serological tests; 4. Phage typing; 5. Analysis of nucleic acids
Alkaline Methylene Blue
Basic dye--(cationic) green powder
Acid-fast--mix of phenol and basic fuchsin
Crystal Violet
Simple Stain--strong purple color
Gram Stain Method
Prepped and CV stain (cells purple); Treat smear with iodine (mordant--tighter binding of CV); Decolorize w/EtOH or isopropanol:acetone (some purple, some clear); Counterstain with safranin (clear to pink)
Acid-Fast: Hot stain
Heat smear prep with carbolfuchsin; Rinse; Decolorize with acid alcohol until pink; Rinse; Counterstain with methylene blue; Rinse--> Red=acid-fast; Blue=non-acid-fast
Acid-Fast: Cold stain
Add carbolfuchsin with surfactant; Rinse; Decolorize with acid alcohol until pink; Rinse; Counterstain with alkaline brilliant green; Rinse-->Red=acid-fast; green=non-acid-fast
Osmium Tetraoxide
Stain for EM with high lipid affinity
King Phillip Cried Out For Good Soup
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