Microbiology Final

Elle Ashe
Flashcards by Elle Ashe, updated more than 1 year ago
Elle Ashe
Created by Elle Ashe almost 7 years ago


Flashcards on Microbiology Final, created by Elle Ashe on 05/05/2014.

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Question Answer
Robert Hooke . First person that came up with a way to magnify things.
Anton Van Leeuwenhoek He is the first person to see live microbes. -He refused to share his microscope lenses and they had to wait until he died – he was 90.
Francisco Redi, MD He decides to test the idea that maggots arise from rotting meat. Takes 3 jars and places a piece of rotting meat in each. One jar is open, one is closed and one jar is covered with netting/gauze. If spontaneous generation is true then a
Pasteur’s Experiment Made swan-necked flasks because he wanted to be sure that air could get in, but anything from the air would settle in the curved area. He put broth in the flasks that was similar to beef or chicken broth. Once the broth is inside, he boils the broth to kill all microbes. Meaning the broth is actually sterile. He then went to place in incubator, but the incubator was full. So, he placed then in an empty space under the staircase. He checked the flasks daily for 18 months and nothing grew. The experiment is not that different then Redi’s experiment. He then tilted one flask so the broth filled the swan neck. Within hours microbes started growing. He then publishes a paper about the experiment and states that spontaneous generation is false. People accept (this time) that spontaneous generation is false.
Semmelwies a test to see what would happen if the MD’s washed their hands after the cadavers before attending to patients and wash the scalpels, too. The idea is not accepted well by the MD’s. He made a solution to wash with. After implemented, the death rates on the MD side decreased by 2/3.
John Snow There is a massive outbreak of deadly diarrhea in London. It occurred in a concentrated area. He marks where each person with it comes from. He notices that there is a concentration near Broad St. Discovered the water in that area was contaminated. Had the water co shut off the water and the outbreak ended.
Jenner MD . He took fluid from a lesion on a milkmaid’s arm and injected it into a boy. He then injected him with small pox. The boy lived. He continued the experiment on many more kids. In 1798 he published a pamphlet about what he did. By 1801 100K people just in England had been vaccinated.
Pasteur: Germ theory of disease Hypothesis: In good wine the yeast would ferment the grape juice to produce alcohol. In the sour wine he thought that bacteria were able to enter and ferment the grape juice and produce acid. Take grape juice and heat it to kill the yeast and the bacteria then, add yeast back. If you do that, there shouldn’t be an issue. **He writes a paper about the experiments and the results, but at the end he asks if bacteria can sour wine, can it sour people i.e. make people sick, cause human disease. **5 years later he develops the Germ Theory of Disease. There are microbes that are the cause of infectious disease. **He develops a chicken cholera vaccine, a sheep anthrax vaccine and a human rabies vaccine.
Lister Antisepsis. Surgeon that specializes in amputation. 50% of patients die, but he does not think it’s from surgery, it is from something else. He reads Pasteur’s spontaneous generation paper with the swan-necked flasks. He decides to use Phenol on the wounds and dressings of his patients. Deaths decrease by 2/3. to find a less toxic and less caustic option. Uses Boric Acid. Basically, he invents antiseptics.
Robert Koch as Koch’s Postulates. 1. Same microbe must be found in every case of the disease. 2. Have to isolate the microbe then grow it in pure culture (only that microbe is growing) in the lab. 3. Then, have to inoculate a healthy host with the pure culture and it must get the identical disease. 4. Have to re-isolate the microbe from the experimental host and compare it to his pure culture that he put into the sheep and they have to be identical i.e. Prove nothing changed along the way. **Koch’s Postulates verified what we now know to be the Germ Theory of Disease. Use the Postulates to determine which microbe causes an infectious disease.
Florence Nightingale Set the standards of hygiene for patient care. Hospitals weren’t cleaned, bed sheets not changed/washed, clothes not washed. Food provided by family, not hospital. She instituted changes and kept statistics on it.
Paul Ehrlich Can I make a chemical that will kill the microbe, but not the person? He called it a Magic Bullet.
Compound (light) microscope uses light to help view 1000x total max magnification Immersion oil to increase resolution View Bacteria View live organisms
Electron Microscope A. Scanning Electron Microscope 1) Great for external structures 2) Max magnification 650,000x B. Transmission Electron Microscope 1) Great for internal structures (need slices) 2) Generally about 100,000x magnification
Simple Stain use one positively charged dye on the smear.
Differential Stain use two positively charged dyes. The first dye is the primary stain and the second positively charged dye is called the secondary stain or the counter stain. Will be able to see size, shape, arrangement AND learn something else.
Gram Stain Differential stain. Gram positive bacteria will remain purple Gram negative bacteria will retain the pink/red color Can see size, shape, arrangement and learn if your bacteria is gram + with a thick wall or gram – with a thin wall. *Gram stain actually divides bacteria into two groups, gram+ and gram-. *If you could only do one stain for the rest of your career, this is the one to do. It is the most important stain in microbiology. * If you do a gram stain and don’t see anything, then it is NOT a bacteria.
Acid-fast Stain use two positively charged dyes to stain two types of bacteria – mycobacterium that cause diseases like tuberculosis, leprosy and Nocardia which causes skin and lung infections. *Can see size, shape, arrangement, and learn whether or not the bacteria has a waxy wall or not. The Mycobacteria and nocardia will remain pink. The non-acid fast bacteria will be blue.
Endospore stain Differential stain. use two positively charged dyes. There are two bacteria that produce endospores – bacillus and clostridium. *At the end the endospores will be green and regular bacteria will be pink/red *See size, shape, arrangement, and learn if there are endospores, bacteria or both. (endospore is not a bacteria)
Negative or Capsule stain want to see if the bacteria can actually produce a capsule. Can’t heat fix your smear because capsules are usually made of protein and heat denatures protein. This is the only stain in micro where they are alive and use a cover slip. *The bacteria in the background are purple and the capsule is a clear halo that surrounds the bacteria because the capsule is non-ionic. ie. it’s not positive or negative and cannot be stained with a charged dye.
Cocci Arrangements: Diplococci – Binary fission in one plane. Ie. Two bacteria stay together
Cocci Arrangements: Streptococci Binary fission in one plane and long chains of bacteria stay together.
Cocci Arrangements: Tetrad Binary fission in two planes and four bacteria stay together
Cocci Arrangements: Sarcinae Binary fission in three planes and eight bacteria stay together
Cocci Arrangements: Staphylococci Binary fission in random planes and get clusters of bacteria that stay together
Bacilli Arrangements (Rod): Diplobacilli Binary fission in one plane and two bacteria stay together
Bacilli Arrangements (Rod): Streptobacilli Binary fission in one plane and long chains of bacteria stay together
Bacilli Arrangements (Rod): Palisade Binary fission in one plane and two bacteria stay together in a “v” shape.
Linneas Taxonomy Kingdom, phylum, class, order, family, genus, species
Whittaker’s Taxonomy Anamalia, plantae, fungi, protista, monera
Woese's Taxonomy Developed it from sequencing rRNA. Archaea: kingdom monera Bacteria: kingdom monera Eukarya: kingdoms anamalia, Plantae, fungi, Protista
Characteristics of life need ability to grow (size and/or number), to reproduce, metabolize (take in nutrition and use it) and responsiveness
cell basics DNA – genetic material, Cytoplasm - open space on the inside of a cell, Cytosol – gel-like fluid, mostly water, that fills that open space, Ribosomes – site of protein synthesis (on average 2/3 weight of cell is made of protein), Cytoplasmic/plasma/cell membrane – boundary, controls traffic in and out of the cell
Bacterial Cell Walls: Functions 1. Provide structure 2. Maintain shape 3. Protection against osmotic forces.
Mycobacterium/Nocardia These two genera of bacteria have waxy walls. The wax is made up of Mycolic acid and their wall is made up of 60% Mycolic acid and 40% Peptidoglycan. Need to use Acid-fast stain
Endospores are resistant to: They are resistant to drying, heat, boiling, radiation, nuclear radiation, bleach, alcohol and peroxide.
Photoautotroph Energy source: light, Carbon source: CO2, Ex: Algae
Photoheterotroph Energy source: light, Carbon source: Organic compound, Ex: Photosynthetic bacteria
Lithoautotroph Energy source: Inorganic compound (hydrogen, hydrogen sulfide, ammonia, nitrogen), Carbon source: CO2, Ex: Archaea
heterotroph Energy source: Organic compound, Carbon source: Organic compound, Ex: Bacteria, fungi, protozoa (most microbes)
Chemical requirements for microbial growth Carbon, Hydrogen, Nitrogen, Oxygen (HONC), trace elements
Obligate Aerobe Need 20% oxygen that is in air. Can do aerobic energy production which means they are going to use oxygen as the final member of the electron transport chain.
Obligate anaerobe (does not like oxygen) - Oxygen will first inhibit growth ly kill. They use anaerobic energy production therefore use things like sulfate/nitrate as the final member of the electron transport chain.
Microaerophile prefer a lower concentration of oxygen than the 20% that is found in air. They still use oxygen as the final member of the electron transport chain.
Aerotolerant Anaerobes – tolerates oxygen, but doesn’t use it. They do anaerobic energy production and if they can’t do that, they do fermentation. Do anaerobic energy production in the presence of oxygen.
Facultative Anaerobe can do aerobic energy production and use oxygen as the final member of the electron energy chain. Can use anaerobic production if nitrate/sulfate is available. If none us available then can ferment
Capnophile Like CO2 to be 3 – 10% (as opposed to .03%)
Psychrophile cold loving temperature. Its optimum temperature is below 15C. These are not human pathogens (Human 37C) But they play a really big role in food spoilage.
Mesophile prefer a temp between 20 – 40C. Human is right in the middle therefore these are human pathogens.
Thermophile heat loving microbe with optimum temp of 45 – 80C. They play a big role in compost piles.
Hyperthermophile - extreme heat loving microbes. Optimum temps are above 80C. These are Archaea
Acidophile like a pH of less than 6.5, ex: Helicobactor pylori (ulcers), lactobacillus (vagina)
Neutrophile like pH 6.5 – 7.5. Most microbes are neutraphiles. Handle acid better than base so add ammonia to disinfectants so they work better.
Alkalinophiles like pH 7.5-11.5 Ex> Vibrio cholerae (cholera)
beaker with 50% is a hypertonic solution the solution has a higher solute concentration than the cell. Water go from the cell to the beaker and the cell will shrivel.
The beaker with 1% is a hypotonic solution it has a lower concentration of solute outside the cell than in the cell. So water will move from solution into the cell. The cell will burst.
The beaker with 10% is an isotonic solution a cell that has 10% salt it has an equal solute concentration in and out of the cell. No osmosis because already at equilibrium.
Defined Media (Synthetic Media) The exact chemical composition is known. It’s expensive so it is not very common.
Complex media the composition varies from batch to batch. Never exactly the same thing twice because it contains extracts (ex: meat, yeast). Not expensive and therefore very common. They are great for an unknown microbe because you don’t know what to feed it. (Ex. Tryptocase soy agar, Tryptocase soy broth)
Selective Media encourages the growth of one wanted microbes and inhibits the growth of unwanted microbes. Ex: Manitol salt agar – contains very high salt. Most microbes cannot tolerate so it selects for staphylococcus
Differential Media Makes it easier to distinguish different microbes. Ex: Blood agar. Differentiates based on what the microbes do to the blood in the agar.
Bacterial Growth Curve Phases 1. Lag Phase – There is no increase or decrease in the number of bacteria because they are adjusting to their new environment. They are finding out what nutrients are available and then they need to synthesize enzymes that are needed to use those nutrients. This can last from hours to days. 2. Log Phase – Big increase in the number of bacteria. Constantly dividing by binary fission. Most metabolically active (using nutrients and making ATP). This is when signs and symptoms become evident. This is when they are the most susceptible to antibiotics, disinfectants. 3. Stationary phase – no increase or decrease in the number of bacteria. Line is flat because growth equals death. This is because wastes are accumulating and starting to run out of nutrients, oxygen, pH change, etc. 4. Death Phase – decrease in the number of bacteria because they are overwhelmed by the waste products, the pH issue, lack of nutrients, etc.
Direct Methods of Measuring Microbial Growth Plate count – count colonies – 1 colony = 2 bacterium. Membrane Filtration – then count colonies on the filter. Grid Count – Count the number of microbes in each section of the grid Electronic Counter – place sample in the counter and it will count for you
Indirect Methods of Measuring Microbial Growth Turbidity or cloudiness., Dry weight – broth culture –remove water, Nutrient utilization, Waste accumulation
Metabolism The collection of controlled biochemical reaction that take place within the microbe; all the chemical changes occurring in a microbe during its growth and development.
Catabolism – breaks down larger molecules into small molecules. When catabolism occurs energy is released; microbes store some of this released energy in the bonds of ATP, thought much of this energy is lost as heat
Anabolism synthesis of larger molecules from smaller molecules. The energy for anabolism usually comes from ATP produced during catabolism.
Glycolysis Glucose is converted into smaller molecules and eventually into the 3 Carbon molecule, pyruvic acid. Overall, glycolysis breaks down glucose into two pyruvic acid molecules with a net gain of 2 ATP and 2NADH. NADH is an electron shuttle holding electrons and their energy and “shuttling” them to the electron transport chain. Glycolysis releases less than ¼ of the energy in glucose. Most of the energy remains stockpiled in the 2 pyruvic acid molecules
Bridge Before pyruvic acid can enter the Kreb’s cycle it must first be converted to acetyl-coA. The conversion generates 2 CO2 molecules and 2 NADH molecules.
Kreb’s Cycle – Takes place in the cytoplasm in prokaryotes and in the mitochondria in eukaryotes. The enzyme catalyzed biochemical reactions in the Kreb’s Cycle release the energy stored in the 2 acetyl –coA. It produces 4 CO2 molecules, 6 NADH molecules, 2 FADH2 molecules, and 2 ATP molecules.
ETC The energy extracted from the electron shuttles, NADH and FADH2, will be stored in the bonds of ATP. The electrons are passed down the chain and lose energy that is used to pump H+ across the membrane creating an H+ gradient. The H+ will flow back across the membrane via an ATP synthase. The force of the H+ concentration gradient will add the final phosphate group onto adenosine diphosphate to for ATP. FADH2 drops its electrons a little further down the ETC and results in a lower H+ concentration gradient. For each NADH the ETC produces 3 ATP and for each FADH2 it produces 2 ATP.
Fermentation – Involves glycolysis only. The pyruvic acid is transformed into other products like alcohol, lactic acid, acetic acid. Only produced 2 molecules of ATP
Active Transport movement of a substance across a membrane from an area of low concentration to an area of high concentration using a protein channel. Requires energy or ATP.
Diffusion Passive Transport - does not require ATP. – movement of a substance from an area of high concentration to an area of low concentration across a membrane
Facilitated Diffusion Passive Transport - does not require ATP. movement of a substance from an area of high concentration to an area of low concentration across a membrane using a protein transport channel.
Osmosis Passive Transport - does not require ATP. movement of water from an area of high water concentration to an area of low water concentration
Sterilization this means that you destroy all microbes. (endospores, bacteria, viruses, etc.) ie destroys all pathogens (disease causing organisms)
Disinfection use a chemical or physical agent (disinfectant) to inhibit or destroy microbes on inanimate objects or surfaces. Does not destroy all pathogens – not all eliminated. 1. Sanitization – reduce the number of pathogens on a surface to meet public health standards. 2. Antisepsis – Disinfection of tissue via a chemical (antiseptic) that is safe to use on living tissue. (Cleaning a wound) 3. Pasteurization – use heat to reduce the number of spoilage organisms and eliminate pathogens in foods
Microbes: Hardest to easiest to kill Bacterial Endospores, Mycobacteria, Cysts of Protozoa, Active state protozoa (trophozoites), Gram (-) bacteria, Fungi, Nonenveloped viruses, Gram (+) bacteria, Enveloped viruses
Resistance to Antibiotics/Antimicrobial Drugs Few microbes are naturally resistant. Acquire resistance through mutation, conjugation, transduction and transformation. Resistance means they might be able to produce an anzyme that breaks apart the antibiotic, there might be an alteration in the target, they might be able to block access to the target.
Antibiotics/Antimicrobial drugs. Inappropriate uses. Inappropriate for viral infections. 50% of scrips for sore throat are inappropriate. 30% of scrips for ear infections are inappropriate. 100% of scrips for colds are inappropriate. Must educate. Must take as directed. Reconsider large doses pre and post opp. Use narrow-spectrum. HAND WASHING.
Operon Section of DNA that contains a regulatory gene and one or more structural genes.
Lactose Operon Structural gene that if transcribed and translated produces enzymes needed to break apart lactose. INDUCIBLE. Genes are usually off but can be turned on when lactose is present and binds to the repressor protein.
Tryp Operon Structural genes that if transcribed and translated produce the amino acid tryptophan. REPRESSIBLE. Means it is always on and can be turned of if production of tryptophan is not needed. Ie. eating a big turkey dinner.
Mutation A permanent change in an organisms DNA. In bacteria there is 1 mutation per billion replications meaning 1 mutant per pinhead sized colony.
Point Mutation Most common type. Change in just one nucleotide of DNA.
Ames Test Used to determine if a chemical is a mutagen of salmonella.
Genetic Recombination An event where a donor bacterium donates DNA to a recipient bacterium and the recipient bacterium adds the donor DNA to its existing DNA to get a whole new combination.
Genetic recombination: Transformation Transfer and integration from a lysed donor bacterium to a recipient bacterium. Griffith experiment with mice and 2 strains of pneumonia. Can transfer things like antibiotic resistance, capsule production, enzyme production.
Competent Bacteria Only competent bacteria can take up DNA from its environment. Only 1% of bacteria are naturally competent. Can make bacteria artificially competent by growing in calcium chloride and exposing to extreme temperature changes.
Transduction Transfer of donor bacterium DNA to recipient bacterium via a bacteriophage.
Conjugation Transfer of DNA from a donor bacterium to a recipient bacterium via cell to cell contact using a pilus.
Conjugation and the F plasmid The gene for pili production is on the F plasmid. If a bacterium has the F plasmid it is considered F+ and F- if it doesn't. F+ do not conjugate with other F+. HFR when not a complete transfer and the recip remains F- because F plasmid not transferred.
Viruses Small obligate intracellular parasites. Can infect a wide range of hosts. Very specific about the host they infect.
Viral Components Nucleic acid:DNA/RNA, single or double stranded. -Capsid:protein coat. Protects nucleic acid. -Envelope:Only some animal viruses. Membrane that surrounds capsid acquired from host cell during replication. Sometimes has spikes which help with attachment.
Viral Morphology Helical: capsid is shaped like a spiral -Polyhedral(isohedral):Capsid is round -Complex:Not helical or polyhedral
Lytic Viral Replication Viruses go inside the host cell and use the host cell machinery for replication. 1.Attachment 2.Entry 3.Synthesis 4.Assembly 5.Release -25 minutes for whole process resulting in 100-200 new phage.
Lysogenic viral replication 1.Attachment 2.Entry 3.Insertion and Replication 4.Induction 5.Synthesis 6.Assembly 7.Release
Animal Viral Replication 1.Attachment (random collision) 2.Entry (direct penetration, membrane fusion, endocytosis) 3.Synthesis 4.Assembly 5.Release
Prions Proteinacious infectious particles. Made of only protein - no nucleic acids. Causes spongiform encephalitis. (mad cow disease, scrapie, chronic wasting syndrome, kuru, cj disease, fatal familial insomnia) No cure.
Virulence Factors Extracellular enzymes (coagulase, staphylokinase, leukociden, hyaluronidase). Toxins (exotoxins, endotoxins(LPS)). Antiphagocytic factors (capsule,, slime layer)
Fungi Eukaryotes. 30% of known species are pathogenic. Includes yeast and mold. Decomposers/recyclers. Produce medications. Produce enzymes.
Yeast Unicellular, non-filamentous. Oval shaped. Asexual and budding. Moist, creamy, white.
Mold Multicellular, filamentous (hyphae). Asexually via spores. Mycelium is mass of intertwined hyphae.
Anti fungal drug classes Polyenes: work by attaching to the sterol component. Causes cell to become porous and die. -Azoles: Stop fungal growth by preventing fungi from making an essential part of cell wall. -Echinocandins: Works by disrupting the wall that surrounds the fungus. Works on aspergillus.
Coccidiomycosis Valley fever. Southwest. Inhaled spores. Joint aches, rash.
Histoplasmosis Ohio, Missouri and Mississippi river valleys. Spores (birds/bats). 95% no signs or symptoms. (Dracula)
Cryptococcosis Bird droppings (pigeons). Inhale spores. Pneumonia-like illness. Bone pain, Skin lesions. 90% in lungs.
Reservoirs of Infectious Disease 1. Animal reservoirs. 2.Human carriers. 3.Non-living reservoirs.
Portals of Entry 1.Broken skin 2.Mucus membranes 3.Placenta 4.Parenteral route.
Pathogen "hangs on" with 1. Glycocalyx, slime layer, capsule 2.Fimbriae 3.Suction cups/hooks
Stages of Infectious Disease 1. Incubation 2.Prodromal 3.Illness 4.Decline 5.Convalescence **Contagious at every state
Modes of Transmission of Infectious Disease 1. Contact Transmission (Direct, Indirect via fomite, Droplet) 2.Vehicle (Airborne,Waterborne, Foodborne,Bodily Fluid) 3.Vector (Biological, Mechanical)
Common sites of nosocomial infections 32% - Urinary Tract, 22% Sugical site/wound, 15% lungs, 14% systemic
Needle stick: Hep B 6-30% transmission rate. There is a Hep B vaccine. Hep B virus gammaglobulins - 95% effective in preventing transmission.
Needle stick: Hep C 1.8% transmission rate. No vaccine. No other treatment to stop transmission. Have anti-viral medications.
Needle stick: HIV .3% transmission rate. No vaccine. No other treatment to stop transmission. HAART (highly active antiretroviral therapy)
Innate Immunity: First lines of defense Skin (multi-layered, sweat,sebum,demicidin, dendritic cells, normal flora, collagen) - Mucus membranes
Types of Leukocytes Basophils, Eosinophils, Neutrophils, Lymphocytes, Monocytes/Macrophages, Dendritic cells. (Never Let Monkeys Eat Bananas, Dude)
Innate Immunity: Second Line of Defense Phagocytosis, Extracellular killing, Complement, Interferons, Inflammation, Fever (PICKI Fever)
Steps in Phagocytosis 1.Chemotaxis 2.Adherance 3.Ingestion 4.Killing 5.Elimination (CAIKE)
Classes of Antibodies IgM: first produced, IgA: in tracts and fluids, blocks attachment. IgD: antigen receptor on B cells, IgG:most abundant, critical in secondary responses, IgE:Worms and allergies
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