A plot of various wavelength versus their absorption is an b. Absorption maximum
ID: 164513 • Letter: A
Question
A plot of various wavelength versus their absorption is an b. Absorption maximum c Optimum absorption d. Absorption spectrum. 2. Absorption spectrum can be used to identify: a. Unknown compound b. Kinetic of biochemical reaction c Characterization of macromolecule interaction d. All of the above 3. A plot e. None of the above absorptions is called of several known verses their corresponding a. An absorption spectrum. b. An absorption maximum c, An optimum absorption 4. in which of the following assays for quantification of protein concentration, the colored product is as a result of coordination of protein peptide bond with alkaline copper sulfate b. Bradford d, LCMS 5. A calibration curve (standard curve), for any biochemical test must be prepared. a. Prior to the running actual test for unknown detection Once for every new detection kit c. There is no specific compellation d. Along with running actual test for unknown detection 6. in comparison with other assays for protein m method IS a. Rapid b. Destructive to the protein Time consuming d. High-interference presence of 7. The intense ultraviolet absorption by nucleic acid molecule is due to a. Aromatic rings of amino acids b, Aromatic rings of nucleotides a and bExplanation / Answer
Answer 1: Absorption spectrum
Plot of wavelength versus absorbance is a commonly used graph in UV-Visible light spectrometers. A single organic compound may absorb multiple wavelength of light therefore to find out the wavelength maxima (max) of that compound, it subjected to full wavelength scan (190-800 nm) and which gives a graph between wavelength versus absorbance. With the help of this graph you can easily find out that, at what wavelength a particular compound has maximum absorbance.
Answer 2: All of the above
Absorption spectrum has multiple used in spectroscopic analysis. Each compound has specific pattern in their absorption spectrum. Therefore it can be used in identifying unknown compounds. During kinetics of biochemical reactions, decrease in absorbance of substrate or increase in absorbance of product at particular wavelength spectrum is monitored by recorded Absorption spectrum. It is also used for monitoring macromolecule-ligand interactions. Independently, both macromolecule and ligand have specific wavelength maxima whereas; interaction between them generates a new chemical compound which has wavelength maxima different from macromolecule and ligand, therefore with help of absorption spectrum we can easily find out level of interaction between macromolecule and ligand.
Answer 3: Standard curve
In spectroscopy, standard curve is generally used to find out the concentration of unknown compound in a solution with help of known concentration of that particular compound. For the preparation of standard curve, a graph is plotted between different known concentrations (at x-axis) and absorbance (at y-axis). With increase of concentration, absorption value increases linearly and with the help of this linear relationship, concentration of unknown can be calculated.
Answer 4: Biuret
The biuret test is also known as Piotrowski's test which is used for detecting the presence of peptide bonds in proteins. In the presence of peptides, a copper (+2) ion forms violet-colored coordination complexes in an alkaline solution. The intensity of violet-color is directly proportional to the protein concentration which can be measured by spectroscopically. The Bradford is also a colorimetric protein assay which based on an absorbance shift of the dye Coomassie Brilliant Blue G-250. Under acidic conditions the red form of the dye is converted into its bluer form.
Answer 5: Along with running actual test for unknown detection
Calibration curve/standard curve must be prepared at the same time with detection of unknown sample. Prior or after preparation of standard curve is not recommended because of change in spectrophotometer running condition, reagent concentration or room temperature with time. That may influence absorbance of sample.
Answer 6: High interference
Direct spectrophotometric method of proteins involved the detection of proteins in solution with absorbance maxima at 280. Amino acids with aromatic rings are the primary reason for the absorbance peak at 280 nm. The method has some disadvantages, including interference from other chromophores like nucleic acids. The extinction of nucleic acid in the 280 nm region may be as much as 10 times that of protein at their same wavelength, and hence, a few percent of nucleic acid can greatly influence the absorption.
Answer 7: a and b
Ultraviolet light absorbed by both aromatic ring present in amino acids and nucleotides.
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