Study guide Exam !

Question 1

Prokaryotes vs. eukaryotes

Answer 1

What is a Prokaryotic: • No nuclear membrane (not absolute) What is a Eukaryotic cells: • Nucleus membrane organelles, larger than prok.

Question 2

2) Definition of life

Answer 2

o Metabolism, growth, reproduction, genetic variation/evolution, adaptation to outside, homeostasis (uses energy)

Question 3

How the classification schemes have evolved over time

Answer 3

• Animal and plant What are the five kingdom systems of Robert Whittaker? o protist,monerans,fungi,plant,animals

Question 4

Make list of the features of each of the 3 domains so you can easily compare them

Answer 4

Who divided microorganism into three groups based on ribosomal RNA, and which groups? o Carl woese Bacteria, Archea , Eukaryotes Which domain is single-celled, cell wall with peptidoglycan, lacks a membrane bound nucleus, some lives in extreme environment, can be harmful and helpful and recycle? o Domain Bacteria Which domain are slightly different from bacteria by rRNA, lacks a peptidoglycan in cell wall but have a unique membrane lipid, can excrete methane gas, and most live in extreme environments? o Domain Archea Which domain are the largest of the three, and can be p,a, algae, protozoa, molds, water molds, fungi? Domain Eukarya

Question 5

Know where viruses fit in

Answer 5

What is an aceulluar infectious Agent that is not part of the 3 domains? That is the smallest, made out of proteins and nucleic acids, requires a host to replicate, causes diseases? o Viruses (not alive) –non reactive outside the host What is a viroid and virusoids ? o Infectious agents made out of RNA

Question 6

Stanley Miller and his experiment

Answer 6

How did Stantly Miller experiment help understand how the first microbial life arose? o He formed Organic compounds( Amino acids) from primordial soup(clear-red)

Question 7

RNA’S place in evolution

Answer 7

What were the earliest molecules and who is Thomas Cech ? o Ribozymes (RNA and enzyme) that can form peptide bonds, replicate, and cellular work, Catalyzing and store. It is believed earlier cell RNA inside liposomes

Question 8

.What is micelle and it role in RNA? (early form of a cell)

Answer 8

o Help separate outside by holding RNA inside

Question 9

Endosymbiotic theory and hypothesis

Answer 9

o Endosymbiotic (inside helping each other out) ingested microbes like (Mitochondria /o2 to ATP). Chloroplasts Co2 +energy to make sugar) Both looks like bacteria, DNA and Ribosomes and similar SSU rRNA aswell to bacteria!

Question 10

Correct microorganism naming

Answer 10

What is binomial nomenclature and who developed it? o Carolus Linnaeus, in which Genus and species epithet o First letter in the word Cap and the second word not, all utilized or underline Escherichia coli or Escherichia coli after one use E. coli

Question 11

) Robert Hooke and his contribution to the cell theory Who was the first to discover Microorganism?

Answer 11

o Robert Hooke looking at cork, called cells, composed the cell theory: All living things are composed of cells

Question 12

Antony van Leeuwenhoek and his contribution to microscopy Who was the first microbiologist?

Answer 12

o Antony Van Leeuwenhoek(Fabric worker), wrote and published with 50-300 times mangnfication, called microbes animalcules, studied teeth and diarrhea

Question 13

) The theory of spontaneous generation and Redi’s experiment to discredit it Who are the scientist that discredited spontaneous generation and their experiment.

Answer 13

o Francesco Redi- Three containers with meat, one with paper(none),guaze(on top of it),open(inside)

Question 14

) The conflicting results of Needham and Spallanzani and the very important difference in their experimental design Who is the scientist who tried to support spontaneous generation?

Answer 14

o John Needham-brooth-boiled-sealed ( growth) contamination o Lazzaro Spallanzani-Broth in flask-sealed-boiled (this way no micro in the air)-novital fo

Question 15

Louis Pasteur and his famous experiment,o Who are the scientist that discredited spontaneous generation and their experiment?

Answer 15

Louis Pasteur-flask showing when exposed to the dust with bacteria it grew-Biogenesis

Question 16

Tyndall, Cohn, Semmelweis, Lister, Snow, and Chamberland’s contributions to microbiology

Answer 16

o John Tyndall-dust carries microorganisms, showed air(no growth without dust)-found heat resistant forms of bacteria exist

Question 17

What did Ferdinand Cohn found?

Answer 17

o Heat resistant bacteria could produce endospores

Question 18

What are two doctors who help the medical coexist with microbiology?

Answer 18

o Ignaz Semmelweis- urged doctors to wash their hands(direct) o Joseph Lister-developed a surgery designed to prevent infection in patients-surgical dressing phenol-(indirect

Question 19

Who was the first Epidemiologist associated with Cholea.

Answer 19

o John Snow-Broad Street well-sewer pipe was leaking into well, after remove of pump handle, no more death. Local brewer not affected-drinking :D

Question 20

Who discovered viruses?

Answer 20

o Charles Chamberland-porcelain bacterial filters /called (filterable particles)

Question 21

Koch and his postulates….know them inside and out

Answer 21

1. Microorganism must be present in every case besides the healthy one 2. The suspected microorganism must be isolated and growth in pure culture 3. The same disease must show up in a healthy host which as been implanted it 4. The same microorganism must be isolated from the disease host. 5. Pure because so no other thing is there.

Question 22

Know some of the developments in microbiology that came from Koch’s lab.

Answer 22

o Agar(Fanny Hess) Petri dish ( Richard Petri) o Nutrient broth and nutrient agar, Method for isolating microorganism, Aseptic technique .Why is agar a good choice? o Not broken down, melt @ 100C, does not solidify until 50C, produces clear product

Question 23

Jenner, Ehrlich and Fleming’s contribution to microbiology

Answer 23

What did Edward Jenner vaccine do? o Vaccination to protect against small pox ,milk-maid, tested on 8 yro What did Paul Ehrich-German physician cured? o Syphilis by a drug name Savarsan What did Alexander Fleming discover by mistake? o First antibiotic, (penicillin) that kills S. aureus.

Question 24

Resolution-its importance as well as all of the factors that can influence resolution (ex: wavelength, numerical aperature, immersion oil, working distance etc.)

Answer 24

..

Question 25

Determining total magnification of a microscope.

Answer 25

• total magnification – product of the magnifications of the ocular lenses and the objective lenses

Question 26

The Bright-Field Microscope

Answer 26

produces a dark image against a brighter background both stained and unstained specimens

Question 27

The Dark-Field Microscope

Answer 27

image is formed by light reflected or refracted by specimen. produces a bright image of the object against a dark backgroundobserve living, unstained preparations(Internal structure eukaryotic)

Question 28

The Phase-Contrast Microscope

Answer 28

: Produces an image where cells are dark and the background is light • excellent way to observe unstained, living cells – studying microbial motility – detecting bacterial structures such as endospores and inclusion bodies that have refractive indices different from that of water

Question 29

Differential Interference Contrast Microscope

Answer 29

3-dimensional image of the specimen • Excellent way to observe living cells – Live, unstained cells appear brightly colored and three-dimensional – Cell walls, endospores, granules, vacuoles, and nuclei are clearly visible

Question 30

The Fluorescence Microscope:

Answer 30

specimens usually stained with fluorochromes (fluorescent dyes) • shows a bright image of the object resulting from the fluorescent light emitted by the specimen • has applications in medical microbiology and microbial ecology studies

Question 31

Confocal Microscopy

Answer 31

: composite 3-D, Specimen is usually fluorescently stained • numerous applications including study of biofilms

Question 32

Electron Microscopy

Answer 32

allows for study of microbial morphology in great detail(inside)2D

Question 33

The Transmission Electron Microscope (TEM):

Answer 33

electrons scatter when they pass through thin sections of a specimen

Question 34

The Scanning Electron Microscope

Answer 34

produces a realistic 3-dimensional image of specimen’s surface features can determine actual in situ location of microorganisms in ecological niches (e.g. human skin, gut, etc) – samples must be dehydrated and coated with a thin film of metal

Question 35

Electron Cryotomography

Answer 35

images are recorded from many different directions to create 3-D structures, cytoskeletal elements, magnetosomes, inclusion bodies, flagellar motors, viral structures

Question 36

Scanning Probe Microscopy

Answer 36

magnification 100 million times, can view atoms on surface of a solid, is detected and Used to create image of surface of specimen that do not conduct electricity well

Question 37

The major differences between the various light and electron microscopes.

Answer 37

..

Question 38

Remember for any type of fluorescent imaging your specimen needs to either be naturally fluorescent, or labeled with a fluorescent dye or fluorescently labeled antibody – understand the concept of immunofluorescence

Answer 38

• Immuno-Fluorescence: essential tool in microbiology – fluorochrome-labeled probes, such as antibodies, or fluorochromes tag specific cell constituents for identification of unknown pathogens – localization of specific proteins in cells • Photosynthetic organisms naturally fluoresce when excited with specific wavelengths. • Can also be used to localize specific proteins within cells – One method is to fuse the gene of the protein of interest to the jellyfish (Aequorea) protein, green fluorescent protein (GFP)

Question 39

Why we stain plus different types of fixations pros and cons

Answer 39

1. increases visibility of specimen,accentuates specific morphological features,preserves specimens Fixation: preserves internal and external structures and fixes them in position 1. organisms usually killed and firmly attached to microscope slide 1. heat fixation – routinely used with bacteria and archaea 1. preserves overall morphology but not internal structures, inactivates enzymes and can destroy some proteins 2. chemical fixation – used with larger, more delicate organisms 1. protects fine cellular substructure and morphology

Question 40

Dyes, simple staining, Gram stain (know inside and out), Acid Fast, endospore, capsule and flagella staining

Answer 40

• dyes – make internal and external structures of cell more visible by increasing contrast with background – have two common features • chromophore groups – chemical groups with conjugated double bonds – give dye its color • ability to bind cells Dyes • ionizable dyes have charged groups • basic dyes have positive charges that bind to negatively charged molecules (e.g., nucleic acids, many proteins, and cell surfaces) – methylene blue, basic fuchsin, crystal violet, safranin, malachite green • acid dyes have negative charges that bind to positively charged cell structures but are repelled by the cell surface (produces negative staining, nigrosin, good for seeing capsules) – eosin, rose bengal acid fuchsin

Question 41

simple stains

Answer 41

• a single stain is used (easy and quick) • can determine size, shape, and arrangement of bacteria

Question 42

Gram Staining

Answer 42

• most widely used differential staining procedure • Developed by Christian Gram, 1884 • divides bacteria (but not archaea) into two groups, Gram positive and Gram negative, based on differences in cell wall structure) Make a smear of a bacterial suspension on a glass slide • 2) Heat fix by passing through a flame • 3) Stain with primary stain – Crystal Violet, let stand for 1 minute, rinse with water – (all cells stain) • 4) Treat with iodine for 1 minute (a mordant which binds with the CV to make a large crystal inside the cell), rinse with water • 5) Decolorize with alcohol to remove the stain if it is a Gram neg. organism. Stain can’t be removed in a Gram pos. organism due to thick cell wall peptidoglycan • 6) Counter stain with Safranin • Gram positive cells are purple, Gram negative cells are pink

Question 43

Acid-Fast Staining

Answer 43

• particularly useful for staining members of the genus Mycobacterium (which don’t stain well with the Gram stain) e.g., Mycobacterium tuberculosis – causes tuberculosis e.g., Mycobacterium leprae – causes leprosy – high lipid content in cell walls (mycolic acid) prevents dyes from readily binding - Uses high heat and phenol to drive basic fuchsin into the cells

Question 44

endospore staining

Answer 44

exceptionally resistant to staining (e.g. Bacillus sp. and Clostridium sp.) o heated, double staining technique o bacterial endospore is one color and vegetative cell is a different color

Question 45

capsule stain

Answer 45

used to visualize capsules surrounding bacteria (India ink or nigrosin) o negative stain - capsules may be colorless against a stained background

Question 46

flagella staining

Answer 46

very thin and can only be seen with an electron microscope o Uses a mordant and a stain. The mordant is used to increase thickness of flagella

Question 47

Disadvantages and advantages of TEM, SEM, Scanning Probe, etc.

Answer 47

• TEM(Transmission Electron Microscope) • Electrons can only penetrate very thin specimens • Usually gives only 2D image • Specimens must be viewed under high vacuum • Specimens are dead • Because of harsh treatment (dehydration, etc) specimens are shrunken and distorted (artifacts) SEM(Scanning Electron Microscope) - Samples must be dehydrated and coated with a thin film of metal.

Question 48

Nutritional requirements • What do microorganisms generally need to grow?

Answer 48

– Macronutrients - All cells need access to large amounts of carbon, nitrogen, phosphorus, sulfur, and oxygen to build macromolecules. – Micronutrients - are also required by microbes: • Includes several metal ions (Na+, Mg2+, Mn2+, etc.) • Often required for protein structure/activity, biosynthesis of ATP by electron transport-related processes All organisms require Carbon, Hydrogen, Oxygen, and Electrons • carbon is backbone of all organic components present in cell • hydrogen and oxygen are also found in organic molecules • electrons play a role in energy production used for cellular work and reduction of CO2 to form organic molecules

Question 49

27) Naming an organism based on its energy source, electron source and carbon source IN THAT ORDER (they are always named energy, electron, carbon even if our information is given in a different order)

Answer 49

.

Question 50

) Growth factors-what are they

Answer 50

• Some organisms can synthesize all organic molecules from a single carbon source and inorganic salts, but some require growth factors to support growth • Growth factors are organic compounds that cannot be synthesized by an organism but are essential for growth • must be supplied by the environment if the cell is to survive and reproduce

Question 51

There are 3 Major Classes of Growth Factors

Answer 51

• amino acids – needed for protein synthesis • purines and pyrimidines – needed for nucleic acid synthesis • vitamins – Small organic molecules that function as enzyme cofactors, needed in very small amounts • Other less common growth factors include heme (cytochromes, Haemophilus influenzae) and cholesterol (required by some mycoplasmas)

Question 52

) Factors effecting microbial growth including nutrient availability, oxygen, temperature, pH, water availability

Answer 52

• Nutrient concentration – Growth rate will depend on the amounts of nutrients in the environment. – One key nutrient, available in the lowest amount, will dictate how much growth can occur over time (i.e., it will be a limiting factor). Oxygen(below) • Effects of pH on microbial growth – pH affects macromolecule structures and transmembrane electrochemical gradients. – Each microbe will have an optimal pH range for growth. • Acidophiles = pH < 5.5 • Neutrophiles = pH 5.5 to 8.5 • Alkalophiles = pH > 8.5 • Water :changes in osmotic concentrations in the environment may affect microbial cells – Hypotonic solution (lower osmotic concentration outside) • water enters the cell • cell swells may burst – Hypertonic (higher osmotic concentration outside) • Water leaves the cell • Membrane shrinks from the cell wall (plasmolysis) may occur `

Question 53

Aerobes vs. anaerobes vs. everything in between. Importance of SODs and catalase and who needs them.

Answer 53

• Effects of oxygen on microbial growth – Aerobes grow in the presence of oxygen. • Obligate aerobes REQUIRE oxygen. • Microaerophiles grow best when there is less oxygen than normal. – Anaerobic growth occurs without oxygen. • Aerotolerant anaerobes aren’t harmed by oxygen but don’t use it, either. • Obligate anaerobes cannot grow when oxygen is present. • Facultative anaerobes CAN use oxygen but can also grow in the absence of oxygen.

Question 54

Generally how we grow anaerobes

Answer 54

• Growth in an anaerobic culture medium containing reducing agents (thioglycollate or cysteine) • Work in an anaerobic chamber • GasPak jar • Plastic bag or pouch system

Question 55

Halophiles and water activity

Answer 55

• halophiles – grow optimally in the presence of NaCl or other salts at a concentration above about 0.2M • extreme halophiles – require salt concentrations of 2M and 6.2M – extremely high concentrations of potassium – cell wall, proteins, and plasma membrane require high salt to maintain stability and activity (e.g., Halobacterium in Dead Sea)

Question 56

Adaptations of thermophiles • thermophiles – 55o C to 85o

Answer 56

• thermophiles – 55o C to 85o C • protein structure stabilized by a variety of means • e.g., more H bonds • e.g., more proline • e.g., chaperones • histone-like proteins stabilize DNA • membrane stabilized by variety of means • e.g., more saturated, more branched and higher molecular weight lipids

Question 57

Growing organisms in a lab-different classifications of media (including functional classifications), what each type is used for, examples of each type

Answer 57

• supportive or general purpose media – support the growth of many microorganisms – e.g., tryptic soy agar • enriched media – general purpose media supplemented by blood or other special nutrients – e.g., blood agar • Selective media • favor the growth of some microorganisms and inhibit growth of others • e.g., MacConkey agar – selects for gram-negative bacteria • Differential Media distinguish between different groups of microorganisms based on their biological characteristics • e.g., blood agar • hemolytic versus nonhemolytic bacteria • e.g., MacConkey agar • lactose fermenters versus non-fermenters

Question 58

peptones and extracts…why they are used

Answer 58

• Media for microbial growth – Can be either complex (unknown chemical composition) or defined/synthetic (precisely defined chemical composition) • peptones – Protein hydrolysates prepared by partial digestion of various protein sources • extracts – aqueous extracts, usually of beef or yeast • agar – sulfated polysaccharide used to solidify liquid media; most microorganisms cannot degrade it – usually extracted from red algae

Question 59

How we obtain a pure culture: streak, spread, pour

Answer 59

• pure culture (population of cells arising from a single cell, One of the benefits of a solid medium is that cells are held in place on the surface and can be isolated. Streak plate This can lead to separating a mixture of cells into a pure population technique of spreading a mixture of cells on an agar surface so that individual cells are well separated from each other – involves use of bacteriological loop each cell can reproduce to form a separate colony (visible growth or cluster of microorganisms)-non count • spread plate • Sample is serially diluted • small volume of diluted mixture containing approximately 30–300 cells is transferred • spread evenly over surface with a sterile bent rod • pour plate • sample is serially diluted • diluted mixture containing approximately 30–300 cells is mixed with liquid agar • mixture of cells and agar are poured into sterile culture dishes • both may be used to determine the number of viable microorganisms in an original sample

Question 60

Generally how can we get information from uncultureable organisms?

Answer 60

• Unculturable bacteria: What if it won’t grow? – Cultivation independent methods • DNA from unculturable bacteria can be amplified and sequenced by PCR. • Sequences can be used to produce fluorescent probes that will bind to complementary DNA (fluorescent in situ hybridization or FISH). • Unculturable bacteria: Metagenomics • DNA is isolated from an environmental sample and sequenced. • The genetic content of microorganisms in an area can be examined and compared to those from a different area… EVEN IF THEY CAN’T BE GROWN. • Metagenomic information must still be confirmed in cultured organisms, however—but they may help us to better formulate growth media recipes.

Question 61

E.coli

Answer 61

single rods,(-)(harmless),flagellum,F.Enerobe

Question 62

Bacillus Cereus

Answer 62

Large rods(+)(harmless)(spore)(flagullum).F.Enerobe

Question 63

Stapyloccuss epidermis

Answer 63

cocus,(+)opportunist,nonspore,non motile,F.Enerobe

Question 64

vibrio cholerae

Answer 64

Rod,(-) (harmful/dep)nonspore,flagullum,F.Anerbe