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147 Cards in this Set
- Front
- Back
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Define microbiology
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specialized area of biology that involves things that are too small to be seen without magnification.
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Are all prokaryotes microorganisms?
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Yes
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Are all eukaryotes microorganisms?
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No, only some are (such as algae, protozoa, fungi and helminths)
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What are infectious agents? Are they living orgnanisms?
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Viruses, viroids and prions. Not living
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What is type of genetic material does a virus have? What type of disease does it cause?
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Can have DNA or RNA, surrounded by a protein coat. Causes influenza and heptitis
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What distinguishes a viroid? What does a viroid infect?
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A Viroid has only RNA, with no protein coat. Viroids infect only plants.
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What is a prion? Give an example of the disease a prion causes
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Infectious protein, with no protein coat. Causes Mad Cow Disease
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What was Robert Hooke responsible for?
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Inventing the first microscope, which was really just a magnifying lens.
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What was Anthony Van Leeuwenhoek responsible for?
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Improved Hooke's microscope; given credit for the first microscope; identified "animacules," which were protozoa.
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Where did the idea of invisible living creatures come from?
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Lucretius (Roman) and Aristotle (Greek) from changes that occurred with food; Aristotle believe air could lead to life.
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What is spontaneous generation?
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Life comes from non-living sources or from decomposing material, ie. frogs from nile river flooded mud
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What is biogenesis?
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Life comes from pre-existing life of same kind.
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Who was the first to question spontaneous generation and what did he do?
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Francesco Redi; performed experiment with meat - one left open (covered in maggots and then flies), other exposed to air but covered with guaze (no maggots or flies); proved flies came from flies, but source of microorganisms
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Who disproved spontaneous generation?
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Louis Pasteur; nutrient broth placed in swan-necked flasks, which allowed air to enter but not dust. No microbial growth for years until dust allowed access to broth.
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define Sterile
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Free of microbial growth
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What is the scientific method?
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1. observe something
2. formulate a question 3. develop a hypothesis 4. test the hypothesis 5. repeat 6. draw a conclusion |
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What is the germ theory of disease?
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microorganisms can invade other organisms and cause disease.
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What are Koch's postulates? What microorganism did he study?
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To establish the cause of a specific infectious disease
1. determine organism is always present in diseased animal 2. grow in pure culture 3. inoculate healthy animal and observe disease 4. re-isolate from diseased animal Koch studied anthrax |
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Who developed the first vaccine? For?
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Jenner for smallpox
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Who developed antiseptic surgery?
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Lister
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Who discovered the first antibiotic? What was it?
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Fleming; penicillin
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What did John Tyndall discover?
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that some microorganisms can be killed by heat and others are heat-resistant.
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What is Ferdinand Cohn known for?
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He identified heat-resistant bacterial endospores.
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How are microbes useful in nutrient recycling and decomposition?
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Nitrogen fixation (conversion of N2 to NH3 that plants can use) and cellulose breakdown
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How are microbes useful in bioremediation?
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toxic products and oil spills; waste water treatment.
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How are microbes useful in food microbiology?
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production of wine, beer, bread and dairy products
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How are microbes useful in industrial microbiology?
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antibiotics, cellulose for stereo headsets; amino acids; ethanol; baby diapers; medical glue
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How are microbes useful in genetic engineering?
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making human proteins, such as insulin
agriculture - pest resistant crops |
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How are microbes useful in immunology?
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vaccines using whole or parts of viruses to make vaccines against bacteria and viruses that cause disease.
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What is normal flora and how is it important?
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organisms that live in our body to keep us health; they use our nutrients to survive; kill off bad stuff with disease-causing microbes.
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Who was Carolus Linnaeus and what did he do?
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Developed taxonomy of life (binomial system of nomenclature) classification system based on organism characteristics
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Key characteristics of Eukaryotes
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single or multi-cellular
membrane-bound organelles nucleus cytoskeleton |
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Key characteristics of prokaryotes
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only single cell
no mitochondria or nucleus nucleoid with DNA some have cytoskeletons bacteria have peptidoglycan |
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What is the correct way to write a scientific name?
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italicize or underline if handwritten
Capitalize first letter of genus species all lower case Can use the first letter of the genus with a period and the full species |
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How was Leewenhoek's microscope different from the modern microscope?
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L's had:
only one lens no artificial light source both have: handle or place to hold focusing screw specimen holder/stage |
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How many lens does the modern microscope have? Which are not used for magnification? What is it's purpose?
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Typically three: occular lens, objective lens, condenser; the condenser is not used for magnification; it is used for taking light from the bottom and focusing it on to the specimen.
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Define magnification
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enlargement of the image of the specimen
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define resolution
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ability to distiguish between small objects that are close together
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define contrast; what are two ways to provide contrast to a specimen?
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the number of visible shades in a specimen; staining the specimen; using a contrast microscope
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What is refraction and how does it affect resolution?
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bending of light as it passes through a medium; smaller space equates to loss of light rays into objective lens
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why is oil immersion oil important to use with the 100x objective lens?
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Oil has a similar refractive index to glass, which allows most of the light rays to be captured by the objective lens; if no oil is used, the space between the specimen and the objective is small and most of the light rays escape, leaving a blurry image
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Describe the three visible light microscopes
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Bright field microscope - light is transmitted through the specimen; stained dead and living unstained specimens
Phase contrast microscope -- uses differences in refractive index within specimen and transforms into different light intensities; used most for living unstained specimens (appears dark against light background) Dark Field microscope - illuminates specimen; object appears bright against dark background; best for living unstained specimens |
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How is electron microscopy different from light microscopy?
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light is replaced by a beam of electrons from an electron gun. Specimen is viewed in a vacuum; condenser is a magnet that focuses the beam on the sample
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Describe the TEM
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TEM is the Transmission Electron Microscope. Electrons pass through the specimen so you can see inside the cell. allows you to observe fine cell structure. Have to prepare a very thin section of the specimen (1 micrometer)
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Describe the SEM
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SEM is the Scanning Electron Microscope. Beams of electrons scan over the surface of the specimen to observe surface details. See the entire cell vs. a thin cross section
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What are the two types of Scanning Probing Microscopes? Give a general description of how they work
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Scanning Tunneling Microscope and Atomic Force Microscope. Work like a record player type arm with a needle that has the width of an atom to provide the highest resolution and most magnification.
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Describe the STM and give an example of what it is used for.
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Scanning Tunneling Microscope scans over the surface of the specimen. Use for first close up view of DNA and for detecting defects in computer chips.
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Describe the Atomic Force Microscope and provide an example of its use.
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Atomic Force Microscope uses the needle to insert into the specimen. commonly used for studying biological structures such as enzymes and proteins
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what is nanotechnology? Why is it important?
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Nanotechnology is the science of the small. Can be used to manipulate small molecules and atoms; very small computers for treating disease, DNA analysis, military and medicinal uses
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What are the limits of resolution for the light microscope, electron microscope and scanning tunneling microscope?
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light microscope - 200 nm
electron microscope - .5 nm scanning tunneling microscope - .1 nm |
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What is a dye and how is it used?
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Dyes bind to cells or cell components by ionic or covalent or hydrophobic interactions. Dyes are used to stain specimens.
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What is an acidic dye vs. a basic dye?
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Acidic dye is negatively charged and binds to positively charged components of the specimen. Basic dye is positively charged and binds to negatively charged components of specimen.
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What is the simple staining technique?
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Increases contrast; only one dye used
Can be positive (specimen stained, not background) or negative (background stained not specimen) staining technique |
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What is the differential staining technique?
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Uses 2 dyes
provides contrast divides bacteria into different groups based on staining properties ie. gram stain |
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How does the Gram stain divide bacteria into groups?
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Based on the amount of peptidoglycan
Gram + purple stain, lots of peptidoglycan Gram - pink color, litte peptidoglycan in cell walls |
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How does Acid-Fast stain divide bacteria into groups
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Based on the amount of mycolic acid in cell walls
acid fast has the lipid, mycolic acid (members of the mycobacterium species) Non-acid fast bacteria have no mycolic acid in cell walls |
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What are the three components of an atom?
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Neutrons, electrons and protons
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What is an element?
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pure substance of one type of atom
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what is the atomic number?
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equal to the number of protons in an atom. in a neutral charged atom, also equal to the number of electrons.
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what is the mass number?
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protons plus neutrons. electrons weigh very, very little
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why do atoms gain or lose electrons?
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to form bonds with other atoms, fill outer shell
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what is the valence number?
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number of electrons found in the outer shell of an atom
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What is a covalent bond?
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electrons are shared between atoms simultaneously to fill outer shells
Very strong, difficult to break - need to apply heat or chemicals |
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What makes a molecule polar?
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when the electrons do not have equal affinity for both atoms
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Describe hydrogen bonds
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polar covalent bonds
electrons are shared with unequal attraction Very important in structure of DNA and water molecules |
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What is an ion?
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an atom that has a charge
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What are the chemical components important to a cell?
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water
organic and inorganic molecules macromolecules - proteins, carbohydrates, nucleic acids, lipids |
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Why is water important to a cell?
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polarity increases affinity of water molecules for each other
allows for hydrogen bonding ideal solvent can readily interact with polar molecule |
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Define hydrophillic
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attracted to water molecules, polar or charged molecules
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define hydrophobic
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repel water molecules, non-polar molecules
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define amphipathic
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a molecule that has both hydrophobic and hydrophilic properties, ie phospholipid
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what are the properties of inorganic molecules?
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do not contain both carbon and hydrogen
can have one or the other but not both no C-C bonds |
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what are the properties of organic molecules?
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contain both carbon and hydrogen
if more than one carbon, will form a C-C bond |
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what are macromolecules?
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macromolecules - proteins, carbohydrates, nucleic acids, lipids
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what is a monomer?
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a repeating subunit
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what is a polymer? what is the process of creating a polymer? Which macromolecules polymerize?
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monomers or repeating subunits that bind directly to each other; process is polymerization (proteins, carbs, nucleic acids polymerize, not lipids)
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what is dehydration synthesis?
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bond forms when an H2O molecule is formed and removed; peptide bonds are created this way; all four macromolecules form bonds using dehydration synthesis
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what is hydrolysis?
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bond is broken by addition of water
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What is the makeup of an amino acid? How many are there?
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Central sp3 Carbon with H, amino group (NH3), carboxyl group (O=C-OH), attached to a unique side chain;
20 naturally occurring aminos |
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How do the amino acids bond together?
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peptide bonds formed by dehydration synthesis (b/w carboxyl group and amino group)
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What is the primary structure?
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long chain of amino acids connected by peptide bonds; most proteins canno perform function as a primary structure
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What is the two types of secondary structures?
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Alpha helix (coiled)
Beta sheet (pleated sheet) |
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What is a tertiary structure?
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a globular protein; can have both alpha helix and beta sheet; hydrophobic regions fold in to stay away from water; also have sulfur in side chains that create di-sulfide bonds that stabilize tertiary structures
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What is a quaternary structure?
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multiple tertiary structures
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what does it mean if a protein is denatured?
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proteins are denatured when they are unfolded; cannot perform function when they are not in their proper shape. affected by high temperature, high or low pH or solvents
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What are chaperone proteins?
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proteins that are resistant to denaturation
some of them can aid in protein refolding |
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What are carbohydrates?
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sugars
energy source repeating subunit = saccharide |
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what are monosaccharides?
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single subunit sugars
glucose, fructose |
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what are disaccharides?
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two subunit sugars
maltose (2 glucose), sucrose (glucose and fructose) |
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what are polysaccharides?
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5+ subunits
cellulose, starch |
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what type of bond connects saccharides?
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glycosidic bond
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what are nucleic acids? What are they made up of (subunit)
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contain genetic information of cell (DNA, RNA)
nucleotides = subunit |
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What are the components of a nucleotide?
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1 - sugar (deoxyribose for DNA, ribose for RNA)
2 - phosphate group 3 - nitrogenous base |
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what are the types of nitrogenous bases? Which bond to each other?
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purines (adenine and guanine)
pyrimidines (thymine and cytosine, uracil - only in RNA) adenine bonds with thymine (uracil in RNA) cytosine bonds with guanine |
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What type of bond does a nucleotide have?
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phosphodiester bond
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What is the function of lipids?
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major component of membranes
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what are the simple lipids?
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fats (fatty acid + glycerol)
steroids sterols |
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what is a compound lipid?
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phospholipid
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what makes a fatty acid saturated?
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no C-C double bonds; straight, so it stacks nicely
solid fats at room temperature |
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what makes a fatty acid unsaturated?
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at least one C=C double bond
mono - one double bond poly - more than one double bond cannot stack neatly, usually liquid at room temperature |
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Where do fats bond to each other? What type of bond?
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COOH on fatty acid bonds to glycerol molecule via dehydration synthesis
Ester bond |
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What is a steroid?
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four membered ring
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What is a sterol?
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4 rings + OH
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What are the parts of a compound lipid?
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fatty acid plus other parts, ie phosphate
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What is the round cell morphology? Example?
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Round = coccus
Staphylococcus Streptococcus |
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What is the rod shaped cell morphology? Example?
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Rod = bacillus
Escherichia coli |
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What is the coccobacillus cell morphology?
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Compressed rod shape
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What is the the vibrio cell morphology?
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Vibrio = comma shaped
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What is the spirillum cell morphology?
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spirillum = regularly or evenly shaped coil that is very stiff
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What is the spirochete cell morphology?
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spirochete = irregular coil, flexible
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What is a chain arrangement of cells? Provide an example
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Chain = cell divides in one plane
diplococcus (2 cells) chain of coccus ie genus Streptococcus |
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What is the sarcina arrangement of cells? Examples
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Sarcina = cells divide in one or more planes perpendicular to one another
8, 16 or 32 present in a sarcina or packet; 4 = tetrad |
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What is the cluster arrangement of cells? example
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Cluster = cells divide in random planes
ie genus Staphyloccocus |
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What are the three layers of the cell envelope? Do all prokaryotes have each?
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1) Cell membrane (aka cytoplasmic membrane, plasma membrane, lipid bilayer) = all prokaryote cells have
2) Cell wall = in most 3) Outer membrane = in some bacteria (gram -) |
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What are other names for the cell membrane?
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cytoplasmic membrane
plasma membrane lipid bilayer |
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What is the innermost/outermost layer of the cell envelope
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innermost = cell membrane
middle = cell wall (not all have) outermost = outer membrane (not all have) |
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what are the characteristics of the cytoplasmic membrane?
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selectively permeable (a lot goes through; some substances have to pass through membrane proteins)
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What does the fluid mosaic model refer to?
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description of the way the cytoplasmic membrane moves when surrounding cell; not stationary; proteins in membrane move laterally
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What is the purpose of the cell wall?
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prevents cell from bursting from osmotic pressure
confers cell shape |
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What is the cell wall made of?
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Peptidoglycan
gram - = thin cell wall with small amount of peptidoglycan gram + = thick cell wall with large amount of peptidoglycan |
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What is peptidoglycan made up of?
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NAM (N-acetylmuamic acid) and NAG (N-acetylglucosamine) sugars and peptide chains
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what is unique about the peptidoglycan in gram+ cells
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only gram+ cells have a peptide interbridge that links the tetrapeptide chains of amino acids; acidic polysaccharides that give bact cells negative charge - teichoic acid and lipotechoic acid
gram- 3 layers; thin peptioglycan layer; have no peptide interbridge; outer membrane with porins |
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What is the sugar chain called in the cell wall?
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Glycan chain
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what links the glycan chains of NAM and NAG sugars?
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2 tetrapeptide chains ALWAYS connect to the NAM sugar on opposite glycan chain
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What are the components of the outer layer of the outer membrane of a gram- cell?
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1) Lipid A - contains fatty acids so toward inside; endotoxin because of immune response, diarrhea, shock
2) Core polysaccharide - has phosphate groups 3) O-specific polysaccharide - identifying marker for species; negatively charged |
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What is the glycocalyx?
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Some cells produce another layer for attachment purposes.
1) Slime layer - loose, easily washed away, protects against drying 2) Capsule - thick, not easily removed, offers protection from immune cells |
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What is a flagella?
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an appendage that confers swimming motility
slender, rigid, threadlike extending from surface taxis - movement of cell using flagella |
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What is chemotaxis?
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movement toward or away from specific chemicals using flagella
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What is phototaxis?
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movement toward or away from light using flagella
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What is aerotaxis?
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movement toward or away from concentrations of oxygen using flagella
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What is magnetotaxis?
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movement along earth's magnetic field using flagella
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What portion of the flagella is attached to the cell? In what structure of the cell is it embedded?
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the Basal body is embedded in the cell envelope
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What is the term for a cell that has one polar flagella?
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monotrichous
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What is the term for a cell with a bunch of flagella on one end?
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lophotrichous
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What is the term for a cell with a bunch of flagella on both ends of the cell?
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amphitrichous
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What is the term for a cell with a bunch of flagella all over the cell?
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peritrichous
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What are fimbriae and what are they used for?
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short fibers around the edge of the cell that are used for attachment
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What are pili and what are they used for?
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thicker and tubular structure used to attach to other cells and for twitching motility
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What is in the nucleoid of a cell?
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chromosomal DNA that is required by the cell for life; contains essential genes
a small amount of plasmid DNA, that contains non-essential genes |
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What are ribosomes?
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Site of protein synthesis
made of ribosomal RNA and protein 30S subunit and 50S subunit form 70S |
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What are the two types of storage bodies?
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Inclusions - membrane bound, organic compounds and air
Granules - no membrane, inorganic compounds |
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What is unique about Mycobacterium?
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Acidic fast due to mycolic acid present in cell walls
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What is unique about Mycoplasma?
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No cell wall
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What is unique about spirochetes?
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have periplasmic flagella inside of cell
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Which genera have cells that create endospores?
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Clostridium and Bacillus genera
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Phenotypic classification
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classification by looks, shape, how cell makes energy and habitat
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Phylogenetic classification
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classification by ribosomal RNA
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