Lecture exam 2 Vocabulary
clone
(1) A group of genetically identical cells or organisms derived by a sexual reproduction from a single parent. (2) A DNA sequence that has been isolated and replicated using a cloning vector.
Discuss the ways various agents actually kill or inhibit microbes, focusing on cell wall, plasma membrane, nucleic acid, denature proteins.
-damage to proteins and nucleic acids, alteration of cell walls and membranes The ways the various agents actually kill or inhibit microbes 1.) Alteration of Cell Membrane Permeability *loss of selective permeability *damage to cell membrane/ cell wall 2.) Damage to Proteins *denature or inhibitor 3.) Damage to Nucleic acids
What factors influence the effectiveness of antimicrobial treatments? Discuss how these factors impact choosing and using a disinfectant.
1) bacterial status (susceptibility and resistance, tolerance, persistence, biofilm) and inoculum size; (2) antimicrobial concentrations [mutant selection window (MSW) and sub-inhibitory concentration]; (3) host factors (serum effect and impact on gut micro-biota). Number Environmental influences Time Microbial characteristics biofilms?
Understand the differences between obligate aerobes, facultative anaerobes, obligate anaerobes, aerotolerant anaerobes and microaerophiles. Compare their specific growth requirements and growth patterns.
1. Obligate Aerobes: Absolute requirement for oxygen 2. Obligate Anaerobic: Cannot live in presence of oxygen. Oxygen is toxic 3. Facultative Anaerobes: Grow better with oxygen, but can live without. Use fermentation or anaerobic respiration. 4. Microaerophiles: Require oxygen in lower than atmospheric concentration. 5. Caprophiles: Require increased CO2 concentrations.
How does your Bunsen burner work? Is in a form of sterilization?
A busen burner works by burning flammable gas which is passed through to produce flame. Theres a tube connected to the gas supply with a adjustable air to allow oxygen to be introduced to gas before ignition. Yes it is a form of sterilization.
What is the difference between a fungicide and a fungistatic? When would either best be used?
A fungistat prevents the spread of a fungus, whereas a fungicide kills the fungus.
Explain the process of transcription. What is used? What is the outcome?
A process which occurs during DNA synthesis. Its when the DNA helix is unwound and are of the strands read and copied by RNA. When amino acid bases are copied onto this RNA strand Uses complimentary pairing principles Uses pool of nucleotides Forms mRNA A sequence of codons Units 3 bases long that code for a particular a.a.
recombinant DNA technology
A technique mainly used to change the phenotype of an organism (host) when a genetically altered vector is introduced and integrated into the genome of the organism.
Be familiar with the chemical agents of control covered in the PPt notes. What is there mode of action? For example, how does alcohol work?
Alcohols - ethyl and isopropyl Dissolve membrane lipids (surfactant) Will denature proteins Won't work against naked viruses or endospores. Detergents - synthetic chemicals acting as strong surfactants. Aldehydes Powerful disinfectant that if given time can act like a sterilizing agent Will disrupt protein structure by binding to amino acids. Heavy metals Selenium, mercury, copper, and silver Once common to treat an infant's eyes with a few drops of silver nitrate to prevent gonococci infection 1. Cell Wall Alcohol - esp against Gram negs 2. Plasma Membrane Ex: surface acting agents (surfactants) • disrupt membrane by inserting themselves into the membrane 3. Nucleic Acid or NA syn Knock out ribosomes Bind irreversibly to DNA Breakage by chemical agents 4. Denature Proteins Moist heat Alcohol or acidic solvents TDT = time necessary for killing the population at a given temp. Autoclave Moist Heat - effective control method! Steam under Hg By increasing the pressure, one can increase the temp of water vapor thereby increasing death rates Autoclave = a special device that can regulate the pressure and temperature.
Hetrotroph
An organism that denies its nutritional requirement from complex organic substances
To which category would human pathogens belong, thermophiles, mesophiles, or psychrophiles? What is the difference between these, and where would they all be able to live?
An organsim that grows best at moderate temperature between 20-45 degrees C (68-113 degrees F) Mesophiles survives and grow best at moderate and human temperature Thermophiles- an organsim that thrives at high temperatures of 45-122 degrees C (107-251 degrees F) and is an archea Physchrophiles- extremeophilic organsima capable of growth and reproduction in cold temperatures. -15 degrees c(59 degrees F). can be found in pockets of very salty water by sea ice.
Why have antibiotics not yet wiped out disease?
Antibiotic overuse doesn't just lead to drug-resistant superbugs, it may also permanently wipe out the body's good bacteria. Good bacteria in the gut help people in many ways, including helping make vitamins and boosting immunity. Some researchers think that killing them off with antibiotics may be contributing to rises in chronic health conditions such as obesity, asthma, and cancer.
The thermal death time for a Bacillus subtilis endospore is 30 minutes of dry heat and less than 10 minutes in an autoclave. Which type of heat is more effective? Why?
Autoclave because of high heat of water, moist heat is readily transferred to cells. The higher the temperature pressure, the hotter it is.
human parasites would best fit in?
Autotrophs
Understand the microbial death curve.
Bacterial populations die at a constant logarithmic rate The death curve shows how long it takes to kill all bacteria. When the death curve is plotted logarithmically, the death rate is constant (straight line) You can determine the length of treatment by creating a logarithmic line 1) Plotting the typical microbial death curve logarithmically (red line) results in a straight line. 2) Plotting the typical microbial death curve arithmetically (blue line) is impractical: at 3 minutes the population of 1000 cells would only be a hundredth of the graphed distance between 100,000 and the baseline.
What is a biofilm and what is its purpose?
Biofilms are multi-cellular communities formed by bacteria, and they consist of bacteria encased within a non-crystalline extracellular matrix (ECM) of proteins, polysaccharides, and small molecules. Biofilm formation provides increased protection of bacteria from antibiotics and host defenses.
biotechnology
Biotechnology is the application of living organisms and their products in industrial processes on large scale
What is a chromosome? What do they determine?
Cellular structure made of DNA & protein DNA/traits
What are the three major methods of control? List examples of the methods of control that were covered in the notes to demonstrate an understanding of the method. For example, one method of physical control is the use of moist heat using an autoclave. An autoclave will etc.,
Chemical- Alcohols - ethyl and isopropyl Dissolve membrane lipids (surfactant) Mechanical- masks and physical-Pasteurization Heat is applied to liquids to kill potential agents of infection/spoilage
Why clean fomites in a hospital before performing disinfection?
Cleaning fomites removes 90-95% of pathogens present on fomites. Disinfectant can remove some but not all of the pathogens.
What is recombination? What is the outcome?
Combining DNA from two different individuals. Crossovers result in recombination and the exchange of genetic material between the maternal and paternal chromosomes. As a result, offspring can have different combinations of genes than their parents. ensure that each gamete includes both maternally and paternally derived genetic information
Describe what a DNA fingerprint is and how and why restriction enzymes can be used to form a unique DNA pattern?
DNA fingerprinting is a laboratory technique which is used to identify the genetic makeup of a person or other living thing It involves following steps: Isolation of DNA digestion of DNA by restriction enzyme electrophoresis seperation of fragments of DNA Transfer of DNA fragments to nylon Probing Hybridization Autoradiography Interpretation of results Restriction enzymes are useful for many different applications. Each DNA sequence is different in each organism, the pattern of restriction sites will also be different for different organism hence restriction enzyme will cut at different location for different organism and different DNA thus making a completely new and unique DNA fingerprint 2.enzyme isolated from bacteria that cuts DNA molecules at specific sequences is called a restriction enzyme Their main function is that they recognize specific sequences in DNA and then cut the DNA and then cut the DNA to produceor create fragments of DNA called restriction fragments. DNA fingerprinting is a technique that simultaneously detects lots of minisatellites in the genome to produce a pattern unique to an individual. This is a DNA fingerprint. The probability of having two people with the same DNA fingerprint that are not identical twins is very small. During DNA fingerprinting, fragments are placed in agar gel and an electric field is applied along the gel plate. As DNA fragments are electrically charged, they travel through the gel. ... Restriction enzymes attach to DNA and cleave it (cut it) randomly or at specific locations. restriction enzymes are so significant in the process of DNA Fingerprinting because, in order to be able to sequence DNA, a method of cutting the DNA molecule into smaller fragments at precise locations is necessary. If two DNA samples were identical, the same restriction enzyme woul
What is a DNA probe? Give an example when a DNA probe would be used in Microbiology.
DNA probe is a piece of DNA that differentiates one individual from and for designed using DNA from the subject where DNA is being tested. DNA probes is used when scientists need to ID suspects or victims of a crime. DNA finger prints Forensic Micro example: Bacterial DNA isolates from a disease outbreak - used for disease epidemiology DNA probes is used when scientists need to ID suspects or victims of a crime.
Be able to compare chemically defined, complex, reducing, selective, differential and enrichment media. What are they each used for? Can a media fall under more than one category?
Enriched Media-This media contains organic substances and complex growth factors such as blood. Reducing Media- This media has ingredients such as sodium thioglycolate chemically combined with dissolved oxygen which supports the growth of anaerobic bacteria. Selective Media-This media is designed to suppress the growth of unwanted bacteria and to encourage the growth of desired microbes. Chemically Defined Media (synthetic)-This medias nutrients are digests or extracts. The composition varies from batch to batch and it is economical. General Purpose Media & Complex Media (non-synthetic)-This media grows most nonfastidious bacteria. Differential Media-The growth of several bacteria types are readily distinguished from one another based on color changes in this media. The growth of different colored colonies etc.
What conditions would be necessary to grow a fastidious, gram negative, anaerobic mesophilic bacterium?
Fastidious microorganisms requires specific nutritional components to grow. Anaerobic organism will grow in absence of oxygen. Mesophilic bacteria thrive at a temperature range of 11 to 45 degrees.
How could RNAi be used as a gene splicer?
Gene splicing is a post-transcriptional modification in which a single gene can code for multiple proteins. Gene Splicing is done in eukaryotes, prior to mRNA translation, by the differential inclusion or exclusion of regions of pre-mRNA. Gene splicing is an important source of protein diversity. During a typical gene splicing event, the pre-mRNA transcribed from one gene can lead to different mature mRNA molecules that generate multiple functional proteins. Thus, gene splicing enables a single gene to increase its coding capacity, allowing the synthesis of protein isoforms that are structurally and functionally distinct. Gene splicing is observed in high proportion of genes. In human cells, about 40-60% of the genes are known to exhibit alternative splicing. RNAi has been rapidly adopted as a functional genomics tool in a wide range of species, has been adapted to allow for the transient or stable knockdown of gene expression generation in cell lines and animals, and has been developed for high-throughput anal
Understand the functions of helicase and DNA polymerase in replication.
Helicases bind at the origin of replication. Site rich in A&T- unwinds the helix allowing each strand to be copied. DNA Polymerase III - adds new nucleotides & proofreads DNA poly I Removes RNA primer, closing gaps, and repairs mismatches of nucleotide. Creates DNA from nucleotides, and add the DNA to each separated strand, producing two identical strands of DNA. There are many types of this enzyme, including one that fills in the needed nucleotide in the Okazaki fragments. Can only replicate DNA from the 5' end to the 3' end.
What kind of environment would one find thermophilic bacteria?
Hot environments. marine and terrestrial geothermally-heated habitats
What do eukaryotes use for recombination?
In eukaryotes, recombination during meiosis is facilitated by chromosomal crossover. The crossover process leads to offspring having different combinations of genes from those of their parents, and can occasionally produce new chimeric alleles.
If pasteurization does not achieve sterilization, why is food treated by Pasteurization?
It is used to preserve the product. Its to eliminate pathogenic microbes and lowers microbial numbers to prolong its quality. Damages bad microbes, preserves good microbes.
What kind of medium might you make to selectively grow a bacterium that lives in the ocean? How about one that lives in the stomach?
MSA Mannitol salt agar. Mac MacConkey Agar
E. coli grows on MacConkey agar but not on Mannitol Salt Agar. S. epidermidis does the opposite. Explain why there are such differences and what it is that specifically inhibits growth.
MacConkey's is a selective medium that inhibits the growth of Gram-positive bacteria due to the presence of crystal violet and bile salts. Gram-negative bacteria grow well on MAC. Sterile Specialized Bacterial Growth Media. Clockwise from top left MacConkey's, Mannitol Salt and Blood Agar.
Why is each of the following bacteria often resistant to disinfectants and why?
Mycobacteria-species share a cell wall that is hydrophilic, waxy, and rich in mycolic acids. The cell wall makes a substantial contribution to the genus. Pseudomonas-resistant because of its ability to pump out antibiotics. They contain proteins called porins that show little permeability for hydrophilic solute. Porins change their structure to escape from antibacterial pressure. Bacillus-resistant because of its ability to pump out antibiotics. They contain proteins called porins that show little permeability for hydrophilic solute. Porins change their structure to escape from antibacterial pressure.
Why is each of the microbes (Mycobacterium, Bacillus, Clostridium) harder to kill with disinfectants than most microbes?
Mycobacterium has a layer of my colic acid surrounding them. The waxy coating acts as a shield. Bacillus forms spores which protects them from toxins and high temperature levels. Clostridium spores can survive in an environment for a long time because they have a hard shell thats resistant to quays and phenolics.
Is it possible to sterilize the skin? Explain.
No, because it will kill the organisms that live in the skin.
Why would an older culture of cells have a slower response to a bactericide than a younger culture?
Older cultures have a slower response because bactericide is a disinfectant that kills growing forms. Since young cultures are still growing, bactericide has a faster response and it can destroy before it fully grows. Old cultures already has spores because it fully developed, bactericide does not kill spores, so the response is slower
What is a prokaryotic operon?
Operon - section of DNA consisting of a related group of genes.
Autotrophs
Organisms that are able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.
Chemoheterotrophs
Organisms that obtain energy by the oxidation of electron donors in their environments.
List the physical methods of microbial control. When would each of these be most effective? Explain.
Pasteurization- Heat is applied to liquids to kill potential agents of infection/spoilage Quick 15 second exposure to 72ºC Effectiveness Kills about 99% of all vegetative bacterial and fungi cells Does not kill endospores/ certain milk bacteria Primary goal is to wipe out potential food borne pathogens such as Campylobacter Dry heat Basically makes ashes out of the microbes Good for metals or non-metal disposables Chilling & desiccation are marginally effective Metabolic rate Staph Strepto Salmonella Desiccation Works by removing water from cells Radiation
What is PCR? What is it used for? How does this allow scientist to rapidly produce copies of DNA in the laboratory?
Polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete copies or partial copies) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) to a large enough amount to study in detail. The polymerase chain reaction (PCR) is used to make millions of copies of a target piece of DNA PCR amplifies a specific region of a DNA strand (the DNA target). Most PCR methods amplify DNA fragments of between 0.1 and 10 kilo base pairs (kbp) in length, although some techniques allow for amplification of fragments up to 40 kbp.[5] The amount of amplified product is determined by the available substrates in the reaction, which becomes limiting as the reaction progresses Polymerase Chain Reaction PCR Used to make many copies of DNA PCR is a technique by which small maples of DNA can be quickly amplified, increased to quantities large enough to be analysis. 1) Incubate DNA @ 94 degress for 1 min. to separate strands. 2) Add primers, nucleotides and DNA polymearse. 3) Primers attach to single stranded DNA during incubation at 60 degree C. for 1 min. 4) Incubate at 72 degrees C. for 1 min. DNA copes DNA at this temp. 5) Repeat cycle of heating and cooling to make 2 more copies.
What is the function of RNA polymerase?
RNA polymerase (green) synthesizes RNA by following a strand of DNA. RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, duyring the process of transcription. Or RNA polymerase binds to DNA, separates the strands, then uses one of the strands as a template from which to assemble nucleotides into a complementary RNA strand.
What are the three major recombination mechanisms? Explain them.
Radiative, Defect, and Auger. Auger and Defect recombination dominate in silicon-based solar cells. Among other factors, recombination is associated with the lifetime of the material, and thus of the solar cell.
What is rDNA? What does it involve?
Recombinant DNA (rDNA) is a technology that uses enzymes to cut and paste together DNA sequences of interest. The recombined DNA sequences can be placed into vehicles called vectors that ferry the DNA into a suitable host cell where it can be copied or expressed. DNA derived from two different source genomes.(ppt) Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) that bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.
What are restriction enzymes? What function do they serve? What do they "Create"?
Restriction enzymes - Also known as restriction endonucleases, these are the class of enzymes which cleaves the DNA at or near a specific site (known as restriction site) and creates DNA fragments. The cleaving properties of restriction enzymes serves two main functions - protection against foreign DNA entering any cell and a molecular scissors for recombinant DNA technology. Restriction enzymes create fragments of DNA in living cells. They create binding site in recombinant DNA technology. Examples - EcoRI, Hind-III Molecular scissors Recognize particular DNA sequences and can break the bonds between nucleotides within this sequence Cuts create "tails" that are sticky
How would you rank these (bactericide, sporicide, bacteriostatic)? Explain.
Sporicide - kills spores of bacteria Bactericide - a chemical that destroys bacteria Bacteriostatic - an agent that prevents the growth, but does not destroy.
Which of these two is more powerful? Sporocide or bactericide? Explain.
Sporicide because it kills spores of bacteria. While bactericide is like a germicide, it kills growing forms but not spore forms of microbes.
Understand the bacterial growth curve. What happens in each the lab, log, stationary and death phases?
The bacterial growth curve represents the number of live cells in a bacterial population over a period of time Bacterial growth curve on the back of syllabus Lag phase, log phase (exponential growth), /stationary, dying exponentially 1. Lag Phase: Bacteria do not increase in number, but they are active. 2. Log phase: Bacteria grow exponentially 3. Stationary/equilibrium Phase: Bacterial growth & death are equal. 4. Decline Phase: Bacterial death is greater than bacterial growth.
What is complementary pairing for DNA? What are the corresponding pairs?
The four nitrogenous bases are A, T, C, and G. They stand for adenine, thymine, cytosine, and guanine. The four different bases pair together in a way known as complementary pairing. Adenine always pairs with thymine, and cytosine always pairs with guanine.
Give a summary of the flow of DNA to proteins.
The journey from gene to protein is complex and tightly controlled within each cell. It consists of two major steps: transcription and translation. Together, transcription and translation are known as gene expression. The DNA is a type of coded message for a protein to be made. The seque
Discuss three adaptive mechanisms bacteria may acquire to develop resistance to antibiotics.
The main mechanisms of resistance are: limiting uptake of a drug, modification of a drug target, inactivation of a drug, and active efflux of a drug. These mechanisms may be native to the microorganisms, or acquired from other microorganisms Or DNA bacteria changes and alters protein shapes. DNA changes are random= mutations Antibiotic kills by attaching to a certain site on bacterial ribosomes.
What are base pairs held together by? Why is base pairing important in DNA?
The nucleotides in a base pair are complementary which means their shape allows them to bond together with hydrogen bonds. The A-T pair forms two hydrogen bonds. The C-G pair forms three. The hydrogen bonding between complementary bases holds the two strands of DNA together. Complementary base pairing is important in DNA as it allows the base pairs to be arranged in the most energetically favourable way; it is essential in forming the helical structure of DNA. It is also important in replication as it allows semiconservative replication.
Understand figure 9.2. Why are restriction enzymes used to make rDNA?
The restriction enzymes have the property of cleaving DNA molecules at a specific sequences. This restriction enzymes are used to cut DNA sequences at specific points of nucleotides. Some foreign genes are inserted into plasmids to make recombinant DNA.
Understand the difference between streak plate, pour plate and spread plate, and the appropriate situation for each.
The streak plate method is used to isolate pure cultures. Pour Plate method: A method of inoculating a solid nutrient medium by mixing bacteria in the melted medium and pouring into a Petri dish to solidify (colonies grow on surface and in solidified medium). Spread plate method: A plant count method in which the inoculum is spread over the surface of a solid culture medium (colonies grow only on surface).
Urinary tract infections are generally diagnosed by the presence of at least 100,000 microbial cells per milliliter of urine. A patient's urine specimen contains 1,000 bacterial cells/ml when collected, but the specimen was not sent immediately to the hospital lab. It remained on the counter in the medical ward for 4 hours. Explain how this improper handling of the urine specimen will affect the diagnosis.
There is some controversy about the true definition of a UTI. Traditionally, a UTI was diagnosed if more than 100,000 organisms were cultured from one ml of urine (AKA >100,000 coliforms/ml or CFU). However, studies have shown acutely symptomatic infections in able-bodied (or normally healthy) patients with cultures as low as 200 CFU! After collecting the urine sample, the sample is generally cultured to observe its growth. However, some of the bacteria and yeast can grow in the sample itself during the next 24 to 48 hours of sample collection. The microbes probably multiply if the sample is not refrigerated.
Understand generation time as it pertains to cell division.
Time it takes the cell to divide
What is the role of tRNA?
Transfer ribonucleic acid (tRNA) is a type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein. tRNAs function at specific sites in the ribosome during translation, which is a process that synthesizes a protein from an mRNA molecule. Or Each tRNA carries a specific amino acid based on its anticodon. The function of tRNA is to bring the amino acids and place them in the correct potsition to create the desired protein. The ribosomes are made up of rRNA and proteins.
How do you make a transgenic plant?
Transgenic organism is the end product of the insertion of a desirable gene into the genome of the recipient. A genetically modified organism is the end result (GMO) Select desired gene that will be moved into plant obtain a common soil bacterium genus known as Agrobacterium This natural bacteria lives in soils and can invade plant tissues and can insert its T DNA into the plant genome Once incorporated it stimulates: Nutrient production for the bacteria Hormones that cause plant tissue growth Evidence of the growth is seen in a tumor mass
What is synthesized in the process of translation? Explain the basics of this process. What is involved? What is the end result?
Translation- It occurs in the cytoplasm where the ribosomes are located. It consists of 4 phases. Activation, initiation, elongation, termination. Translation is the process by which a protein is synthesized from the information contained in a molecule of messenger RNA Translation is the process that takes the information passed from DNA as messenger RNA and turns it into a series of amino acids bound together with peptide bonds. It is essentially a translation from one code (nucleotide sequence) to another code (amino acid sequence). involves the decoding by a ribosome of an mRNA message into a polypeptide product. The amino acid sequence is the final result of translation, and is known as a polypeptide.
What are codons? What is the significance of a stop codon?
What are codons? What is the significance of a stop codon? Codon- A structure of 3 nucleotides that together form a unit of genetic code in a DNA or RNA. the start codon (AUG) marks the beginning of a protein and where translation needs to begin.the stop codons (UGA, UAA, and, UAG) mark the end of the protein and where translation needs to end.
Is refrigeration a sufficient means to control the growth of most microbes? Explain how low temperatures affect microbes.
Yes, after time, refrigeration has a bactericstatic effect. Pshycrotrophs grows but at a slow pace and will alter appearance. At low temperatures, microbes don't die but dormant. Slow freezing is more harmful to bacterias. Ice crystals kill them slowly by disrupting their cellular and molecular structure. Freezing is a slow process of killing.
sticky ends
a short extensions that can form hydrogen-bonded base pairs with complementary sticky ends on any other DNA molecules cut with the same enzyme.
What is a genome? Where is it found?
a single copy of all the heritable genetic material found in the nucleus of a single cell Or The total sum of genetic material in cell of a cell (in ppt)
vector
a substance, usually a piece of DNA that carries a sequence of DNA or other genetic material and introduces it into a new cell. Vectors act as vehicles to transfer genetic material from one cell to the other for different purposes like multiplying, expressing, or isolation.
What is a mutation? How can a mutation be beneficial?
a. Changes in Genetic code A change in the genetic material b.= A permanent change in the genetic code. Some mutations — known as beneficial mutations — have a positive effect on the organism in which they occur. They generally code for new versions of proteins that help organisms adapt to their environment.
Using recombinant DNA technology, explain/diagram how you would produce insulin. Be sure to include plasmid, a restriction endonuclease, ligase, an antibiotic resistant gene, and E. Coli.
a. The insulin producing genes are cleaved and isolated from the human pancreatic cells using particular restriction endonuclease. b. The plasmid DNA found in E.coli bacteria is also isolated and cleaved using same endonuclease and used as a vector (carrying agent). c. The insulin producing gene and the vector plasmid are then joined together to form the recombinant plasmid DNA using ligase enzyme. d. These recombinat plasmid DNA are then transfered back into the bacterial host cell i.e. E. coli and cloning is done to multiply the cells. e. After many cycles of multiplication of bacterial cell when enough insulin is produced in the bacteria, the insulin is extracted from the bacteria using extraction techniques. f. Recombinant DNA technology has other applications also such as insertion of antibiotic resistant genes in certain plants and animals. Other commercial products can also be obtained using similar technology such as antibiotics, drugs etc. 1) scientists build the human insulin gene in the laboratory. 2) they then remove a loop of bacterial DNA known as the plasmid 3) they then insert the human insulin gene into the plasmid 4) researchers return the plasmid to the bacteria 5) they put the recombinant bacteria in large fermentation tanks 6) in the tanks, the bacteria begin producing human insulin 7) scientists harvest the insulin made by the bacteria 8) the insulin is then purified for use.
How do bacteria normally reproduce? Is DNA replication before or after division?
after replicating their DNA, they just grow and divide. Most bacteria, including Salmonella and E.coli, reproduce by binary fission. During this type of asexual reproduction, the single DNA molecule replicates and both copies attach, at different points, to the cell membrane. As the cell begins to grow and elongate, the distance between the two DNA molecules increases. Once the bacterium just about doubles its original size, the cell membrane begins to pinch inward at the center. Finally, a cell wall forms which separates the two DNA molecules and divides the original cell into two identical daughter cells.
TACCCTACAATCT- What is the amino acid sequence?
atgggatgttaga
What does CFU stand for?
colony forming unit
Why do we subculture in the lab?
in biology, a subculture is a new cell or microbiological culture made by transferring some or all cells from a previous culture to fresh growth medium. Subculture is used to prolong the life and/or expand the number of cells or microorganisms in the culture
What cell structure "reads" the codons of mRNA?
mRNA is read by ribosomes in order to build proteins. What is read? The CODONS of mRNA
What is DNA built from? Draw a DNA molecule and label it.
made of chemical building blocks called nucleotides. deoxyribose (5-carbon sugar), a phosphate group, and a nitrogenous base
What is DNA replication? Explains the basic steps.
mechanism by which a single DNA molecule (1 chromosome) becomes two DNA molecules (eventually two separate chromosomes). initiation, elongation, and termination. the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment.
Is it possible for soap bar to harbor potentially harmful bacteria? Explain
no , Bacteria lives quite happily in the "slime" of bar soap, but doing a few simple things (which you probably do already) will make it so the germs are of no consequence to you.
Compare autotrophs and heterotrophs with respect to the form of carbon-based nutrients they require.
require inorganic nutrients; it uses inorganic CO2 as its carbon source. Heterotrophs require inorganic and organic nutrients and it must obtain carbon in an organic form.
What is a serial dilution and what is its purpose in the laboratory?
series of sequential dilutions used to reduce a dense culture of cells to a more usable concentration.
The antimicrobial effect of gamma radiation is due to ___________. The antimicrobial effect of ultraviolet radiation is due to _____________.
the ability of ionizing radiation to break DNA directly because of the high water contact of the cells, free radicals (H and OH) that breaks DNA stands are likely to form. Formation of thymine dimers.
Write a two-sentence description of DNA semi-conservative replication.
the result of DNA replication is two DNA molecules consisting of one new and one old chain of nucleotides. This is why DNA replication is described as semi-conservative, half of the chain is part of the original DNA molecule, half is brand new.
restriction enzymes
to defend bacteria against specific viruses called bacteriophages.
