60 Questions
What is the Latin meaning of spectroscopy?
Ghost or spirit
How is spectroscopy defined in Greek?
Ghost or spirit
What property of matter does spectroscopy study?
Matter properties
What does each type of spectroscopy provide when interacting with different light frequencies?
Different picture in the spectrum
What is the main focus of spectroscopy applications like UV/vis absorbance and photoluminescence?
Interaction with light
In spectroscopy, what does the term 'spectrum' refer to?
Visual representation of data
What is the main concept behind the Beer-Lambert Law?
Absorption of light by a molecule
Which process involves nonradiative relaxation through vibrational states?
Internal Conversion
In absorption spectroscopy, what property can be used to determine concentration?
Extinction coefficient
Which type of emission has a longer timescale compared to fluorescence?
Phosphorescence
What is the primary deduction from the Beer-Lambert Law?
Light intensity exponential attenuation
Which part of the molecule determines what happens after light energy transfer in absorption spectroscopy?
Characteristics of the molecule
What is the quantum yield range for excited state molecules returning to the ground state by fluorescence?
0 to 1
In fluorescence spectroscopy, what aspect can be compared with standard solutions for qualitative analysis?
Shapes and peak positions of excitation spectra
What parameter in fluorescence spectroscopy is directly proportional to the concentration of the fluorescent substance at low concentrations?
Fluorescence intensity of the solution
Which factor can lead to the relaxation of the excited state in fluorescence?
Collisions with other species in the sample
What is a key feature of fluorescence decay once the excitation source is removed?
Rapid decay
Which applications involve quantification using fluorescence spectroscopy?
DNA, antibodies, antigens
What is the main parameter that controls the optical characteristics of a sample in absorption spectroscopy?
Polarization
What is the primary principle behind measuring absorption in absorption spectroscopy?
Measuring the change in light intensity as it passes through a sample
Which of the following is a common application of absorption spectroscopy in biochemistry?
Determining the kinetics of enzymatic reactions involving NADH
Which wavelength is typically used to assess the purity of DNA samples in absorption spectroscopy?
The ratio of absorbances at $260$ nm and $280$ nm
What is the difference between fluorescence and phosphorescence?
Fluorescence involves the emission of light from the singlet excited state, while phosphorescence involves the emission of light from the triplet excited state.
Which of the following is a type of photoluminescence?
Chemiluminescence
What is one of the primary advantages of fluorescence spectroscopy?
It can qualitatively and quantitatively analyze substances based on their fluorescence characteristics.
Which of the following is a limitation of fluorescence analysis?
It cannot be used for analytes that undergo photochemical reactions at the wavelength range of interest.
What is the difference between an excitation spectrum and an emission spectrum in fluorescence spectroscopy?
An excitation spectrum is obtained by monitoring emission at a fixed wavelength while varying the excitation wavelength, while an emission spectrum is obtained by monitoring emission at a fixed excitation wavelength.
What is the principle behind the use of activatable optical contrast agents for molecular imaging?
Quenching and dequenching of fluorescence
Which of the following techniques is based on fluorescence spectroscopy?
Fluorescence microscopy
In which field is fluorescence spectroscopy widely used for detecting minerals, metallic elements, and vitamins?
Food analysis
Fluorescence spectroscopy can be used to quantify the concentration of a single analyte in solution, provided that the analytes do not interfere with each other.
True
Fluorescence spectroscopy is not suitable for analyzing intransparent, not clear or colloidal samples.
True
The excitation spectrum in fluorescence spectroscopy is obtained by monitoring the emission at a fixed wavelength and varying the excitation wavelength, while the emission spectrum is obtained by fixing the excitation wavelength and monitoring the emitted wavelength intensity.
True
Fluorescence microscopy is not based on the principle of fluorescence spectroscopy.
False
Quenching and dequenching is not the basis for activatable optical contrast agents used in molecular imaging.
False
Fluorescence spectroscopy is not widely used for detecting minerals, metallic elements, vitamins, and fungal contamination in food and environmental analysis.
False
Turbidity of a sample does not affect the optical characteristics of the sample in absorption spectroscopy.
False
The extinction coefficient of NADH at 340 nm is 6,220 M$^{-1}$ cm$^{-1}$.
True
The 260/280 ratio is used to assess the purity of DNA samples in absorption spectroscopy.
True
Fluorescence and phosphorescence both involve the emission of light from excited state molecules, but phosphorescence has a shorter timescale compared to fluorescence.
False
Absorption spectroscopy can only be used to determine the concentration of a sample, and cannot provide any information about the structure or composition of the sample.
False
The primary principle behind measuring absorption in absorption spectroscopy is the Beer-Lambert law, which states that the absorbance of a sample is directly proportional to the concentration of the absorbing species.
True
Spectroscopy exclusively involves the interaction of matter with visible light frequencies of the electromagnetic spectrum.
False
In fluorescence spectroscopy, the excitation spectrum and emission spectrum are identical.
False
The Beer-Lambert Law states that the absorbance of a sample is directly proportional to the concentration of the absorbing species and the path length of the light through the sample.
True
In fluorescence spectroscopy, the emission spectrum is always at shorter wavelengths compared to the excitation spectrum.
False
Phosphorescence is a type of photoluminescence with a longer timescale compared to fluorescence.
True
The quantum yield of fluorescence is the ratio of the number of photons emitted to the number of photons absorbed, and it can never exceed 1.
True
Luciferase assays are used to determine if a protein can activate or suppress transcription of a gene of interest.
True
Chemiluminescence always involves the oxidation of $H_2O_2$ catalyzed by Fe.
False
In epifluorescence microscopy, the nucleus is stained blue with DAPI, the microtubules are stained green, and the actin is stained red.
True
Confocal microscopy is a type of fluorescence microscopy.
True
Near-infrared (NIR) absorption spectroscopy is used to measure the visible spectrum of compounds.
False
The blueness of water is due to selective absorption in the blue portion of the visible spectrum.
False
Förster resonance energy transfer (FRET) occurs when the emission spectrum of the donor molecule does not overlap with the absorption spectrum of the acceptor molecule.
False
In the Fluorescence Recovery After Photobleaching (FRAP) technique, the uniform fluorescence intensity is restored due to the diffusion of bleached and unbleached fluorescent molecules.
True
Bioluminescence involves the release of a photon after excitation in a biochemical reaction, such as the reaction catalyzed by the enzyme luciferase.
True
In FRET, the distance between the donor and acceptor molecules must be between $1$ and $10$ nanometers for efficient energy transfer.
True
If the acceptor molecule in a FRET system is not a fluorophore, the transferred energy from the donor is emitted as fluorescence.
False
Self-quenching in dyes can be utilized in sensors for detecting proteolysis.
True
Study Notes
- Objectives of the lecture series include identifying key features of different spectroscopy methods and their uses in various applications like clinical diagnosis, basic science, and forensics
- Spectroscopy is the study of matter through its interaction with different frequencies of the electromagnetic spectrum, involving the interaction of light with the "ghost" of matter
- Fluorescence spectroscopy is advantageous for qualitative and quantitative analysis of substances based on fluorescence characteristics and intensity, commonly used to analyze biological macromolecules
- Fluorescence analysis is suitable for analytes that can be dissolved in solvents like water, provided they absorb UV or visible light and emit visible or near-infrared radiation
- Excitation and emission spectra are important in fluorescence spectroscopy, with molecules having single excitation spectra but two emission spectra (fluorescence, phosphorescence)
- Energy levels play a crucial role in absorption and emission processes in spectroscopy, involving transitions between ground state and excited state with different relaxation mechanisms
- Absorption spectroscopy involves the transfer of light energy to molecules, and the Beer-Lambert Law can be used to determine concentration by measuring light attenuation
- Fluorescence spectroscopy includes features like relaxation of excited states, collisions with other species, emission of photons, and quantum yield indicating the efficiency of fluorescence
- Uses of fluorescence spectroscopy include qualitative and quantitative analysis, such as quantification of DNA, antibodies, antigens, drug analysis, and pharmacokinetics
Learn about the key features and uses of different methods of spectroscopy in the field of analytical and clinical biochemistry. Topics include UV/vis absorbance spectroscopy, photoluminescence (Fluorescence), and bio- & chemi-luminescence. This quiz series is linked to prior learning in BMS1041/BMS1030.
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