Microbiology - Exam 1
Compare and contrast the structures of DNA and RNA.
DNA - - has deoxyribose - exists as a double helix - sugar phosphate backbone connected y phosphodiester bonds RNA - has ribose - single stranded - U instead of a T
Explain the importance of observations made by Hooke and Van Leeuwenhoek.
Hooke - - marked beginning of cell theory (all living things are composed of cells), ex: slice of cork (poor resolution) Van Leeuwenhoek - - observed live organisms through magnifying lenses ('animalcules' in rainwater, feces, tooth scrapings)
Define active transport.
- requires transporter protein & ATMP - AGAINST concentration gradient - amino acids & simple sugars
Explain how wavelength is related to resolution.
- resolution is inversely proportion to wavelength of radiation used for illumination - shorter wavelengs = greater resolution
Identify the contributions to microbiology made by Ehrlich and Fleming.
Ehrlich - - "magic bullet" search for a substance that could destroy pathogen and not harm host - develeped 1st synthetic drug (*salvarsan*) - treated syphilis (offered salvation from diseases and contained arsenic) Fleming - - bacteria plates contaminated by mold - penicillium fungus made an antibiotic (penicillin) that killed S. aureus
Describe 'run and tumble'.
run - - movement in one direction tumble - - abrupt, random changes in direction
Define group translocation.
- EXCLUSIVE to prokaryotes - substance chemically altered during transport so can't leave - requires ATP & transporter
Describe the function of endospores.
- allow survival in adverse environment - resistant to desiccation, heat, chemicals, radiation
List 3 properties of water that make it important to living cells systems.
- an excellent solvent - no organism can survive without it (most abundant substance in cells) - polar molecule - temperature buffer
Describe how the Gram stain works.
- differential staining procedure - purple dye retained by thick peptidoglycan (gram-positive) - red counterstain (safranin) used to see gram-negative
Recognize the system of scientific nomenclature that uses two names.
- each organism has two names 1) Assign Genus (capitalize) 2) Species - after first use names may be abbreviated with first letter of genus followed by species name - should be descriptive or honor a scientist - ex: Staphylococcus aureus (S. aureus), Escherichia coli (E. coli)
Identify the basic shapes and arrangements of bacteria.
- most are monomorphic (single shaped) - few are pleomorphic (many shapes) - three basic shapes: bacillus (rod shape), coccus (spherical), spiral
What is the germ theory of disease?
- proves that bacterium causes disease - originally thought disease was a punishment for crimes caused by demons
Understand the fluid mosaic model.
- viscous membrane (olive oil) - proteins move to function - phospholipids move laterally & flip (more rare)
Define 3 important parameters in microscopy.
1) magnification - apparent increase in size of an object 2) contrast - accentuating visible differences in parts of sample 3) resolution - minimum distance 2 points can be separated & still be distinguised as 2 points (measure of image clarity)
List four beneficial activities of microorganisms.
1) recycle vital elements (generate useable forms carbon, nitrogen, oxygen) 2) sewage treatment (bacteria used to clean up water by degrading organic material) 3) bioremediation (bacterial enzymes break down toxins in underground wells, chemical & oil spills) 4) insect pest control (dusting powder contains bacterial protein toxic to insects)
Identify the importance of Jenner's work.
Jenner - - created smallpox vaccine - inoculated 8 year old volunteer with cowpox blister scrapings from milkmaid; scratching with pox-contaiminated needle - raised bump, mild sickness - never contracted either pox
Identify Koch's contributions to microbiology and the importance of his postulates.
Koch - - 1st to prove bacterium causes disease (anthrax) - experimental steps to prove that a specific microbe causes a specific disease
Identify contributions to microbiology made by Needham, Spallanzani, and Pasteur.
Needham - - for spontaneous generation - nutrient broth boiled briefly placed in cork-sealed flask CREATED microbial growth ("life force") Spallanzani - - against spontaneous generation - boiled broth 1 hour, glass necks melted to seal flasks, NO microbial growth unless seal broken - Needham said "life force" was destroyed by prolonged boiling and there wasn't enough O2 to support life Pasteur - - proved biogenesis
Define simple diffusion.
SOLUTE moves from HIGH to LOW concentration until equilibrium reached.
Differentiate the major characteristics of each group of microorganisms. (algae)
algae (alga) - - photosynthetic eukaryotes - cellulose containing cell walls - use photosynthesis for energy (need light, water, co2) - produce O2 used by animals
Define an atom and its structure.
all matter is made up of atoms. composed of: - electrons ( - ) - protons ( + ) - neutrons (no charge)
Differentiate anabolism and catabolism.
anabolism - synthesis of molecules in a cell (combine to form something) catabolism - decomposition reactions in a cell
Define polar molecules.
any molecule having unequal distribution of charge
Differentiate the major characteristics of each group of microorganisms. (archaea)
archaea - - prokaryotic BUT lack peptidoglycan - live in extreme environments 1) methanogens - produce methane as respiration waste product (marshes, swamps) 2) extreme halophiles - (halo = salt, philic = loving) great salt lake and dead sea 3) extreme thermophiles - (heat), hot sulfurus water, yellowstone national park
Compare & contrast the cell walls of Gram-positive bacteria, Gram-negative bacteria, acid-fast bacteria, archaea, & mycoplasmas.
archaea - - wall-less or contain pseudomurein (like peptidoglycan) - extremophiles mycoplasmas - - smallest known bacteria - lack cell walls - sterols in plasma membrane
Define atomic number and atomic weight.
atomic number - # of protons in nucleus atomic weight - total # of protons + neutrons
Differentiate prokaryotic flagella types, axial filaments, fimbriae & pili.
axial filaments - - endoflagella - bundles of fibrils wrapped around cell (anchored at one end) - rotation causes outer sheath to move, proe;lling in spiral motion fimbriae - - at poles/evenly distributed - adhere to each other & to surfaces (biofilms, epithelial surfaces) pili - - longer than fimbriae; 1 or 2/cell - facilitate transfer of DNA from one cell to another conjugation (sex) pili bring bacteria together allowing transfer of DNA
Differentiate the major characteristics of each group of microorganisms. (bacteria)
bacteria - - unicellular (single-celled) - prokaryotes (no nucleus, pre-nucleus) - several shapes (bacillus - rod like, coccus - spherical, spiral - corkscrew) - several formations: forms in pairs, chains, clusters - enclosed in cell walls made of peptidoglycan (carbohydrate:protein complex) - reproduce by binary fission - division into 2 equal cells
Define biofilm.
biofilm - - microbes attach to solid surfaces & grow into masses - protect mucous membranes from harmful microbes - food for aquatic life
Differentiate biotechnology and recombinant DNA technology.
biotechnology - use of microbes to produce foods and chemicals recombinant DNA technology - - new technique - DNA made from two different sources - expands potential use of microbes to produce variety of proteins including vaccines and enzymes
Define chemical element and isotope.
chemical element - atoms with the same # of protons that behave the same way chemically isotope - atoms with different # of neutrons
Differentiate the structures of simple and complex lipids and steroids.
complex lipids - (steroids, cholesterol) prevent packing of phospholipids, keeps membranes fluid at low temps, component of cell membranes simple lipids - called fats or triglycerides, contain glycerol and 3 fatty acids; formed by dehydration synthesis
Define dehydration synthesis and hydrolysis.
dehydration synthesis - chemical reaction that causes water to be released from molecule hydrolysis - chemical breakdown of a molecule caused by water
Know the three domains and the taxanomic hierarchy.
domains = 1) bacteria (cell walls contain peptidoglycan) 2) archaea (cell walls - if present - LACK peptidoglycan) 3) eukarya (protists = protozoa and algae, fungi = yeasts, molds, mushrooms, plants = mosses, ferns, conifers, flowering plants, animals = sponges, worms, insects, vertebrates) taxanomic hierarchy = 8 taxa of DECREASING relatedness following DOMAIN 1) kingdom 2) phylum 3) class 4) order 5) family 6) genus 7) species "King Philip Came Over For Grandma's Spaghetti."
Define electronic configuration and valence.
electronic configuration - arrangement of electrons in shells/energy levels in atom valence - number of extra/missing electrons in outermost shell of an atom
Define emerging infectious disease and provide examples.
emerging infectious disease - - new/changing diseases and diseases increasing in incidence - acquired immunodificiency syndrome (AIDS) - West Nile Encephalitis - E-coli - Ebola
Differentiate between endergonic and exergonic.
endergonic - reactions absorb energy exergonic - reactions release energy
Identify the chief differences between prokaryotes and eukaryotes. (eukaryotes)
eukaryotes - TRUE NUCLEUS - multiple paired chromosomes in nuclear membrane - histones - membrane-enclosed organelles - simple cell walls if present (chitin, cellulose) - divide by mitosis
Differentiate prokaryotic and eukaryotic flagella.
eukaryotic - - move in wavelike manner - few, long prokaryotic - - rotates
Differentiate prokaryotic flagella types, axial filaments, fimbriae & pili.
flagella - - peritrichous - flagella distributed over entire cell - polar - at one/both poles/ends of cell - monotrichous - at ONE POLE - lophotrichous - tuft at ONE pole - amphitrichous - at BOTH poles
Differentiate the major characteristics of each group of microorganisms. (fungi)
fungi (or fungus) - - eukaryotes (have nucleus) - chitin cell walls - two forms: unicellular (yeasts) and multicellular (molds, mushrooms) - absorb organic materials from environment for nourishment (soil, water, animal, plant) - sexual (spores) OR asexual (budding) reproduction 1) molds - masses of mycelia composed of filaments (hyphae) that branch and intertwine
Describe the structure and function of the glycocalyx. Differentiate capsule and slime layer.
glycocalyx - - sugar coat OUTSIDE cell wall - sticky secreted polymer (polysaccharide/polypeptide) - prevents phagocytosis - facilitates adherence (biofilms) capsule - organized, firmly attached slime layer - unorganized, loosely attached
Discuss how Gram-positive & Gram-negative bacteria are uniquely damaged through cell wall targeting.
gram-positive - - lysozyme (tears, saliva, mucus) digests peptidoglycan disaccharide - penicillin-sensitive: prevents cross bridge formation of peptidolgycan gram-negative - - partially resistant to lysozyme - penicillin does not penetrate outer membrane well - cephalosporins penetrate & block peptidoglycan syntehsis
Compare & contrast the cell walls of Gram-positive bacteria, Gram-negative bacteria, acid-fast bacteria, archaea, & mycoplasmas.
gram-positive bacteria - - MANY layers of peptidoglycan - contain teichoic acid linked to peptidoglycan - provides rigidity & regulate enzyme activity gram-negative bacteria - - ONE/few layers of peptidoglycan - outer membrane: lipoprotein, lipopolysaccarhides (LPS), phospholipids & porins (channels) acid-fast bacteria - - waxy lipid layer (mycolic acid) outside peptidoglycan - prevents uptake of gram stain
Differentiate inorganic and organic compounds.
inorganic - typically lack C; simple. Water is the most important. (H2O, salts, acids, bases) (water is a good solvent, temperature buffer) salts - substances that dissociate into cations & anions base - substance that dissociate into one or more positive ions acids - substance that dissociate into one or more H & one or more negative ion organic - compounds always contain C & H; complex (sugars, proteins, nucleic acids)
Define chemical reaction.
involve making or breaking bonds between atoms
Describe an ion, ionic bond, covalent bond, hydrogen bond.
ion - charged atoms that have gained/lost electrons ionic bond - attractions between ions of opposite charge. one atom loses electrons while another gains electrons. (MIDDLE BOND) covalent bond - two atoms share one or more pairs of electrons to fill outermost shells (STRONGEST BOND) hydrogen bond - form when hydrogen atom covalently bonded to an O or N atom is attracted to another N or O atom in another molecule (WEAKEST BOND)
Differentiate between isotonic, hypertonic, & hypotonic osmotic solutions.
isotonic - - no net movement of water hypertonic - - water moves out of the cell causing it's cytoplasm to shrink hypotonic - - water moves into the cell (cells swell and can burst)
Describe the 3 types of microscopy discussed including how they work, resolution capability, what they are used for, and disadvantages & advantages.
light microscopy - - advantage: can visualize live cells - disadvantage: suffers due to lower resolution - visible light passed through specimen and then through 2 lenses (objective and ocular lens), this reflacts light and magnifies image - resolution of 200 nm electron microscopy - - uses a beam of electrons for illumination - more powerful than light microscopy - advantage: much GREATER resolution - disadvantage: cells must be dead - resolution 2nm - 0.2nm transmission electron microscopy - used to study internal structures - beam of electrons pass through ultrathin section of tissue coated with heavy metals - transmitted electrons are detected and used to generate image
Define macromolecules, polymer, and monomer.
macromolecules - usually polymers, consisting of many small repeating molecules polymers - many parts monomer - one part
Define molecule, compound, and chemical bond.
molecule - full complement of electrons compound - contain at least two different kinds of atoms chemical bond - formed by the sharing of electrons by two different atoms
Describe the three major groups of carbohydrates and known an example of each.
monosaccharides - simple sugars with 3-7 C atoms disaccharides - 2 monosaccharides joined by dehydration synthesis; broken down by hydrolysis oligosaccharides - 2-20 monosaccharides; disaccharides most common polysaccharides - tens or hundreds of monosaccharides joined through dehydration synthesis
Define osmosis.
movement of water from HIGH to LOW
Define normal microbiota and resistance.
normal microbiota - microbes normally present in & on the human body (protect us from overgrowth of harmful microbes, produce vitamins) resistance - ability of body to ward off disease - responses by our immune system can destroy microbes - factors include: skin, stomach acid, antimicrobial chemicals
Identify the functions of the nucleoid and ribosomes.
nucleoid - contains bacterial chromosomes ribosomes - sites of protein synthesis
Identify the chief differences between prokaryotes and eukaryotes. (prokaryotes)
prokaryotes - PRENUCLEUS - one circular chromosome not in membrane - no histones (chromosomal proteins) - no membrane-enclosed organelles - complex cell walls (peptiglycan) - divide by binary fission
Compare & contrast prokaryotic & eukaryotic cell walls and glycalyxes.
prokaryotic - - cell walls: more complex than eukaryotic eukaryotic - - cell walls: more simple than prokaryotic - no peptidoglycan!!!
Differentiate the major characteristics of each group of microorganisms. (protozoa)
protozoa (protozoan) - - unicellular eukaryotes - categorized by motility - free entities or parasites (nutrients from living hosts) - absorb or ingest organic chemicals in environment - sexual/asexual reproduction motility forms = 1) pseudopods - "false feet" - extensions of cytoplasm 2) cilia - numerous short appendages 3) flagella - long appendage 4) non-motile
Define facilitated diffusion.
solute moves through integral transporter protein in membrane from HIGH to LOW.
Define functional group.
specific groups of atoms most commonly involved in chemical reactions; responsible for most of chemical properties of a particular organic compound.
Compare spontaneous generation and biogenesis.
spontaneous generation - - living organisms arise from nonliving matter, a "vital force" forms life (toads, snakes, mice could be born in moist soil, flies emerge from manure) biogenesis - all living things arise only from preexisting living cells (microbes present in air can contaminate sterile solutions; air itself does not create microbes)
Define sporulation and germination.
sporulation - - endospore formation; triggered when key nutriet scarce/missing germination - - return to vegetative state - triggered by physical/chemical stimuli
Describe the structure, chemistry, & functions of the prokaryotic plasma membrane.
structure/chemistry - - phospholipid bilayer (polar head/nonpolar tail) - peripheral proteins - integral/transmembrane proteins (channels) functions - - selectively permeable barrier (small molecules & ions pass, large molecules don't) - ATP production - site of photosynthesis
Describe the three major types of chemical reaction.
synthesis reactions - new bonds are formed decomposition reaction - bonds are broken exchange reaction - part synthesis and part decomposition reversible reaction - can readily go in either direction, each direction may need special conditions (can break down or combine to form new bonds)
Define taxis & two types.
taxis - movement toward or away from stimuli chemotaxis - chemical phototaxis - light
Differentiate the major characteristics of each group of microorganisms. (viruses)
viruses - - acellular - virus particle contains a core that houses either DNA or RNA - core may be enclosed in a lipid envelope - viruses need to use cellular machinery to replicate - inactive outside of host
