Sterilization Methods in Microbiology
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Questions and Answers

What is the efficiency of an ULPA Filter at 0.12 microns?

  • 99%
  • 99.999%
  • 99.99%
  • 99.9999% (correct)

    • Which program is recommended to control arthropods and rodents in a biosafety environment?

  • Decontaminating Medical Wastes program
  • Arthropod and Rodent Control program (correct)
  • Curtain of Air program
  • Health and Medical Surveillance program

    • What is one of the ways to ensure biosafety in laboratories?

  • Facilitating early detection of laboratory-acquired infections (correct)
  • Excluding pregnant women from hazardous work
  • Conducting regular training in laboratory safety
  • Providing active immunization only

    • What is a key component in maintaining biosafety in laboratories?

    <p>Calibrating biosafety cabinet filters regularly</p> Signup and view all the answers

    Which type of immunization is an example of passive immunization mentioned in the text?

    <p>Hepa B Ig vaccine</p> Signup and view all the answers

    Why is it important to provide effective personal protective equipment and procedures?

    <p>To protect personnel from potential hazards</p> Signup and view all the answers

    What is the primary goal of the Laboratory Quality Management System (LQMS)?

    <p>Ensuring lab personnel safety from infectious agents</p> Signup and view all the answers

    What is a fundamental objective of biosafety in a molecular biology lab?

    <p>To contain potentially harmful agents</p> Signup and view all the answers

    Why are alcohol-based cleansers not recommended after contact with spore-forming bacteria?

    <p>Because they are ineffective against spores</p> Signup and view all the answers

    What should individuals do after working with potentially hazardous materials in the Laboratory?

    <p>Wash their hands with soap and water</p> Signup and view all the answers

    Why is it important to wash hands after working with certain chemicals in the laboratory?

    <p>To avoid infections or poisoning</p> Signup and view all the answers

    What is key to preventing laboratory and personnel exposure to potentially infectious agents or biohazards?

    <p>Proper hand hygiene practices</p> Signup and view all the answers

    What is the purpose of using Geobacillus stearothermophilus as a biological indicator in an autoclave?

    <p>To monitor the effectiveness of the autoclave in sterilizing equipment and materials by detecting the presence of viable G. stearothermophilus spores after the cycle.</p> Signup and view all the answers

    What is the primary function of HEPA filters in a biosafety cabinet?

    <p>To capture and trap microorganisms, including viruses, bacteria, and fungal spores, present in the air inside the biosafety cabinet.</p> Signup and view all the answers

    What is the recommended method for decontaminating medical wastes according to the given information?

    <p>Autoclaving at 132°C and 15 psi for 30-60 minutes.</p> Signup and view all the answers

    According to the information given, what is the primary requirement for working with infectious specimens in a biosafety cabinet?

    <p>The biosafety cabinet must be calibrated and certified by the supplier before use.</p> Signup and view all the answers

    What is the purpose of the autoclave tape used during the sterilization process?

    <p>To provide a visual indication of whether the sterilization process was successful or not.</p> Signup and view all the answers

    What is the significance of the $0.3$ micron pore size mentioned in the context of HEPA filters?

    <p>The 0.3 micron pore size represents the minimum size of particles that HEPA filters can capture with an efficiency of 99.97%.</p> Signup and view all the answers

    What is the primary difference between RNA and DNA based on the given information?

    <p>RNA strands lack complementary partner strands, unlike DNA.</p> Signup and view all the answers

    What is the function of RNA polymerase in gene expression based on the provided text?

    <p>RNA polymerase synthesizes RNA as a single strand.</p> Signup and view all the answers

    Which nucleotide base is NOT present in RNA molecules according to the text?

    <p>Thymine</p> Signup and view all the answers

    How does RNA differ from DNA in terms of size according to the information provided?

    <p>RNA is smaller than DNA.</p> Signup and view all the answers

    What role does RNA play in protein synthesis based on the text?

    <p>RNA carries amino acids to assemble proteins.</p> Signup and view all the answers

    How does the structure of RNA differ from that of plasmids based on the provided information?

    <p>Plasmids carry genetic information, but RNA does not have this function.</p> Signup and view all the answers

    What is the function of small nuclear RNA in eukaryotes?

    <p>Assisting in mRNA splicing</p> Signup and view all the answers

    Which type of RNA polymerase is primarily responsible for polymerizing mRNA in eukaryotes?

    <p>Pol 2</p> Signup and view all the answers

    What is the role of RNA Helicase during transcription?

    <p>Unwinds double-stranded DNA for transcription</p> Signup and view all the answers

    Which enzyme is responsible for attaching the primer to the specific start site of transcription?

    <p>Primase</p> Signup and view all the answers

    What is the main function of non-coding RNA (ncRNA) transcribed by RNA polymerase 1?

    <p>Regulating gene expression</p> Signup and view all the answers

    During transcription, what is the role of RNA Polymerase in relation to the DNA double helix?

    <p>Uses one DNA strand as a template for RNA synthesis</p> Signup and view all the answers

    Which of the following statements about ribosomal RNA (rRNA) is correct?

    <p>It plays a crucial role in protein synthesis by being a part of ribosomes.</p> Signup and view all the answers

    What is the primary function of transfer RNA (tRNA) during translation?

    <p>To carry specific amino acids to the ribosome for protein synthesis.</p> Signup and view all the answers

    Which of the following statements about messenger RNA (mRNA) is correct?

    <p>mRNA transports genetic information from DNA to the ribosomes for protein synthesis.</p> Signup and view all the answers

    What is the significance of the three-letter nucleotide sequence (UAG) in transfer RNA (tRNA)?

    <p>It codes for a specific amino acid to be carried by the tRNA.</p> Signup and view all the answers

    Which of the following statements about transcription is correct?

    <p>Inducible or regulatory transcription is the process of synthesizing mRNA.</p> Signup and view all the answers

    Which of the following statements about protein structure is correct?

    <p>The sequence of amino acids in a protein is determined by the mRNA sequence.</p> Signup and view all the answers

    Which substance is used in DNA extraction to dissolve lipids and lipoproteins?

    <p>Phenol and chloroform</p> Signup and view all the answers

    What is the purpose of using cetylmethylammonium bromide (CTAB) in DNA extraction from fungi?

    <p>To separate polysaccharide (chitin) from DNA</p> Signup and view all the answers

    What is the main function of adding ethanol in the DNA extraction process?

    <p>To precipitate DNA</p> Signup and view all the answers

    In DNA extraction, which step involves the formation of three layers, including an aqueous phase, an amphiphilic phase, and an organic phase?

    <p>Extraction</p> Signup and view all the answers

    What is the primary purpose of low pH in DNA extraction after alkaline lysis?

    <p>To renature DNA</p> Signup and view all the answers

    Which enzyme is added at either the first or last step of the DNA extraction procedure to degrade RNA?

    <p>RNase enzyme</p> Signup and view all the answers

    What is the purpose of using xylene in the DNA extraction procedure from paraffin-embedded tissues?

    <p>To remove the wax from the tissue sample</p> Signup and view all the answers

    Which dye is specifically mentioned to bind to adenine and thymine base pairs in DNA?

    <p>Hoechst 33258</p> Signup and view all the answers

    In DNA extraction, why are particulate matter, phenol, and protein considered common contaminants when using spectrophotometry?

    <p>They absorb light at 260nm</p> Signup and view all the answers

    Which step of the DNA extraction process involves adding proteinase K to lyse the proteins in the sample?

    <p>Buffering with Tris-EDTA buffer</p> Signup and view all the answers

    What is the main function of 3,5-diaminobenzoic acid (DABA) in DNA extraction?

    <p>To bind specifically to adenine-thymine base pairs</p> Signup and view all the answers

    What technique measures fluorescence related to DNA concentration using specific fluorescent dyes?

    <p>Fluorometry</p> Signup and view all the answers

    Which enzyme is preferred for enzymatic digestion in DNA extraction due to its ability to digest proteins?

    <p>Proteinase K</p> Signup and view all the answers

    What is the primary concern with mechanical disruption in DNA extraction methods?

    <p>Can degrade the nucleic acid</p> Signup and view all the answers

    Which method is used in DNA extraction when the sample is solid?

    <p>Grinding</p> Signup and view all the answers

    What is the primary purpose of using glass beads in DNA extraction?

    <p>To facilitate mechanical disruption</p> Signup and view all the answers

    In DNA extraction, what is the role of centrifugation?

    <p>To separate nucleic acids from other cellular components</p> Signup and view all the answers

    What method is utilized to quantify DNA concentration in fluorometry during DNA extraction?

    <p>Spectrophotometry</p> Signup and view all the answers

    What is the optimal GC content range for a primer?

    <p>40-60%</p> Signup and view all the answers

    Why is it important for a primer's length to be 18-22bp?

    <p>To ensure high specificity</p> Signup and view all the answers

    What happens if the primer annealing temperature is too low?

    <p>Nonspecific products are produced</p> Signup and view all the answers

    Why must the DNA template be free of contaminants before amplification?

    <p>To reduce nonspecific product formation</p> Signup and view all the answers

    What is the purpose of analyzing PCR products before further processes?

    <p>To determine if there is only one product</p> Signup and view all the answers

    Why should a primer have specific binding to the target DNA segment?

    <p>To prevent amplification of unwanted sequences</p> Signup and view all the answers

    Which factor primarily determines the specificity of a PCR primer?

    <p>The nucleotide sequence of the primer</p> Signup and view all the answers

    What is the primary consideration when determining the optimal annealing temperature for a PCR primer?

    <p>The melting temperature (Tm) of the primer</p> Signup and view all the answers

    Which of the following statements about the GC content of a PCR primer is correct?

    <p>Higher GC content increases the melting temperature (Tm) of the primer</p> Signup and view all the answers

    Which technique is commonly used to analyze the products of a PCR amplification?

    <p>Gel electrophoresis</p> Signup and view all the answers

    What is the recommended length range for PCR primers?

    <p>20-30 nucleotides</p> Signup and view all the answers

    Which factor can contribute to non-specific amplification during PCR?

    <p>All of the above</p> Signup and view all the answers

    Which of the following statements about forward primers in PCR is correct?

    <p>They run in the 5' to 3' direction and attach to the bottom DNA strand, which runs from the 3' to 5' direction.</p> Signup and view all the answers

    What is the primary consequence of mispriming in PCR?

    <p>Misprimed products will take components away from the intended reaction and interfere with proper interpretation of results.</p> Signup and view all the answers

    Which of the following factors can make it more difficult to optimize PCR amplification?

    <p>High GC content and secondary structure in the DNA template.</p> Signup and view all the answers

    What is the primary concern associated with primer dimers in PCR?

    <p>Primer dimers consume reaction components and interfere with the interpretation of results.</p> Signup and view all the answers

    What is the recommended amount of genomic DNA template for routine clinical analysis using PCR?

    <p>100 ng to 1 ug</p> Signup and view all the answers

    Which of the following characteristics is desirable for an optimal DNA template in PCR?

    <p>Free of contaminating proteins, without nicks or breaks.</p> Signup and view all the answers

    What enzyme is responsible for repairing nicks in the sugar-phosphate backbone of DNA during the DNA extraction process described in the text?

    <p>DNA ligase</p> Signup and view all the answers

    Which enzyme is crucial for the protection of DNA from methylation, ensuring the integrity of the genetic information?

    <p>Methyltransferase</p> Signup and view all the answers

    In the context of DNA extraction, what role does DNA ligase play in the formation of recombinant DNA molecules?

    <p>Facilitating the exchange of genetic material between DNA strands</p> Signup and view all the answers

    During the recombination process in sexual reproduction, what is the primary function of restriction enzymes?

    <p>Introducing specific breaks in DNA strands</p> Signup and view all the answers

    What is the main purpose of nucleic acid protection mechanisms described in the text related to DNA extraction?

    <p>Preventing DNA degradation by nucleases</p> Signup and view all the answers

    Which of the following probes does not have a negatively charged phosphodiester backbone, allowing for stronger hydrogen bonding with the target sequence?

    <p>Peptide Nucleic Acid (PNA)</p> Signup and view all the answers

    Which of the following non-radioactive labels is commonly used for probe labeling and can be covalently attached to nucleotide triphosphates like UTP or CTP?

    <p>Both biotin and digoxigenin</p> Signup and view all the answers

    Which of the following statements about RNA probe labeling is correct?

    <p>Both (a) and (b) are correct.</p> Signup and view all the answers

    Which type of nucleic acid probe is designed to have increased flexibility by locking or unlocking the 2nd and 3rd carbons (C2 and C3), potentially destabilizing the double helix?

    <p>Unlocked Nucleic Acid (UNA)</p> Signup and view all the answers

    Which type of nucleic acid probe is designed to be inaccessible to RNA by locking the 2nd and 4th carbons (C2 and C4)?

    <p>Locked Nucleic Acid (LNA)</p> Signup and view all the answers

    Which type of nucleic acid probe is chemically synthesized and resistant to nucleases that degrade DNA and RNA, but lacks the negatively charged phosphodiester backbone?

    <p>Peptide Nucleic Acid (PNA)</p> Signup and view all the answers

    Which of the following enzymes is responsible for joining two DNA fragments by forming a phosphodiester bond?

    <p>DNA ligase</p> Signup and view all the answers

    What is the primary function of a methyltransferase enzyme in relation to DNA?

    <p>It introduces methylation patterns to DNA, which can regulate gene expression.</p> Signup and view all the answers

    During sexual reproduction, which process facilitates the exchange of genetic material between homologous chromosomes?

    <p>Recombination</p> Signup and view all the answers

    Which of the following enzymes is responsible for cleaving DNA at specific recognition sequences?

    <p>Restriction endonuclease</p> Signup and view all the answers

    What is the primary function of nucleic acid protection mechanisms in cells?

    <p>To protect nucleic acids (DNA and RNA) from degradation by nucleases</p> Signup and view all the answers

    Which of the following enzymes is involved in the process of DNA replication?

    <p>All of the above</p> Signup and view all the answers

    What is one of the disadvantages of the Vacuum Transfer method described in the text?

    <p>It has a slow transfer rate compared to other methods</p> Signup and view all the answers

    How much RNA is typically applied to 0.8% to 1.5% agarose gel/polyacrylamide gels for analysis as mentioned in the text?

    <p>30 μg total RNA</p> Signup and view all the answers

    What must be done to the gel before transferring RNA to a membrane using Polyacrylamide gel, according to the text?

    <p>Rinsing in deionized water to remove denaturant</p> Signup and view all the answers

    What is a drawback associated with the C.Vacuum Transfer method, as noted in the text?

    <p>Inefficient for large DNA fragments</p> Signup and view all the answers

    Which of the following statements accurately describes the purpose of standard precautions in a healthcare setting?

    <p>Standard precautions are minimum infection prevention practices that apply to all patient care, regardless of the patient's suspected or confirmed infection status.</p> Signup and view all the answers

    According to the information provided, which of the following microorganisms is considered the most resistant to disinfectants?

    <p>Bacterial spores</p> Signup and view all the answers

    Which of the following practices is not mentioned as part of standard precautions in the given information?

    <p>Refraining from eating or drinking in the laboratory</p> Signup and view all the answers

    What is the main difference between primers and probes in terms of their usage as described in the text?

    <p>Primers are designed to contain complementary sequences to regions to be analyzed, while probes determine the amplified product size.</p> Signup and view all the answers

    What is the effect of mispriming during amplification based on the information provided?

    <p>Mispriming leads to larger amplicons caused by attachment of primers away from the target sequence.</p> Signup and view all the answers

    Why is it crucial for forward and reverse primers to anneal at the same temperature or within a 2-degree difference?

    <p>To prevent mispriming and ensure specific amplification of the target region.</p> Signup and view all the answers

    What role does primer placement play in determining the size of the amplified product?

    <p>Primer placement dictates the size of the amplified product by defining where DNA synthesis initiates.</p> Signup and view all the answers

    What is the critical component of a PCR reaction according to the text?

    <p>The specificity determined by the primers used.</p> Signup and view all the answers

    How do commercially purchased primers determine their synthesis according to the provided information?

    <p>The gene you wish to amplify determines the exact sequence of primers needed.</p> Signup and view all the answers

    What is the primary structural difference between DNA and RNA?

    <p>DNA contains the nitrogenous base thymine, while RNA contains uracil instead.</p> Signup and view all the answers

    Which carbon position on the pentose sugar determines whether it is ribose or deoxyribose?

    <p>The second carbon (C2)</p> Signup and view all the answers

    What is the primary function of the third carbon on the pentose sugar?

    <p>It attaches to the phosphate group of the next nucleotide.</p> Signup and view all the answers

    What is the distinction between a nucleotide and a nucleoside?

    <p>A nucleotide contains a phosphate group, while a nucleoside does not.</p> Signup and view all the answers

    What structural characteristic distinguishes single-stranded nucleic acids from double-stranded ones?

    <p>The formation of hydrogen bonds between complementary bases.</p> Signup and view all the answers

    Which of the following is a key difference between DNA and RNA in terms of their composition?

    <p>DNA contains cytosine, while RNA does not.</p> Signup and view all the answers

    What was the significance of Gregor Mendel's discovery in 1865?

    <p>He established the laws of inheritance and the concept of traits being passed from parents to offspring.</p> Signup and view all the answers

    What was the groundbreaking contribution of James Watson and Francis Crick in 1953?

    <p>They described the double-helix structure of DNA.</p> Signup and view all the answers

    What is the primary function of nucleic acids, as stated in the text?

    <p>To store and transmit genetic information from DNA to proteins.</p> Signup and view all the answers

    What was the significance of Kary Mullis's discovery in 1985?

    <p>He discovered the in vitro amplification of DNA, known as the Polymerase Chain Reaction (PCR).</p> Signup and view all the answers

    What are the three functional groups that make up a nucleotide, the building block of DNA and RNA?

    <p>Nitrogenous base, pentose sugar, and phosphate group.</p> Signup and view all the answers

    What was the significance of the recombinant DNA technology discovery in 1970?

    <p>It enabled the manipulation and modification of genetic material through the combination of DNA from different sources.</p> Signup and view all the answers

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