QBM Final Exam Questions And Answers With Complete Solutions 2024

QBM Final Exam Questions And Answers With Complete Solutions 2024 Define recombinant DNA technology Using molecular biology technique such as cloning, PCR, restriction enzymes digestion, and gel electrophoresis to take a gene from one source and joint it with another piece of DNA, creating a new recombinant DNA molecule that can be inserted in bacteria and further studied. What are 3 characteristics of DNA ? - Double strand - 5' to 3' directionality - antiparallel - base pairing [adenine with thymine, cytosine with a guanine] via hydrogen bonding What is the Central Dogma of molecular Biology ? DNA encodes RNA [transcription] wich encodes proteins [translation] Describe an amino acid. What is meant when one says proteins are translated "N to C"? Consists of an amino-terminus, an alpha-carbon with an R group [viable, 20 total], and a carboxyl-terminus. Protein are synthesized by the ribosome "N to C" which means that the first amino acid [methionine] will have free N-terminus, and its carboxyl group will form a peptide bond with the amino group of the next amino acid. End would have a free C-terminus Describe the 4 level of protein structure? - Primary: [amino acid sequence] - Secondary: [alpha helices and beta-sheet] - Tertiary: [3 dimensional folded structure] - Quartenary: [multiple polypeptide chains interacting] When viewing a DNA or protein structure which of the following best represents what it would look like if you could "see it" ? Molecular surface representation Biosafety level [BSL] - BSL -1: laboratories have minimal potential hazards to laboratory safety - BSL 2: laboratories work with organisms that are of moderate potential hazard Biosafety level [BSL] - BSL 3: laboratories work with pathogenic organisms that can cause serious disease [proper ventilated, access is restricted, and special protective equipment must be used] - BSL 4: Dangerous pathogens that cause fatal disease for which treatments are not available * most at UCF are BSL-2 [MSDS] Material Safety Data Sheet - States Physical and chemical properties - Associated physical hazards to health - Primary route of entry - Exposure limits - Toxicity - Carcinogenic - Flammable - radioactive - Proper safe handling - Emergency and first aid procedure What are Occupational Safety and Health Administration [OSHA] requirements ? - That All Employers must informer employees of potential hazards, and that every hazardous substance must have an MSDS [PPE] Personal Protective Equipment Are essential to protect one from hazardous chemicals and pathogens - Always wash hands after taking the globes off - Special globes are used for hot and cold glassware - UV eye protection - Specific site for toxic waste disposal - lab coats - Pants - Decontamination with Ethanol latex gloves vs. Nitrile gloves - Both accepted - Latex: Fit best in the hand, good chemical resistance, but can cause Allergies [Anaphylactic shock in worst case] - Nitrile: NO natural rubber latex so NO Allergies. good chemical resistance Plastic Globes - Not resistant to chemicals - Fit loosely into the hand - not acceptable in Molecular Biology labs To transfer Large volumes [25 ml to 2 L, what instrument is used ? Graduated Cylinder For volumes between 1 and 25 ml what type of transfering instrument is used? Glass or Plastic pipettes with a rubber bulb or a battery-powered mechanical pipetter. What are the 2 most common serological pipette? - Mohr: has a pointed tip that allows for finer measurements because the drop would be SMALLER. - Transfer Pipette [Pasteur]: Only when accuracy is not requiered what type of instrument is used to to accurately transfer 0.1 microliters to a 1 ml solution? Micropipette How are micropipettes used steps: 1) Place tip 2) Push down to 1st stop 3) put the tip in the liquid you would like to collect 4) Release plunger to pic up desire liquid 5) Place tip into receiving tube and push down all the way pass the second stop 6) remove tip from tube, release plunger and eject tip What does the accuracy of micropipetting depends on? Calibration and proper technique - Tip should only be immersed 1 cm into the liquid - Pipette perfectly vertical - DON'T place the tip deep into liquid Analytical centrifugation vs. Preparative centrifugation - Analytical centrifugation: where the sedimentation can be analized. Requires only small amounts of material and utilize specially designed rotors and detector systems to continuously monitor the process of sedimentation Useful in: determin sample's purity, molecular weight, size, conformational changes, sedimentation, diffusion coefficients, stoichiometric, equilibrium constant, thermodynamics and absorbance of fluorescence. Used in sucrose and cesium chloride gradient. [balance within 0.1 grams] Analytical centrifugation vs. Preparative centrifugation Preparative centrifugation: Used to prepare samples for further used. This separate molecules and can help to isolate or purify a sample: - Small Benchtop centrifuge: used to collect small amounts of material that rapidly sediment. - Large-capacity refrigerated centrifuge: For large volumes [up to 1L] used to separate large amount of materials - High-speed refrigerated centrifuge: Samples in need of high speed. [25000 rpm and 60000g]. Must be balnaced 0.25 grams Fixed- Angle Rotors - Allows Excellent pelleting of a sample Swinging-bucket rotors - Do not create a tight Pellet - BEST for Cesium chloride and Sucrose density gradient Swinging-bucket can be useful for? - Best for sample analysis - Useful in Virus Purification * used in Meselson-Stahl Experiment: DNA replication Clear [Polycarbonate] vs Opaque [polypropylene] Clear [Polycarbonate]: - Better visibility - Less resistant to chemicals - More breakable Opaque [polypropylene]: - More resistant to chemicals Spectrometry - Measurement of this interaction - Produces spectra that are used for theoretical studies on the structure matter, or concentration of a solution - Quantitative and qualitative analysis Electromagnetic-base Spectroscopy - Include those that use: Visible light and ultraviolet, - infrared light and fluorescence spectroscopy, - Flame spectroscopy, - X-ray spectroscopy [crystallography] - nuclear magnetic resonance spectroscopy [NMR] - Circular dichroism Non- Electromagnetic Spectroscopy - IOn [mass spectroscopy] - Electrons [electron spectroscopy] - Sound wave [acoustic spectroscopy] Infrared Spectroscopy - Similar to UV-vis, but less precise, wavelength ratio nm. - Energy transitions due to change in vibration, rotational and kinetic energy - Qualitative analysis of functional groups [carbonyls, alcohols, aromatics] - Fourier Transform Infrared [FTIR]: analysis of plasma membranes, microorganism ID, secondary structure Spectrophotometer Used to measure intensity of a specific wave light as it passes through a sample. It compares the amount of light transmitted through a blank sample [lacking the colored compound] to that transmitted through a colored sample. What are the 5 basic components of a spectrophotometer? - Light source: Tungsten [visible 400-1000 nm] or Deuterium [UV, 200-400 nm] lamp - Monochromator: selects particular wavelengths of light for measurement. - Prism: disperse light and narrow exit still selects only a small range of the dispersed spectrum - Sample compartment with special cuvet Plate Reader This can quickly read microliters volumes of dozens or hundreds of samples from a single plate. - Often used in ELISA - drug screening - Enzyme assays - Concentration determination 260 nm DNA absorption/concentration 280 nm Protein absorption/concentration 595 nm Broadford Assay [protein concentration] 600 nm Bacterial growth in LB media As the Concentration of a sample incr