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Terms in this set (100)
What are examples of how microorganisms help people?
Food, biotechnology using organisms to mine precious metals or for bioremediation, digestive tract of humans
What are examples of ways microorganisms harm humans
Act as pathogens that cause disease like AIDS, hepatitis C, West Nile and TB
Describe a prokaryotic cell
no true nucleus. Microscopic, unicellular organisms, lack nuclei and membrane bound organlles
Describe a eukaryotic cell
True nucleus. Unicellular (microscopic) and multicellular nucleus and membrane bound organelles. Tend to be bigger than prokaryotes.
Completely free of all life forms including spores and virus particles
Aimed at reducing microbes in a medical setting and preventing wound infections
Microbes that cause disease
older disease such as TB once thought to be under control are becoming a serious threat again
the accumulation of changes that occur in organisms as they adapt to to changes in their environment
live on or in the body of another organism called a host and damages the hose.
Acellular, parasitic particles composed of a nucleic acid and protein. NOT CELLS
They chop up DNA in specific ways. They can be harvested from the bacteria and be used in research labs to cut up DNA in controlled ways. This paved the way for genetic engineering and the treatment of disease.
Was a breakthrough in our ability to detect tiny amounts of DNA then amplify them into quantities sufficient for studying. It has provided new and powerful method for discovering new organisms and diagnosing infectious disease and for forensic work like
the accumlulations of bacteria and other microbes on surfaces. They are found on ship hulls, rocks, and are even relatively common in the human body like dental plaque. They are also a danger to the success of any foreign body implanted on the body.
Much RNA doesnt end up with a protein counterpart. They have critical roles in regulating what happens in the cell and has led ot new approaches to how diseases are treated for example they are important in bacteria infecting humans so they are a target for anytimicrobial therapy.
studied microbes in fermentation of alcoholic beverages using flasks with broth to disprove abiogenesis (spontaneous generation of life). Heating milk kills disease. Know what pasterurization means
studied objects using simple magnifying glass
manufactured simple microscopes (up to 300x). First to observe microbes
First to refute abiogeneis (flies from maneur). Disproves spontaneous generation
demonstrated presence of heat resistant forms of some microbes
Tyndall and Cohen
observed that mothers of home births had fewer infections than at hospitals
Correlated infections with physicians coming directly from autopsy room to maternity ward
Introduced aseptic techniques reducing microbes in medical setting to prevent infections (chemical and heat sterlization).
Contributed to theory that disease are caused by the growth of microbes in the body not by sin (disproved spontaneous generation) developed pasteurization, showed that microbes caused fermentation and spoilage, demonstrated Germ Theory of Disease, developed rabies vaccine
Contributed to theory that disease are caused by the growth of microbes in the body not by sin. Established Kochs postulate (experimental steps to verified germ theory).
Founders of cell theory, discover Schwann cells in PNS, discovery of pepsin, invention of term metabolism
Schleiden & Schwann
German bacteriologist who is credited with inventing the Petri dish
importance of aseptic techniques and hand washing by physicians attending patients
Holmes and Semmelweis
worked out 3D structure of DNA based on work by Rosalind Franklin
Watson and Crick
American biochemist worked with research involving nucleic acids and DNA hybridization
AIDS research famous for pioneering use of protease inhibitors with treating HIV-infected patients
Mono and disaccharide, glucose and fructose. Sugars involved in metabolic reactions. Important in product of starch, cell wall and food storage
Triglycerides, phospolipis, waxes and steroids. Ringed structure or fatty acid +glycerol. Fats oils, membrane components, cholesterol. Major component of cell membranes and storage
Amino acid chains. Enzymes; part of cell membrane, cell wall, ribosomes, antibodies. Serve as structural components and perform metabolic reaction.
Pentose sugar + phosphate+nitrogenous base. DNA and RNA. Chromosomes; genetic material of viruses. Ribosomes; mRNA, tRNA, small RNAs. Mediate inheritance and facilitate expression of genetic traits
What are the 3 primary concerns of taxonomy
naming, classifying and identifying
What are the taxonomic categories from top to bottom
domain, kingdom, phylum, class, order, family, genus and species
What are the 3 domains
Eukary which includes animals plants fungi etc., bacteria which includes cyanobacteria, or archaea which includes halophiles and thermophiles. Archea and bacteria lack a nucleus whereas all eukaryotes are placed in the domain Eukarya.
multicellular, autotrophic eukaryotes which conduct photosynthesis. Includes herbs, shrubs, trees, aquatic plants. Etc.
Single celled organisms like protozoa and algea
Considered the most primitive group of organism and include various types of bacteria and blue green algae. They are the most abundant of organisms due to their versatility of habitat. They are unicellular microorganisms known as bacteria and are prokaryotes.
heterotrophic organisms that obtain nutrients by absorption. They are non-vascular and reproduce by spores. Include mycorrhizae, and lichens. They are important for recycling, food and medicines.
State how the Carl Woese and George Fox classification system differs from that of Whittaker.
1. Based on conserved small subunit ribosomal RNA sequences.
2. Analysis of sequences revealed a separate group from the acrhaebacteria called Archaea
3. New system proposed based on domains- bacteria, archaea, eukarya
4. Whittakers tree was based on structural similarities and differences such as cellular organization and the way organisms obtained nutrition.
5. Carly Woese and Geroge Fox proposed separate taxonmomic unit for the archaebacteria which they named Archaea. Based on this information they proposed an entirely new system that assigned all organisms to one of 3 major taxonomic domains, each being a different type of cell.
What are the 5 major techniques (5 I's) used by microbiologists to culture and characterize organsims
The implantation of microorganisms into or onto culture media. Specimens include blood, cerebrospinal fluid, sputum, urine, feces, diseased tissue.
media containing inoculants are placed in temp controlled chambers. During incubation, microbes grow and multiply producing visible growth in the media.
Based on the concept that if an individual cell is separated from other cells on a nutrient surface, it will form a colony
Microbes can be identified through microscopic appearance, characterization of cellular metabolism, determination of products given off during growth, presence of enzymes, and mechanism for deriving energy. Major purpose of Five I's is to determine type of microbe usually to the level of species/
The propagation of microorganism with various media
A nutrient used to grow microorganisms outside their natural habitat
The implantation of microorganisms into or onto culture media
Container of medium that grows only a single known species or type of microorganisms. Most frequently used for laboratory study because it allows the systematic examination and control of one microorganism by itself.
a container that holds two or more identified easily differentiated species of microorganisms.
A once pure or mixed culture but has been contaminated with unwanted microbes of uncertain identity.
- water-based solutions that do not solidify at temps above freezing and flow freely when container is tilted. Growth occurs throughout container and can present a dispersed, cloudy, or particulate appearance.
has more body than liquid media but less than solid. Does not flow freely and have a soft clotlike consistence at room temp. Used to determine the motility of bacteria and to localize a reaction at a specific site.
Solid enough to remain in place when they are tilted or inverted but can be converted to liquid via heat and resoldifiedc.
Solid (can be converted to a liquid)
Solid enough to remain in place when they are tilted or inverted but cannot be converted to liquid
Solid cannot be liquefied
Contains at least one ingredient that is not chemically definable that extracts of animals plants or yeasts. A rich mixture of nutrients for microbes that complex nutritional needs.
Media whose compositions are precisely chemically defined
contains complex organic substances such as blood, serum, hemoglobin or special growth factors.
-Contains nothing more than a few essential compounds such as salts and amino acids. Designed to grow as broad a spectrum of microbes as possible-Selective- contains one or more agents that inhibit the growth of certain microbes but not others. Important in the primary isolation of a specific type of micorganisms from samples containing dozens of species
General purpose media
Allow multiple types of microrganisms to grow but are designed to display differences among those microorganisms
Important for growing anaerobic bacteria
used to test the effectiveness of antimicrobial drugs and by drug manufactures to assess the effect of disinfectants, antiseptics, cosmetics, and preservatives on the growth of micorganims.
Used by industrial and environmental microbiologists to count the numbers of organisms in milk, water, food, soil, and other samples.
A small droplet of culture or sample is spread over the surface of the medium with an inoculating loop in a pattern that gradually thins out the sample and separates the cells spatially over several sections of the plate. Goal is to allow a single cell to grow into an isolated colony
- The sample is inoculated serially into a series of cooled but still liquid agar tubes so as to dilute the number of cells in each successive tube. They are then plated out into sterile petri dishes and are allowed to solidify. Result is that number of cells per volume in the later
A small volume of liquid, diluted sample is pipetted onto the surface of the medium and spread around evenly by a sterile spreading tool. Cells are pushed onto separate areas on the surface so that they can form individual colonies.
occurs in 2 phases. The first lens in this system (closest to specimen) is the objective lens and second is the ocular lens. Objective forms initial image of specimen (real which is hen projected through the ocular lens which forms the second image (virtual image). Eye receives virtual image.
Bending of light
Revolving power. It is the capacity of an optical system to distinguish or separate 2 adjacent objects or points from one another. It is the factor that most limits clarity of microscopes image
necessary when working with the 100X objective. Without it some of the peripheral light that passes through the specimen is scattered into the air or onto the glass slide which decreases resolution.
Measured by refractive index which refers to the degree of bending that light undergoes as it passes from one medium to another. The higher the difference the more bending of light.
used for magnifying specimen
Light passes through the condenser, forms a solid beam that is focused on specimen. Light leaving specimen enters objective lens is refracted so that an enlarged primary image, real image is formed. Real image is projected through ocular and virtual image is formed. Virtual image is magnified that is received by retina.
How microscope works
Discuss how to calculate the total power of magnification
Take the power of the objective multiplied by the power of the ocular
Most widely used type of light microscope. Forms its image when light is transmitted through the specimen
Used to visualize living cells that would be distorted by drying or heat or that cannot be stained with the usual methods.
The amount internal detail visible by this method is greater than by either bright field or dark field methods. The phase contrast microscopes is by most useful for observing intracellular structures such as bacterial endospores, grandules, and organelles, as well as locomotor structures of eukaryotic cells such as cillia
Specially modified compound microscope furnished with UV radiation source and a filter that protects viewers eyes. Most useful in diagnosing infections caused by specific bacteria, protozoans and viruses.
Differential interference microscopy
Produce extremely well-defined images that are vividly colored and appear 3D
method of choice for viewing the detailed structure of cells and viruses. Speciment must be sectioned into extremely thin slices and stained with metals that will increase image contrast.
Transmission Electron Microscope
Provides dramatic and realistic images. Creates 3D view of all kinds of objects. To transmit image it bombards the surgace of a whole metal coated specimen with electrons while scanning back and forth over it. Show of electrons deflected from the surface is picked up with great fidelity by a sophisticated detector.
Scanning Electron Microscope
How does an electron microscope differ from a light microscope.
Electron microscopes use beams and showers of electrons as opposed to ultraviolet rays as source of illumination.
State the use of the hanging drop method in microbiology
Live samples of microorganisms are placed in wet mounts or in hanging drop mounts so that they can be observed as near to their natural state as possible. The cells are suspended in a suitable fluid that temporarily maintains viability and provides space and a medium for locomotion. The hanging drop mount preparation is made with a special concave deression slide, a Vaseline adhesive or sealant, and a coverslip from which a tiny drop of sample is suspended. It provides ture assesement of size,shape, arrangement, color and motility of cells (short term).
colored by dye, background is not stained, ex. Crystal violet, methylene blue
Require only a single dye in an uncomplicated procedure. Crystal violet
Uses 2 different colored dyes, a primary and a counterstain to distinguish between cell types and parts
cell is clear and colorless and background is stained dark gray or black. Examples are nigrosine/india ink.
Different results in the Gram stain are due to differences in the structure of the cell wall and how it reacts to the series of reagents applied to the cells. Bacteria that stain positive are purple, that that stain red are negative.
Important diagnostic stain that differentiates acid fast bacteria (pink) from non (blu) Originated as a method to detect mycobacterium TB in speciments
Acid fast stain
Similar to acid fast method in that dye is forced by heat into resistant bodies called endospores. It is designed to extinguish between endospores and the cells that they come from. Important are the gram-positive, endospore forming members of the genus bacillus (cause of anthrax) and clostridium (cause of botulism and tetanus)
method of observing the microbial capsule, an unstructured protective layer surrounding the cells of some bacteria and fungi. Can be useful in identifying bacteria that causes fungal meningitis.
A method of revealing flagella, the tiny slender filaments used by bacteria for locomotion. Presences, number, and arrangement on a cell are useful for identification of bacteria
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