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BIOL 2230 Exam 1 Questions and
Answers
Who was the first to see microorganisms? How? When? - Anton Leeuwenhoek, with the lens he grinded, 1674 Who developed the germ theory of disease? - Pasteur & Kock What are the various types of microorganisms? - Bacteria, Eukarya, and Archaea What are prokaryotes and eukaryotes? - Prokaryotes - no nucleus or internal membranes Eukaryotes - have nucleus and internal membranes What are bacteria and archaeans? - Bacteria - domain of prokaryotic organisms, characterized by peptidoglycan cell walls Archaeans - domain of prokaryotic cells lacking peptidoglycan; one of the three domains What are viruses, viroids, and prions? - Viruses - a submicroscopic, parasitic, filterable agent consisting of a nucleic acid surrounded by a protein coat Viroids - infectious RNA Prions - an infectious agent consisting of a self-replicating protein, with no detectable nucleic acid How are microorganisms named and classified? - Binomial Naming System What roles do microorganisms play in the environment, food production, and biotechnology? - Environment - oxygen production via photosynthesis, decomposition Food Production - fermentation and pasteurization, beer, wine, cheese, yogurt, bread Biotechnology - genetic engineering What impacts have microorganisms had on history? - The Plague, Cortez Conquers the Aztecs (Spaniards brought smallpox over to the new world and killed all of the Aztecs with infection), Civil War (infection) When was the "Golden Age of Microbiology"? - 1857 - 1914, 50 year period (mid 1800's to early 1900's) What questions did scientists attempt to answer? - 1) Does life arise spontaneously? 2) What causes fermentation? 3) What causes disease? 4) How can disease be treated/prevented? What is the theory of spontaneous generation? - The idea that life could arise from nothing. The idea that toads, snakes, and mice could be born of moist soil; that flies could emerge from manure; and that maggots could arise from decaying corpse.
Who contributed to disproving spontaneous generation? - Redi, Spallanzani, and Pasteur What is fermentation? - The enzymatic degradation of carbohydrates in which the final electron acceptor is an organic molecule, ATP is synthesized by substrate-level phosphorylation, and O2 is not required, the process by which sugar is turned into alcohol What did Pasteur learn about fermentation? - He found that yeast converts the sugars into alcohol in the absence of air What was Buchner's contribution? - He repeated Pasteur's experiments and used yeast, discovered enzymes What were historically thought to be causes of disease? - God's wrath for sin, Satan and evil spirits, foul vapors, and imbalance of fluids Who developed the germ theory of disease? - Louis Pasteur What contributions did Koch make to microbiology? - He discovered the cause of anthrax How did humans begin to combat microorganisms? - Handwashing, general cleanliness, sterile surgery, antibiotics, and vaccines What roles were played by Lister, Nightingale, Semmelweis, Jenner, and Fleming? - Lister - Germicides and sterile surgery Nightingale - general cleanliness Semmelweis - handwashing Jenner - vaccines Flemming - discovered antibiotics (Penicillin) What are the distinguishing features of prokaryotic cells? - 1) Typically their DNA is not enclosed within a membrane and is usually singular, circularly arranged chromosome 2) Their DNA is not associated with histones (special chromosomal protiens found in eukaryotes); other proteins are associated with DNA 3) They generally lack organelles
- Their cell walls almost always contain the complex polysaccharide peptidoglycan 5) They usually divide by binary fission, DNA is copied and cells split into two How small are prokaryotic cells? - 1 - 10 micrometers What are the primary shapes and arrangements of prokaryotic cells? - Bacilli - single rod Vibrio - bent rod Spirillum - corkscrew shape Spirochete - spirals which use propeller-like external appendages called flagella to move Cocci - spherical like berries Single - one Strepto - chain Staphlyo - cluster Diplo - chain of two What is a glycocalyx? - Outer covering composed of carbohydrates used for attachment and to avoid white blood cells
What are chromosomes and plasmids? - Chromosomes - Nucleoid, genetic material, DNA, closed loop of double stranded DNA Plasmid - small double stranded loop of DNA, contains "accessory" genes, can be used to exchange genetic material and used in genetic engineering What are inclusions (storage granules)? - Precipitated rock of storage molecules What are ribosomes? - Site of protein synthesis, prokaryotic ribosomes are structurally different from eukaryotic ribosomes, target for some antibiotics What are endospores? How and when do they form? - "Cell within a cell," produced by some bacteria in response to stressful environments, highly resilient, they are formed inside a cell under stressful situations and then the original bacteria forms when the environments return to normal What is metabolism? - All biochemical reactions within a cell What are anabolic and catabolic reactions? - Anabolic - synthetic, A+B → C, endergonic, requires energy Catabolic - degradative, Z → x+y, usually exergonic, releases energy What are endergonic and exergonic reactions? - Endergonic - requires energy Exergonic - releases energy What is meant by energy coupling? Examples? - The energy released by one reaction is used to fuel another reaction C6H1206 + O2 → CO2 + H2O ADP + P → ATP ATP → ADP + P CO2 + NH3 → UREA What is ATP? Why is it necessary? - Adenosine Triphosphate, used to fuel energy What are enzymes? - Proteins with specific shapes that catalyze (speed up) specific biochemical reactions by lowering activation energy requirements What are substrate, product, and active site? - Substrate - the specific substance on which the enzyme reacts Product - the product of the substrate and the enzyme Active Site - the site on the enzyme which the substrate attaches to What allows for enzyme specificity? - Shape What factors affect enzyme activity? - Temperature, pH What is meant by negative feedback? - Products of a process inhibits the process What is meant by competitive inhibition? - When a substance (other than the product) competes for binding to the active site
How do sulfa drugs work? Why are they safe? - They competitively inhibit bacterial enzymes What is the overall reaction of aerobic cellular respiration? How many ATP are produced from it? - C6H12O6 → 6C02 + 6H20 38 ATP What is glycolysis? ATP production? - Glycolysis is the oxidation of glucose into pyruvic acid with production of 2 ATP What is the transition reaction? - Pyruvic acid is transformed into acetyl-CoA, two hydrogen ions are released and two electron carriers collect electrons What is the Kreb's cycle? ATP production? - The Acetyl-CoA is broken up into two carbons and two CoAs. Eight hydrogens are released and eight electrons are released 2 ATPs are produced What is the electron transport chain? How does it produce ATP? How many ATP? - The ETC consists of a sequence of carrier molecules that are capable of oxidation and reduction. As electrons are passed through the chain, there occurs a stepwise release of energy, which used to drive the chemiosmotic generation of ATP. Found in the plasma membrane of prokaryotic cells. 34 ATPs are produced. What is the importance of hydrogen in metabolism? - It creates a gradient that energizes the ATP synthase What are electron carriers? - They grab the electron when hydrogen is broken into a hydrogen ion and an electron What role does oxygen serve? - The hydrogen ions and the oxygen meet in the ETC to form water How do aerobic and anaerobic metabolism differ? - Aerobic uses oxygen and anaerobic does not What waste products are produced by anaerobic metabolism? Importance? - Lactic acid in animals, Ethanol in fungi What is a pure culture? Importance? - A population of organisms descended from a single cell, it allows us to find out more about the individual bacteria How many prokaryotic species have been successfully cultured? Why so few? - .1%, we don't know a lot about the other ones. They might not be able to grow by themselves. Who pioneered the culturing of bacteria? How? - Kock, he began with potatoes, then gelatin, finally agar
removal of microorganisms from a limited area Preserve - slow or inhibit bacterial growth, raise the generation time What are disinfectants and antiseptics? - Disinfectants - chemical or process used for disinfection Antiseptics - disinfectant suitable for use on live tissues What are the advantages of using hand soaps? - Mechanical degerming Why is sterilization particularly important for hospitals? - The spread of bacteria in hospitals can be detrimental with no sterilization What makes Bacillus and Clostridium difficult to control? - They both produce endospores and endospores are very hard to kill What are critical, semicritical, and noncritical instruments? Examples? - Critical Items - penetrate tissues, ex. Scalpel, Needle Semicritical Items - contact unbroken skin, ex. Endoscope Noncritical Items - contact unbroken skin, ex. Stethoscope How does heat kill microorganisms? - It denatures proteins Conditions for dry heat sterilization? - Flaming loop or an oven at 170◦C for 3-4 hours (sterilizes) Conditions for moist heat sterilization? Effectiveness? - Boiling at 100◦C for 10mins (does not kill endospores), autoclave uses pressure to increase the boiling temp of H2O, 121◦C @ 15psi for 15mins sterilizes What is an autoclave? How does it work? - Autoclave uses pressure to increase the boiling temp of H2O, 121◦C @ 15psi for 15mins sterilizes What is pasteurization? Examples? - Rapid heating process, 72◦C for 15 seconds, does not sterilize Ex. Milk, OJ, beer, fruit juice, creamers How does membrane filtration work? Pore size? - Pour liquid through filter with very small pores (smaller than 0.4 micrometers) the bacteria is caught in the filter How does irradiation work? Wavelengths? - Wavelengths of electromagnetic energy, 254 nanometers works best to denature bacterial protein DNA What are alcohols, aldehydes, biguanides, ethylene oxide, halogens, peroxide, and phenolics? - Alcohol - antiseptic, cheap, best diluted with water, alcohol is usually 50- 90% Aldehydes - example is formaldehyde which is a carcinogen Biguanides - antiseptic, example is chlorhexidine (Listerine) Ethylene Oxide - pressurized gas, used to sterilize linens and pillows, explosive and carcinogen Halogens - Fluoride is most effective but also the most toxic, it is in
toothpaste and drinking water, Chlorine used to sanitize pools, Bromine used in hot tubs because of the high temperatures, and Iodine least effective but safest and is an antiseptic Peroxides - example is hydrogen peroxide (H2O2), antiseptic, toxic to bacteria, must be used in high quantities Phenolics - carbolic acid (carcinogen), example is triclosan and hexachlorophene (normally in hand soaps) How do salting, pickling, sugaring, and drying work? - They either slow down the generation time or help to kill bacteria
