Liquid Handling & GDP
To accurately measure and dispense a volume of 750uL of buffer solution, this specific micropipette model should be selected.
What is a P1000 micropipette?
If a compound light microscope has a $10\times$ ocular eyepiece and a 40x high-power objective lens, its total magnification is this value.
What is 400x?
This chemical reagent requires heating in a hot water bath to produce a color change from blue to brick red/orange in the presence of reducing sugars.
What is Benedict's reagent?
In an investigation comparing enzyme cell lysis, a treatment group containing buffer only without any enzyme serves as this crucial experimental component.
What is a negative control?
To calculate solute potential using the formula Psi^s = -iCRT, a room temperature of 22C must be converted to absolute temperature in Kelvin, which equals this value.
What is 295K? (22 + 273 = 295K)
According to Good Documentation Practices (GDP), if a technician writes down an incorrect measurement volume in a laboratory batch log, this is the required procedure to correct it.
What is drawing a single horizontal line through the mistake, writing the correct value next to it, and signing with initials and the date in blue or black permanent ink?
In the Gram staining procedure, this specific reagent acts as the mordant to form a large complex with crystal violet inside bacterial cell walls.
What is Gram's Iodine?
A positive Biuret test turns from blue to this color when peptide bonds in proteins are present.
What is purple (or violet)?
Between a cube shaped cell and a thin column shaped cell of identical total volume, this shape has a higher surface area-to-volume (SA:V) ratio.
What is the column shaped cell?
A micropipette volume of 450uL expressed in milliliters (mL) is this value.
What is 0.45mL (4.5 x 10^-1 mL)?
Used, contaminated plastic micropipette tips must be disposed of in this designated laboratory container.
What is a biohazard waste container (or biohazard bag)?
If a microscope's field of view diameter at 400x magnification is 450um and 9 eukaryotic cells fit end-to-end across the diameter, the estimated length of a single cell is this value.
What is 50um? (450um/9 = 50um)
Lugol's Iodine solution changes from amber/yellow to dark blue-black when it detects this complex polysaccharide.
What is starch?
Based on diffusion principles, drug delivery via the small intestines exhibit a faster rate of drug diffusion, for this physical reason, compared to the stomach lining.
What is the microvilli and villi in the small intestines increase the SA:V ratio?
A spectrophotometer reading yields an unformatted concentration value of 82.4 x 10^-5 M. Re-write this value in proper standard scientific notation.
What is 8.24 x 10^-4M?
To transfer 2.5mL of a liquid reagent into a conical tube at a performance station, this volumetric tool should be selected instead of a micropipette.
What is a serological pipette?
A technician mistakenly applies 95% ethanol decolorizer to a Gram-positive Bacillus slide for 1 minutes instead of 15 seconds. Under oil immersion, the cells will incorrectly appear this color.
What is pink / red (due to over-decolorization washing out crystal violet and taking up safranin)?
An unknown solution tests negative with Benedict's and Iodine, but turns purple when Biuret reagent is added. This unknown solution contains this macromolecule.
What is protein?
In an experiment testing how buffer pH affects the lysis rate of E. coli cells, buffer pH represents this type of experimental variable
What is the independent variable?
A technician needs to prepare 200mL (0.2L) of a 1.0M glucose solution (Molar Mass = 180.16 g/mol). Calculate the total mass of glucose required. Mass needed= Volume x molar mass x Concentration
What is 36.03 grams? (0.2L x 1.0mol/L x 180.16g/mol = 36.03g)
This document provides essential safety details regarding chemical health hazards, required personal protective equipment (PPE), handling precautions, and spill cleanup procedures for laboratory reagents.
What is a Safety Data Sheet (SDS)?
Name two structural features visible under a light microscope that distinguish a eukaryotic cell from a prokaryotic cell.
What are a membrane-bound nucleus and membrane-bound organelles (or larger cell size / compartmentalized organelles)?
Unlike qualitative spot testing, this analytical instrument measures exact light absorbance to quantitatively determine total protein concentration in a cell extract.
What is a spectrophotometer?
In an assay investigating pH optima, temperature must be held constant across all treatment groups for this scientific reason.
What is to ensure that differences in reaction rates are caused only by pH changes and not by temperature changes?
A purified viral stock contains 2.0 x 10^5 uL viral particles . If a researcher pipettes 4.0 x 10^2 uL of this stock into a tube, calculate the total number of viral particles transferred in scientific notation.
What is 8.0 x 10^7 uL of viral particles? ((2.0 x 10^5) x (4.0 x 10^2 = 8.0 x 10^7))