QBM All of the Practice Exams Questions And Answers With Complete Solutions 2024

QBM All of the Practice Exams Questions And Answers With Complete Solutions 2024 d. protein as a cartoon model, DNA as a ball-and stick model. The image below shows a. protein as a ball-and-stick model, DNA as a molecular surface representation. b. DNA as a ball-and-stick model, protein as a molecular surface representation. c. both as ball-and-stick models. d. protein as a cartoon model, DNA as a ball-and stick model. e. both as cartoon models. b. DNA is responsible for bacterial transformations Oswald Avery showed that a. proteins are encoded by RNA. b. DNA is responsible for bacterial transformations. c. protein is responsible for bacterial transformations. d. point mutations are the cause of the polymorphisms observed by Griffith. e. the ratio of As to Ts and Gs to Cs in a cell are equal. c. Recombinant DNA technology. Which of the following refers to manipulating a piece of DNA and putting it into a plasmid for the purposes of gene studies, protein expression, and gene therapy? a. Bioinformatics. b. In silico research. c. Recombinant DNA technology. d. Interdisciplinary research. e. Gene Chip technology. a. OSHA. Employers must inform employees and train them in the safe handling of potentially harmful chemicals. This is required by a. OSHA. b. the MSDS. c. the CDC. d. individual employers who set their own standards. e. The Laboratory Safety Officer, who enforces the rules and assesses monetary fines for those in violation. d. BSL-4 Research labs that handle pathogenic organisms for which there is no vaccine that can cause diseases which are generally untreatable and fatal are assigned a rating of a. BSL-1 b. BSL-2 c. BSL-3 d. BSL-4 e. BSL-5 e. In the fume hood. Where should you open bottles that contain volatile chemicals such as HCl or SDS? a. In the flammable cabinet. b. In the sharps container. c. In the chemical cabinet d. In the cell culture hood. e. In the fume hood. a. Plastic. Which type of gloves offer the least amount of protection from chemical/biological hazards? a. Plastic. b. Latex. c. Chloroprene. d. Nitrile. c. autoclave. A device used to clean glassware and sterilize media using heat and pressure is a(n) a. sonicator. b. ultrafiltrator. c. autoclave. d. fume hood. e. biosafety hood. Pasteur (transfer) pipette. The least accurate way to transfer a specific volume would be with a micropipette. Mohr pipette. volumetric pipette. serological pipette. Pasteur (transfer) pipette. C. dispense specific volumes several times from a single aspiration. A Mohr micropipette has a thinner tip, which is beneficial when using the pipette to A. transfer over 100 ml of sample in a single step. B. work with viscous liquids. C. dispense specific volumes several times from a single aspiration. D. generate a standard curve when performing protein quantification. E. deliver exactly 10 microliters. d. prevent contamination of the pipettes and samples. Some tips have cotton swabs in them to a. increase the accuracy of pipetting by decreasing air vortices. b. mark the maximum volume of the tip so you do not exceed it. c. reduce pressure variations as you dispense the liquid. d. prevent contamination of the pipettes and samples. e. help the tip fit more snugly on the pipette. a. To remove any liquid from inside the cap. You have a 1.5 ml tube of frozen enzyme. Upon removing it from the freezer you should thaw it and spin it down briefly in a centrifuge. What is the purpose of this? a. To remove any liquid from inside the cap. b. To activate the enzyme. c. To increase the sample's rate of thawing. d. To reduce the surface tension so pipetting is more accurate. b. To prevent protein degradation. Why are most centrifuges refrigerated? a. To prevent DNA aggregation. b. To prevent protein degradation. c. To reduce the temperature increase that results from friction. d. To reduce bacterial growth inside the centrifuge chamber. e. To increase the sedimentation rate which is related to density and temperature. b. small bench top centrifugation. A type of centrifugation used in the lab to rapidly collect samples in 1.5 ml tubes is a. analytical ultracentrifugation. b. small bench top centrifugation. c. large capacity or high speed refrigerated centrifugation. d. Swinging bucket centrifugation. a. Calculate the relative centrifugal field of the SA-600 to determine what rpm to use in the SS-34. A protocol you are following says to spin a sample in a Sorvall SA-600 rotor at 10,000 rpm. You are using a Sorvall SS-34 rotor, which is much smaller. What must you do? a. Calculate the relative centrifugal field of the SA-600 to determine what rpm to use in the SS-34. b. Spin the sample at 10,000 rpm in the SS-34. c. Spin the sample slower in the SS-34 since it is a smaller rotor. d. All of the answer choices are correct. d. holding the pipette perfectly vertical. When using a pipette, the greatest accuracy is achieved by a. pushing down to the second stop before aspirating the sample. b. pushing down to the first stop after dispensing the sample. c. holding the pipette deep into the liquid (>4 cm). d. holding the pipette perfectly vertical. e. sterilizing the pipette first via flame. b. Ultracentrifuge. With regards to potential destructive ability, which type of centrifuge is most dangerous and must be balanced within 0.1g? a. Bench top centrifuge. b. Ultracentrifuge. c. Large capacity centrifuge. d. High speed centrifuge. e. Continuous flow centrifuge. b. Fixed angle rotor. Which type of rotor allows you to spin samples into the best pellet possible? a. Swinging bucket rotor. b. Fixed angle rotor. c. Zonal rotor. d. Triangular rotor. a. swinging-bucket centrifugation The Meselson-Stahl Experiment relied on ____________ to study the replication of DNA. a. swinging-bucket centrifugation b. the A260:A280 ratio c. infrared spectroscopy d. DNA transformation of S. pneumoniae e. a standard curve b. plate reader. A device that can check the absorbance of hundreds of samples per run, and is often used for ELISAs and drug screenings is a a. spectrophotometer. b. plate reader. c. calorimeter. d. chromatography machine. e. analytical centrifuge. b. 280 Which wavelength would you use to measure protein concentration directly (without any chro- mogenic assay)? a. 260 b. 280 c. 340 d. 595 e. 600 a. 0.147 What would you expect absorbance of a sample to be if it had a transmittance of 71.28%? a. 0.147 b. 28.72 c. 0.194 d. 0.2872 e. -1.85 c. 1.14 x 10-5 M You measure a solution containing BSA (ε = 43,824 M-1 cm-1) in the spectrophotometer. The absorbance you read off of the machine is 0.5. What is the concentration of BSA? a. 11.4 M b. 114 mM c. 1.14 x 10-5 M d. 21912 M e. 87648 M b. Direct measurements require quartz or UV-compatible cuvettes. Why are chromogenic assays (as opposed to