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Microbiology

Exam 1

QuestionAnswer
What defines a microorganism? Living things that can't be seen by the naked eye.
What are some basic examples of microorganisms? Why are they difficult/easy to study? Bacteria, Archae, Protozoa, Fungi, Helminths and Viruses Easy because the reproduce so rapidly and we can quickly grow large populations in the lab:Difficult because they can't be seen by the naked eye. We rely on indirect methods for analyzing them.
What are the 3 domains? Describe briefly. Where are microbes found? Bacteria, Archae, Eukarya. The three domains stemed fromthe last common ancestor. All biological life falls into these three categories. Microbes are found in the earth's crust, the polar ice caps, oceans, and inside the bodies of plants and animals.
What are some uses of microorganisms?(Food, bio-remediation, useful products)Be able to give examples bread production, cheese production, alcohol production, treatment of wounds and lesions(recombinant dna tech), cleaning up human created contamination(bio-remediation)
What are the past, present, and future triumphs of medical microbiology? (emerging/re-emerging diseases) Vaccinations Aids, Hepatitis C, TB, West Nile virus(re-emerging/emerging diseases) from deforestation and industrialization, antibiotic overuse making microbes resistant to drugs, herd immunity when a large population becomes immune to an infection through the use of
What is spontaneous generation? Who disproved it? Who tried to prove it true? What did they do in their experiments? How were the experiments set up? Spontaneous generation is the theory that living things rose from nonliving things. leeuwenhoek,redi,spallanzani, and pasteur tried to disprove it and needhamtried to prove it.
What is the germ theory of disease? theory that microorganisms can cause disease
The microbial world/cellular organiizations= 3 domains Eukaryotic cells contains organelles encased by membranes that perform specific functions. Bacteria and Archae are prokaryotic and don't have organelles, have complex structures and can engage in every activity that eukaryotic cells can
What are some characteristics of bacteria? all bacteria have cell membrane, cytoplasm, cytoskeleton, ribosome, one of few chromosomes
Archae- Conditions for survival? (Salt, high temp, low pH) low temperature archae are psychrophilic, high temperature loving are hyperthermophilic, extremophiles can live in high salt concentrations
Eukarya- What groups are found here/ animals, fungi, plants
What are viruses and how do they affect us? non living, non cellular having microbes that can infect any living cell and cause disease.
Nomenclature-binomial method. How does it work? the assignment of scientific names to the various taxonimic categories and individual organisms. The scientific name is always a combination of the genus name followed by the species name. genus is capitalized, species is lowercase. both underlined
What is the Woese- Fox system of taxonomy? what is it based upon? system that assigned all organisms into the 3 domains. based on conserved small subunit ribosomal RNA sequences (ssu rRNA)
What is Spontaneous Generation? Spontaneous generation was a theory that living things came from nonliving things.
Know the history of who did what(Hooke) Invented the microscope making it easier to study microorganisms because they were too small for the naked eye to see.
Know the history of who did what(Redi) disproved spontaneous generation by putting fresh meat in 2 separate jars, one sealed off with cheese cloth and the other was left open. The open jar filled with maggots on the meat proving that maggots came from fly eggs.
Know the history of who did what(Needham) tried to prove spontaneous generation by putting gravy in 2 separate flasks, melted the top of one and left the other open. he heated both flasks but not enough to kill the microbes thus creating false results that life rose from nonliving things
Know the history of who did what(Spallanzani) disproved spontaneous generation by boiling two separate bottles of broth, sealing one and leaving the other open. The sealed bottle had no sign of life while the other had microbes floating inside.
Know the history of who did what(Pasteur) disproved spontaneous generation by putting broth in 2 separate flasks with long swan neck openings. The openings were free to air but curved so that dust particles could become trapped. He then heated the flasks and incubated them. The necks stopped micr
Know the history of who did what(Koch) four criteria to help identify the causative agent of a disease.
Know the history of who did what(Leeuwenhoek) contributed to microbiology by discovering protozoa and improving the microscope through lens grinding
What dimensions do we use when looking at microorganisms? 4x(scanning resolution), 10x(low power), 40x(high power), 100x (oil immersion)
How do we get good resolution when looking at a specimen in the microscope? by adjusting the magnification and regulating the light
Who is christian gram and what is his contribution to microbiology? Danish bacteriologist who contributed to microbiology through the development of the gram stain for bacteria classification and identification.
What is a stain? A reagent or dye that is used for staining( any procedure that applies colored dyes to a specimen)
what are the 2 types of dyes that we use? basic(cationic) which have a positive charge or acidic(anionic) which have a negative charge. cells with negative charge attract basic dyes. Acidics are good for staining the backgrounds. basic dye stains cell
Simple vs differential Simple uses one due while differential uses 2. Differential are more complex. Simple stains all appear the same color
Why is differential so important to the field of microbiology? Because it is used to help identify bacterial species and guide treatment.
How do we perform a gram stain? What is the purpose of each step? 1.Crystal violet is added to cells staining them all the same color. 2.mordant grams iodine is added which is a stabilizer 3.alcohol is added dissolving away the outer membrane of the gram -4applying safranin demonstrates the presence of gram-
Different microscopes (darkfield) Visualize living cells. The background is dark but the specimen is bright
Fluorescent UV source. Diagnosing infections and pinpointing cellular structures
Brightfield/compound For every day use to look at cells. Light is transmitted thru the specimen, live unstained materiail, preserved stained material
Scanning electron Electromagnetic source detailed 3 dimensional view of all kinds of objects
Transmission electron For cells and viruses. Specimen have to be sectioned into extremely thin slices
Acid fast stain Distinguish acid fast (pink) bacteria from non acid fast (blue) detect mycobacterium TB using the carbol fuchsin dye
Endospore Distinguish between endospores and the cells that they came from (vegetative) detecting anthrax, botulism, and tetanus. Malachite green dye
Capsular Known as a special stain, used to observe the microbial capsule . Repels most stains, often negatively stained with India ink or special positive stains. Cryptococcus -fungal meningitis in aids patients
How are bacteria and archae different from eukaryotes The way their DNA is packaged, their internal structure, their cell wall
What do all bacteria cells have? Cell membrane, cytoplasm, cytoskeleton, ribosome, one of few chromosomes
Morphology (cocci) Spherical or round shape
Morphology(bacilli) Rod shape, cylyndrical, spindle shape, blocky, round ended
Morphology(spiral) Slightly curled spiral shape
Cell arrangements(diplococcus) Two cells
Cell arrangements (stretocococcus) Variable # of cocci in chain
Cell arrangements(tetrads) Packets of 4
Cell arrangements(sarcina) Packets of 8-64
Cell arrangements(staphylococcus) Cluster (grapes)
External structure (flagellum) Motility
Pillus Long rigid tubular structure made of special protein. Motility, transfer of DNA , attachment
Fimbriae Attachment-small bristlelike, lead to biofilms
Nanotubes Thin long tubular extensions of the cytoplasmic membrane used to transfer amino acids or electrons
Glycocalyx capsule or slime layer (composed of sugar)Slime layer is loose shield. Capsule fits more tight denser and thicker
What is the cell envelope? External covering that lies outside the cytoplasm composed of 2-3 layers: cell wall, cytoplasmic membrane, outer membrane(gram-)
Gram+ cell wall Thick sheath of peptidoglycan, contains acidic polysaccharides including teichoic acid and lipoteichoic acid which functions I'm cell maintenance, enlargement and acidic charge.
Gram- cell wall Thin sheath of peptidoglycan containing lipoprotein, lipopolysacchirides, phospholipids , porin proteins
Targeting peptidoglycan Penicillin and cephalosporins are effective bc they target peptide crosslinks in the peptidoglycan causing it to disintegrate
Mycobacterium Does not contain cell wall thus making it resistant to drugs and dyes so the use of an acid fast dye bc it is composed of mycolic acid
Internal structures (chromosomes) Bacteria DNA found here
Plasmid (nonessential DNA) Protective traits such as resisting drusgs
Ribosome Sites of protein synthesis
Inclusions Storage for environmental conditions like food
Cytoskeleton Cell shape and stability
Endospores Dormant bodies produced by bacteria when environmental conditions become challenging
What are the members of the eukaryotic world Protozoa, fungi, heminths
What is a glycocalyx and why is it important An outermost layer that comes in contact with the environment. Contributes to protection, adherence and reception of signals from other cells
Which eukaryotes have a cell wall and which do not Protozoa and helminths do not have cell walls but fungi do
What is a cell wall made of? The inner layer of polysaccharides is composed of chitin or cellulose, the outer layer is mixed glycans
How does it differ from bacteria? They are different I'm chemical composition. Rigid, provide structural support and shape.
How does cell wall vary in eukaryotes? They have 2 layers, an inner layer of polysaccharides that can be composed of cellulose or chitin and an outer layer of mixed glycans
What is the nucleus? Why important? It is a compact sphere and the most prominent organelle. It contains the genetic material, the DNA, which is responsible controlling and directing all activities of the cell.
What groups are found within the fungi and what forms do they take Yeasts, molds, puffballs, and mushrooms with the cell types of hyphae and yeasts
What are some important characteristics of fungi Isomorphic- can take either form of a mold to yeast in response to growth conditions such as temperature.
What is a fungus made of? Hyphae that that make up a tangled web of mycelium
Where are fungi found? In any habitat from sea water to fresh water, in soil, in plants and animals and human skin
What are hyphae Long threadlike cells found in the bodies of fungi of the filamentous type
What are mycelia Mass or group of hyphae that make up the body or colony of mold
Reproduction -production of spore Spores are dispersed widely throughout the environment by air, water and living things. Asexual spores are the products of mitotic division and sexual spores are product of meiosis the fusing of 2 parental nuclei.
Reproduction -propagating Simple outward growth of an existing hyphae
Reproduction -fragmentation Separate piece of mycelium can generate a whole new colony
How do fungi affect us economically (negative) Damages field plants such as corn and grain. Reduce crop production and cause disease in domestic animals
How do fungi affect us economically (positive) The aid in production of antibiotics, alcohol, organic acids and vitamins. Decomposing organic matter and and returning essential minerals to the soil
How do fungi affect humans They cause mycoses in humans through hospital acquired, opportunisticly from immunocompromised individual, and via the environment
What is a lichen? What are mycorrhizae? Lichens are the first sign of life after a natural disaster occurs. Mycorrhizae are structures that help increase the ability of roots to absorb water and nutrients
What defines protozoa Single celled microscopic animal, reproduce by asexual methods of mitotic cell division
How do we characterize them? Cytoplasm is divided into 2 layers. Ectoplasm responsible for locomotion,feeding, and protection. Cytoplasm responsible for housing the nucleus, mitochondria, food and contractile vacuoles.
What are some characteristics Unicellular, no cell wall, freeliving inhabitants of water and soil
What are helminths? How do they affect us? Tapeworms and flukes are flatworms. Nematodes are round worms. They affect humans through infection by ingestion of through penetration of tissue by the worm. Contaminated good soil or water or other infected animals
How do they reproduce? A complete cycle includes the fertilized egg, larval, and adult cycle. Reproduce sexually. I'm trematodes the sexes are hermaphoditic. Nematodes the sexes are separate.
What is the goal? Completing the entire life cycle.
Intermediate host? Host in which the larval develops
Definitive host? Host in which adult mating occurs
Created by: jduma511