Module 4 - SET B

Question 1

It is one of the more common and easy to understand forms of spectroscopy.

Answer 1

Absorption Spectroscopy

Question 2

the light of a specific wavelength is incident through a sample and measure the intensity of the light that comes out the other side

Answer 2

Absorption spectroscopy

Question 3

it is about measuring the absorbance, or how much light does not come through to the other side (i.e., how much light is absorbed)

Answer 3

Absorption spectroscopy

Question 4

light is converted into the kinetic energy of electrons in an atom or molecule; this bumps the electrons into a higher or excited energy state.

Answer 4

absorption

Question 5

Where does the absorbance of a given sample depends?

Answer 5

1. The intrinsic ability of the molecules in solution to absorb light
2. The concentration of the molecules in solution.
3. The path length of the light as it passes through the sample.

Question 6

True or False: If the sample container is larger, then the light has to pass through more of the solution before getting to the other side, and so more light will be absorbed

Answer 6

True

Question 7

measure that accounts for both concentration and thickness of the sample being studied

Answer 7

molar extinction coefficient

Question 8

express the absorbance in units that are per concentration and per length

Answer 8

molar extinction coefficient

Question 9

graph of the absorbance versus the wavelength or frequency of light

Answer 9

absorption spectrum

Question 10

True or False: Many molecules have unique characteristic absorption spectra, so an absorption spectrum can be used to identify types of molecules in a sample.

Answer 10

True

Question 11

True or False: Many molecules have unique characteristic absorption spectra, however, an absorption spectrum cannot be used to identify types of molecules in a sample.

Answer 11

False

Question 12

used to measure the concentration of molecules in solution (once the identity of the molecule is known)

Answer 12

Absorption spectroscopy

Question 13

True or False: We can use the absorption spectroscopy to measure concentration of molecules in solution even if the molecule is unknown

Answer 13

False, the molecule must be known in order to know its concentration in a particular solution

Question 14

True or False: Absorption of light does not vary with conformation and presence/absence of bound ligands.

Answer 14

False, it varies with conformation and presence/absence of ligands

Question 15

can be used to follow conformational transition and ligand binding

Answer 15

absorption spectroscopy

Question 16

measures absorbance (usually at single wavelength) across a range of temperatures)

Answer 16

Temperature scanning absorption spectroscopy

Question 17

useful for studying temperature-induced conformational transitions, that is, changes in molecular shape that can be brought by changes in temperature

Answer 17

Temperature scanning absorption spectroscopy

Question 18

common technique for studying conformational transitions in membranes, proteins, and DNA (nucleic acids)

Answer 18

Temperature scanning absorption spectroscopy

Question 19

electrons drop down from their excited state, emitting light in the process

Answer 19

fluorescence

Question 20

True or False: Fluorescence is caused by absorption, but not all absorption causes fluorescenece

Answer 20

True

Question 21

Which is longer? The wavelength of the emitted light or absorbed light?

Answer 21

emitted light

Question 22

can be used to characterize molecules and to measure and follow conformational transitions and ligand binding

Answer 22

Fluorescence spectroscopy and Absorption spectroscopy

Question 23

small molecule or the specific part or a molecule that is responsible for the fluorescence

Answer 23

fluorophore

Question 24

technique in which a fluorophore is attached to another molecule in order to track that molecule through some biological process

Answer 24

fluorescent tagging

Question 25

one of the techniques used to determine the sequence of residues in DNA

Answer 25

fluorescent tagging

Question 26

protein quantitation ratioing (PQR) technique uses a genetic tag that produces a stoichiometric ratio of a fluorescent protein reporter and the protein of interest during protein translation

Answer 26

Quantitation of protein levels in single cells in vivo

Question 27

type of EM spectroscopy that differs from most forms of EM spectroscopy

Answer 27

Nuclear magnetic resonance spectroscopy

Question 28

how does NMR differ in most forms of EM spectroscopy?

Answer 28

1. NMR involves interaction of light with nuclei of atoms, whereas most forms of EM spectroscopy involve interaction of light with electrons in the molecule.
2. Although most forms of spectroscopy provide some structural information, NMR can provide much more structural details (higher resolution) than other forms of spectroscopy.
3. NMR involves the application of a strong magnetic field to the sample being studied. This magnetic field alters and limits some of the energy states available to the nuclei; this is what makes it possible to measure the absorption and emission of EM by the nuclei in the sample.
4. NMR uses EM in Radio Frequency portion of the spectrum and fluorescent spectroscopy typically rely on ultraviolet, visible, infrared.

SHORT VER:
1. NMR interaction of light with nuclei of atoms in molecule while other interaction of light with electrons of molecule.
2. provide higher resolution
3. involves strong magnetic field that makes measuring absorption and emission possible
4. NMR uses Radio Freq while Fluorescent Scpetroscopy uses UV, visible, and infrared.

Question 29

works on the basic principle that a spinning charge (such as the nucleus of an atom) generates a magnetic field

Answer 29

Nuclear Magnetic Resonance Spectroscopy

Question 30

is like a small magnet

Answer 30

nucleus

Question 31

True or False: under normal conditions, spins of nuclei are randomly oriented in any direction while in strong magnetic field, it is constrained to only certain orientations with respect to external magnetic field

Answer 31

True

Question 32

typically parallel and antiparallel to the magnetic field

Answer 32

external magnetic field

Question 33

True or false: when a nucleus jumps from one spin orientation to another, it will absorb or emit EM radiation

Answer 33

True

Question 34

true or false: the frequency of the EM radiation emitted or absorbed during the change in spin orientation is inversely proportional to energy difference between the two spin states.

Answer 34

False, it must be proportional

Question 35

True or False: The bigger energy difference between spin states means that nuclei will resonate with lower frequencies or less energy

Answer 35

False: The smaller energy difference

Question 36

True or False: nuclei that are less shielded by electrons and other atoms will be more exposed to magnetic field and will resonate to higher frequency

Answer 36

true

Question 37

technique in which molecules or parts of molecules are ionized and then passed through a magnetic field

Answer 37

Mass spectrometry

Question 38

used both for determining molecular weights and for identifying molecules (once the molecular weight is known

Answer 38

Mass spectrometry

Question 39

can be difficult to ionize in a quantifiable way and can be difficult to fly through a vacuum (a requirement for mass spectrometry)

Answer 39

large molecules