Exam 2 for Micro205
Broth dilution test (also called?, steps how to do it and results/ what question it answers?)
-Minimum inhibitory concentration tests (MIC) -Wide range of concentrations of a single antibiotic within different broth tubes 1. It goes from the low concentration of antibiotic in a broth to a highest concentration tube 2. These tubes have a single bacteria at the same concentration 3. After being incubated, the tube with the least concentration that did not presented cloudiness or turbidity would be the Minimum inhibitory concentration -Lack of turbidity indicates no growth. -what is the lowest dose necessary to inhibit the growth of the microbe?
where is the extranuclear DNA in eukaryotes? which shape DNA have?
-Mitochondria -Chloroplast -circular shape as prokaryotes -Plasmids (some fungi and protozoa have)
Singlet oxygen
-Molecular oxygen with electrons that have been boosted into a higher energy state, during aerobic metabolism -Very reactive oxidizing agent -Used by phagocitic cells to oxidize pathogens
Can you List 4 benefits of a semi-synthetic derivative of penicillin over the original? (4)
-More stable in acidic environments (aka stomach) -More readily absorbed in intestinal tract by the body -Less susceptible to deactivation by bacterial enzymes -More active against more types of bacteria (spectrum of action)
Point mutation
-Most common -one base pair is affected
binary fission
-Most unicellular microorganisms reproduce -process in which a cell grows to twice its normal size and divides in half to produce 2 daughter cells of equal size
The tools used by recombinant DNA technology are_(4)
-Mutagens -reverse transcriptase -Restriction enzymes -vectors
what is the difference between organisms that reproduce asexually and reproduce sexually in regard to keeping a mutation in the genes?
-Mutations in unicelllular (asexually reproduce) organisms are passed on the organism's progeny -Mutations in multicellular organisms (sexually reproduce) typically are passed to the offspring only if a mutation occurs in gamete or gamete-producing cells
gross mutation
-Mutations that include inversions, duplications, transportation, and ever larger deletions and insertions
What are the two ways that an organism can acquire drug resistance (How genetically can they acquire resistance)?
-New mutations of chromosomal genes -Acquisition of R-plasmids via transformation, transduction, and conjugation (horizontal gene transfer)
Genetic screening involves the screening of_
-Newborn screening -Screening prospective parents and fetuses for inherited diseases caused by mutations. -Look for diseases in the future
Plasmids function
-Not essential for normal bacterial metabolism, growth, or reproduction -Can confer survival advantages -give specific characteristics to bacteria
when is recombination found in bacteria?
-Not in reproduction because bacteria is identical to offspring -So to get variation they use horizontal gene transfer to change DNA -bacteria only perform recombination in horizontal gene transfer*
Vector
-Nucleic acid molecules (DNA or RNA) that deliver a gene (gene of interest) into a cell -is a small DNA molecule (such as a viral genome, transposon, or plasmid) that carries a particular gene and a recognizable gene marker into a cell so that the cell will develop a new phenotype
Chemical mutagen types
-Nucleotide analogous -Nucleotide altering chemicals -Frameshift mutagens
what are the mechanisms of action of microbial drugs within inhibition of nucleic acid synthesis? (2 examples)
-Nucleotide analogs Quinolones Rifampin
What are some common complex media?
-Nutrient broth -Trypicase soy agar -MacConkey agar
concurrent RNA transcription
-Once an RNA polymerase molecule has cleared the promoter, another molecule can recognize the promoter and initiate transcription. In this manner, multiple copies of RNA are transcribed simultaneously -A lot of RNA polymerases doing transcription at the same time
Describe the ends of a DNA molecule
-One end of a DNA strand is called the 5' end because it terminates in a phosphate group attached to a 5' carbon -the opposite end of the strand is called the 3' end because it terminates with a hydroxyl group bound to a 3' carbon of deoxyribose.
Specialized transduction
-Only certain host sequences are transferred (along with phage DNA)
autotroph
-Organism that utilize an inorganic source of carbon (carbon dioxide) as their sole source of carbon -"feed themselves"
chemotrophs
-Organisms that acquire energy from redox reactions involving inorganic and organic chemicals -aerobic respiration, anaerobic respiration, and fermentation depending on the final electron acceptor
How is the replication of animal viruses compared to the replication of bacteriophages? (similarities and differences)
-Animal viruses have the same basic replication pathway as bacteriophages (attachment, entry, synthesis, assembly, and release) -but some differences result in part from the presence of envelopes around some of the viruses and in part from the eukaryotic nature of animal cells and their lack of a cell wall.
What is mode of action of polymyxin? (effective to treat which pathogen?)
-Antibacterial agent -disrupts outer membranes of Gram-negatives; -toxic to human kidneys (so use in skin creams or on external diseases) -Binds to Lipid A (LPS, endotoxin), and disrupts outer membrane -Effective against Pseudomonas external infections
what are the parts of tRNA? who attach the amino acids to tRNA?
-Anticodon triplet -acceptor stem for a specific amino acid at its 3' end -specific enzymes charge each tRNA molecule with the appropriate amino acid to the acceptor stem
What is meant by beta-lactam?
-Antimicrobial whose functional proportion is composed of beta-lactam rings, which inhibit peptidloglycan formation by irreversibly binding to the enzymes that cross-link NAM subunits -lactam ring irreversibly bind to the enzymes that cross-link NAM subunits (peptidoglycan layers) -Block linkages that actually bond one layer of peptidoglycan to the next
What is the difference between antiseptic and disinfectants?
-Antiseptic act on living organisms and disinfectants act on non living organisms -Disinfectants are more concentrated or can be left on a surface for longer periods of time
What is principally targeted for anti-viral drugs (can you name some uniquely viral metabolic activities)? (include the normal process of virus that is affected by the drug)
-Antiviral agents can target unique aspects of viral metabolism -Drugs block activation of viruses -NORMAL PROCESS OF VIRUSES: After attachment to a host cell, virus must penetrate cell's membrane and be uncoated to release viral genetic instructions and assume control of the cell's metabolic machinery. Some viruses are uncoated as a result of the acidic environment within phagolysosomes -Amantadine, rimantadine, and weak organic bases neutralize acidity of phagolysosome and prevent viral uncoating (remove of capsid)
Retrovirus (definition and example of organism)
-Any +ssRNA virus that uses the enzyme reverse transcriptase carried within its capsid to transcribe DNA from its RNA -HIV
Semiconservative
-Applies to DNA replication -new strands composed of one original strand (parental strand) and one daughter strand. -One is original and the other is a new strand
What is the dual role of triphosphate deoxyribonucleotides? In which process?
-As building block (monomer) and energy source (stored in the high-energy bonds between phosphate groups) -anabolic polymerization in DNA synthesis or replication
lithotrophs
-Autotrophic organisms -they acquire electrons from inorganic molecules
Organisms can be categorized into two broad groups based on their source carbon:
-Autotrophs -heterotrophs
Examples of of -stasis or -static
-Bacteriostatic -Fungistatic -Virustatic
nucleosomes
-Bead of DNA bound to histone in eukaryotic chromosomes
what indicates if there it no bacterial growth in the Ames test media?
-Because ames test uses Salmonella that lacks the ability (point mutation) to synthesize histidine (his-), it would not be able to grow because they cannot produce proteins and there is no hisitidine in the environment -So indicates that there was no point mutation in the his- nuclotide sequence. Thus, there is no presence of carcinogens or mutagens
Carotenoids
-Because singlet oxygen is also photochemically produced by the reaction of oxygen and light -Phototrophic microorganisms often contain this pigment (carotenoids) -Pigment that prevent toxicity by removing the excess energy of singlet oxygen
why new strands are synthesized differently? what are the main difference between this two strands?
-Because strands are antiparallel -Leading strand synthesized continuously -Lagging strand synthesized discontinuously
why budding allows an infected cell to remain alive for some time?
-Because the host cell is not quickly lysed
quorum sensing
-Biofilms often form as a result of this process -In which microorganisms respond to the density of nearby microorganisms by utilizing signal and receptor -Regulate genes in cells
what is a side effect of Antiprotozoan drug Flagyl? what type of side effect is this? (include when it results)
-Black, Hairy Tongue (results when the breakdown products of hemoglobin accumulate in the papillae of the tongue) -toxic side effect
What is one important negative consequence of using an antibacterial drug that has a broad spectrum of action?
-Broad-spectrum antimicrobials may allow for secondary or superinfections to develop -Killing of normal flora reduces microbial antagonism (competition between the normal microbes and pathogens for nutrients and space->reinforces body's defense by limiting the ability of pathogens to colonize the skin and mucous membranes)
what are the functions of nucleotides?
-Building block of DNA/RNA -Energy (Nucleotide Triphosphates (ATP))
when frameshift mutations happen? how they affect translation?
-By chemicals that alter DNA -By mistake during transcription -affects translation by moving the order of the codons after insertion or deletion (reading frame)
Colony-forming unit
-CFU -A single cell or group of realted cells that produce the colony -"parent of the colony" -Progenitor is termed a CFU
The solely source of carbon for autrotophs is_, thus they do not need to_
-CO2 -not acquire carbon from organic compounds from other organisms
autrotophs take carbon from_and make their_
-CO2 -own chains of carbon
Bacteriocin plasmid
-Carry genes for proteinacceous toxins called bacteriocins -compound, made by bacteria, kills neighboring bacteria (which lack this plasmid) -Allow bacteria to be able to compete with more bacterias, so they can have more nutrients
Resistance plasmid
-Carry genes for resistance to one or more antimicrobial drugs or heavy metals -allow bacteria resist antibiotics -Bacteria that does not have it respond to antibiotic
Fertility plasmid
-Carry instructions for conjugation -allows bacteria to build pilus or pilli to perform conjugation -Also called F-plasmid, F-Factor, F+ -Always connect pillus with F- bacteria (which does not have fertility plasmid)
What does have aerobes to contrast the effects of perioxide anion?
-Catalase (converts hydrogen perioxide in water and molecular oxygen) -Peroxidase (breaks down hydrogen perioxide without forming oxygen, using a reducing agent like NADH ) -both enzymes that detoxify perioxide anion
Semisynthetics (include benefits of them over antibiotics)
-Chemically altered antibiotics -alterations to natural antibiotics -made by scientists by twinkling the natural antibiotic -synthesis reaction derived form a natural product -more effective, longer lasting, or easier to administer than naturally occurring antibiotics -Derivates of penicillin
Describe the shape of plasmids
-Circular -smaller than chromosomes
what is the importance of genetic engineering in producing insulin?
-Codon w/ 3 nucleotides gives you an amino acid, which is universal -Universal: A codon always codes the same amino acid in all organism -So we can get human insulin DNA in regardless what organism we put it in, that is what will be transcribed into mRNA Human insulin and then into human insulin protein (enzyme) -we can put in other organism to get human insulin, does not matter what organism it is introduced
What is the role of methylation?
-Control of genetic expression (turn off/turn on transcription of genes) -Initiation of DNA replication (plays a role in initiating DNA replication) -Protection against viral infection (enables cell to distinguish their DNA from viral DNA, to selectively degrade viral DNA) -Repair of DNA
What are the electronic counters?
-Coulter counter -Flow cytometry
Microscopic counts
-Count microorganisms directly from a microscope -stained prokaryotes and large eukaryotes -sample placed on cell counter, count bacteria in several of the large squares and then calculate the mean number of bacteria per square -No. bacteria per squareX 25 squares= no. of bacteria per 0.02mm^3 -No of bacteria per 0.02mm^3X 50=no. of bacteria per mm^3 -No of bacteria per mm^3X1000= no. of bacteria per cm^3 (mL)
What is the sugar in DNA? what is the sugar in RNA?
-DNA has deoxyribose sugar -RNA has ribose sugar
what two characteristics of DNA are used in gel electrophoresis? Describe what happen to it for having this characteristics in this technique
-DNA has negative charge; drawn by electric current toward positive electrode -Smaller fragments migrate faster and further than larger ones (determine size by distance it travels comparing to distance traveled by standard DNA fragments of known sizes)
What enzymes are involved in DNA replicaiton?
-DNA helicase -DNA primase -DNA polymerase III -DNA polymerase I -DNA ligase
what does unzips DNA in DNA replication? How? What does this action form? what interaction it has with the strand?
-DNA helicase unzips the double helix - by breaking hydrogen bonds between complementary base pairs (unwinds the double helix) -to form a replication fork. -physical interaction
What are triphosphate deoxyribonucleotides? what are the types?
-DNA nucleotides with three phosphate groups linked together by two high-energy bonds -the building blocks used in the large molecule to create the molecule of DNA and energy source which is found in the bonds phosphate groups -dATP, dGTP, dCTP, dTTP
what is the requirements of DNA polymerase to work?
-DNA polymerase can only add to an existing nucleotide. -It cannot start the process. -It needs a primer.
During the first step of central dogma of genetics, what are the processes that take place?
-DNA replication -DNA repair -Genetic recombination
In what 2 processes ligase is involved?
-DNA replication during formation of lagging strand -In combining DNA fragments created by restriction enzymes in recombinant DNA technology
where is DNA viruses replication different from the RNA viruses replication?
-DNA viruses often enter the nucleus -RNA viruses often replicated in the cytoplasm
lagging strand
-Daughter strand of DNA synthesized in short segments that are later joined -Synthesis of the lagging strand always moves away from the replication fork, and lags behind synthesis of the leading strand -Synthesized in 5'->3' but in short segments
What are the types of media?
-Defined media -complex media -selective media -Differential media -Anaerobic media
Second generation drugs (how obtain them, what type of drugs?, and what is developed when the bacteria develop resistance to them?)
-Developing new variations of existing drugs can be done by adding novel side chains to the original molecule -They are considered to be semisynthetic drugs -If resistance develops to these drugs, third generation drugs may be developed to replace them
With the agarose gel electrophoresis you can determine_
-Different rates of movement depends on size -So compare the size of DNA fragments -How many pieces of DNA within the sample
Membrane Filtration
-Direct method of estimating population size in which a large sample is poured through a filter small enough to trap cells -Used when population density is small -Colonies, after being filtered and incubated in solid medium, are counted -Equal to CFUs in the original sample
what are the mechanisms of entry of animal viruses?
-Direct penetration -Membrane fusion -Endocytosis
what is the side effect of tetracycline? what type of side effect is this? (include when it results/reason)
-Discoloration, Damage to tooth enamel (drug form complexes with calcium that can be incorporated into bones and developing teeth, causing malformation of skulls and stained, weakened tooth enamel) -Toxic side effect
Penicillin (who discovered it, who produces it, what it does, one of the first_)
-Discovered by Alexander Flemming -Secreted by a mold Penicillium -Inhibits the growth of bacteria -One of the first microbiotics discovered
what is the result of the microbial growth?
-Discrete colony -Biofilm
how plasmid replication is performed in relation with chromosomes?
-Do not link together with the replication of bacterial chromosomes -Do not happen at the same time of chromosome replication -Multiple copies of the same plasmid are found within porkaryotic cells -Plasmids reproduce all the time (not before asexual reproduction as chromosomes) -They have things that help them to replicate more frequently than chromosomes -They have their own information to replicate
Describe "Efficacy" of the clinical considerations when selecting an antimicrobial agent (3)
-Dosages required to be effective -Routes of administration -Overall safety
Why can we target protein synthesis of bacterial cells since our cells also make proteins? (include the name of the process that synthesis proteins)
-Drugs can selectively target translation -Prokaryotic ribosomes differ from eukaryotic ribosomes in structure and size -Many antimicrobial agents take advantage of the differences between ribosomes to selectively target bacterial protein translation without significantly affecting eukaryotes
Can you list the six (6) categories/mechanism of antimicrobials? (major ways to fight microbial infections)
-Drugs that inhibit cell wall synthesis. These drugs are selectively toxic to certain fungal and bacterial cells, which have cell walls, but not to animals, which lack cell walls -Drugs that inhibit protein synthesis (translation) by targeting the differences between prokaryotic and eukaryotic ribosomes -Drugs that disrupt unique components of the cytoplasmic membrane (different between humans and prokaryotes) -Drugs that inhibit general metabolic pathways not used by humans -Drugs that inhibit nucleic acid synthesis (DNA or RNA synthesis) -Drugs that block a pathogen's recognition of or attachment to its host
Prophage
-During lyzogenic replication cycle -An inactive bacteriophage, which is inserted into a host's chromosome -It is passed on to daughter cells when chromosome replicates
What is drug efficacy?
-Effectiveness of the drug to kill the bacteria -Dose necessary to actually achieve what we want: kill the bacteria
Cold enrichment
-Enrich culture with cold tolerant microorganisms -Incubation of a specimen in a refrigerator to enhance the growth of col-tolerant species
depending on the presence of the enevlope in viruses, how they can be categorized?
-Enveloped viruse -naked virus
what viruses use the membrane fusion method to enter their host's cells?
-Enveloped viruses -measles and AIDS viruses
PCR is critical to amplify DNA in variety of situations:
-Epidemiologists use to amplify genome of unknown pathogen (SARS->severe acute respiratory system) -Amplify DNA from Bacillus anthracis spores in 2001 to identify source of spores. -AZ Office of public health microbiology: 15 different PCR tests for potential pathogens
3 examples of broad spectrum antimicrobials within prokaryotic diseases?
-Erythromycin -Tetracycline -Sulfonamides
because of the rapidly reproduction of microorganisms, how laboratory personal know how many bacteria are in the medium?
-Estimate the number of cells in a population by counting the number in a small, representative sample, and then multiplying to estimate the number in the whole specimen
Viable plate count
-Estimation of the size of a microbial population based upon the number of colonies formed when diluted samples are plated onto agar media -plates with 25-250 colonies and multiply the number by the reciprocal of the dilution to estimate the number of bacteria per ml in original culture
Germicides include_
-Ethylene oxide -Prophylene oxide -Aldehydes
why the eukaryotic mRNA made by reverse transcriptase makes possibel for the prokaryotes to produce eukaryotic proteins?
-Eukaryotic DNA cannot be expressed by prokaryotic cells because they cannot remove introns presented in eukaryotic pre-mRNA -Since eukaryotic mRNA has already been processed to remove introns, cDNA produced from it lacks noncoding sequences -Scientists can successfully insert cDNA into prokaryotic cells to produce eukaryotic proteins
How eukaryotic transcription differs from bacterial transcription?
-Eukaryotic cells transcribe RNA in the nucleus, while prokaryotic transcription occurs in the cytosol. -Eukaryotes have three types of nuclear RNA polymerase and multiple transcription factors. -Eukaryotic cells process mRNA before translation. RNA processing involves capping, polyadenylation, and splicing.
what are the differences in DNA replication between eukaryotes and prokaryotes?
-Eukaryotic cells use four DNA polymerases to replicate DNA. -Due to the large size of eukaryotic chromosomes there are many origins of replication. -Okasaki fragments of eukaryotes are smaller than those of bacteria. -Finally, plant and animal cells methylate cytosine bases exclusively.
Defined media
-Exact chemical composition is known -also called synthetic medium
Log phase is_or represented in a graph as_; death is_or represented in a graph as_; stationary is represented in a graph as_; lag is represented in a graph as_
-Exponential -increasing -decline -declining or lowering -horizontal line (no change) -horizontal line (no change)
how are called the bacterial cells that contain F plasmid? what they serve for?
-F+ cells -they serve as donors during conjugation
How are called bacterial cells that do not contain F plasmid? what they serve for?
-F- cells -they serve as recipient during conjugation, and they do not have conjugation pilli
what are some of the advantages that plasmids offer? (examples)
-Fertility -Resistance -Bacteriocin -Virulence
F plasmid
-Fertility plasmid of F factor -small, circular, extrachromosomal molecule of DNA coding for conjugation pilli
what was the principal source of insulin for the treatment of diabetes during 60 years? How the insulin was introduced in the human?
-For 60 years cows and pigs were used as principal source of insulin. -Injected into humans.
Genetic method of quantitation
-For bacteria and archea that cannot be grown in laboratory -Isolate DNA sequences representing unculturable prokaryotic species using genetic technique such as polymerase chain reaction (PCR) and hybridization of DNA that codes for ribosomal RNA
what happens to the capsid within endocytosis when it is already inside the host?
-For those viruses that penetrate the host cell with their capsids intact, the capsids must be removed to release their genomes before the viruses can continue to replicate
Superoxide radical
-Form during the incomplete reduction of O2 during electron transport in aerobes and during metabolism by anaerobes in the presence of oxygen -Solution to it: superoxide dismutases (produced by aerobes) to detoxify
topisomerase
-Found in prokaryote replication and eukaryote replication -Solves the tension of DNA molecules ahead of the replication fork due to excessive supercoiling, which was produced by the unzipping and unwinding actions of helicase -It removes these supercoild by cutting DNA, rotating the cut ends in the direction opposite the supercoiling, and then rejoining the cut ends
what type of rays, within radiation, damage DNA? what type of radiation are they?
-Gama rays -X-rays -Both are ionizing radiation
what are some of the characteristics of the bacteria that tell us that it received the vector with the gene of interest?
-Genetic markers: 1. antibiotic resistance 2. code for enzymes that metabolize a unique nutrient 3. radioactive or fluorescent labels
genome mapping (definition and what involves)
-Genetic sequencing -involves locating genes on a nucleic acid molecule
What are some of the things that genetic engineering can produce?
-Genetically modified plants and corps -Increase growth in animals -Medicine production in microorganisms at a faster and in more quantities -Create plastics that do not rely on petroleum, genetically modified organism that can make the products -Create biodiesel
Spectrum of action
-Give an antibiotic that kills a larger number of pathogens because we don't know what person have instead of giving a specific antimicrobial that attacks a specific pathogen
Polyenes
-Group of antifungal drugs -Group of antimicrobial drugs such as amphothericin B that disrupt the cytoplasmic membrane of targeted cells by becoming incorporated into the membrane and damaging its integrity
what were the two problems of using cow and pig insulin? Explain why
-Growing number of diabetics: So the process of obtaining insulin from cows and pigs was a very difficult and not efficient process that did not met the demand for insulin -Allergic reactions: Because the insulin obtained was the cow and pig version of insulin, which sometimes the body did not accept it
serial dilution
-Happens before viable plate counts -stepwise dilution of a liquid culture to low the number of cells in the sample
what happens to R strain of streptococcus are injected to a mouse with death S strain?
-Harmless, unencapsulated strain R bacteria had been transformed into deadly, encapsulated strain S bacteria by taking the DNA of death S strain bacteria and incorporate it to their genomes through transformation -R strain cells had acquired the ability of producing their own capsules by assimilating the capsule-coding genes of strain S cells
what are the three basic shapes of viruses? this shapes are used as_
-Helical, Polyhedral and complex -categories to classify viruses
organotrophs
-Heterotrophs -They acquire electrons from the same organic molecules that provide them carbon
Describe Polyhedral virus shape
-Hexagon shaped put in together (like a soccer ball) -Build tridimentional structure into a cage that would be the viral coat
Hfr
-High Frequency of Recombination cells. -Bacterial cells in which F plasmid integrates at a special sequence in the chromosome.
what two questions you must consider within the synthesis and assembly of each type of animal virus?
-How is mRNA--needed for the translation of viral proteins to make capsids--synthesized? -what molecules serves as a template for nucleic acid replication?
what other type of vaccine is found? (possible cure to malaria)
-Involves producing a recombinant plasmid carrying a gene from a pathogen and injecting the plasmid into a human, whose body then synthesize polypeptide characteristics of the pathogen -Polypeptides stimulates immunological memory within the human body, readying it to mount a vigorous immune response and prevent infection should it be subsequently be exposed to the real pathogen
Flow cytometry
-Is a variation of counting with a Coulter counter -uses a light-sensitive detector to record changes in light transmission through a tube as cells pass -Count fluorescent dyed or tagged organisms
what scientists do in recombinant DNA technology?
-Isolate specific genes from a cell -Manipulate in vitro -Insert it into the genome of almost any kind of recipient organism
what are the two rules that must be follow so DNA polymerase III works? who resolves the problems by following the rules?
-It can never add the first base in the growing or new strand. (primase adds first base or short strand of nucleotides (RNA) so the DNA polymerase III can start the new strand) -Always adds nucleotides to 3' end of growing strand (strands grow from 5'->3')
what a virion consists of?
-It consists of a protein coat, called a capsid, surrounding a nucleic acid core.
when does RNA transcription begin? what is being add to the new strand of RNA? where does RNA polymerase get energy to drive anabolic reactions?
-It does not occur at the promoter region, but at a spot 10 nucleotides away -rATP rUTP rGTP rCTP -From the phosphate bonds of the first tiphosphate ribonucleotide
Is the control of genotypes over phenotypes direct? why?
-It is not direct -because ultimately phenotypic traits result from the actions of RNA and protein molecules that are themselves coded by DNA
Osmotic pressure
-It is the pressure exerted on a semipermeable membrane by a solution containing solutes that cannot freely cross the membrane -Related to the concentration of dissolved molecules and ions in a solution
Keys of drug action:(4)
-Key is selective toxicity -Antibacterial drugs constitute largest number and diversity of antimicrobial agents -Fewer drugs to treat eukaryotic infections -Even fewer antiviral drugs
what is the key of replication?
-Key to replication is complementary structure of the two strands -Remember your base pairing combinations
Diffusion susceptibility test (other name and definition/ what question answer?/ benefit/ what discovers(what determine about the results))
-Kirby-Bauer test -Simple, inexpensive test widely used to reveal which drug is most effective against a particular pathogen. Procedure involves inoculating a petri plate uniformly with a standardized amount of the pathogen in question and arranging on the plate disks soaked in the drugs to be tested -How the bacteria grow in the presence of antibiotics? -test variety of antibiotics at the same time -See how bacteria grow in presence of antibiotics and determine if bacteria is susceptible, resistant, or intermediate to a drug
peptidoglycan
-Large, interconnected polysaccharide composed of chains of two alternating sugars (NAG-NAM) and crossbridges of short peptide chains extending between NAM subunits -Main component of cell walls
why the ames test need liver extract?
-Liver break chemicals within our body to detoxify -Liver extract has enzymes that break down or metabolize drugs or chemicals -So this would test if any component of the suspected mutagen chemical is a mutagen when it is break down into smaller molecules (especially those that are ingested by humans) -It is used to simulate body conditions under which liver enzymes can turn harmless chemicals into mutagens
What types of viruses use lytic versus lysogenic replication?
-Lytic cycle is being used by lytic viruses like bacteriophages like T4 which have tail fibers for attachment -Lysogenic replication is being used by temperate phages or lysogenic phages like lambda phage that has a tail for attachment
polyribosome
-Many ribosomes associated with the same mRNA molecule at the same time, which all of them make the exact protein sequences of the same mRNA -As elongation proceeds, ribosomal movement exposes the start codon, allowing other ribosome to attach behind the first one -One ribosome after another attaches at the start codon and begins to translate identical polypeptides molecules from the same message -This group of ribosomes is called polyribosomes
Describe the genomes of viruses (how they differ)
-May be DNA or RNA; never both -Can be dsDNA, ssDNA, dsRNA, ssRNA -ds= double stranded -ss= single stranded -May be linear and composed of several segments or single and circular
Disruption of normal microbiota (category of drug side effect) (result in_,what happens?,great concern about_)
-May result in secondary infections -Overgrowth of normal flora (Candida; C. difficile) that are not affected by a drug, which cause superinfection -Of greatest concern for hospitalized patients
Dry weight
-Measure abundance of particularly filamentous microorganisms -These organisms filtered from their culture medium, dried, and weighted -Suitable for broth cultures
spectrophotometer
-Measures amount of microorganism by the method of turbidity -Measures the amount of light transmitted through a culture under standardized conditions -The greater the concentration in the broth, the more light will be absorbed and scattered, and the less light will pass through and strike a light-sensitive detector
what methods are used in DNA fingerprinting by scientists and_investigators?
-Medical laboratory technicians and forensic investigators use gel electrophoresis and Southern blotting for so-called genetic fingerprinting or DNA fingerprinting
Thermoduric organisms
-Mesophiles that can survive brief periods at higher temperatures
Function of mRNA
-Messenger RNA -which carry genetic information from chromosomes to ribosomes -Its sequence code for amino acids in translation
what are the semi-syntethic derivative of penicillin?
-Methicillin -Cephalosporin -Monobactram
transformation
-Method of horizontal gene transfer in which a recipient cell takes up DNA from the environment
Polymerase Chain Reaction
-Method to amplify a specified region of DNA. -is a technique by which scientists produce a large number of identical molecules of DNA in vitro.
barophiles
-Microorganism requiring the extreme hydrostatic pressure found at great depth below the surface of water (ocean) -Their membranes depend on the high pressure to maintain the 3-dimensional shape
Obligate anaerobes
-Microorganism that cannot tolerate oxygen as the final electron acceptor of the electron transport chain -Oxygen is deadly poison to them
normal microbiota
-Microorganisms that colonize the surfaces of the human body without normally causing disease -they may be resident or transient
Diabetes is a defect in how the human_
-regulates glucose or sugar in blood -Defect in the pathway that regulate glucose
DNA polymerase I
-removes RNA primer and synthesizes DNA by replacing RNA primer with DNA nucleotides
Blunt end cut
-restriction enzymes looks for specific sequence in both strands and cuts in the middle of the sequence (double stranded sequence) -Results when restriction enzyme cur both strands of DNA at the same point->blunt ends -Combined to other fragments of DNA easier because they are not specific. However, difficult to do because they are no sticky
Nucleotide-altering chemicals
-result in base-pair substitution mutations and missense mutations -Chemical mutagens that alter the structure of nucleotides (change existing nucleotide in the link like A for C)
DNA ligase
-seals the gap -form phosphodiester bond between the fragments within the new strand or daughter strand -seals the gap within the carbon skeleton (along the newly made strand)
start codon (definition, list them, and the nucleotide that produce if applies, additional function)
-sequence of three nucleotides where translation starts -AUG -Methionine (Met) -sets reading frame (codons)-> set brackets of three that will read the codons until stop codon
conjugation pilli
-sex pilli -Proteinaceous, Rod-like structure extending from the surface of a cell -mediates conjugation
What are the physical categories to identify and differentiate bacteria?
-shape -Margin -elevation -size -texture -appearance -pigmentation -optical property
Describe "selectively toxic against a wide range of pathogens" of the clinical considerations when selecting an antimicrobial agent
-should kill the microorganism but have no negative effect on patient -range of pathogens against which antimicrobials are effective
Defect in individual genes result in_. This diseases are caused by_
-sickness -point mutation that has occur within their genetic material, so they change one amino acid of a protein in our body and does not work well
Determine how fast a DNA fragment moves, would determine its_. Explain if DNA is short or long what happens
-size -if DNA short, less nucleotides in the chain, so move faster and moves a greater distance -If DNA long, more nucleotides in the chain, so move slower and move less distance
To store living cells, what a scientists do?
-slows the cells' metabolism to prevent the excessive accumulation of waste products and the exhaustion of all nutrients in a medium
plasmid
-small, circular, extrachromosomal molecule of DNA that works independently of the chromosome
spikes
-some proteins are virally-coded glycoproteins within envelopes
Mutations can be_
-spontaneous -result from recombination
What are the two major characteristics of anabolism?
-start with small molecules and build big molecules -requires energy
Most probable number
-statistical estimation of the size of a microbial population based upon the dilution of a sample required to eliminate microbial growth -Based on the more bacteria are in the sample, the more dilutions are required to reduce their number to zero -95% correct -use 5 tubes inoculated -Used for microorganisms that do not grow on solid media and samples of wastewater, having too few to count or too numerous to count
Sterilization is typically achieved by _
-steam under pressure -incineration -ethylene oxide gas
Priming (PCR)
-step 2 also called annealing -addition of nucleotide mixture followed by cooling (65 degree C) -DNA polymerase: Cannot add 1st letter/nucleotide to synthesize strand->we use a short strand of DNA (PRIMER) that we know exactly what it is -Cold temperature to bind primer to form base pairs with the strands (strands are more likely to bind to primers than to one another) -Primers determine stop and start part that we want to make more copies (region)->copy only what is between the two primers (region) -Primers provide DNA polymerase with the 3' hydroxyl group it requires for DNA synthesis
Extension (PCR)
-step 3 -heating (72 degree C) to increase the rate of replication by DNA polymerase -DNA polymerase add nucleotides to the end of the primer (3' hydroxyl group) -It adds: dNTPs: building blocks of DNA (A,G,C,T) -5'->3' direction of DNA polymerase -DNA polymerase replicates each strand to produce more DNA
Erythropoietin
-stimulates blood (erythrocytes) production -athletes use them so their blood can carry more oxygen and they have better performance
stop codons (definition, list them, and the nucleotide that they produce if applies)
-stop process of translation -UGA, UAA, UAG -They do not code for any amino acid, expect UGA that sometimes code for Selenocysteine
what direction does lagging strand is synthesized?
-strand is synthesized in a direction away from the replication fork in fragmented strands that are synthesized in a 5'->3' direction (toward origin of replication)
Deoxyribonucleotides are linked through their_and_to form_(shape)
-sugars -phopshates -two backbones of a helical, double-stranded DNA molecule
examples of 3 that work in inhibition of metabolic pathway (antimetabolic agents)?
-sulfanilamide -Heavy metals -Antiviral agents
What are the usages of sulfur in cell?
-sulfur-containing amino acids -disulfide bonds (protein tertiary structure) -Vitamins
What are the ways to treat the 4 toxic forms of oxygen in aerobes?
-superoxide dismutase -catalase -perioxidase -antioxidant (vitamin C and E) by providing electrons to reduce toxic forms of oxygen
classification of pathogens by diffusion susceptibility test?
-susceptible -intermediate -resistant *to each drug*
What are the two types of beneficial relationships?
-synergisitc relationships -symbiotic relationships
Quinolones (type of drug, part of which mechanism of action of microbial durgs, what it does and little effect on which organism(s)?)
-synthetic drug -part of inhibition of nucleic acid synthesis (mechanism of action of microbial drugs) -act against prokaryotic DNA gyrase; -little effect on eukaryotes or viruses
which molecules change in translation? Which molecules does not change in translation?
-tRNA: bring amino acid to transfer from itself to the amino acid chain -protein: amino acid links created -mRNA is unchanged in this process-> read over and over again to make many proteins , which amplifies the amount of products
Can you name four physical parameters that can affect growth of microbes?
-temperature -pH -Osmolarity -Pressure
genotype
-the actual set of genes in an organism genome -All the series of DNA nucleotides that carry instructions for an organism's life
what two things drive DNA replication?
-the antiparallel running of two strands -Base pairing
transduction (how happens?)
-the capsid assembles around leftover pieces of host DNA instead of viral DNA (mistakenly) -A virion formed in this manner is still able to attach to a new host by means of its tail fibers, but instead of inserting phage DNA it transfers DNA from the first host into a new host
Latent
-the cell is not actively making virus but still have (carrier) the virus DNA -synonym with prophage
genetic code
-the complete set of triplets of mRNA nucleotides called codons that code for specific amino acids. -The genetic code contains 64 codons, of which 61 specify amino acids and 3 do not. -The genetic code is unambiguous and almost universal.
nitrogen fixation
-the conversion of atmospheric nitrogen to ammonia -performed by cyanobacteria and Rhizobium -Organisms provide nitrogen in a usable form to other organism
Where is envelope derived from? (describe also in which activities it is obtained)
-the host cell membranes -Envelope is acquired from host cell during viral replication or release; envelope is portion of membrane system of host
Each type of animal virus requires a different strategy for synthesis that depends on _
-the kind of nucleic acid involved: DNA or RNA, and ds versus ss
Differential media are formulated such that either the presence of visible changes in _or differences in the_ help microbiologists differentiate among different kinds of bacteria growing in the medium
-the medium -appearance of colonies
Pour plate rather than reducing the number of microbes in _like in streak plate, It does the reduction_
-the plate -It does the reduction prior to putting in the plate
what are the ethical issues about genetic screening?
-the rights of governments, employers, or insurers to routinely screen people for certain diseases -the rights of individuals to refuse either screening or treatment for genetic disease -the rights of both institutions and individuals to privacy and confidentiality of genetic data.
restriction sites
-the specific location where restriction enzymes cut DNA molecules -specific nucleotide sequences, which are usually palindromes (have same sequence when read forward or backward)
what the gel electrophoresis involves? (describe what happens)
-the technique involves drawing DNA molecules, which have an overall negative charge, through a semisolid gel by an electric current toward the positive electrode within an electrophoresis chamber. -Smaller DNA fragments move faster and farther than larger ones.
Generalized transduction
-the transducing phage carries a random DNA segment from a donor host cell's chromosome or plasmids to a recipient host cell -The transduction is not limited to a particular DNA sequence
What is a major characteristics of viruses that contribute to their pathogenicity?
-the viral ability to attach to the host or recognize it -bind to cells and somehow get inside
generation time
-time is the time required for a bacterial cells to grow and divide -Time required for a population of cells to double.
what will happen if a scientist could remove the sigma factor?
-transcription would not happen -If you don't have sigma factor, the sigma factor helps to recognize the promoter, so RNA polymerase would not be able to start transcription because it cannot recognize the start and bind to promoter
Function of tRNA
-transfer RNA -which deliver amino acids to the ribosomes. -Deliver the correct amino acids to ribosomes based on the sequence in mRNA -Function in translation
Some opponents of recombinant DNA techniques argue that transgenic organisms could _
-trigger allergies or cause harmless organisms to become pathogenic -whereas others caution that the long-term effects of transgenic manipulations are unknown - that unforeseen problems arise from every new technology.
why the genetic code is unambigous and almost universal?
-unambiguous: if we take a given codon (3 nucleotides) that particular codon always do the same thing or codes for the same amino acid -almost universal: This code is used by all organisms (translation of mRNA into protein is the same across all the organisms; only some exceptions)
what is the first step of DNA replication? who performs this?
-unwind/ separating strands (separate or break hydrogen bonds between complementary nucleotide bases) -DNA helicase
Personalized genomics
-use genetic screening -how likely are you to get a specific disease by percentages
what information can you obtain from gene maps?
-useful facts about metabolism and growth characteristics -potential relatedness to other microbes
semilogarithmic graph
-uses only one axis logarithmic in which it increases by 10 times -each division is 10 times larger than the preceding one -Solves problem of having too little or too many bacteria
How most of bacteria reproduce? How this is known?
-using binary fission -Logarithmic or Exponential growth
A vector includes_(types)
-viral genomes -transposons -plasmids
transducing phages
-virus that transfers bacterial DNA from one bacterium to another -Result from mistakenly incorporating remaining fragments of bacterial DNA in a phage
Explain viral medicines (how they act)
-viruses do not have enzymes that proof read DNA or RNA when produced as cells so medicines use nucleotide analog -viral cannot fix the nucleotide analog -humans can fix the nucleotide analog
what are some growth factors for various microbes?
-vitamins -amino acids -purines -pyrimidines -cholesterol -NADH -Heme
Complex media is called like this because?
-we don't know the components within the media that are important for bacteria to grow, but it grows on it
Can microorganisms survive below the minimum growth temperature? If yes, why is called minimum growth temperature?
-yes -The minimum growth temperature is defined as the lowest temperature that supports metabolism. Many organisms can survive at low temperature but do not actively metabolize, grow, or reproduce
What does polyribosomes create?
1 mRNA can lead to many copies of protein by the polyribosomes. This amplifies production
Steps of Lysogenic cycle (describe them by using the example of the lambda phage)
1. Attachment: Virion randomly contacts the bacteria cell and attaches via its tail 2. Entry: The viral DNA enters the cell, but the host cell's DNA is not destroyed, and the phage's genome does not immediately assume control of the cell. The virus remain inactive (prophage) 3. Prophage in chromosome: A prophage remains inactive and it is inserted into the DNA of bacterium , becoming a physical part of the bacterial chromosome (fuse pieces of DNA) 4. Replication of chromosome and virus; cell division Every time the cell replicates its infected chromosome, the prophage is also replicated -all daugther cells are infected with the virus 5.Induction: The prophage excises from the host chromosome and reenters the lytic cycle 6. Synthesis 7. Assembly 8. Release: The cell becomes filled with virions and breaks open
Describe the steps of Conjugation - Hfr to F-
1. F Plasmid integrates into chromosome by integration or recombination 2. Cells join via conjugation pillus 3. Portion of F plasmid partially moves into the recipient cell trailing a strand of donor's DNA 4. Conjugation ends with pieces of F plasmid and donor DNA in recipient cell; cells synthesize complementary DNA strands 5. Donor DNA and recipient DNA recombine making a recombinant F- cell
what are the three steps of transcription? describe them briefly
1. Initiation: start to make the strand 2. Elongation: put more nucleotides, grow the strand, add links to the chain 3. Termination: finish the chain and stop transcription
Recombinant approach within the vaccines->describe steps and example
1. Insert the gene that codes for a pathogen's antigens into a vector 2. Inject vector or Inject purified gene product (protein or portion of protein) 3. Thus the patient's immune system is exposed to a subunit of the pathogen (pathogne's antigens) but not pathogen itself Ex. Hep B vaccine.
List the steps of the overview of the methodology utilized in recombinant DNA technology
1. Isolate plasmid 2. Enzymatically cleave DNA intro fragments 3. Isolate fragment with the gene of interest 4. Insert gene into plasmid 5. Insert plasmid and gene into bacterium 6. Culture bacteria: a. Harvest copies of gene to insert into plants or animals-> Eliminate undesirable pehonyptic traits or Create beneficial combination of traits b. Harvest proteins coded by gene->Produce vaccines, antibiotics, hormones, or enzymes
what you get as a result in gel electrophoresis?
1. Number of different DNA's that are present 2. Sizes of DNA's 3. Quantity/ amount of given DNA fragment (staining-> tells us the amount of DNA present)
describe the steps of transduction
1. Phage injects its DNA (for replication) 2. Phage enzymes degrade host DNA 3. Cells synthesizes new phages that incorporate phage DNA and, mistakenly, some host DNA (phage controls cell's functions) 4. Transducing phage injects donor DNA (after being removed from bacteria by lysing bacteria) 5. Donor DNA is incorporated into recipient's chromosome by recombination
How are PABA, Folic Acid, sulfonamides, and nucleotides involved in this process?
-PABA is crucial in synthesis of nucleotides required for DNA and RNA synthesis by being converted to dyhydrofolic acid->tetrahydrofolic acid (THF), which is a form of folic acid that is used as a coenzyme in the synthesis of purine and pyrimide nucleotides of RNA and DNA -Sulfonamides (as analog of PABA) compete with PABA molecules for the active site of the enzyme involved in the production of dihydrofolic acid-> competition lead to decrease in production of THF->decrease in production of DNA and RNA->decrease and cessation of metabolism->cell death -Important only for bacteria because obtain folic acid from alimentation
complex media
-Partial digests so composition is not known. (contain nutrients digested and unknown because partial digestion releases many different chemicals in a variety of concentrations) -Supports wider variety of microbes.
what antimicrobial agents inhibit cell wall synthesis? (6)
-Penicillin -Isoniazid -Vancomycin -Bacitricin -Cephalosporin -Methicillin
Examples of disinfection
-Phenolics -alcohols -aldehydes -surfactants
what are nucleotides composed of?
-Phosphate Group -Nitrogenous Bases (A, G, C, T/U) -Pentose sugar (Deoxyribose, Ribose)
Organism can be categorized based on their carbon and energy sources into one of four basic groups:
-Photoautotrophs -Chemoautotrops -Photoheterotrophs -Chemoheterotrophs
Mutagens (definition)
-Physical and chemical agents that produce mutations -agents used to create changes in a microbe's genome to effect desired changes in the microbe's phenotype
what are the types of mutagens?
-Physical mutagens (radiation) -chemical mutagens
Gene of interest
-Piece of information (piece of interest DNA) within a huge set of information (genome) -The piece of genetically information that we want to introduce in the plasmid
To get the results of Etest, which greately depends on_, look for_. Answers the question:_
-Plastic strip with concentration gradient. -Look for intersection of ellipse. -what is the lowest dose necessary to inhibit the growth of the microbe?
what is the type of mutations?
-Point mutations
Examples of aseptic
-Preparation of surgical field -Hand-washing -Flame sterilization of laboratory equipment
Can you summarize the action of cell wall inhibiting drugs? (prevent bacteria from_, effect on what?, type of cells that are affected?, no effect on which type of cells and reason)
-Prevent bacteria from increasing amount of peptidoglycan -Have no effect on existing peptidoglycan layer (only new cell walls) -Effective only for growing cells (dividing cells) -No effect on plant or animal cells; no peptidoglycan
What does selective toxicity mean in regards to antimicrobials? (include why this is possible?)
-Principle in which an effective antimicrobial agent must be more toxic to a pathogen than to the pathogen's host -an effective antimicrobial agent must be more toxic to a pathogen than to the pathogen's host -Kill the bacteria but not negatively affect the physiology of the human -selectively toxicity is possible because of differences in structure or metabolism between the pathogen and its host
Oral (route of administration) (advantage and disadvantage)
-Pro: simplest (it requires no needles and is self-administered) -CON: lower drug concentrations achieved in the body (comparing with other routes) -no reliance on health care provider -patients do not always follow prescribing information (CON)
lysogenic replication cycle (lyzogeny)
-Process of viral replication in which a bacteriophage enters a bacterial cell, inserts into the DNA of the host, and remains inactive. The phage is then replicated ever time the host cell replicates its chromosome. Later, the phage may leave the chromosome
What does prokaryotes use as their genetic material? what does eukaryotes use as their genetic material? what does viruses use as their genetic material?
-Prokaryotic and eukaryotic cells use DNA as their genetic material -some viruses use DNA, and other viruses use RNA.
Prokaryotic cells have how many chromosomes? what is the term used for this?
-Prokaryotic cells have a single copy of each chromosome -haploid
Describe viruses helical shape
-Proteins are put together in a helical fashion -we considered helical (spiral virus)
How the change of proteins may affect or benefit an organism? How is this called?
-Proteins provide characteristic (phenotype) that results in improvement of an organism -sometimes mutations results in beneficial proteins -This can be considered to be evolution in action
What are the 4 overlapping classifications of temperature in microorganisms ?
-Psychrophiles -Mesophiles -Thermophiles -Hyperthermophiles
What are the two major classes of nucleic acids?
-RNA -DNA
what is the most important enzyme in replication ("key player of replication")? what does it does?
-RNA polymerase III -add nucleotides to the new strand of DNA
what is the difference between RNA polymerase and DNA polymerase?
-RNA polymerase does not need primer (like DNA pol.) -RNA polymerase unwinds and opens DNA by itself (helicase is not required) -RNA polymerase transcribes only one of the DNA strands -RNA polymerase is slower than DNA polymerase III -RNA polymerase incorporates ribonucleotides instead of deoxyribonucleotides -Uracil nucleotide are incorporated instead of thyamine nucleotides -The proofreading function of RNA polymerase is less efficient
what are the roles of RNA polymerase in transcription?
-RNA polymerase unwinds DNA. -RNA polymerase synthesizes in 5' to 3' direction. -RNA polymerase links RNA nucleotides that are complementary to genetic sequences in DNA.
DNA primase (definition, what enzyme it helps, type of nucleotides it uses, where it starts, how many nucleotides it adds, in which strand it works the most)
-RNA primers synthesized by DNA primase -initiate DNA replication -adds first base or short strand of nucleotides so the DNA polymerase III can start the new strand -Uses nucleotides that are ribose nucloetides (RNA) -Start within the Origen replication -Adds: 10 or less sequence of nucleotides -In lagging strand it adds more RNA primers than in leading strand
what viruses need to get inside the host? This determines their_(example)
-Recognition sites: You need proteins (found on the surface of capsids) so they are very specific to what they bind and enter in the cell -hepatitis enter the liver cells
Medical diagnoses
-Recombinant DNA techniques (PCR) are used for diagnostic applications -Patient specimens can be examined for the presence of gene sequences unique to certain pathogens
any molecule that is protein can be make by_
-Recombinant DNA technology -After inserting gene in bacteria, Grow many bacteria to produce a lot of the product
what is a technique to do slow down cells metabolism?
-Refrigeration (shorts periods of time) Long periods of time are: -Deep-freezing: freezing the cells at temperatures from -50degree C to -95 degree C -lyophilization: involves removing water from a frozen culture using an intense vacuum-> ice sublimates (becomes gas) and is removing from cells without permanently damaging cellular structures and chemicals
terminator
-Region of DNA where transcription ends -Recognized by RNA polymerase -sequence within DNA that causes RNA polymerase to fall apart and the transcript (RNA)
Describe how to change penicillium using mutagens
-Researchers exposed the fungus Penicillium to mutagenic agents and then selected strains that produce greater amounts of penicillin. -for the goal to make a strain of penicillium that can make more penicillin, more quickly or variant -We don't know where mutagens change, but if mold does not grow-> it did not grow -If it grows we could get a strain that does this things, so we can cultivate it and make more of this molds to produce more penicillia -BY IMPROVING PHENOTYPE OR PHYSICAL CHARACTERISTICS
Function of rRNA
-Ribosomal RNA which combine with ribosomal polypeptides to form ribosomes, the organelles that synthesize polypeptides
what are important factors to avoid resistance? (6)
-Right dose and right duration of antibiotics -Limit use of antimicrobials to necessary cases -Development of new variations of existing drugs (novel side chains added to original molecule): Second-generation drugs; Third-generation drugs -Use antimicrobial agents in combination so that pathogens resistant to one drug will be killed by other drug, and vice versa (use combos) -use synergistic combination of drugs -Not use antagonistic combination of drugs
Describe Polyhedral virus morphology (and which type is the most common)
-Roughly spherical -With a shape similar to a geodesic dome -Most common type is icosahedron, which has 20 sides
why a virus is not considered to be alive?
-They cannot carry out any metabolic pathway -They can neither grow nor respond to the environment -They cannot reproduce independently but instead must utilize the chemicals and structural components of the cells they infect -They must recruit the cells's metabolic pathways in order to increase their numbers
what is the time period of longevity of viruses?
-They would not be always protected because the capsid can be damaged -they have different lengths of time in which remain infections (survival) They have some longevity outside the cell
toxicity (category of drug side effect)
-Though antimicrobial drugs are ideally selectively toxic against microbes and harmless to humans, many infact have toxic side effects -Exact cause of many adverse reactions poorly understood -Drugs may be toxic to kidneys, liver, or nerves -Considerations needed when prescribing drugs to pregnant women (effects on developing fetus)
Replication (purpose, start, and end)
-To duplicate the cell's genome -origin -Origin or the end of a linear DNA molecule
Encrichment culture
-To isolate potentially important microbes that might be otherwise overlooked -Technique used to enhance the growth of less abundant microorganisms by using a selectively medium
Why DNA needs to be copied?
-To perform asexual reproduction (make sure DNA goes to daughter cells) -replicate prior asexual reproduction
Transcription (purpose, start, and end)
-To synthesize RNA -Promoter -Terminator
Translation (purpose, start, and end)
-To synthesize polypeptides -Start codon (AUG) -Stop codon (UGA, UAA, UAG)
tropical or local administration
-Topical application of drug if infection is external -For external infections -can be applied directly
describe the steps of elongation and main features
-Triphosphate ribonucloetides align with their DNA complements and RNA polymerase links them together, synthesizing RNA -No primer is needed -The triphosphate ribonucleotides also provide energy required for RNA synthesis
4 types of routes of administration?
-Tropical or local administration -orally -intramuscularly (IM) -intravenously (IV)
Indirect 3 methods of quantifying bacterial numbers.
-Turbidity -Dry weight -Metabolic activity
Which diabetes is acquired after born? what are some of the factors that influence if a person gets diabetes?
-Type II -can get by genetics, depending on ancestry, diet, exercise level
Recombinant DNA technology (definition)
-Type of biotechnology (sciences) -Intentionally modifying genomes of organisms, by natural and artificial processes, for practical purposes -change genotypes and phenotypes of organisms
what are the characteristics used to distinguish different viral groups? (classification) This classification was established by_ and the higher taxa and taxonomic groups that viruses are classified are_
-Type of genetic material they contain (DNA or RNA) -The kinds of cells they attack -Their size -The nature of their capsid coat -Their shapes (helical, complex. Polyhedral) -The presence and absence of an envelope (naked virus vs. enveloped virus) -By the Internation Committe on Taxonomy of Viruses (ICTV) -Order, family, genus, specific epithet (species)
Transduction
-Type of horizontal gene transfer -a virus such as a bacteriophage carries DNA from a donor cell to a recipient cell. -Donor DNA is accidentally incorporated in transducing phages (when manufacturing viruses). -transfer of DNA from one cell to another via a replicating virus
Transformation
-Type of horizontal gene transfer -a "competent" recipient cell takes up DNA from the environment.
subunit vaccines (definition and benefit)
-Type of vaccine developed using recombinant DNA technology, which exposes the recipient's immune system to a pathogen's antigens but not the pathogen itself -Useful in safely protecting against pathogens that either cannot be cultures or cause incurable fatal diseases
How are chromosomes in prokaryotes?
-Typically circular and localized in the region of the cytosol called the nucleioid
what is the typical delivery system for gene therapy? How this method is called?
-Typically engineered virus is used as delivery system. -transduction
metabolic activity
-Under standard temperature conditions -the rate at which a population of cells utilizes nutrients and produces wastes is dependent on their number -Once established the metabolic rate->indirectly estimate the number of cells in a culture by measuring changes in such things as nutrient utilization, waste production, or pH
Direct penetration
-Used by naked viruses -a process in which a viral capsid attaches and sinks into the cytoplasmic membrane. This creates a pore through which the viral genome alone enters the cell. -Capsid remains outside of the cell
What does Reverse transcriptase do? How is the flow of information by this enzyme compared to the normal flow of genetic information?
-Uses RNA template (mRNA) to transcribe molecule of cDNA (complementary DNA) -Flow of genetic information in the opposite direction form the flow in conventional transcription
what Ames test media contains?
-Uses Salmonella that lacks the ability (due to point mutation) to synthesize histidine (his-) -His- Salmonella mixed with liver extract and suspected mutagen.
What does vaccines contain?
-Vaccines often contain weak (attenuated) forms of pathogen or killed. -use a portion of a pathogen rather than the pathogen itself -antigens
Negative-strand RNA (-RNA)
-Viral single-stranded RNA transcribed from the +ssRNA genome by viral RNA polymerase -Serves as the template for the transcription of multiple +ssRNA genomes -Transcription from RNA to RNA -cannot be use directly in translation, so something has to happen to it first to be able to make proteins
Conjugation
-a bacterium containing an F fertility plasmid (factor) forms a conjugation pilus that attaches to an F- recipient bacterium. -Plasmid genes are transferred to the recipient, which becomes F+ as a result. -Hfr (high frequency of recombination) cells result when an F plasmid integrates into a prokaryotic chromosome. Hfr cells form conjugation pili and transfer cellular genes more frequently than normal F+ cells.
What are the 3 things that all cells need for metabolism?
-a carbon source -a source of energy -source of electron or hydrogen atoms
methylation
-a cell adds a methyl group to one or two bases that are part of specific nucleotide sequences. -In some cases, genes that are methylated are "turned off" and are not transcribed, whereas in other cases, they are "turned on" and are transcribed.
What is the function of matrix within biofilms?
-a matrix adheres cells to one another -sticks a biofilm to its substrate -forms microenvironments within a biofilm -sequester nutrients -may protect individuals in a biofilm from environmental stresses -concentrate and conserve digestive enzymes -organize the biofilm community, allowing individual members to display metabolic and structural traits different from those expressed by those expressed by the same cells living individually (assume different roles)
Isolation techniques only work well if_
-a relatively large number of CFUs of the organism of interest are present in the initial sample -if the medium supports the growth of that microbe
bacteria typically methylate _bases and only rarely a_base
-adenine -cytosine
Agricultural uses of recombinant DNA technology include: (give examples of each) (5)
-advances in herbicide resistance (Gene from Salmonella (Agrobacterium) impacts resistance to Roundup) -salt tolerance (Gene for salt tolerance inserted into tomato and canola plants. These plants grow in produce fruit and remove salt from soil) -freeze resistance (Crops sprayed with genetically modified bacteria (pseudomonas) can tolerate mild freezes) -pest resistance (Toxin from Bacillus thuringiensis (Bt Toxin) kills insects. Bt-toxin gene inserted into cotton and corn.) -as well as improvements in nutritional value and yield. (Ripe tomatoes - gene for pectin breakdown surpressed. and rBGH - 10% more milk with reduced fat content.)
DNA gyrase (who affects it and what it does?)
-affected by Quinolones -DNA replication enzyme -an prokaryotic enzyme necessary for correct coiling and uncoiling of replicating bacterial DNA
During replication, how much of DNA is use? during translation, how much DNA is used?
-all the DNA -a needed potion of DNA
DNA contains_. In which organisms DNA is found?
-all the information that organism needs to survive -In all organisms
Horizontal gene transfer
-also called lateral gene transfer -Acquisition of genes/genetic material from other microbes; donor contributes part of genome to recipient;
bacteriophage (other name, definition, where reproduce?)
-also called phage -virus that infects bacteria -Reproduce inside bacterial host
Describe "nontoxic and nonallergenic" of the clinical considerations when selecting an antimicrobial agent
-an antimicrobial that does not lead to toxic reactions (affect negatively the patient) and allergic reactions
what is a difference between bacteriophages attachment and animal viruses attachment? what they have instead?
-animal viruses lack both tails and tail fibers -They have glycoprotein spikes or other attachment molecules on their capsids or envelopes
examples of chemoheterotrophs
-animals -fungi -other protozoa -some bacteria and yeast
DNA structure is_
-anti-parallel double helix held together by hydrogen bonding between bases -has polarity
Narrow-spectrum drugs
-antimicrobial that works against only a few kinds of pathogens
budding (to what type of virus applies, describe this process in viruses, what each virus obtain through this process what budding allows to an infected cell?)
-applies to enveloped animal viruses -As virions are assembled, they are extruded through one of the cell's membranes—the nuclear membrane, the endoplasmic reticulum, or the cell membrane. -Each virion acquires a portion of cell membrane, which becomes its envelope. -Budding allows an infected cell to remain alive for some time.
What are genes composed of? What does this parts code for?
-are composed of specific sequences of nucleotides that code for polypeptides or RNA molecules.
Among the ethical and safety issues surrounding recombinant DNA technology are
-are concerns over the accidental release of altered organisms into the environment -the ethics of altering animals for human use -the potential for creating genetically modified biological weapons.
Restriction enzymes
-are enzymes used by bacterial cells to protect against phages (virus) by cutting phage DNA into nonfunctional pieces. -Bacterial enzymes that cut DNA molecules only at specific locations (restriction sites)
heavy metals (ex and function within inhibition of metabolic pathways, why not a good choice?)
-arsenic & mercury -inactivate enzymes -It is not toxicity selective, so it can affect the human enzymes as well->have negative effects on humans
During commercial sterilization of _, the process does not kill all_, but this is not a problem because_
-canned food -hyperthermophilic microbes -They do not cause diseases and they cannot grow and spoil food at ambient temperatures
Describe helical capsid morphology
-capsomeres that bond together in a spiral fashion to form a tube around the nucleic acid
what are the 4 main macromolecules?
-carbohydrates -proteins -lipids or fats -nucleic acids
all cells require source of_,_,and_
-carbon -electrons -energy
Together what elements make up 95% of the dry weight of cells? what other elements constitute the rest?
-carbon, hydrogen, oxygen, and nitrogen -phosphorus, sulfur, calcium, maganese, magnesium, copper, iron, and a few other elements
Virulence plasmids
-carry instructions for structures, enzymes, and toxins that enable a bacterium to become pathogenic -Related to pathogens (make sick) -measure of how sick can make us -Factors (plasmids) needed to cause diseases -If bacteria have this plasmid, have some cellular trait that allow to make us sick -Create capsule, toxin, digestive enzyme
Lysogenic conversion
-change in phenotype due to insertion of a lysogenic bacteriophage into a bacterial chromosome -change bacteria from harmless to pathogenic that can secrete toxins
Categories of source of energy is based on whether organisms use _for such cellular processes as_
-chemical or light as a source of energy -anabolism, intracellular transport, and motility
Categories of source of energy:
-chemotrophs -phototrophs
Edible vaccines
-chew leaf to get vaccine and use plants to provide vaccines instead of shot -Produced by recombinant approach -Made by introducing genes coding for antigenic proteins of pathogens into common fruit or vegetables -The immune system of people and animals that such altered produced would develop immunological memory against the pathogen -Advantages: being painless, easy to administer, vaccination would not require a visit to a health care provider
The haploid genome of a prokaryotic cell consists of_
-chromosomal DNA (single and circular shape) -Extrachromosomal DNA (Plasmids)
DNA exists as_. why?
-chromosomes (DNA wind around proteins) -DNA is packed in a way that is easier to keep inside of the cells -If need DNA unwind it, then wind again after used it
describe prokaryotic chromosomes. Where are they localized within the prokarytic cell?
-circular molecules of DNA associated with protein and RNA molecules -localized in a region of the cytoplasm called the nucleoid.
turbid
-cloudiness of a broth when bacteria reproduces in a broth culture -indicates that microorganisms are growing in the media
gene library
-collection of bacterial or phage clones (identical descendants) each of which contains a portion of the genetic material of interest -may contain clones with all the genes of a single chromosome or of the set of cDNA (complementary DNA) that is complementary to an organism's mRNA -Saves time and effort required to isolate an specific gene
What are the distinctive characteristics of colonies that are used to identify different microbial species ?
-color -shape -size -elevation -texture -appearance of the colony's margin (edge)
Etest (what aspects combines, definition, steps, how get result)
-combines aspects of MIC test and a diffusion susceptibility test -test for determining minimum inhibitory concentration; a plastic strip containing a gradient of the antimicrobial agent being tested is placed on a plate inoculated with the pathogen of interest 1. after incubation, an elliptical zone of inhibition indicates antimicrobial activity, and the minimum inhibitory concentration can be noted where the zone of inhibition intersects a scale printed on the strip
nutrient broth
-common media -contains powdered beef extract and peptones dissolved in water
Biofilms are an example of_. They are considered to be a primary_
-complex relationships among numerous microorganisms, often different species, attached to surfaces -residence of microorganisms in nature
what plasmids contain? (give examples)
-contain genes that regulate nonessential life functions -Such as: bacterial conjugation; resistance to one or more antimicrobial drugs, heavy metals, or toxins; destruction of competing bacteria; and pathogenicity.
leading strand is synthesized in a_way; lagging strand is synthesized in a_way
-continuous -discontinuous or fragmented
DNA fingerprinting is used in _to establish identity by_
-criminal system to establish identity. -Isolating genetic material from different samples to link with specific individual (never 100%)
candle jars
-culture plates are sealed in a jar along with a lit candle -Flame consume O2, replacing it with CO2 -Create environment ideal for aerotolerant anaerobes, microaerophiles, and capnophiles
where in eukaryotes can you find ribosomes? what process they will perform?
-cytosol and rough ER -translation -Also they can be found in mitochondria and chloroplast (prokaryotic ribosomes)
Modifications to disinfection include:
-degermining -sanitization -pasuterization
Mutations are almost always_and rarely lead to_
-deleterious -a protein having a novel property that improves ability of organism and its descendents to survive and reproduce
Is penicillium a broad or narrow spectrum drug in contrast with other antimicrobials? include what group affects and how? why is better with this group?
-depends to which antimicrobial you are comparing -gram positive (better for this group because has a thick layer of peptidoglycan) -cell wall inhibiting
Coulter counter
-device that directly counts cells as they interrupt an electrical current flowing across a narrow tube held in front of an electronic detector -large numbers of yeast, unicellular algae, and protozoa (no good for bacteria)
polarity
-directionality -antiparallel -something different at each of the ends of each strand -Used to label
animal and cell culture
-disease must be grown on an animal (leprosy and syphilis) -Grow them within living cells (bird eggs and cultures of living cells)
Nucleotide analogous
-disrupt DNA and RNA replication and cause point mutations -Compound structurally similar to a normal nucleotide that can be incorporated into DNA -may result in mismatched base pairing or inhibit nucleic acid polymerases -because machinery mistakenly tries to transcribed the incorporated nucleotide analogous but it does not know what to do with it.
How can you create a solid media?
-dissolve 1.5% agar into hot broth -pour the liquid mixture into an appropiate vessel -allow it to cool provides a solid surface to support colonial growth
when is recombination in eukaryotes, especially humans?
-during crossing over, a process in which portions of homologous chromosomes are recombined during the formation of gametes (sex cells). -combination of different gametes (eggs and sperms) to get a different DNA combination, which will result in a very different offspring
Inactivation of the antimicrobial agent (what specifically is doing to avoid action of drug?) (often where can be obtained?)
-enzyme inactivates the antimicrobial agent (b-lactamase) -Often on R-plasmids
pH and temperature important for bacteria because these affect:
-enzymes -proteins (pH) -Nucleic acids (pH) -Also affects the membrane (phospholipi bilayer) (temperature)
standard precautions
-established by Centers for Disease Control and Prevention (CDC) -Guidelines to protect health care professional from contamination by pathogens
what is found in the vitro before PCR starts? (necessary reagents)
-excess of DNA primers (synthesized such that they are complementary to the nucleotide sequences near the ends of the target DNA) -DNA polymerase -4 deoxyribosenucloeotide triphosphates (dNTPs)-> A, T, G, C -DNA template -buffer
RNA structure
-exists in single strand -has U nucleotide instead of T (DNA) -has ribose sugar -it has polarity
Describe the things used in Griffith's Experiment
-experimental mouse -Streptococcus peunomiae: -Alive encapsulated strain S -Death encapsulated strain S -unencapsulated strain R -media (slant and vitro)
Biofilms develop_
-extracellular matrix, composed of DNA, proteins, and primairly the tangled fibers of polysaccharides of the cells' glycocalyces
what are the problems of lagging strand? (2) Describe who fix them.
-fragmented (DNA ligase) -RNA primers at the beginning of each fragment (DNA polymerase I)
what are the types of point mutation?
-frameshift mutation -substitution
what type of mutation produce the most serious damage? why?
-frameshift mutations (insertions and deletions) -Frameshift mutations affect proteins much more seriously than mere substitutions because a frame shift affects all codons subsequent to the mutation
DNA fingerprinting
-genetic fingerprinting -Technique in which identifies unique sequences of DNA to: determine paternity; connect blood, semen, or skin cells to suspects in criminal investigations; or identify pathogens -to identify individuals or organisms by their unique DNA sequences.
What does rifampin target? (prefers what type of whatever it affects? and especifically give an example of an organism that is affected by it)
-inhibit action of RNA polymerase during transcription (RNA->DNA) -Prefers prokaryotic RNA polymerase. -Affects bacterial transcription -Used primarily against M. tuberculosis (metabolize slowly thus are less susceptible to antimicrobials targeting active metabolic processes)
what stages in translation require energy? from where they obtain it?
-initiation and elongation -from molecules of the ribonucleotide GTP, which are free in the cytosol
The phenotype of a cell is dependent upon_
-integrity and accurate control of its genes (genotype)
What is a nucleotide analog and what are they mostly used to treat...why?
-interfere with function of nucleic acids -Compound structurally similar to a normal nucleotide that can be incorporated into DNA or RNA of pathogens -Distort shapes of nucleic acid molecules: prevent further replication, transcription, or translation -Most often used against viruses: viral DNA polymerases lack proofreading ability (our cells have this ability to check the DNA/RNA strand, after being made, for errors and correct the mistakes) (viral nucleic acid synthesis is more rapid than cellular nucleic acid synthesis) -Also effective against rapidly dividing cancer cells
mRNA of eukaryotes have_removed, so can be_
-introns -can be cloned into prokaryotic cells -Since eukaryotic cDNA lacks noncoding sequences, scientists can insert it into prokaryotic cells, making it possible for the prokaryotes to produce eukaryotic proteins such as human growth factor, insulin, and blood-clotting factors.
Genome (describe also what it includes)
-is the sum of all the genetic material in a cell or virus. -the entire genetic complement of an organism; includes its genes and nucleotide sequences
Biotechnology
-is the use of microorganisms to make practical products -such as bread, wine, paper, and antibiotics.
Origin of replication
-is where replication begins. -As double stranded DNA "unwinds" replication proceeds at what is called the replication fork (where strands are being pulled apart and bases are being exposed).
what is the direction of synthesis of the new DNA strand during replication taking into account the other strand?
-it is antiparallel -Parent strand (3'->5') -daughter strand (5'->3')
how is DNA replication in prokaryote DNA?
-it is bidirectional -it has a single origen, so it involves two sets of enzymes, two replication forks, two leading strands, and two lagging strands -Topoisomerase -methylation of the daughter strand
What are the name of the two strands that are formed in DNA replication?
-lagging strand -leading strand
provirus
-latent viruses -Inactive virus in an animal cell
Ergesterol
-lipid constituent of fungal membranes -the antifungal group of drugs called polyenes, including amphoterecin B, attach to it to disrupt the membrane and cause lyse of the cell
Temperatures also effect the sensitive_, such as those that are _
-lipids -components of the membranes of the cells and organelles
Thermophiles are temperature_, Hypermophoes are _, Mesophiles are_, and psychrophiles are_
-loving -extreme temperature loving -so kind of love it (middle) -psychoes that like very cold temperatures
what are the two reproductive cycles for viruses?
-lytic -lysogenic
Types of bacteriophage
-lytic -lysogenic
what RNA polymerase transcribes? (products)
-mRNA -tRNA -rRNA
Describe synthesis of +ssRNA
-mRNA syntehsized: Genome acts as mRNA -Template for Genome replication: -RNA complementary to the genome is synthesized to act as template
Describe synthesis of +ssRNA (retroviridae)
-mRNA synthesis: DNA is synthesized from RNA by reverse transcriptase; mRNA is transcribed from DNA by RNA polymerase -Template for genome replicaiton: DNA -Do not use their genome as mRNA, use DNA -DNA intermediary serves as template for synthesis of additional +RNA molecules, which act both as mRNA for protein synthesis and as genomes for new virons
Describe the synthesis of dsRNA
-mRNA synthesized: Positive strand of genome acts as mRNA -Template for genome replication: Each strand of genome acts as template for its complement -When dsRNA functions as the genome of some viruses, one strand of the RNA molecule functions as the genome, and the other strand functions as a template for RNA replication.
Describe synthesis of -ssRNA
-mRNA synthesized: by RNA-dependent RNA transcriptase -Template for genome replication: +RNA (mRNA) complementary to the genome (-RNA) -Transcription form RNA to RNA
what is another use of genomics?
-make gene maps of organisms -is to relate DNA sequence data to protein function.
Microorganism must be in a _environment to be metabolically active.
-moist
DNA is composed solely of_, whereas RNA is composed of_
-molecules of deoxyribonucleic acid (DNA) -ribonucleic acid
nucleotide analogs
-mutagen -Compound structurally similar to a normal nucleotide that can be incorporated into DNA -May result in mismatching pairing
Is isoniazid a broad or narrow spectrum drug in contrast with other antimicrobials? include what group affects and how?
-narrow -mycobacterium (tuberculosis and leprae) -by targeting mycolic acid synthesis
chemical mutagens can occur_
-naturally or synthesized
Some pathogens are _ or _ (deals with resistance)
-naturally partially -completely resistant
frameshift mutation
-nucleotide triplets after the mutation displaced -nucleotide triplets subsequent to an insertion or deletion are displaced, creating new sequences of codons that result in vastly altered polypeptide sequences.
Organisms use a variety of _for their energy needs and to build _and _
-nutrients -organic molecules and cellular structures
What is antagonism?
-opposite to synergism -Drugs interfere with each other -The effect of one drug contrasts or almost eliminates the effect of the other drug -they both might fight the disease well alone but together they cannot do it efficiently
which type(s) of routes of administration are used for systemic infections?
-orally -intramuscularly (IM) -intravenously (IV)
growth factor
-organic chemical such as vitamins required in very small amounts for metabolism -Organism need them because they cannot synthesize
Vertical gene transfer
-organisms replicate their genomes and provide copies to descendants -is the transmission of genes from parents to offspring
fastidious
-organisms that require a relatively large number of growth factors -Such organisms may be used as living assays for the presence of growth factors (know if an specific growth factor and its quantity is present in the sample)
phototrophs
-organisms that use light as their energy source
Examples of pausterization
-pausterized milk and fruit juices
bacteriophage
-phage -Virus that infects and usually destroys bacterial cells
Restriction enzyme cut_bonds. Ligase _
-phosphodiester -seal gaps (paste) DNA by creating phosphodiester bond between the fragments of DNA
what is the usage of phosphorus in cells?
-phospholipid bilayer -DNA -RNA -ATP -Proteins
Scientists use a variety of _ to manipulate_ and create ._
-physical agents, naturally occurring enzymes, and synthetic molecules -genes and genomes -gene libraries
examples of photoautrophs
-plants -some protozoa -algae -cyanobacteria -Green sulfur bacteria and purple sulfur bacteria
Amphotericin B
-polyene -Disrupts the cytoplasmic membrane of a targeted cell -antifungal drug -It attaches to ergesterol in the process disrupting the membrane and causing lysis of cell -treats systemic fungal infections
sigma factor
-polypeptide subunit of RNA polymerase -It is necessary for recognition of promoter -It adheres to promoter sequence -is subunit of RNA polymerase that recognizes Promoter DNA sequence.
Where is the environmental species are taken? where is clinical species are taken? what is another source of the inoculum?
-ponds, streams, soils, and air -taken from patients and handled in ways that facilitate the examination of or testing for the presence of microorganisms -Culture originally grown from an environmental or clinical specimen and maintained storage in a lab
what is another function of polymerase III besides adding nucleotides to the new strand in DNA replication? what is the name of this role?
-proofreading functions -Correct mismatched nucleotide pairs -DNA polymerase III recognize most such errors and removes the incorrect nucleotides before proceeding with synthesis -This role is called "proofreading exonuclease"
what is the function of the caspid?
-protect nucelic acid of viruses
In the extracellular stage, all viruses have_and some viruses have_
-protein coat and piece of nucleic acid that can be either DNA or RNA -envelope
Lysozyme (definition and in what parts of lysogenic cycle is used)
-protein enzyme carried within the capsid (in T4) that weakens the peptidoglycan of the cell wall -used in entry and release
Capsomeres (definition, shape they form, and components)
-protein units that make up capsid -form the tridimensional shape of virus -may be composed of only a single type of protein, or of several different protein molecules.
A medium must have_to grow and multiply microorganisms
-provide essential nutrients -water -appropriate oxygen level -required physical conditions (pH, osmotic pressure, and temperature)
Stab
-put stuff inside the media and stab it into the media (reap surface) -anaerobic media
rBGH
-rBST -recombinant cow hormone -produce more milk, and less fat content
How does DNA polymerase III works?
-read nucleotide in the parent 1 strand -Form hydrogen bond between pairing nucleotides (automatically because their affinity between nucleotides) -Form phosphodiester bonds between nucleotides within the same strand -Catalyze the formation of the forms (speed up)
promoter
-region of DNA where transcription begins -It is recognized by RNA polymerase
what are the 5 steps of synthesizing the leading strand?
1. Primase synthesize a short RNA molecule that is complementary to the DNA strand. This RNA primer provides the 3' hydroxyl group required by DNA polymerase III 2. Triphosphate deoxyribonucleotides form hydrogen bonds with their complements in the parental strand (A-T/G-C) 3. Using the energy in the high-eneryg bonds of the triphosphate deoxyribonucleotides, DNA polymerase III covalently joins them one at a time to the leading strand. 4. DNA polymerase III also performs a proofreading function. DNA polymerase III recognize mismatched nucleotide errors and removes the incorrect nucleotides before proceeding with synthesis. 5. DNA polymerase I replaces the RNA primer with DNA
what are the steps of initiation in transcription?
1. RNA polymerase attaches nonsignlifically to DNA and travels down its length unit it recognizes a promoter sequence. Sigma factor enhances promoter recognition in bacteria 2. Upon recognition of the promoter, RNA polymerase unzips the DNA molecule beginning at the promoter
Describe the steps used to make a recombinant vector
1. Restriction enzyme cuts both DNA molecule containing the gene of interest and the vector DNA into fragments with sticky ends 2. Ligase anneals the fragments to produce a recombinant plasmid 3. The recombinant plasmid has been inserted into a bacterial cell 4. The bacteria are grown on a medium containing the anitbiotic 5. Only those cells that contain the recombinant plasmid can grow in the medium
How the structure of DNA explains its ability to act as genetic material?
1. The linear sequence of nucleotides carries the instructions for the synthesis polypeptides and RNA molecules 2. The complementary structure of two strands allows a cell to make exact copies to pass to its progeny
What is one of the various ways to perform pour-plate method?
1. an initial 1mL sample is mixed into 9.0mL of medium in a test tube. 2. After mixing, a new sample from this medium is then used to inoculate a second tube of liquid medium. 3. The process is repeated to establish a series of dilutions 4. Samples from the more diluted media are mixed in petri dishes with sterile, warm medium containing agar 5. After agar solidifies and cools down, the petri plates are incubated 6.Isolated colonies form in the dishes from CFUs that have been separated via the dilution series
List explain four tests used to determine drug efficacy?
1. broth diffusion test 2. Etest 3. Diffusion susceptibility tests (Kirby-Bauer test) 4.Minimum Bactericidal Concentration (MBC) Test
Phases of microbial growth
1. lag 2. log 3. Stationary 4. Death
what are the differences between RNA and DNA?
1. nucleotides in DNA (A,T,G,C) are different from nucleotides in RNA (A,U,G,C) 2. Type of sugar in DNA (deoxyribose) and RNA (ribose)
Transport media
A special type of medium used to move clinical specimens from one location to another while preserving the relative abundance of organisms and preventing contamination of the specimen or environment
During DNA replication, the enzyme primase is_ a. Used more on the lagging strand b. Used more on the leading strand c. Not used during replication
A. used more on the lagging strand
AFB Stain
AFB cells contain MYCOLIC ACID in their cell wall. When the mycolic acid is heated, AFB+ cells are penetrated by the primary stain CARBOLFUSCHIN which is retained after cooling through treatment with the decolorizer ACID ALCOHOL and appear PINK. Non-AFB cells are stained blue with the counterstain methylene blue and appear BLUE.
How ATP fits within DNA and RNA?
ATP is a building block for nucleic acids
the ability of a microbe to contrast the effect of sulfonamides will be what kind of mechanism of resistance?
Altered target site
Facultative halophiles
Although microorganism does not require high salt concentrations, they can tolerate them
What are the antimicrobials that disrupt the cytoplasmic integrity?
Amphotericin B Polymyxin
What category/mechanism does penicillin use?
Cell Wall Inhibitor
What is wrong with a person that has Type II diabetes?
Cells do not respond appropriately to insulin.
carcinogen
Chemical mutagen capable of causing cancer
drugs
Chemicals that affect physiology in any manner ex: caffeine, alcohol, and tobacco
How are chromosomes in eukaryotes?
Chromosomes are threadlike and are most visible during mitosis and meiosis
who sets the reading frame of mRNA?
Codons
incubation
Colonies develop from each isolate
when a cell can be competent?
Competency is found naturally and can be created artificially in some cells.
bacterial conjugation is mediated_
Conjugation pili or sex pilli
Catalase Test
Conversion of H2O2 to O2 & H2O by catalase. After incubation in any solid medium, H2O2 added which cause bubbling indicates a positive result. No bubbles indicate a negative result.
Nitrate Broth
Conversion of NO3 to NO2 by nitrogen reductase. If addition of reagent A (sulfanilic acid) & B (N, N-dimethyl-I-napthylamine) after incubation turns broth red, positive for NO3 reduction to NO2. If colorless and addition of C (zinc dust) causes red color change, negative result confirmed. If colorless and addition of C does not cause color change, NO3 denitrified to N2 (also positive).
During transformation, where is the source of the DNA that a competent cell takes and incorporates it to its genome?
DNA that might be released by dead organisms
DNA template
DNA to be copied
leading strand
Daughter strand of DNA synthesized continuously (5'->3') toward the replication fork as a single long chain of nucleotides
Phenylalanine Agar Slant
Deamination of amino acid phenylalanine by phenylalanine deaminase. Addition of ferric chloride* after incubation causes a color change to green in the presence of phenylpyriuvic acid, resulting from the deamination of phenylalanine. Yellow or no color change indicates a negative result.
Amino Acid Decarboxylase Media lysine OR ornithine
Decarboxylation of amino acids by lysine or ornithine decarboxylases. Bromcresol purple in the medium causes a pH sensitive color change when the environment has been kept anaerobic by the addition of mineral oil. Color change to purple indicates a decarboxylation of the amino acid and the production of an alkaline environment. Color change to yellow indicates a negative result. Cultures incubated without mineral oil may result in a false negative result.
Pressure
Deep of the ocean (pressure) some organisms need this pressure to keep their shape
Nitrate Durham Broth
Denitrification of NO3 to N2 by nitrate-, nitrite-, nitric oxide- and nitrous oxide reductase. N2 gas trapped in inverted Durham tube indicates a positive result. No gas indicates a negative result. Nitrate reagents A, B, & C can also be used to further test nitrate use by the organism.
Motility Deep
Determine motility via production of structural protein flagellin. Growth is visualized using the redox indicator 2,3,5-triphenyl-tetrazolium in the medium. Movement through the agar is facilitated by a semisolid environment (5% agar). Growth away from the line of inoculation indicates motility. Growth along the entire surface of the medium may also indicate motility of an aerobe. Growth only along the line of inoculation indicates no motility.
E site
Discharged tRNAs exit from this site
Petri plates
Dish filled with solid medium used in culturing microorganisms
Describe "inexpensive" of the clinical considerations when selecting an antimicrobial agent
Does not cost too much
How does the enveloped animal viruses obtain the glycoptroteins on the surface of the envelope? (what they become once they are attached to envelope?)
During synthesis, some viral glycoproteins are inserted into cellular membranes, and these proteins become the glycoproteins spikes on the surface of the viral envelope
What is an example of facultative anaerobes?
E. Coli
what is the benefit of using reverse transcriptase?
Easier to isolate mRNA molecule for desired protein first (than finding the gene of interest in the cell genome to get mRNA and then get protein)
Temperature has effect on_
Effect of temperature on proteins (tertiary structure) Effect of temperature on lipid-containing membranes of cells and organelles
Selectively media
Either favors growth of particular microbe or inhibits growth of unwanted ones.
lagging strand synthesis 5 steps
1. Primase synthesis RNA primers. in the lagging strand, primase synthesizes multiple primers (different in leading strand which is only once) 2. Nucleotides pair up with their complements in the template (A-T/C-G) 3. DNA polymerase III joins neighboring nucleotides and proofreads. The lagging strand is synthesized in discontinuous segments called Okizaki fragments (each okizaki fragment has a RNA primer) 4. DNA polymerase I replaces the RNA primers of Okazaki fragments with DNA and proofreads the short DNA segment it has synthesized 5. DNA ligase seals the gaps between adjacent Okizaki fragments to form a continuous DNA strand
Tryptone Broth
Indole production via the hydrolysis of tryptophan by tryptophanase. A red layer on top of medium with the addition of Kovacs' reagent* after incubation indicates the presence of indole, a by-product of tryptophanase activity. A yellow or no color change indicates a negative result.
SIM: Indole Production/Tryptophan Hydrolysis
Indole production via the hydrolysis of tryptophan by tryptophanase. Red color change by addition with Kovac's reagent* after incubation indicates indole production from tryptophan. Yellow or no color change with addition of reagents indicates a negative result.
Reverse transcriptase is isolated from what organism? (specify if their genome is of DNA or RNA)
Isolated from retroviruses (RNA genomes)
what is one difference between the streak and pour plates methods?
It is that colonies form both at and below the surface of the medium in pour plates method
what encodes genetic information?
Linear sequence of nucleotides
Ex of aerotoleran, microaerophilic, or obligate anaerobes?
Many prokaryotes and a few protozoa
what are the 3 indirect methods of quantifying bacterial numbers?
Metabolic activity Dry weight Turbidity
Ames test
Method for screening mutagens that is commonly used to identify potential carcinogens
streak plate
Method of culturing microorganisms in which a sterile inoculating loop is used to spread an inocolum across the surface of the solid medium in Petri dishes
Pour plate
Method of culturing microorganisms in which colony-forming units are separated from one another using a series of dilutions
Transduction
Method of horizontal gene transfer in which DNA is transferred from one cell to another via a replicating virus
Using thioglycollate growth medium, how you would know an organism is microaerophilic aerobe?
Microaerophiles would be found slightly below the surface, but neither directly at the surface nor in the depths of the tube
obligate halophiles
Microbes that are adapted to growth under high osmotic pressure
Chemoautrotoph
Microogranism that uses carbon dioxide as a carbon source and catabolizes organic molecules for energy
alkinophiles
Microorganism requiring alkaline pH environments
Psychrophiles
Microorganism requiring cold temperatures (below 20 degree C)
neutrophiles
Microorganism requiring neutral pH
Termophile
Microorganism requiring temperatures above 45 degree C
Hyperthermophile
Microorganism requiring temperatures above 80 degree C
What eukaryotic organelle is mostly affected by treatment with these types of drugs and why?
Mitochondria of animals and humans contain 70S ribosomes; can be harmful
How most DNA viruses are assembled? (where?)
Most DNA viruses assemble in and are released from nucleus into cytosol
how most RNA viruses are assembled?
Most RNA viruses develop solely in cytoplasm
What viruses use the endocystosis method to enter their host's cells?
Most enveloped viruses and some naked viruses Adenoviruses (naked) and Herpesviruses (enveloped)
how determine which route of administration will be better for an infection? (besides considering the route of administration)
Must know how antimicrobial agent will be distributed to infected tissues
anticodon
Portion of tRNA molecule that is complementary to a codon on mRNA
Examples of sterilization
Preparation of microbial culture media and canned food
Genetic screening
Procedure by which laboratory tests are used to screen patient and fetal DNA for mutant genes
Viral latency
Process by which an animal virus, sometimes not incorporated into the chromosomes of the cell, remains inactive in the cell, possibly for years
transcription
Process in which the genetic code from DNA is coped as RNA nucleotides sequences
translation
Process in which the sequence of genetic information carried by mRNA is used by ribosomes to construct polypeptides with specific amino acid sequences (proteins)
Lytic replication
Process of viral replication consisting of five stages ending with lysis of and release of new virions from the host cell
How are prokaryotic ribosomes different from eukaryotic ribosomes?
Prokaryotic ribosomes are 70S (30S and 50S) Eukaryotic ribosomes are 80S (40S and 60S)
SIM: Hydrogen Sulfide Production
Removal of sulfur group from amino acids by cysteine or other desulferase. Cleaved sulfur groups from amino acids complex with iron salts in the medium to produce a black precipitate. Black precipitate indicates H2S production. No black precipitate indicates a negative result.
if a cell obtains the ability to absorb folic acid from the environment or synthesis folic acid in other way different of using PABA, which affects the ability of sulfonamide, what type of mechanism of resistance is?
Replacement of a sensitive pathway
what is the direction that DNA polymerase replicates DNA?
Replicates DNA only 5′ to 3′
what does virus replication cycles result? (ultimately outcome/end of the host)
Replication cycle usually results in death and lysis of host cell
Diagram the central dogma of genetics
Replication->DNA->Transcription->RNA->translation->protein
why viruses received their name? (meaning)
Scientists named this tiny agents "viruses," from the Latin word "poison"
Explain the basis of inhibition of nucleic acid synthesis
Several drugs function by blocking DNA replication or mRNA transcription
how can you determine the amount of DNA in gel electrophoresis technique?
Smaller and thinner lines has less amount of DNA than big square-shaped lines
Describe "Chemical stable" of the clinical considerations when selecting an antimicrobial agent
So that it can be transported easily and stored for long periods of time
Spore Stain
Spores are protected by a thick spore coat. When the spore is heated, it is penetrated by the primary stain MALACHITE GREEN and appears BLUE/GREEN. After cooling, WATER serves to decolorize vegetative cells which are then counterstained with SAFRANIN and appear PINK.
What are two common isolation techniques?
Streak plates Pour plates
-stasis -static
Suffixes indicating inhibition, but no complete destruction, of a type of microbe
what was the first practical antimicrobial agent in efficacious in treating a wide array of bacterial infections?
Sulfanilamide
what are the three types of horizontal gene transfer?
Transformation Transduction Bacterial Conjugation
the end product of DNA replication is
a copy of DNA
What does the slanted surface provides?
a larger surface area for aerobic microbial growth while the butt of the tube remains almost anaerobic
to infect a cell, a virus has to be_which can be either_
a nucleic acid which can be either DNA or RNA
what shape does viruses take when they are intracellular?
a piece of nucleic acid that can be either DNA or RNA
competence
ability of a cell to take up DNA from the environment (this also applies to plasmids)
A site
accommodates a tRNA delivering an amino acid
DNA polymerase III
adds deoxynucleotides to the 3' end of the RNA primer.
Microaerophiles (detoxify what)
aerobes that require oxygen levels from 2-10% and have a limited ability to detoxify hydrogen peroxide and superoxide radicals
colony
aggregations of cells arising form a single parent cell
Ex of obligate aerobes?
algae, most fungi, and protozoa, and many prokaryotes
Defined media is called like this because?
all the components known and more exclusive for the bacteria that grow within it
competent cells results from alterations in_
alterations in cell wall and cytoplasmic membrane that allow DNA to enter cell
what was gotten by searching to get protein synthesized by Recombinant DNA technology?
Erythropoietin (Epo) rBGH (rBST)
Genetic recombination
Exchange of nucleotide sequences often mediated by DNA segments composed of homologous sequences (identical or nearly identical nucleotide sequences )
Induction
Excision of a prophage from the host chromosome, at which point the prophage reenters the lytic phase
what is one difference between the exocytosis and lytic cycle performed by a naked virus to get out of the cell?
Exocytosis keeps the bacterial cell alive, while the lysis cycle burst it
R-plasmid
Extrachromosomal piece of DNA containing genes for resistance to antimicrobial drugs
Using thioglycollate growth medium, how you would know an organism is facultative anaerobes?
Facultative anaerobes can grow with or without oxygen, but their ability to use aerobic respiration pathways enhances their growth near the surface, so they would be found predominantly on the top but also dispersed throughout the tube
Starch Agar
Hydrolysis of starch to maltose by the EXOenzyme amylase. Iodine added after incubation turns black in the presence of starch in the medium. A clear zone adjacent to growth indicates a lack of starch and a positive result. No clear zone is a negative result.
Skim Milk Agar
Hydrolysis of the milk protein casein by the EXOenzyme caseinase. Hydrolysis of casein in the medium noted by a clear zone in the medium adjacent to growth indicates production of caseinase. No clearing is indicative of a negative result.
A clear zone of phage infection in a bacterial lawn is a. a prophage b. a plaque c. naked d. a capsomere
b. a plaque
A DNA gene synthesized from an RNA template is_ a. reverse transcriptase b. complementary DNA c. Recombinant DNA d. Probe DNA
b. complementary DNA
The synthesis of RNA from a DNA template is called_ a. Replication b. Transcription c. Translation d. Mutation e. Recombination
b. transcription
plasmids are only found in which organism?
bacteria
Contrast between bacteriophages and animal virus: site of synthesis
bacteriohage: in cytoplasm Animal virus: RNA viruses in cytoplasm; most DNA viruses in nucleus
Contrast between bacteriophages and animal virus: Nature of chronic infection
bacteriophage: Lysogeny, always incorporated into host chromosomes, may leave host chromosomes animal viruses: Latency, with or without incorporation of DNA; incorporation is permanent
Contrast between bacteriophages and animal virus: site of assembly
bacteriophage: in cytoplasm animal virus: RNA viruses in cytoplasm; most DNA viruses in nucleus
Contrast between bacteriophages and animal virus: Mechanism of release
bacteriophage: lysis animal viruses: Naked virions: exocytosis or lysis; enveloped virions: budding
Contrast between bacteriophages and animal virus: uncoating
bacteriophage: none animal virus: removal of capsids by cell enzymes
why there is redundancy in the amino acids that are coded by two or more codons?
because of the flexibility angle of the third loop of tRNA, which fits with the third codon
why a portion of a F plasmid and donor's chromosome are transferred instead of the entire donor chromosome?
because the movement of the cells breaks the intercellular connection before an entire donor chromosome is transferred
why the recipient cell remains as F- cell?
because the recipient receives only a portion of the F plasmid
why is important to not over prescribe antibiotics?
because the resistant strain of bacteria will grow in large amounts or become the majority of the population since the sensitive-drug bacteria will not give competition to the resistant strain by decreasing in number due to the antimicrobials
Why DNA viruses enter the nucleus of the animal cell?
because there is the machinery to perform replication and transcription of the cell
When clinical specimens are collected in order to identify a suspected pathogen, why we have to isolate them?
because they are together with normal microbiota
why viruses are obligate intracellular parasites?
because they do not have organelles that are needed for reproduction, so they use host cell's metabolic pathways to increase their numbers (reproduction)
Why Hydroxyl does not affect aerobes?
becuase hydrogen perioxide does not accumulate in aerobic cells due to catalase and perioxidase
Phosphodiester bonds are found between_
between 5' phosphate group and 3' hydroxyl group of another nucleotide
Given that many microorganisms become more harmful when they are part of a_
biofilm
phosphodiester bonds
bonds that are found between nucleotides to form nucleic acids (DNA and RNA)
Eukaryotic genomes consist of_
both nuclear and extranuclear DNA
In which processes of getting out of the cell by viruses result in an alive bacteria?
budding (enveloped virus) Exocytosis (naked virus)
the electrophoresis chamber is filled with_
buffer solution and agarose (similar to agar)
How the two strands of DNA are held together?
by base-pairs of nucleotides bases connected by hydrogen bonds
How nucleic acids are formed?
by linking nucleotides together by phosphodiester bonds.
How cells controls over the relative amount of transcription?
by using different sigma factors and different promoter sequences
what type of replication takes more time? (bacteriophages or animal viruses)
animal viruses replication
antibacterial drugs are commonly called_
antibiotics
normal microbiota
are microorganisms associated with a certain area of the body without causing a disease
where does helicase starts to separate the DNA strands in DNA replication?
at the origen of replication
where does transcription begins?
at the promoter
where does translation happens?
at the start codon AUG
where does transcription ends?
at the terminator
what is wrong with a person that has Type I diabetes ?
b cells of pancreas do not make insulin.
Which of the following is not a growth factor for various microbes? a. cholesterol b. water c. vitamins d. heme
b water
the lyzogenic replication cycle involves which phages?
called lysogenic phages or temperate phages
Facultative anaerobes
can maintain life via fermentation or anaerobic respiration or by aerobic respiration
Recombinants
cells with DNA molecules that contain new nucleotide sequences
Attachment of virus depends on_
chemical attraction and precise fit between attachment proteins onthe phage's tail fibers (in this case T4) and complementary receptor protein on the surface of the host's cell wall
_plays a secondary role to the mechanical removalof microbes
chemicals
what are some examples of viruses that are latent?
chickenpox viruses herpes viruses
What are the two principal genomic structures within prokaryotes?
chromosomes plasmids
petri dishes
clear, flat, culture dishes with loose-fitting lids
transport media
clinical specimens are transported in transport media that are chemically formulated to maintain the relative abundance of different microbial species or to maintain an anaerobic environment
anticodon are complementary to_
codons of mRNA
biofilm
collection of microbes living on a surface in a complex community
medium
collection of nutrients used for cultivating microorganisms
Pour plate is based on_of bacteria
dilution
Microbiologists use _methods to estimate microorganisms
direct and indirect
Antiseptics are frequently_
disinfectants whose strength has been reduced to make them safe for living tissues
Unlike sterilization,_does not guarantee that all pathogens are eliminated
disinfection
"the sterols in the cell membrane become nonfunctional" with which action of microbial drugs?
disruption of cytoplasmic membrane
Colonies have_ that can help identify and classify microbe.
distinctive characteristics
after incubation, the various types of organism present are_
distinguished from one another by differences in colonial characteristics.
Anaerobes
do not use aerobic metabolism
what happens in termination phase in translation?
does not involve tRNA; instead, proteins called release factors halt elongation. The ribosome then disoociates into its subunits.
temperature range
each organism survives over a temperature range, within which its growth and metabolism are supported
Simplest beta-lactams effective only against_
effective only against aerobic Gram-negative
hyperglycemia
elevated blood glucose levels
who makes DNA replication reactions to occur?
enzymes
sterile
free of any microbial contaminants
where restriction enzymes are isolated?
from bacterial cells
The creation of injections for diabetes is an example of the use of _
genetic engineering
Recombinant DNA technique provides a simpler and universal methods for_
genetic mapping
how genotype differs from genome?
genome also includes nucleotides that are not part of genes, such as nucleotide sequences that link genes together
cell counter
glass slide composed of an etched grid positioned beneath a glass cover slip -It has 25 large squares which are divided into 16 small squares
P site
holds a tRNA and the growing polypeptide
What is the most common chemical element in the cells?
hydrogen
what are the bonds found between the base pairs?
hydrogen bonds
The two strands of DNA are held by_
hydrogen bonds between complementary bases of nucleic acids called base pairs (BP)
where does viruses cause most diseases? (_world)
in industrial world
where are macrophiles found within a Thioglycollate tube?
in the middle
substitutions
in which a single nucleotide is substituted for another, possibly leaving the amino acid sequence unaffected because of the redundancy of the genetic code.
Selective media differentiate bacteria by_
inability to grow within the media
"the replication of cells, including cancer cells, slows down" is associated with which action of microbial drugs?
inhibition of nucleic acid synthesis
Genetics
is the study of inheritance and inheritable traits as expressed in an organism's genetic material
what is the specific epithet of viruses?
is their common English designations: virus
what will happen to damaged DNA?
it can be repaired by the molecular mechanisms of the cell
what will happen to the protein if you change the sequence of nucleotides?
it changes the way it works, most of the times in a negative way (does not work) and rarely in a positive way (improves ability of organism and its descendents to survive and reproduce )
where does the energy required in DNA replication is obtained?
it is carried within the the building blocks of DNA when they are in triphosphate deoxyribonucleotide form
what are the ethical consequences of medical diagnosis?
know beforehand what is wrong with someone (human)
Polymer
large chains of building blocks that are repeated
how are called the viruses involved in latency?
latent viruses or proviruses
obligate anaerobes must derive the energy they need for metabolism from_
light
Recombine (in recombinant DNA technology)
linking two pieces of DNA that were not together before creating a new DNA
what translation uses to determine the sequence of amino acids?
mRNA
what are the three important molecules in translation?
mRNA (start with) tRNA rRNA
carbon dioxide incubators
machines that electronically monitor and control CO2 levels, provide atmosphere that mimic environments of the intestinal tract, respiratory tract, and other body tissues
pH
measurement of the concentration of hydrogen ions in a solution
human pathogens are in which category of temperature?
mesophile because they can stand 37 degree Celsius of the human body
what is a major characteristic of all living things?
metabolism
conjugation
method of horizontal gene transfer in which a bacterium containing a fertility plasmid forms a conjugation pilus that attaches and transfers plasmid genes to a recipient; in reproduction of ciliates: coupling of mating cells
What happens after DNA replication?
methylation occurs
genetic engineering can also be called as_
recombinant DNA technology
transgenic organisms
recombinant plants and animals that have been altered for specific purposes by the addition of genes from other organisms.
Heat treatment in pasteurization is brief to_
reduce alteration of taste and nutrients
_is important prior cell division
replication
What is the ultimate outcome of metabolic activity?
reproduction
A vaccines primes the immune system to_
respond quickly and effectively when confronted with pathogens and their toxins
what is a type of +ssRNA?
retrovirus
Scientists now use recombinant DNA technology to produce _
safer vaccines
inocolum
sample of microorganisms
Anaerobic media
see differences in oxygen requirements
The fewer drugs to treat eukaryotic infections and the even fewer antiviral drugs is related to_
selective toxicty
why the strands of DNA do not join together again into the helix shape after DNA helicase separated them?
stabilizing proteins: other protein molecules stabilize the separated single strands so that they do not rejoin while replication proceeds (found all along DNA strands)
In Pasteruization microbes _
still remain and eventually cause spoilage
What is the most common used isolation technique in microbiological laboratories?
streak plate
NAM
subunit of peptidoglycan in cell wall - n-acetylmuramic acid
NAG
subunit peptidoglycan in cell wall n-acetylglucosamine
what happens in elongation phase in translation?
tRNAs sequentially deliver amino acids as directed by the codons of mRNA. Ribosomal RNA in the large ribosomal subunit catalyzes a peptide bond between the amino acid at the A site and the growing polypeptide at the P site.
Goal of recombination DNA technology
take two pieces of DNA that weren't together before and to link them together
how are nucleic acids form? (basic process and explain it in terms of catabolic or anabolic)
taking small parts (nucleotides) to putting them together to form a large molecule (anabolic reactions)
Differentiate media take advantage of the fact_
that different bacteria utilize the ingredient of any given medium in different ways
The specificity of attachment proteins for the receptors ensures_
that the virus will atach only to certain kind of bacteria (in T4: E. coli)
what is the difference between disinfecting and sanitizing?
the arena (private vs public), which public is sanitizing, in which activity takes place
what makes viruses inside the bacterial host cell?
the bacterial enzymes that chunk bacterial chromosome and make viruses by being controlled by the virus DNA
Before DNA replication, what happens?
the cell removes histones and other proteins from the DNA molecule
what two codons specify the amino acids?
the first two codons
mRNA is the deliver device of_
the gene of interest
What happens after cycle 1 in PCR?
the process starts again with denaturation
what is unique in viruses respecting the types of genomes?
they can perform transcription from RNA to RNA
where bacteria and archae are classified within these categories?
they exhibit greater metabolic diversity than any other group, with members in all four groups
How ATP and dATP (adenine monomer) differ?
they have similar structures but ATP is a ribonucleotide (RNA monomer) rather than deoxyribonucloetide (DNA)
why anaerobes are susceptible to action of hydrogen perioxide?
they lack catalase and/or perioxidase
List the three main categories of drug side effects.
toxicity allergies disruption of normal microbiota
reverse transcriptase
transcriptase is an enzyme that transcribes DNA nucleotides from an RNA template.
Some of the DNA will be copy in _ in a form of RNA
transcription
what is the main function of tRNA in translation?
transfer the correct amino acid to a ribosome during polypeptide synthesis
what is the faster technique to measure quantity of microbes in a solution?
turbidity by using spectrophotometer
how many hydrogen bonds are found between adenine and thymine (DNA) and adenine and uracil (RNA)?
two hydrogen bonds
Number of viruses produced and released depends on _
type of virus and size and initial health of host cell
what type of rays are considered to be within pyrimide dimers?
ultraviolet light
Aerobes
undergo aerobic respiration
Examples of sanitization
washing tableware in scalding water in restaurants
Microorganisms require_
water
what is the function of chromosomes?
way to store and organize DNA in organisms
What is the important fundamental question to categorize viruses?
what type of nucleic acid it has (DNA or RNA)? (what is inside the capsid in the extracellular stage?)
when transcription terminates?
when RNA polymerase and the transcribed RNA are released from DNA
What is a bacterial colony and how can it be used to identify and classify a microbe?
• A bacterial colony is colonies of bacteria isolated within a petri dish that has distinctive characteristics that help in identifying the microbial species that formed the colony. • It can be used to identify and classify a microbe by using the specific characteristics including color, size, shape, elevation, texture, and appearance of the colony's margin (edge). All taken together aid in identifying the microbial species that formed the colony
What does it mean that bacterial grow logarithimically?
• Bacteria grows exponentially by binary fission • It is calculated as 2^n (n=number of generations) • Logarithmic growth: increase in size of a microbial population in which the number of cells doubles in a fixed interval of time.
Aerotolerant anaerobes
- do not use aerobic metabolism but have some enzymes that detoxify oxygen's poisonous forms
how we use bacteriohages in the lab?
- used in our lab to calculate viral plaques, and consequently the number of viruses in the original sample -In transduction process
Positive strand RNA
-(+RNA), which can be directly translated by ribosomes to synthesize protein. -Viral single stranded RNA that can act directly as mRNA
Glycoproteins (definition, what are important for, other name, how assembled, and where located)
-(sugar) they are outer molecules important for entry within the cell (recognition cell) also called spikes -they assembled by the cell and put on the outer most cell (capsoid or envelope) depending on the virus -recognize the cell and get inside the host cell (key to enter the cell)
Why water is important for microorganisms?
--Because water is needed to dissolve enzymes and nutrients -It is an important reactant in many metabolic reactions
When was insulin isolated? (year) when insulin treatment has been used to treat Diabetes?
-1921 -1924
lag
-1st phase of microbial growth -No growth -bacteria adjusting to conditions -Synthesis enzymes (nutrients in the medium)
Interpret results of broth dilution test
-After incubation -Turbidity (cloudiness) indicates bacterial growth; lack of turbidity indicates that the bacteria were either inhibited or killed by the antimicrobial agent
Chemotherapy (by whom, what it is (2))
-By Paul Ehrlich -The use of chemicals that would selectively kill pathogens while having little or no effect on a patient -Magic bullet that would bind to receptors on germs to bring about their death while ignoring the host cells, which lacked the receptor molecules
MacConkey agar
-Complex media -Selects for Gram Negative -Differentiates between Lactose fermenters.
what an envelope is composed of_
-Composed of phospholipid bilayer and proteins -some proteins are virally-coded glycoproteins
Eukaryotic chromosomes are composed of_
-DNA -globular eukaryotic histones, which DNA is wrapped around them
methylation
-In Bacterial DNA replication -cells adds a methyl group to one or two bases that are part of specific nucleotide sequences
what unique problem does -ssRNA overcome during synthesis?
-In order to synthesize a protein, a ribosome can use only mRNA (+RNA), because -RNA is not recognized by ribosomes -The virus overcomes the problem by carrying within its capsid an enzyme, RNA-dependent RNA transcriptase, which is released into the host cell's cytoplasm during uncoating and then transcribed +RNA molecules from the virus's -RNA genome
what is the difference between the shape, location, and the way is packed DNA in eukaryotes and prokaryotes?
-In prokaryotes, it is circle shape and it is winded to keep it in a compact way around proteins and RNA->into a ball/ They are found in the nucleoid -Linear chomosome is found in eukaryotes around histones within nucleus
DNA polymerase
-In replication -binds to each strand and adds nucleotides to hydroxyl group at 3′ end of nucleic acid
does all the DNA needed in replication? in transcription?
-In replication, all the DNA is needed -In transcription, a part of DNA is needed depending on the need of the cell
RNA polymerase
-In transcription -Enzyme that synthesize RNA -links RNA nucleotides that are complementary to genetic sequences in DNA -binds to promoter -unzips and unwinds the DNA molecule in the promoter region and then travels along the DNA, unzipping the double helix as it moves -it does not need primase and acts like polymerase III and helicase (replication) -Add nucleotides to the 3' end of the growing molecule
What are the types of frameshift mutations?
-Insertions (adds letters) -Deletions (removes letters)
Example of antisepsis
-Iodine -Alcohol
what does virus lack that most cells have?
-Lack organelles, cytoplasmic membrane, and cytosol -metabolic activities -reproduction
why agar is useful compound in microbiology?
-Most microbes cannot digest agar (remains solid) -Powdered agar dissolves in water at 100degree C (temperature that most nutrients remain undamaged) -Agar solidifies at temperatures below 40 degree C (nutrients can be added without having to freezing them, cooling liquid agar can be poured to bacteria) -Solid agar does not melt below 100 degree C (culture many thermophiles)
How can microorganisms survive to without water?
-Myocobacterium tuberculosis has cell walls that retain water -spores and cysts (in suspended animation)
how does Naked viruses are released? (2)
-Naked viruses released by exocytosis (similar to budding but without getting envelope) -or may cause lysis and death of host cell
Is polymyxin a broad or narrow spectrum drug in contrast with other antimicrobials? include what group affects and how?
-Narrow spectrum drug -Gram-negative bacteria -Binds to lipid A (which is only found in the outer membrane of gram negative bacteria)
What is the result of a nonsense mutation?
-Nearly all nonsense mutations result in nonfunctional proteins. -depends on how far away from the normal stop codon the nonsense mutation is located -Shorter mRNA
What are the classification of pH range?
-Neutrophiles -Acidophiles -Alkalinophiles
What is the restriction to genotype?
-Not all genes are active at all times -The information of a genotype is not always expressed as a phenotype
Nucleoid
-Region of prokaryotic cytosol containing the cell's chromosome(s) -It has no membrane
how viruses reproduce?
-Replicated by live host cells -Recruit the cell's metabolic pathways to increase their numbers
What is cross resistance?
-Resistance to one antimicrobial agent may confer resistance to similar drugs. -Typically occurs when drugs have similar structures -EX: Resistant to streptomycin; resistant to similar aminoglycoside drugs?
hydroxyl radical
-Result from ionizing radiation and from the incomplete reduction of hydrogen perioxide
what happens when vaccines are injected in humans?
-When the vectors, or the polypeptides they produce, are injected into a human, the body's immune system is exposed to and reacts against relatively harmless antigens instead of the potentially harmful pathogen. -Immune system builds antibodies against that specific disease by being exposed to antigens
Describe how cell walls are composed and made in bacteria
-a bacterial cell wall is composed of a macromolecule of peptidoglycan composed of NAG-NAM chains (layers) that are cross-linked (bonded) by peptide bridges between the NAM subunits -New NAG and NAM subunits are inserted into the wall by enzymes, allowing the cell to grow. Normally, other enzymes link new NAM subunits to old NAM subunits with peptide cross-links
nonsense mutation
-a base-pair substitution changes an amino acid codon into a stop codon. -Result in the stop of polypeptide synthesis
who determine who between genotype and phenotype? how?
-genotype determines phenotype -by specifying what kinds of RNA and which structural, enzymatic, and regulatory protein molecules are produced
Describe "Readily available" of the clinical considerations when selecting an antimicrobial agent
-get it quick not wait long period of time to get it
Growth curve
-graph that compares number of organisms in growing population versus time. -With a logarithmic scale (each division 10 times larger than previous)
The reproduction of individual microorganisms results in the_of_
-growth -colony or biofilm
for what activities do the cell requires to synthesize proteins?
-growth -reproduction -metabolism -regulation
Examples of of degerming
-handwashing -alcohols swabbing at site of injection
Bidirectional replication
-happens in prokaryotes -DNA synthesis proceeds in both directions from the origin
Describe the morphology of complex capsid virus
-have capsids of many different shapes that do not readily fit into either of the other two categories
Typically how many chromosomes does eukaryotic cells have? what is the term given to this?
-have more than one nuclear chromosome in their genomes -diploid (two copies of each chromosome)
In addition to DNA, eukaryotic chromosomes contain proteins called_arranged as_, which are_
-histones -nucleosomes -(beds of DNA) ) that clump with other proteins to form chromatin fibers
Hydrogen is essential for_
-hydrogen bonding -electron transfer
Temperatures affects the bonds_
-hydrogen bonds of proteins
Solutions with greater concentrations of such solutes are_ relatively to those with a lower solute concentration, which are_
-hypertonic -hypotonic
Where thermophiles can be found? what is one of the members?
-in habitats such as compost piles and hot springs -Archaea
Template strand
-in transcription -The sequence of RNA is determined by this DNA strand
acellular
-includes viruses -Noncellular -without or no cells
Obligate intracellular parasite
-includes viruses -They have to get inside the cell, once inside they will be parasites -They can grow and reproduce only inside another living host -Get inside the cell (host) to increase number of viruses
In translation,_
-information is encoded in 20 amino acids -translate from nucleotide (RNA) language to protein amino acids
What diseases are caused by genetic mutations?
-inherited forms of breast cancer -Huntington's disease
PCR is an_process that_
-repetitive -that alternately separates and replicates the two strands of DNA.
where does replication happens in eukaryotes? transcription? translation?
-replication and transcription happen in nucleus -translation happens in ribosomes which will be either in the rough ER or cytoplasm
Intramuscular (route of administration)
-requires needle for administration -concentration never as high as IV administration (CON) -PRO: allow drug to diffuse slowly into the many blood vessels within muscle tissue
Intravenous (route of administration) (pros, cons, and solution to cons)
-requires needle or catheter -delivers the drug directly into the bloodstream -achieves high concentration of drug in the blood (pro). Amount of concentration of drug initially is very high (pro) -drug concentration diminishes as liver and kidneys remove drug from circulation (con) -Solution: administer drug continuously
What is multi-drug resistance? (how commonly called?, how obtain this?, problem and how arose this problem)
-resistance to more than one drug at a time -superbugs (commonly called) -Common when R-plasmids exchanged -Develop in hospitals and nursing homes; constant use of drugs eliminates sensitive cells and encourages the development of resistant strains
Germistatic agents include_
-some chemicals -refrigeration -freezing
Prokaryote genomes consist of_
1-2 chromosomes
how many chromosomes does bacteria have?
1-2 chromosomes but usually they have only one
Describe the development of a resistant strain of bacteria
1. A bacterial population contains both drug-sensitive and drug-resistant cells, although sensitive cells constitute the vast majority of the population because resistant cells are less efficient than the normal bacteria, in a free-drug environment, because they must expand extra energy to maintain resistance genes and proteins (resistant cells remain minority because they reproduce more slowly) 2. Exposure to an antimicrobial drug inhibits the sensitive cells; so long as the drug is present, reduced competition from sensitive cells facilitates the multiplication of resistant cells 3. Eventually resistant cells constitute the majority of the population
Describe Griffith's Experiment
1. A mouse injected concurrently with killed strain S and live strain R (each harmless by themselves) died and was found to contain numerous living, encapsulated bacteria (strain S)
List the mechanism by which antimicrobials inhibit protein synthesis by targeitng prokaryotic ribosomes (6)
1. Aminoglycosides change the shape of the 30s subunit, causing incorrect pairing of tRNA anticodos with mRNA codons (unable read codons of mRNA correctly) 2.Tetracyclines block the tRNA docking site (A site) on the 30s subunit, preventing protein elongation (prevent additional amino acids into growing polypeptide) 3. Chloramphenicol blocks enzymatic activity of the 50s subunit, preventing the formation of peptide bonds between amino acids 4. Macrolides (erythromicin) bind to the 50s subunit, preventing movement of the ribosomes along the mRNA
what are the stages of the lytic cycle? describe them birefly
1. Attachmen: the virion attaches to the host cell. (random collision) 2. Entry: the virion or its genome enters the host cell. (because it was identified) In bacteriophages, only the nucleic acid enters the cell. 2a. Bacterial chromosome is degraded into its constituent nucleotides by viral enzymes that were brought in the capsid or made by bacterium 3. Synthesis: the host cell's metabolic enzymes and ribosomes are used to synthesize new nucleic acids (DNA/RNA) and viral proteins (capsomeres and viral enzymes). 4. Assembly: new virions are spontaneously assembled in the host cell, typically as capsomeres surround replicated or transcribed nucleic acids to form new virions. (put nucleic acids and capsids together) 5. Release: new virions are released from the host cell, which lyses.
list the step of tRNA in translation
1. Bring tRNA 2. break covalent bond to get amino acid 3. link it to the polypeptide chain 4. Repeat by bringing another tRNA
what are the three goals of Recombinant DNA technology?
1. Create organisms that synthesize products humans need. (Insulin produced by bacteria) 2. Eliminate undesirable phenotypic traits in humans, animals, plants, and microbes. (freeze tolerance or pest resistance/ cure children with genetic disorder) 3. Combine beneficial traits of two or more organisms to create valuable new organisms.
PCR is a Repetitive process consisting of three steps:
1. Denaturation 2. Priming 3. Extension
list the steps of bacterial conjugation
1. Donor cell (F+) attaches to a recipient cell (F-) with its pilus. The pillus draws the cells together 2. The cells contact one another 3. One strand of plasmid DNA transfers to the recipient (F-) 4. The recipient (F-) synthesizes a complementary strand to become an F+ cell; the donor (F+) synthesizes a complementary strand, restoring its complete plasmid
Describe Griffith's observations
1. Encapsulated strain S killed the mice when injected 2. Heating renders strain S (death) is harmless to mice when injected 3. Unencapsulated strain R did not harm mice when injected
Describe Griffith's Experiment in vitro. what this experiment prove?
1. Heat treated dead cells of strain S are put in a vitro where enzymatic cleavage of DNA happens 2. DNA fragments from strain S and living strain R are found in the same vitro 3. While in the same vitro, some cells take up DNA from the environment and incorporate it into their chromosomes 4. Result, transformed cells acquire ability to synthesize capsules -that transformation can happen outside the body
DNA replication steps (in a simplified way)
1. Initial process: 1)The cell removes proteins (histones in eukaryotes and archaea) from the DNA molecule. 2) Helicase unzips the double helix (breaking hydrogen bonds)to form replication fork 2. Continuous synthesis of leading strand: DNA synthesis always moves in 5'->3' direction, so the leading strand is synthesized toward the replication fork (includes proofreading process). 3. Discontinuous synthesis of lagging strand, which proceeds moving away of the replication fork.
Pharmaceutical and Therapeutic Applications (6)
1. Protein synthesis 2. Vaccines 3. Gene therapy 4. Genetic screening 5. Medical diagnosis 6. DNA fingerprinting
List explain the clinical considerations when selecting an antimicrobial agent (9)
1. Readily available 2. Inexpensive 3. Chemically stable 4. Easily administered 5. Nontoxic and nonallergenic 6. Selectively toxic against wide range of pathogens 7. Spectrum of action 8. Efficacy 9. Side effects
4 steps of binary fission
1. Replication of chromosomes (attachment to cytoplasmic membrane) 2.Cell elongates and growth between attachment sites pushes chromosomes apart 3. Cell forms new cytoplasmic membrane and wall (septum) across the midline 4. When the septum is completed, the daughter cells may remain attached or they may remain separate completely
techniques to localize genes (gene mapping)
1. Restriction fragmentation (using restriction enzymes) 2. Fluorescent in situ hybridization (FISH)
Methods to take DNA or plasmid into bacteria
1. Transformation 2. Transduction 3. Conjugation
steps of initiation phase in translation
1. smaller ribosomal subunit attaches to mRNA at a ribosome-binding site, so as to position a start codon (AUG) at its P site 2. tRNA that carries methionie amino acid, attaches to P site 3. The larger ribosomal subunit then attaches to form a complete inititation complex
steps of diffusion susceptibility test
1. uniformly inoculating petri plate with a standardized amount of pathogen in question 2. Then small disks of paper (antibiotic disks) containing standard concentrations of the drugs to be tested are firmly arranged on the surface of the plate 3. Plate is incubated 4. the bacteria grow and reproduce to form a lawn everywhere but the areas where effective antimicrobial drugs diffuse throughout the agar 5. After incubation, the plates are examined for the presence of zone of inhibition *zone of inhibition measured as the diameter of the clear region (mm)
steps of elongation in translation
1.The transfer RNA whose anticodon matches the next codon deliver its amino acid to the A site. Proteins called elongation factors escort the tRNA along with a molecule of GTP. Energy of GTP is used to stabilize each tRNA as it is added to A site 2. A ribozyme in the larger ribosomal subunit forms a peptide bond between the terminal amino acid of the growing polypeptide chain and the newly introduced amino acid 3. Using energy of GTP, the ribosome moves one codon down the mRNA. This transfers each tRNA to the adjacent binding site; that is, the 1st tRNA moves from the P site to the E site, and the second tRNA (with the attached polypeptide) moves to the vacated P site 4. The ribosome releases the "empty" tRNA from the E site. 5. The cycle repeats, each time adding a new amino acid
Nitrogen makes up about_%of the dry weight of microbial cells
14
what process substituted the method of taking insulin from cows and pigs? In what year?
1970's - New genetic techniques were being developed. Recombinant DNA technologies
how many mechanisms cause RNA polymerase to fall apart?
2
How many amino acids exists?
20 amino acids
what is the size of a virus?
20-250nm they are very small, even smaller than organelles of cells and prokaryotes
how many hydrogen bonds are found between Guanine and cytosine?
3 hydrogen bonds
Each cycle of PCR consist of _
3 steps
5' end will be opposite to the _ in the same chain
3' end
Based on the slide, how you classify human bacterial pathogens? 1. Thermoduric 2. Thermophile 3. Mesophile 4. Hyperthermophile 5. psychrophile
3. mesophile because body temperature is 37 degree C
when FDA was searching for the hGH, how many hits for recombinant did?
3000 hits for "recombinant"
What direction is the RNA molecule being synthesized in?
5'->3' direction
How many base pairs are found in Human genome?
6 billion base pairs in 46 nuclear DNA molecules -Numerous copies of a unique mitochondrial DNA molecule
Which of the following is the result of the action of cell wall inhibiting drugs? a. cells become more susceptible to osmotic pressure b. Cells cannot attach to their hosts c. Ribosomes lose their function d. the sterols in the cell wall become nonfunctional e. the replication of cells, including cancer cells, slows down
A
DNA replication is a simple concept:
A cell separates the two original strands and uses each as a template for the synthesis of a new complementary strand.
what is an use of the Ames test?
A method to test for mutagens or carcinogen.
genes
A specific sequence of nucleotides that codes for a polypeptide or an RNA molecule
Virus are considered to be_parasites
Acellular obligate intracellular parasites
Using thioglycollate growth medium, how you would know an organism is aerotolerant aerobes?
Aerotolerant aerobes can grow equally well with or without oxygen; their growth is relatively evenly distributed throughout the medium
Have amplified DNA in tube. How do you visualize what you have?
Agarose Gel Electrophoresis.
separation of DNA molecules is through_
Agarose gel electrophoresis
what a drug must do to be able to be effective?
An adequate amount of an antimicrobial agent must reach a site of infection
chromatin fibers
An association of nucleosomes and proteins found within the chromosomes of eukaryotic cells
Synthetics
Antibmicrobials that are completely synthesiszed in a laboratory
sulfanomides
Antimetabolic drugs that is a structural analog of para-aminobenzoic acid (PABA)
Broad-spectrum drugs
Antimicrobial that works against many different kinds of pathogens
what drive the process in transcription?
Antiparallel strands and base pairing (nucleotides) drives this process
nutrients
Any chemical such as carbon, hydrogen, etc., required for the growth of microbial populations
On what the attachment of an animal virus depends?
As with bacteriophages, attachment of an animal virus is dependent on the chemical attraction and exact fit between proteins or glycoproteins on the viron and complementary protein or glycoprotein receptors on the animal cell's cytoplasmic membrane
what is a disease caused by an animal virus?
Avinaza influenza
Which of the following is not always a part of an extracellular viruses' structure a. Genetic material b. Lipid bilayer c. Protein coat
B. lipid bilayer, which is the envelope
A point mutation that introduces a stop codon earlier is_ A. Frameshift mutation B. Nonsense mutation C. Missense mutation D. Silent mutation
B. nonsense
what is the biggest group of bacteria depending on their carbon and energy sources? what is a big group? what are the small and odd?
BIGGER GROUP: Photoautrotrophs BIG GROUP: Chemoheterotrophs Small and odd: photoheterotrophs/ chemoautotrophs
Can bacteria live without plasmids?
Bacteria can live without plasmids, but if bacteria have they have more benefits by having them
Why is ampho B not used against bacteria?
Bacteria lack sterols in their cell membrane; not susceptible
Some viruses have the size of_that are contained within bacteria
Bacterial ribosome (70s)
Contrast between bacteriophages and animal virus: penetration
Bacteriophage: genome is injected into cell or diffuses into cell (endocytosis and membrane fusion) animal virus: Capsids enters cell by direct penetration, fusion, or endocytosis
Contrast between bacteriophages and animal virus: attachment
Bacteriophage: proteins on tails attach to protiens on cell wall Animal virus: spikes, capsids, or envelope proteins attach to proteins or glycoproteins on cell membrane
what happens in translation within bacteria that cannot happen in eukaryotes?
Because both transcription and the subsequent events of translation occur in the cytosol of prokaryotes, prokaryotic ribosomes can begin translation before transcription is finished
How nucleotide analogs interfere with DNA replication and RNA transcription?
Because of the distortions they cause in nucleic acids, nucleotide analogs do not form proper base pairs with normal nucleotides. This increases the number of mismatches in the transcription of RNA and replication of DNA
Why are we so interested in lytic and lysogenic viral replication?
Because they are very similar to us, so help us to understand how the animal viruses work and about transduction in humans.
Both types of diabetes result in_
Both result in elevated blood glucose levels = hyperglycemia.
How you identify the oxygen requirements of organisms?
By using a liquid thioglycollate growth medium
how can scientists create gene libraries?
By using restriction enzymes, which generate fragments of the DNA of interest, and then using ligase to synthesizing recombinant vectors
How PCR can be automated?
Can be automated using a thermocycler, a device that atomically performs PCR by continuous cycling all the necessary reagents through 3 temperature regimens
How the virus is found in the intracellular stage?
Capsid removed (uncoating) Virus exists as nucleic acid
heterotrophs
Catabolize reduced organic molecules (proteins, amino acids, carbohydrates, and fatty acids) they acquire from other organisms
How restriction enzymes are categorized?
Categorized in two groups based on type of cut -Cuts with sticky ends -Cuts with blunt ends
Recombinant is a method to link_
DNA
During reproduction, viruses depends on_
Dependent on hosts' organelles and enzymes to produce new virions
Sterilization
Destruction of all microorganisms and viruses in or on an object
Disinfection
Destruction of most microorganisms and viruses on nonliving tissue (using disinfectants)
SIM: Motility
Determination of motility via production of the structural protein flagellin. Cloudiness along the inoculation line indicates a non-motile organism, cloudy throughout indicates motility. Growth along the entire surface of the medium may also indicate motility of an aerobe.
MR-VP Medium: Butanediol Fermentation Voges-Proskaeur Test
Determine butanediol fermentation of glucose by acetoin production. Glucose is added to the medium as a carbon source. The addition of VP A & B* reagents (α-napthol & 40% KOH/Barritt's reagents) after incubation indicates the presence of acetoin (a byproduct of butanediol fermentation) when a burgundy color change is noted. Yellow or no color change indicates a lack of butanediol fermentation.
Litmus Milk
Determine milk metabolism: proteins, sugar and fat hydrolysis via multiple enzymes. Litmus provides an indication of pH changes in the medium. Color and/or consistency changes in medium indicate various enzymatic reactions. Pink = acid; blue/purple = alkaline; curds form= coagulation; clear = peptonization; white = litmus reduction. Individual results may not match the combinations pictured above.
MR-VP Medium: Mixed Acid Fermentation Methyl Red Test
Determine mixed acid fermentation of glucose by formic hydrogenlyase, etc. Glucose is added to the medium as a carbon source. Methyl Red added after incubation causes a pH sensitive color change in the medium. Red color changes indicates the fermentation of glucose to acidic products, color change to yellow or no color change indicates a negative result.
Cytochrome Oxidase Test
Determine the production of the membrane bound electron carrier of the ETC- cytochrome oxidase. After incubation on any solid medium, a portion of organism is removed with a sterile cotton swab. Addition of Oxidrops* causing a color change to purple/black indicates positive result. No color change (or slight purple color) indicates a negative result. METAL TOOLS should not be used, they will oxidize reagent and give a false positive result.
What is the treatment for diabetes Type II?
Diet & Exercise.
what plays a role in host recognition? (virus)
Envelope's proteins and glycoproteins
How enveloped animal viruses are released?
Enveloped animal viruses are often released via a process called budding.
which type of viruses (naked or enveloped) cause persistent infections?
Enveloped viruses cause persistent infections
Durham Carbohydrate Broth glucose, lactose, mannitol OR sucrose
Fermentation of chosen carbohydrate (glucose, lactose, mannitol OR sucrose) to acid with/without gas production. Phenol red in the medium causes a pH sensitive color change. Yellow broth indicates acid production from the carbohydrate. Bubbles trapped in the Durham tube indicate gas production from fermentation of the carbohydrate. No color change indicates a lack of fermentation.
burst time
For any phage undergoing lytic replication, the period of time required to complete the entire process, from attachment to release.
What is the result of a frameshift mutation?
Frameshift mutations (insertions or deletions) typically result in drastic missense and nonsense mutations.
Buff
Full media that is solid, within a tube
what is the goal of the intracellular state of the virus?
GOAL MAKE AND RELEASE MORE VIRUSES
Examples of photoheterotrophs
Green nonsulfur bacteria and purple nonsulfur bacteria, some archaea
What is a retrovirus type that can make reverse transcriptase enzyme?
HIV
Given that RNA cannot incorporated direclty into a chromosome molecule, how does the ssRNA of HIV become a provirus incorporated into the DNA of its host cell?
HIV can become a permanent part of a host's chromosome, because it, like all retroviruses, carries reverse transcriptase, which transcribes the genetic information of the +RNA molecule to DNA molecule
what are the two ways that you can find a virus?
Have extracellular and intracellular state
Example of micoaerohiles?
Helicobacter pylori
what is an example of successful subunit vaccine?
Hepatitis B
which transfer cells form conjugation pilli and transfer cellular genes more frequently: normal F+ cells or Hfr cells?
Hfr cells
Explain diabetes using the term homeostasis
Homestasis control things within a window, so individual deficient in homeostasis of blood sugar or glucose in blood
An example of protein synthesis is the production of_enzyme
Human Growth hormone
examples of chemoautotrophs
Hydrogen, sulfuer, and nitrifying bacteria, some archaea
Spirit Blue Agar
Hydrolysis of lipids into glycerol and fatty acids by the EXOenzyme lipase. Spirit Blue in the medium causes a pH sensitive color change. A clearing of the blue color in the medium and/or blue pigmentation of the colonies indicates the presences of lipase. Additionally, a matte appearance due to a depletion of oil is also a positive result.
Gelatin Deep
Hydrolysis of protein gelatin by gelatinase. Once cooled to 4°C after incubation, liquefied medium indicates a positive result. Cooled solidified medium indicates a negative result. Test may require up to 5 day incubation, or false negative results may occur.
Urea Broth
Hydrolysis of urea to NH3 & CO2 by urease. Phenol red in the medium causes a pH sensitive color change. Alkaline conditions resulting from the production of NH3 cause a hot pink/cerise color change in positive organisms. A Neutral/acidic pH with no color change indicates a negative result.
What is the most reactive of the 4 toxic forms of oxygen?
Hydroxyl radical
What happens if temperature is too high in membranes?
If too high, membranes become too fluid and cannot contain the cell or organelle
What happens if the temperature is too low in membranes?
If too low, membranes become rigid and fragile
zone of inhibition
In a diffuse susceptible test, a clear area surrounding the drug-soaked disk where the microbe does not grow
How is a lysogenic cycle different from a lytic cycle?
In a lysogenic cycle, the virus is inserted into bacterial chromosome, and it is replicated and passed on to all daughter cells until it is induced to leave the chromosome; a lytic cycle is a replication cycle that results in cell death
How the point mutation can affect the protein?
In a silent, missense, or nonsense way
donor cell
In horizontal gene transfer, a cell that contributes part of its genome to a recipient
recipient cell
In horizontal gene transfer, a cell that receives part of the genome of a donor cell
what is the importance of specialized transduction?
In nature, specialized transduction is important in transferring genes encoding for certain bacterial toxins into cells that would otherwise be harmless
what is the function of methyleted nucleotide sequences in bacteria?
In some bacteria, methylated nucleotide sequences play a role in initiating DNA replication, repairing DNA, or recognizing and protecting against viral DNA.
where do you insert DNA in the gel electrophoresis technique?
In the sample wells (small holes cut into agarose gel) near the negative plaque
the ability of Staph. aureus to be penicillin resistant is what kind of mechanism of resistance?
Inactivation of the antimicrobial agent by using B-lactamase
how the RNA sequence nucleotides are determined in transcription?
Incoming nucleotide is determined by sequence on template strand of DNA (base pairing).
Recombinant approach
Insert gene into vector
Types of radiation (mutation)
Ionizing radiation Nonionizing radiation
Acidophiles
Microorganism requiring acidic pH
Mesophiles
Microorganism requiring temperatures ranging from 20 degree C to about 40 degree C
Photoheterotroph
Microorganism that requires light energy and gains nutrients via catabolism of organic compounds
obligate aerobes
Microorganism that requires oxygen as the final electron acceptor of the electron transport chain
Chemoheterotrophs
Microorganism that uses organic compounds for both energy and carbon
photoautrotophs
Microorganism which requires light energy and uses carbon dioxide as a carbon source
Define "nitrogenous bases"
Nitrogenous=has nitrogen base: has acid
Fluid Thioglycollate Medium (FTM)
O2 requirement and/or tolerance of cells determined. Organisms remain vertically stable in the medium by the presence of agar. Thioglycollate in the medium reduces O2 and produces an anaerobic environment in the lower portions of the medium. The redox indicator resazurin in the medium is red in the presence of O2 and colorless in anaerobic environments. Growth in the aerobic zone with/without growth in anaerobic zone and relative growth in aerobic vs. anaerobic zones determines O2 requirement. Anaerobe- growth only in anaerobic portion; aerobe- growth only in aerobic portion; microaerophile - growth slightly below top, but in aerobic zone; facultative anaerobe- growth thicker in aerobic relative to anaerobic portion; aerotolerant anaerobe- growth in anaerobic and aerobic portions are equal.
what is the difference between obligate acidopholes and acid-tolerant microbes?
Obligate acidophiles require an acidic environment and die if the pH approaches to 7.0, acid tolerant microbes merely survive in acid without preferring it
Using thioglycollate growth medium, how you would know an organism is obligate aerobes?
Obligate aerobes cannot survive below the depth to which oxygen penetrates the medium, so they are at the top of the tube
Using thioglycollate growth medium, how you would know an organism is obligate anaerobe?
Obligate anaerobes cannot tolerate any oxygen, so they are found at the bottom of the tube
what are ribosomes composed of?
Of two subunits made of polypeptides and rRNA (70s in porkayrotes and 80s in eukaryotes)
How microorganism are sensitive to pH?
Organisms sensitive to changes in acidity because it affects proteins and nucleic acids. (hydrogen and hydroxyl ions interfere with hydrogen bonding)
how termination may be done in transcription?
Other proteins may assist in termination, or it may depend solely on the nucleotide sequence (terminator) of the transcribed RNA.
what the outermost layer provides to the virus? (What function does outermost layer serve within viruses?)
Outermost layer provides protection and recognition sites for host cells
write the Bacterial Enzymatic Pathway of DNA and RNA (including PABA)
PABA--(enzymes)-->Dyhydrofolic acid--(enzyme)-->tetrahydrofolic acid (THF)-->purine and pyramide-->DNA and RNA
what are some of the methods used in medical diagnoses?
PCR, fluorescent genetic probes, and DNA microarrays (genetic sequencing)
where insulin is produced within our bodies?
Pancreas
what is an example of using mutagens?
Penicillium that produced Penicillin
Phosphodiester bond is what type of bond? hydrogen bond is what type of bond?
Phosphodiester is a covalent bond (strong) Hydrogen bond is a weak interaction or bond (weak interaction)
Mutagens
Physical or chemical agent that introduces a mutation in nucleic acids
where have we seen the lytic cycle before? (in lab)
Plaques Transduction
When are plasmids activated?
Plasmids are activated when they are needed, like the formation of endospores
who transcribes RNA primers?
Primase
During the second step of central dogma of genetics, what are the processes that take place?
RNA synthesis=transcription
Primary way scientists categorize and classify viruses: (give examples of viruses that fit this categories)
RNA viruses - picornaviridae (polio, hepA, cold) DNA viruses - herpesviridae (herpes)
_ of the cell because of latent virus
Reactivations or recurrences
Recombinant approach solutions the problem of_when using vaccines
Recombinant approach, solutions the problem of injecting whole organism that could sick us, by producing only a part of the vaccine so less likely to make you sick
Antisepsis
Reduction in the number of microorganisms and viruses, particularly potential pathogens, on living tissue
Aseptic
Refers to an environment or procedure free of pathogenic contaminants
antagonistic relationship
Relationship in which one organism harms or even kills another organism
Degerming
Removal of microbes by mechanical means (scrubbing is important)
Sanitization
Removal of pathogens from objects to meet public health standards
How a piece of DNA of a virus can affect us? (use the steps of central dogma of genetics to explain)
Replication: cells make many copies of viral DNA Transcription and translation: with a single viral DNA, you can get a lot of proteins to make many viruses
Replacement of a sensitive pathway (what specifically is doing to avoid action of drug?)
Resistance can result from the acquisition of a new enzyme to replace the sensitive one
why do resistant strains of bacteria most often develop in hospitals and nursing homes than in college dorms?
Resistant strains are more likely to develop in hospitals and other heath care facilitates because the extensive use of antimicrobial agents in those places inhibits the growth of sensitive stains and selects for the growth of resistant strains
which structure is the polypeptide (protein) factory and has an important function in translation?
Ribosomes
Southern blotting
Technique used in recombinant DNA technology that allows researchers to stabilize specific DNA sequences from an electrosphoresis gel and then localize them using DNA dyes or probes
optimum growth temperature
Temperature at which a microorganism's metabolic activities produce the highest growth rate
Disk Diffusion Test/Kirby Bauer Abx Sensitivity Test
Tests for the bacteriostatic properties of a given disinfectant, antiseptic or antibiotic. A disk saturated with the compound to be tested is laid on the surface on an agar plate seeded with bacteria. Incubated plates are examined for a zone of inhibition (ZOI). The size of the ZOI measured in mm and the organism is rated as RESISTANT, INTERMEDIATE or SENSITIVE/SUSCEPTIBLE to the compound.
why the genetic code is said to be "redundant"?
The code is redundant; that is, more than one codon is associated with all the amino acids except methionine and tryptophan.
what is the important end result of recombinant DNA technology method?
The important end result is not DNA by itself but the protein to change phenotype of organism
synergistic relationships
The individual members of an association cooperate such that each receives benefits that exceeds those that would result if each lived by itself, even though each member could live separately
How the length of DNA is measured?
The lengths of DNA molecules are expressed in base pairs.
How the sterile loop is used in the streak plate process?
The loop is used to lightly streak a set pattern that gradually dilutes the sample to a point that CFUs are isolated from one another
minimum bactericidal concentration (MBC)
The lowest concentration of drug for which no growth occurs in the subcultures
How is the mRNA read?
The mRNA is read in three-letter blocks or codons in a particular reading frame.
nucleocapsid
The name given when nucleic acid and capsid are together
what does DNA nucleotides contain?
The nucleotides in DNA contain deoxyribose and A, G, C, and T.
what does RNA nucleotides contain?
The nucleotides in RNA contain ribose and A, G, C, and U
burst size
The number of new virions released from each lyzed bacterial cell
DNA replication is conservative, semiconservative, no conservative? explain why
The process is semiconservative because each daughter DNA molecule is composed of one original strand and one new strand.
minimum inhibitory concentration (MIC)
The smallest amount of drug that will inhibit a pathogen
how genome mapping has been speeded up?
The technique has been speeded up by an automated machine that distinguishes among fluorescent dyes attached to each type of nucleotide base.
what are the areas where DNA fingerprinting is used?
The technique is used in paternity investigations, crime scene forensics (ID badly damaged human), diagnostic microbiology (ID pathogen), and epidemiology.
How the strands are oriented in relation with each other? (describe them in terms of 5' end and 3' end)
The two strands are oriented in opposite directions to each other: One strand runs in a 3' to 5' direction, whereas the other runs in a 5' to 3' direction
Gene therapy
The use of recombinant DNA technology to insert a missing gene or repair a defective gene in human cells
After determining what type of genome viruses have, what do you ask next to further categorize a virus?
Then ask if several or single piece of DNA/ RNA? Then ask the shape of DNA/RNA-> linear, circular
How scientists combine fragments of DNA formed by restriction enzymes?
They then combine these bits of DNA with ligase to form recombinant DNA molecules.
Why most viruses infect particular types of cells? (host cells)
This specificity is due to the affinity of viral surface proteins or glycoproteins for complementary proteins or glycoproteins on the surface of the host cell.
virus
Tiny infectious acellular agent with nucleic acid surrounded by proteinaceous capsomeres that form a covering called a capsid
what advantage gives genetic screening to patients, especially parents?
To allow parents, before having kids, what mutations they carry if they wan to have kids
_RNA carries amino acids
Transfer
Which diabetes is found in people that born with it?
Type I
what are the names of the two types of diabetes?
Type I diabetes Type II diabetes
what case of gene therapy resulted in the death of the patient?
University of Pennsylvania Study 18yr old died from clinic trial
Adenine is substituted by_in transcription
Uracil (U) (no Thyamine (T))
How can I recognize the difference between the bacteria that got the plasmid and the bacteria that did not get it in transformation?
Use ampicillin plate to selectively cultivate the bacteria that have the plasmid, which is resistant to ampicillin (ampicillin resistant) because of plasmid (Contain recognizable genetic marker)
Pasteurization
Use of heat to destroy pathogens and reduce the number of spoilage microorganisms in food and beverages
How can we use the Dogma of genetics in genetic engineering?
Use the Dogma of genetic, knowing how bacteria work, how diseases work in humans, get products that we cannot make by our own and start to use this information to make bacteria to make this products
how the information about microorganisms can benefit us?
Use what we know about microorganisms and the genetics to change living things to produce things that are useful for us
Simmon's Citrate Agar
Utilization of citrate as a sole source of carbon via citrase. Bromthymol blue in the medium produces a pH sensitive color change. Blue color change indicates presence of citrase. No color change or no growth indicates a negative result. Because this is a SELECTIVE medium, be sure to inoculate with sufficient organism.
Differential media
Utilizes differences in growth or colony characteristics to distinguish between species.
what are the 5 direct methods of quantifying bacterial numbers? (state which require incubation and which not)
Viable plate counts (require incubation) Membrane filtration (require incubation) Microscopic counts (Do not require incubation) Electronic counters (do not require incubation) Most probable number (require incubation)
During the synthesis of animal viruses, what are the two major types of molecules that need to be synthesized?
Viral genome (DNA and RNA) Proteins (capsids and glycoproteins)
what is the difference between a virion and a virus particle?
Virion: complete assembled virus and fully infectious Virus particle: piece that is not a complete virus and can be part of the virion and it is not infectious
Within vectors, who can carry larger genes?
Viruses and transposons can carry larger genes than plasmids
when the intracellular stage of a virus starts?
When a virus penetrates a cell
which two strains did Griffith worked in his experiment? Describe them.
With the two strains of Streptococcus pneumoniae: -S strain: have protective capsules that enable them to escape a body's defensive white blood cells/ cause deadly pneumonia when injected/ receive name from their smooth colony appearance on agar surface -R strain: Received name from their rough appearance on agar surface/ mutants that cannot make capsules/ do not cause disease because a mouse's defensive white blood cells quickly devour them
A naked virus is one that.... a. Has no membranous envelope b. Has injected its DNA and RNA into a host cell c. Devoid capsomores
a. has no membranous envelope
Sigma factor is most important during transcriptional a. Initiation b. Elongation c. Termination
a. initiation
_is the process of by which DNA is copied a. Replication b. Transcription c. Translation d. Mutation e. Recombination
a. replication
what are the building blocks of proteins?
amino acids
microbial growth
an increase in a population of microbes rather than an increase in size of an individual
what happens in initiation phase in translation ?
an initiation complex is formed (2 ribosomal subunits, mRNA, several protein factors, and tRNA(fMET))
Nitrogen is often a growth limit for many organisms; that is, their_
anabolism ceases because they do not have sufficient nitrogen to build proteins and nucleotides
When differences exist between metabolic processes of pathogen and host,_ can be effective
antimetabolic agents
frequently what are the drugs that can inhibit the a pathogen attachment or recognition to host?
antiviral drugs
Mutation
change in the nucleotide sequence of a genome.
cells that take up DNA are_
competent
virion (_assembled)
completely assembled extracellular state of virus
what is more commonly used: defined media or complex media?
complex media
what examples of bacteria can utilize the 79% of nitrogen gas in the atmosphere?
cyanobacteria Rhizobium
Cross-resistance is due to a. the deactivation of an antimicrobial agent by a bacterial enzyme b. the alteration of cells so an antimicrobial agent cannot attach c. cell membrane changes that prevent entry of antimicrobial agents d. the similarly of one antimicrobial agent to another
d
Before producing the Human growth hormone (hGH), where did this enzyme was recovered?
derived from pituitary of human cadavers
Chemotherapeutic agents
drugs that act against diseases
Antimicrobial agents
drugs that treat infections -ex: insulin, anticancer drug, and drugs for treating infections
Which of the following is involved in translation? a. Mrna b. Rrna c.Trna d. a and b e. a, b, c
e
trace elements
elements that are require in very small amounts
With each repetition of the cycle, the number of DNA molecules increases _. Explain how get the number of DNA molecules in PCR
exponentially Multiply the resultant number of DNA molecules by 2 in every cycle (2^n)
what else does eukaryotic cells have? (genetic information) where are they located within the cell?
extrachromosomal DNA in mitochondria, chloroplasts, and plasmids.
plasmids are also called_
factors
Ex of facultative anaerobes?
few yeast and numerous prokaryotes
Function of RNA primers
for DNA polymerase to use during DNA replication.
Okazaki fragments
fragments of lagging strand that are produced during DNA replication
what is the goal of viruses?
get inside of cells to reproduce and make many viruses
Standards of sanitization vary among_
governmental jurisdictions
Genetic samples for genetic fingerprinting can come from_
hair blood
sterilization indicates only the eradication of_
harmful microorganisms and viruses
Enveloped virus
has envelope, protein coat, pieces of DNA outside the cell
Replication is not 100% correct, but cells have_
have fairly low error rate
Naked virus
have protein coat and pieces of DNA outside of the cell but do not have phospholipid envelope
"ribosomes lose their function" is associated with which action of microbial drugs?
inhibition of protein synthesis
what does antibiotics do?
inhibits protein synthesis and ribosomes
what are the steps in translation?
initiation phase elongation phase termination phase.
Scientists can synthesize subunits of vaccines by_
introducing genes for a pathogen's polypeptides into vectors.
Gel electrophoresis
is a technique for separating molecules (including fragments of nucleic acids) by size, shape, and electrical charge.
Genomics
is the sequencing, analysis, and comparison of genomes
what directions does leading strand is synthesized?
it is synthesized toward the replication fork. (5'->3')
bacterocidial
killing concentration of bacteria
example of aerotolerant
lactobacilli
_of prokaryotes have never been grown in culture medium
majority
DNA synthesis requires the coordination of _
many enzymes
Osmolarity
measure of the number of solute particles (Dissolved stuff) dissolved in the solvent (water for example)
Mutagens, restriction enzymes, vectors, and the other tools of recombinant DNA technology are used in a variety of techniques to _
multiply, identify, manipulate, isolate, map, and sequence the nucleotides of genes.
The media are not_
mutually exclusive categories, which means in some cases a given medium can belong to more than one category
During the 20th century, scientists industrialized the _to produce products
natural metabolic reactions of bacteria
Most bacteria and protozoa, including most pathogens, grow best in a narrow range around a _pH
neutral (6.7-7.5)
What is another essential element?
nitrogen (found in amino acids)
DNA in chromosomes function is within_ (in bacteria)
normal bacterial metabolism
nucleic acids are polymers of_
nucleotides
what are the small building blocks of DNA and RNA? (general term)
nucleotides
where is the gene coding for conjugation pili located?
on a plasmid called an F (fertility) plasmid
what is based the ames test?
on the idea that point mutations might change previous changes made to the sequence, like in this case change his- to his+ (back to original)
About_genes contains an error. Mutagens typically increase the mutation rate by a factor of _times.
one of every ten million 10-1000
broths
organism can be grown in a liquid media
How organism in a laboratory environment live very differently than organisms in nature?
organisms in nature live association with other individuals of their own and different species
Symbiotic relationship
organisms live in such close nutritional or physical contact that they become interdependent, such that the members rarely live outside the relationship
capnophiles
organisms that grow better at relatively high concentration of carbon dioxide in addition to low oxygen levels
the thioglicollate growth medium has a _
oxygen gradient from the top to the bottom
what DNA replication allows the cell to do?
pass copies of its genome to its descendants
Disinfection term is used primarily in relation to_
pathogens
Medical laboratory personnel must also grow_
pathogens as an step in diagnosis of many diseases
DNA fingerprinting can be to generate unique_
patterns of DNA separated on gel.
What was the first antibiotic produced by humans?
penicillin
what is the major structural component of a bacterial cell wall?
peptidoglycan
What does make hydrogen perioxide an antimicrobial agent?
perioxide anion
Ligase unites the _of the pieces of DNA cut by the restriction enzyme
phosphate backbones
where within the cell the envelope of viruses can be obtained?
phospholipid bilayer forms all the membranes of host cells (mitochondira, cell membrane, nucleus, etc)
Some virions have _surrounding the_
phospholipid envelope surrounding the nucleocapsid.
phenotype
physical and functional traits expressed by those genes (like structure, morphology, and metabolism)
dissinfectant
physical or chemical agent used to inhibit or destroy microorganisms on inanimate objects
what other genetic material or extrachromosomal DNA molecules can prokaryotes have?
plasmids
what is the most common mutation?
point mutations
who should avoid taking tetracycline?
pregnant women and children should not use tetracycline
the main goal of aseptic techniques is to_
prevent contamination
Aseptic technique is used to _
prevent contamination of sterile substances or objects
conjugation
process involved in transferring genes from one bacterial cell to another
what are the mechanisms created to prevent changes or mistakes in the processes of replication and transcription?
proof reading enzymes that check there is no changes, but if we have changes they repair them
what is one of the functions of the cell wall?
protects a cell from the effects of osmotic pressure
capsids are also called_
protein coat
Elongation of a polypeptide is a cyclical process that involves the_
sequential addition of amino acids to a polypeptide chain growing at the P site
A medium can also become a selectively medium when a_
singular crucial nutrient is left out of it
virus genomes are much_than genomes of cells
smaller
Agar
solidifying agent (what you add to the media to make it solid) Two types of solid media: plate and slant
what type of viruses use the direct penetration method to enter their hosts' cells ?
some naked viruses (no envelope) like poliovirus
Anaerobic media
stab cultures
Scientists, laboratory technicians, and health care workers routinely follow_
standarized aseptic technique
DNA synthesis or replication always moves in_
the 5' to 3' direction
To eliminate phenotype traits you should change_
the genotype of the organism
maximum growth temperature
the highest temperature at which an organism continues to metabolize
minimum growth temperature
the lowest temperature at which an organism is able to conduct metabolism
what is the concern regarding conjugation?
the natural transfer of genes by conjugation among diverse organisms heightens some scientists' concerns about the spread of resistance (R) plasmid along pathogens
obligate or strict
the only condition that it needs to grow!
What happens to the microorganism if the temperature exceeds the maximum growth temperature?
the organism's proteins are permanently denatured, and it dies
Describe "easily administer" of the clinical considerations when selecting an antimicrobial agent
the period of time to take it is comprehensive (2 pills every two hours is worst than 2 pills in the morning)
what point mutation is ames test testing?
the point mutation of his- into his+
In T4 virus during lytic cycle, what does attach it to the host bacterium (E. coli)?
the tail fibers
Temperature plays an important role in microbial life through its effects on_
the three-dimensional configurations of biological molecules
what is the risk behind vaccines?
the use of vaccines entails a risk->they may cause the disease they are designed to prevent
what is the biggest virus that is known?
the virus that causes smallpox
In each of the three cases of an animal virus entry, at the end of the entry, _
the viruses' genome is in cytosol
In which organisms does plasmids are found?
they are found only in prokaryotes
Facultative
they have the option (operate aerobic or anaerobic)
Most common nutrients
those containing necessary elements such as carbon, oxygen, nitrogen, and hydrogen
The smaller subunit of a ribosome is shaped to accommodate _codons at one time
three
how the two DNA strands interact?
through their nucleotide bases
How the scientists use the DNA pieces produced by restriction enzyme?
to combine pieces of DNA from different organism into a single recombinant DNA molecule
Extracellular state goal
to get inside of another cell
what is one goal of recombinant DNA technology that is related to vectors?
to insert a useful gene into a cell so that the cell has a new pheontype
Grifft's experiment explains_
transformation
which process moves plasmids (vector) inside bacteria?
transformation
Recombinant DNA technology has been applied to the realm of agriculture to produce_
transgenic organisms
deeps
tubes that contain solidified agar and they were kept vertical when the agar was solidifying
what is a solution to the becta-lactamase?
use semisyntethic derivatives of penicillin that are less susceptible to deactivation by Beta-lactamase
Latency may be prolonged for years with no_
viral activity, sign, or symptoms
In extrecellular state viruses are called_
virion
Colony
visible population of microorganisms living in one place; an aggregation of cells arising from a single parent cell
when an Hfr is formed?
when an F+ cell integrates its F plasmid into its chromosome
In which two organisms the insulin was first introduced? (they are commonly used in our days)
yeast and bacteria
what is needed to support the idea that the media with the chemical in the ames test is a mutagen and the change is not due to a change that salmonella did by itself?
you need a control group, not containing the suspected mutagen, which it should not show bacterial growth. This will indicate that the chemical (suspected mutagen) in the other media is a mutagen
Haploid (define and tell the type of cell that has it)
• A nucleus with a single copy of each chromosome -1 copy of 1 chromosome • Prokaryotes
Diploid (define and tell the type of cell that has it)
• A nucleus with two copies of each chromosome -2 copies of the same chromosome -Eukaryotes
Agar
• Solid surface media • Gel-like polysaccharides isolated from red algae and used as thickening agent • Media made solid by addition of agar to broth
helicase
DNA is denatured at origin of replication by helicase and single stranded DNA binding proteins
The Griffith's Experiment serve as a conclusive proof that_because_
DNA is genetic material because the transforming agent was DNA
who seals the gaps between adjacent Okazaki fragments to form a continuous DNA strand?
DNA ligase
In genetic screening, laboratory technicians use _.
DNA microarrays to screen a patient's blood or other tissues for these genetic mutations before the patient shows any sign of the disease.
Gel electrophoresis allows scientists to isolate_
DNA of interest
Name the four types of RNA molecules transcribed from DNA.
RNA primers mRNA rRNA tRNA
when does transcription ends?
When RNA polymerase reaches DNA transcription termination site, RNA polymerase dissociates from DNA.
what is the treatment for diabetes Type I? why?
-Insulin injections -Type I diabetes does not make this hormone (within b cells in pancreas) that controls glucose levels in blood, so the person needs to inject it
Be able to give 2-3 examples of antimicrobials that are in this category: inhibition of protein synthesis (include what each affect)
*Inhibit functions of the 30S ribosomal subunit:* aminoglycosides (streptomycin; gentamicin) tetracyclines *Inhibit functions of the 50S ribosomal subunit:* chloramphenicol Macrolides (erythromycin, azithromycin)
Can you briefly describe how penicillin acts? (include the end result of bacteria)
*Penicillin effect on peptidoglycan in preventing NAM-NAM cross links -Penicillin interferes with the linking enzymes, and NAM subunits remain unattached to their neighbors. However, the cell continues to grow as it adds more NAG and NAM subunits -The cell bursts from osmotic pressure (movement of water into the cell) because the integrity of peptidoglycan is not maintained
Altered permeability of the antimicrobial agent (what specifically is doing to avoid action of drug?)
*inability to enter the bacterial cell* -This mechanism typically involves changes in the structure or electrical charge of the cytoplasmic membrane proteins that constitute channels or pores (called poring in gram negative) Altered pore proteins result from mutation in chromosomal genes *active export (pump) of the agent from the cell (out of the cell) So called resistance pumps*
sterol (who has them and who don't)
- it can be incorporated into the lipid bilayers of the cytoplasmic membrane. -sterols only exist in the cytoplasmic membranes of eukaryotes while in prokaryotes, virtually none have sterols in their membranes -Includes cholesterol and ergesterol
culture
- refers to act of cultivating microorganisms or the microorganisms that are cultivated -Grow from inocolum
What is clinical resistance?
- the MIC (minimum inhibitory concentration) of the drug for a particular strain of bacteria exceeds that which is capable of being achieved with safety in vivo. -When the concentration of the drug needed to inhibit growth of the bacteria is too high to be safe in humans. So not effective drug anymore
what are the four types of RNA viruses?
-+ssRNA: positive sense, single stranded RNA -+ssRNA (rertoviridae): retrovirus: type of +ssRNA --ssRNA: negative sense, single stranded RNA -dsRNA: double stranded RNA
What is synergism?
-Interplay between drugs that results in efficacy that exceeds the efficacy of either drug alone -One drug sometimes enhances the effect of a second drug -can also result from the combination of an antimicrobial and a chemical
What is mode of action of sulfonamides? (include the normal mechanism of the organisms using whatever sulfonamide affect) and the name given (starts with M and A)
--Metabolic antagonist --Structurally similar to PABA (para-aminobenzoic acid) which is necessary for nucleic acid synthesis. -Inhibits folic acid synthesis in bacterial cells by binding to the active site of the enzyme, instead of PABA, and blockig the enzyme's action of manufacturing of dihydrofolic acid -Sulfonamide acts as a competitive inhibitor -Structual analogs of (chemically very similar) para-aminobenzoic acid (PABA), which (PABA) is crucial in the synthesis of nucleotides required for DNA and RNA synthesis -Many organisms (including pathogens) enzymatically convert PABA into dihydrofolic acid, and then dihydrofolic acid into tetrahydrofolic acid (THF), a form of folic acid that is used as a coenzyme in the synthesis of purine and pyrimide nucleotides -As analogs of PABA, sulfonamides compete with PABA molecules for the active site of the enzyme involved in the production of dyhydrofolic acid. This competition leads to a decrease in the production of THF, and this of DNA and RNA -The end result of sulfonamide competition with PABA is the cessation of cell metabolism, which leads to cell death
Log
-2nd phase of microbial growth -Population growth increases logarithmically -Researchers interested in this phase because: susceptible to antimicrobial drugs, Gram staining for having intact cell walls, metabolic rate is at maximum
how many possible arrangements of nucleotides are within mRNA?
-3 letter combinations (codon) -64 arrangements, which 61 specify amino acids and 3 do not.
Stationary
-3rd phase of microbial growth # dying = # produced -Nutrients are depleted and wastes accumulate, rate of reproduction decreases -size of population becomes stationary
Death
-4th phase of microbial growth -Too much waste products; Low nutrients. -If nutrients are not added and wastes are not removed -cells die at faster rate than they are produced -"decline phase"
missense mutation
-A change in a nucleotide sequence resulting in a codon that specifies a different amino acid -Results in slightly different amino acid sequence
Base pairs (BP)
-A complementary arrangement of nucleotides in a strand of DNA or RNA
chromosomes
-A molecule of DNA associated with protein and RNA -Main portion of DNA are packaged in 1-2 distinct chromosomes
what are the three binding sites of a ribosome? what attaches to them?
-A site -P site -E site -tRNA
Biofilms
-A slimy community of microbes growing on a surface
plasmid
-A small circular molecule of DNA that replicated independently of the chromosome -each carries genes for its own replication and often for one or more nonessential functions such as resistance to antibiotics -Type of vector
what are some of the diseases that viruses cause?
-AIDS -Common cold -Influenza -Herpes -SARS
Recombinant DNA technology (information it is based on, what manipulates, the areas it benefits)
-Adapt the natural enzymes and processes of DNA replication, replication, transcription, transformation, transduction, and conjugation to manipulate genes for industrial, medical, and agricultural purposes
How is the base pairing in DNA?
-Adenine (A) bonds with thymine (T) -Guanine (G) bonds with cytosine (C)
Classification of based on oxygen requirements
-Aerobes -Anaerobes -Facultative anaerobes -Aerotolerant anaerobes -Microaerophiles
What are the processes that chemohetrotrophs preform? Give examples
-Aerobic respiration: Most animals, fungi, protozoa, and many bacteria -Anaerobic respiration: some animals, protozoa, bacteria, and archaea -Fermentation: some bacteria, yeasts, and archaea
what agarose do in gel electrophoresis technique?
-Agarose makes up gel -acts as molecular sieve that retards the movement of DNA fragments down the chamber and separates the fragments by size -If you heat it up goes to liquid, cool down gets into gel -Similar to agar but it is the purified sugar component of agar -control shape of it
lithotrophic photoautotrophs
-Algae, photosynthetic bacteria -they can synthesize all of their metabolic and structural needs from inorganic nutrients
Altered target site (what specifically is doing to avoid action of drug?)
-Alteration of the target site for the antimicrobial agent. -Alter the target of the drug so that the drug either cannot attach to it or binds it less effectively
DNA replication is what type of process? what does it requires? who fulfills this requirements?
-An anabolic polymerization process that requires monomers and energy - triphosphate deoxyribonucleotides
Minimum bactericidal concentration (MBC) test (definition and what it determines/ what question answers?)
-An extension of the MIC test in which samples taken from clear MIC tubes are transferred to plates containing a drug-free growth medium and monitored for bacterial replication -Determines the amount of drug required to kill the microbe rather than just the amount of inhibit it, as MIC does -what is the minimum concentration that actually kills the bacteria?
stab cultures
-Anaerobic media -Because obligate anaerobes require special culture conditions in that their cells must be protected from free oxygen, they are introduced into the anoxic (oxygen free) depths of solid media
Reducing media
-Anaerobic media -Special culturing medium containing compounds that combine with free oxygen and remove it from the medium
How many times a gene should be introduced in the gene therapy? Thus this method will be long term or short term?
-Introduce gene successfully only once, so patient can make defective protein in a good way -long term
Why are humans not negatively affected by sulfonamides even if we too require folic acid to make nucleotides?
-Humans do not synthesize THF from PABA; instead, humans take folic acids found in their diets and convert them into THF -as a result, human metabolism unaffected by sulfonamides
what is the first genetically engineered drug approved by FDA? in what year?
-Humulin -1982
limiting nutrient
-Hydrogen is never a limiting nutrient -metabolism is never interrupted by a lack of hydrogen
Perioxide amino
-Hydrogen peroxide formed during reactions catalyzed by superoxide dismutase (and during other metabolic reactions) contains perioxide anion
diagnose results of diffusion susceptibility test
-If all drugs were equal, then the larger zone of inhibition, the more effective that drug is -However, the size of the zone depends on the rate of diffusion of antimicrobial (low molecular weights generally move quickly than those with higher molecular weights) -The size of inhibition must be compared to a standard table for that particular drug before accurate comparisons can be made -large zone of inhibition=sensitivity
what indicates if bacterial growth is found in the Ames test media?
-If bacteria grow on media lacking histidine it is because point mutation has been reversed (his+). Thus, salmonella can grow -The exposure to the chemical had changes on DNA (mutagen)
How osmotic pressure can affect the cell?
-If cell put in an hypotonic solution, it is swells up or burst in the case it does not have cell wall -If cell placed in hypertonic solution, it loses water into the surrounding solution. Such cell can die of crenation or shriveling of its cytoplasm -Osmotic pressure restricts organisms to certain environments
what determines if a prophage stays in the chromosome or induces?
-If growth conditions for bacteria are good->strategy that will lead the lysogenic virus to start lysogenic cycle , which will increase number of bacteria and prophages -If bacteria does not grow well->no multiplication of viral DNA-> start induction (switch that back to lytic cycle),
In which mutations are more serious: DNA, RNA, Protein? Explain.
-In DNA, because the sequence change of DNA would be almost permanent because we only have 1 copy of it -In the case of RNA and proteins we can produce more
uncoating
-In animal viruses after endocytosis entry -The removal of a viral capsid within a host cell
what is the difference regarding the donor cell and contact between cells in conjugation compared with transduction and transformation?
-In conjugation the donor cell remain alive -Conjugation requires physical contact between donor cell and recipient cell
How genetic engineering uses gel electrophoresis?
-In genetic engineering, scientists use the technique to isolate fragments of DNA molecules that can then be inserted into vectors, multiplied by PCR, or preserved in a gene library.
Central dogma
-In genetics, fundamental description of protein synthesis which states that genetic information is transferred from DNA to RNA to polypeptides, which function alone or in conjunction as proteins -The central dogma of genetics states that DNA is transcribed to RNA, which is translated to form polypeptides.
coding strand
-In transcription -Not being used for creating RNA
List the four mechanisms of resistance
-Inactivation of the antimicrobial agent -Altered permeability of the antimicrobial agent -Altered target site -Replacement of a sensitive pathway
Fungicide
-Includes amphoterecing B and plymyxin -drug that kills fungi
persistent infections (definition and graph)
-Infections with enveloped viruses in which host cells shed viruses slowly and relatively steadily -its curve in a graph lacks the burst of new virions seen in lytic replication cycles
what are some of the aspects that Geneticists study?
-Inheritance -Physical structure and function of genetic material -Mutations -The transfer of genetic material among organisms
Isoniazid (what it does, and what disease it treats caused by what pathogen? Include the diseases that the pathogen causes)
-Inhibition of cell wall synthesis -disrupts formation of mycolic acid in mycobacterial species (mycobacterium causes tuberculosis and leprosy)
which of the mechanism of action of microbial drugs are not normally used to treat infections? why? other uses?
-Inhibition of nucleic acid synthesis -Only slight differences between prokaryotic and eukaryotic DNA; drugs often affect both types of cells -Not normally used to treat infections; -used in research and perhaps to slow cancer cell replication
Bacitracin (mechanism, what it does, end result)
-Inhibitor of cell wall synthesis -blocks secretion (release from a cell) of NAG and NAM (peptidoglycan) from cytoplasm -Result in cell lysis due to effects of osmotic pressure
Vancomycin (mechanism, what it does in which type of bacteria, end result)
-Inhibitor of cell wall synthesis -interferes with alanine-alanine bridges that link NAM subunits in many Gram-positives -Result in cell lysis due to effects of osmotic pressure -Block linked bonds between peptidoglycan layers
steps and diagnosis of results of Minimum bactericidal concentration (MBC) test
-Samples taken from clear MIC tubes (from broth dilution test) (or, alternatively, from zones of inhibition form a series of diffusion susceptibility tests) are transferred to plates containing a drug-free growth medium -The appearance of bacterial growth in these subcultures after appropriate incubation indicates that at least some bacterial cells survived that concentration of the antimicrobial drug and were able to grow and multiply once placed in a drug-free medium If bacteria colonies grow, you can conclude there were still living bacteria-> concentration was not enough to kill the bacteria -Look for tube with lowest concentration that does not yield colonies on free drug medium-> enough concentration of antibiotic to kill the bacteria->would be the minimal bactericidal concentration
Protein synthesis (example, and benefits)
-Scientists have inserted genes for insulin and other proteins into bacteria and yeast cells so that the cells synthesize these proteins in vast quantities. -Genetically engineered proteins are safer and less expensive than proteins isolated from donated blood or from animals.
How scientists use restriction enzymes?
-Scientists use restriction enzymes to cut DNA at locations with specific and usually palindromic nucleotide sequences called restriction sites. -To get specific little piece of DNA (gene of interest)
How scientists use mutagens? After using mutagens, what scientist do?
-Scientists utilize mutagens to create changes in microbes' genomes so phenotypes are changed -They then select for and culture cells with characteristics considered beneficial for a given biotechnology application
When using mutagens in recombinant DNA technology, scientists have to_. Today _instead of dealing with entire organisms
-Select for and culture cells with beneficial characteristics -Today, mutated genes alone can be isolated
antibiotics (who coined the term and definition)
-Selman Waksman -antimicrobial agents that produced naturally by an organism -Today are used interchangeable with antibacterial agent
Methicillin
-Semi-syntetic derivate of penicillin
What are the 4 toxic forms of oxygen?
-Singlet oxygen (1^O2) -Superoxide radical (O2-) -Perioxide anion (O2^2-) -Hydroxyl radical (OH)
what are the useful properties of the vector? (4)
-Small enough to manipulate in a lab -Survive inside cells (does not degrade becasue are very stable) -Contain recognizable genetic marker (researchers can identify the cells that have received the vector) -Ensure genetic expression of gene (have gene code correctly so you get what you want, which is a protein/ include promoters)
Plasmid
-Small molecules of DNA that replicate (make copies of itself) independently -Carry information required for their own replication, and often for one or more cellular traits
Explain how antimicrobials are a disruption of cytoplasmic membranes (brief)
-Some drugs become incorporated into cytoplasmic membrane and damage its integrity -Disrupt the cytoplasmic membrane of a targeted cell, often by forming a channel through the membrane, damaging its integrity
Allergies (category of drug side effect)
-Some drugs may trigger allergic immune responses in sensitive patients -Although allergic reactions are rare, they may be life threatening -Anaphylactic shock: (immediate, violent reaction) may cause deaths -People with mild allergies frequently lose their sensitivity to the drug over time
How latency is different from lyzogeny?
-Some latent viruses do not incorporated into the chromosomes of their host cells, whereas lyzogenic phages always do -Some animal viruses (like HIV) become integrated into a host chromosome as a provirus, when they are incorporated into its host DNA, the condition is permanent; induction does not occur in eukaryotes. Provirus becomes a permanent, physical part of the host's chromosome->all descendants of the infected cell will carry the provirus
ODD things about viruses genomes
-Some other viruses have single strand (ssDNA) -Some viruses generate double stranded RNA structures (mRNA, rRNA, tRNA) (dsRNA)
Which pathogen has becta-lactamase? (include the meaning of becta-lactamase)
-Staphyloccocus aureus -Enzyme that destroys beta-lactam -bacterial enzyme that breaks the beta-lactam rings of penicillin and similar molecules, rendering them inactive
Denaturation (PCR)
-Step 1 -separation of the two strands of DNA -Using high temperatures: 94 degree (boiling) to denature hydrogen-bonds between base pairs bases in two strands
Sticky end cut
-Sticky end restriction cuts the two strands in a staggered way (NOT IN MIDDLE) with complementary "sticky ends" -Restriction enzymes cuts two strands of DNA producing fragments that terminate in mortise-like sticky ends -Easier to make DNA recombinant than blunt end fragments because they are sticky; however they only bind to complementary, sticky-ended fragments produced by the same restriction enzyme
what is one use of nucleotide analogs in medicine? explain why.
-They are potent antiviral and anticancer drugs because viruses and cancer cell typically replicate faster than normal cells
Antigen (definition, ex, what they cause in contact with human body)
-Substance that stimulates bodies immune system. -foreign substance such as weakened bacteria, viruses, and toxins that simulate the body's immune system to respond to and subsequently remember these foreign materials
what are the successful treatments of gene therapy?
-Successfully treated patients with severe combined immunodeficiency disease -Others that may respond well - cystic fibrosis, sickle cell anemia, some types of hemophilia, some types of diabetes
-cide -cidal
-Suffixes indicating destruction of a type of microbe
Describe synthesis of ssDNA viruses
-Synthesis of mRNA: By RNA polymerase in nucelus -Template for Genome Replication: Complementary strand of DNA is synthesized to act as template -Parvovirus, a human virus with ssDNA, is synthesized by host cell enzymes, which synthesize a complement to the ssDNA. -The complementary strand binds to the ssDNA of the virus to form a dsDNA molecule. -Transcription (mRNA), replication (dsDNA), and assembly then follow.
Describe synthesis of dsDNA viruses
-Synthesis of new dsDNA virions is similar to the normal replication of cellular DNA and translation of proteins. -Template for genome replication:Each strand of viral DNA is used as a template for its complement. -Synthesis of mRNA: is done by RNA polymerase in nucleus (mRNA) or cytoplasm (capsomeres proteins) of cell -After capsomeres are done they enter the nucleus, where new virons spontaneously assemble -This method of replication is seen with herpes and papilloma viruses; in poxviruses, synthesis occurs in the cytoplasm.
Xenotransplants (definition and solve which problem?)
-Technique involving recombinant DNA technology in which human genes are inserted into animal to produce cells, tissues or organs that are then introduced into the human body -solve the problem of transplant recipient rejection for being a foreign tissue
broth dilution test (official definition)
-Test for determining the minimum inhibitory concentration in which a standardized amount of bacteria is added to serial dilutions of antimicrobial agents in tubes or wells containing broth
Categories of bacterial colonies?
-Texture -Pigmentation -Optical property -size -shape -Margin -elevation -appearance
Membrane fusion
-The entire capsid and its contents (including genome) -The viral envelope and the host cell membrane fuse, releasing the capsid into the cell's cytoplasm and leaving the envelope glycoproteins as part of the cell membrane -The two membranes merge into one layer
Endocytosis
-The entire capsid and its contents (including genome) enter the host cell -Attachment of the virus to receptor molecules on the cell's surface stimulates the cell to endocytize the entire virus
Turbidity
-The greater the bacterial population, the more turbid a broth will be -Measure the change in turbidity using spectrophotometer -Transmission of light is inversely proportionally to the population size -The larger the population grows, the less light will reach the detector -Must have of concentration 1 million per milimiter and cells should be suspended uniformly in the medium
what distinguishes one nucleic acid from other? (within the same categories like distinguish between DNA and an other DNA molecule)
-The length (how many nucleotides are linked together) and sequence of nucleotides (the organization of the nucleotide bases)
What is spectrum of action?
-The number of different kind of pathogens a drug acts against -how many different microorganisms does a given antimicrobial kill or affect
What has the stop codons that make translation end? what else can stop translation?
-The stop codons have a release factor that makes the small and big subunits to release and the polypeptide chain will also be released -release factors are enzymes that recognize stop codons, and modify the larger ribosomal subunit to active another of its ribozymes, which severs the polypeptide from the final tRNA. The ribosome then dissociates into its subunits
why phages are useful in laboratories?
-The study of bacteriophages revealed the basic of viral biology -They are easier and less expensive to culture than animal or human viruses
How thioglycollate growth medium works?
-The surface is exposed to atmospheric oxygen and is aerobic -Oxygen concentration decreases with depth; the bottom of the tube is anaerobic
How can oxygen be essential for one group of organisms and yet be fatal toxin for others?
-The toxic forms of oxygen are those that are highly reactive -They are toxic for the same reason that oxygen is the final electron acceptor for aerobes: they are excellent oxidizing agents, so they steal electrons from other compounds -The resulting chain of virgorous oxidations causes irreparable damage to cells by oxidizing important compounds, including proteins and lipids
antiparallel in DNA
-The two strands are oriented in opposite directions to each other (interact in an opposite direction) -One strand runs in a 3' to 5' direction, while the other runs in a 5' to 3' direction
Are psychorphiles pathogenic? where they can be found?
-They are not pathogenic because they cannot stand human body temperature but they can cause food spoilage in refrigerators -Found in ice, snowfield, and cold water
Briefly explain how amphotericin B functions as an anti-fungal drug (including effects on humans and the final outcome ) Include function of cytoplasmic membrane
-attaches to ergosterol found in fungal membranes -In the process of attachment, it disrupts the membrane and causes lysis of the cell -Amph-B has a structure that attaches to the ergesterol, and in doing so forms a large pore in the cell membrane -The function of the cell membrane as a permeable barrier (regulate what gets in and what gets out) is disrupted because of the pore formed by amph-B. Thus cell will not function well -Humans somewhat susceptible because cholesterol similar to ergosterol -Disrupt fungal membranes primarily rather to our own because cholesterol does not bind amphotericin B as well as does ergesterol (selective toxicity)
pure cultures
-axenic -cultures composed of cells arising from a single progenitor
B-lactamase
-bacterial enzyme that breaks the beta-lactam rings of penicillin and similar molecules, rendering them inactive -breaks down penicillin
Examples of -cide or -cidal
-bactericide -fungicide -germicide -virucide
Any drug concentration at which growth occurs in subculture is_, not_for the bacterium
-bacteriostatic -bactericidal
silent mutations
-base-pair substitution -The substitution does not change the amino acid sequence because of the redundancy of the genetic code. -no affect at all in the protein because the mutation results in the same protein
why aerobes can resist superoxide radical an anaerobes cannot?
-because aerobes produce superoxide dismutases which detoxify of superoxide radical by combinig it with protons of hydrogen peroxide -Anaerobes lack these and die as a result of the oxidizing reactions
why complex media has an advantage over defined media?
-because complex medium contains a variety of nutrients, including growth factors, it can support a wider variety of different microorganisms -Complex media used to culture organisms whose exact nutritional needs are unknown
Why the use of petri plates is not appropiate for anaerobic media? How this can be solved?
-because it present a problem to anaerobes because each dish has a loose-fitting lid that allows the entry of air -By putting anaerobes in petri plates with sealable containers containing reducing chemicals
why gene therapy has proven difficult in practice?
-because of unexpected results -Patients' human system react uncontrollably to the presence of vectors, resulting in death (negatively)
why the treatment of viruses is hard?
-because the viral replication uses cellular structures and pathways involved in the growth and maintenance of healthy cells -Any strategy for the treatment of viral diseases that involves disrupting the viral replication may disrupt normal cellular processes as well
Do you understand why there are more antibacterial drugs compared to antiviral? (include why so few antifungal, antiprotozoan, and antihelmintic drugs are available)
-because there are so many differences between the structure and metabolism of pathogenic bacteria and their eukaryotic hosts, antibacterial drugs constitute the greatest number and diversity of antimicrobial agent -Fewer antifungal, antiprotozoan, and anthelminitic drugs are available because fungus, protozoa, and helminthis are eukaryotic and thus share many common features (but there are differences that drugs can target) -The number of antiviral drugs is also limited, despite the major differences in structure, because viruses utilize their host cells' enzymes and ribosomes to metabolize and replicate. Therefore, drugs that are effective against viral replication are likely toxic to the host as well
Acidic substances have a pH_7 and alkaline (basic) substances have a pH_7. Neutral substances are at_
-below -higher -7.0
test that determine the minimum inhibitory concentration
-broth dilution test -Etest
how can you see DNA in a very visual way? who (what organization) uses this method?
-by Agarose Gel Electrophoresis -CIA
How can competence be scientifically manipulate in bacteria?
-by manipulating heat and salt content of the medium -by heating and cooling the organism and using chemicals
How can bacteria perform recombination?
-by sharing or donating DNA to another bacteria to make new arrangements of DNA (recombination)
Complemetary DNA (abbreviation, who makes it by what process, definition)
-cDNA -Reverse transcriptase by transcribing DNA nucleotides from an RNA template -so called because it is complementary to an RNA template.
PABA is a. a substrate used in the production of penicillin b. a type of B-lactamase c. molecularly similar to cephalosporins d. a substrate used to synthesize folic acid
D
what nucleic acids does viruses have?
DNA RNA
Describe pour plate
Get some of the first sample then put it in the second and then get some of the 2nd to put In the next Next tube has less bacterial than the first one
Gram Stain
Gram positive cells contain thick layers of peptidoglycan in their cell walls. G+ cells retain the primary stain CRYSTAL VIOLET and the mordant IODINE through treatment with the decolorizer ACETONE-ALCOHOL and appear PURPLE. Gram negative cells are counterstained with the SAFRANIN and appear RED/PINK.
Capsid
Protein coat surrounding nucleic acid (virus genome)
During the third step of central dogma of genetics, what are the processes that take place?
Protein synthesis=translation
codon
Triplet of mRNA nucleotides that codes for specific amino acids
which type(s) of routes of administration are used for external infections?
Tropical or local administration
why viruses cannot reproduce by themselves?
Viruses cannot reproduce themselves because they have neither the genes for all enzymes necessary for replication, nor do they possess functional ribosomes for protein synthesis
Why viruses are so pathogenic, even thought they are so small?
Viruses utilize a host cell's enzymes, organelles, and membranes to complete their replication cycle
What are the four main types of plasmids?
• Fertility factor • Resistance factor • Bacteriocin factor • Virulence factor
Where does transcription take place in prokaryotes vs eukaryotes.
• In prokaryotes, transcription happens in nucleoid (found in cytosol of prokaryotes) • In eukaryotes, transcriptions happens in nucleus within the nucleolus, in mitochondria, and in chloroplast
slant tubes or slants
•Test tube containing agar media that solidifies while the tube was resting at an angle