module 4 set b

Question 1

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 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 the other side

Answer 3

absorption spectroscopy

Question 4

the absorbance of a given sample depends on three things:

Answer 4

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

Question 5

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

Answer 5

molar extinction coefficient

Question 6

graph of the absorbance versus the wavelength or frequency of light

Answer 6

absorption spectrum

Question 7

can be used to identify types of molecules in a sample

Answer 7

absorption spectrum

Question 8

can be also used to measure the concentration of molecules in solution

Answer 8

absorption spectroscopy

Question 9

can be used to follow conformational transitions and ligand binding

Answer 9

absorption spectroscopy

Question 10

measures absorbance across range of temperatures

Answer 10

temperature scanning absorption spectroscopy

Question 11

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

Answer 11

temperature scanning absorption spectroscopy

Question 12

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

Answer 12

fluorescence

Question 13

true or false:

fluorescence is caused by absorption, although not all absorption results in fluorescence

Answer 13

true

Question 14

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

Answer 14

fluorescence spectroscopy

Question 15

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

Answer 15

fluorophore

Question 16

a technique in which a fluorophore is attached to another process

Answer 16

fluorescent tagging

Question 17

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

Answer 17

fluorescent tagging

Question 18

technique uses a genetic tag that produces a stoichiometric ratio of a fluorescent protein reporter and the protein of interest during protein translation

Answer 18

protein quantitation ratioing

Question 19

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

Answer 19

nuclear magnetic resonance spectroscopy (NMR)

Question 20

involves interaction of light with the nuclei of atoms in a molecule, whereas most forms of EM spectroscopy involve interaction of light with the electrons in the molecule

Answer 20

NMR

Question 21

can provide much more structural details than other forms of spectroscopy

Answer 21

NMR

Question 22

involves application of a strong magnetic field to the sample being studied

Answer 22

NMR

Question 23

uses EM in the radio frequency portion of the spectrum

Answer 23

NMR

Question 24

works on the basic principle that a spinning charge generates a magnetic field

Answer 24

NMR

Question 25

frequency of what radiation will be proportional to the energy between two spin states

Answer 25

EM radiation

Question 26

true or false the nuclei that are less shielded by electrons and other atoms will be more exposed to the magnetic field

Answer 26

true

Question 27

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

Answer 27

mass spectrometry

Question 28

used both for determining molecular weights and for identifying molecules

Answer 28

mass spectrometry

Question 29

can also reveal information about the structure of molecules

Answer 29

mass spectrometry

Question 30

a technique for determining the relative positions of atoms within a crystal

Answer 30

xray crystallography

Question 31

an orderly, three-dimensional, repeating arrangement of atoms or molecules

Answer 31

crystal

Question 32

this means that conditions can be arranged so the intermolecular forces cause the molecules to line up in an organized, repeating manner

Answer 32

many substances can be crystallized

Question 33

provides very precise, high-resolution structural information for molecules in a crystal

Answer 33

xray crystallography

Question 34

was used to discover that DNA is a double helix

Answer 34

xray crystallography

Question 35

advantage of xray crystallography

Answer 35

it provides high resolution of structural detail

Question 36

disadvantage of xray crystallography

Answer 36

the molecules must be in crystalline form in order for the technique to work

Question 37

xray cyrstallography operates on the principle of what

Answer 37

diffraction

Question 38

occurs when light waves pass through an ordered arrangement of openings and interfere with each other on the other side

Answer 38

diffraction

Question 39

the peaks become higher and throughs become lower

Answer 39

constructive interference

Question 40

the waves flatten out and lower the intensity of radiation

Answer 40

destructive interference

Question 41

the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye

Answer 41

microscopy

Question 42

the most powerful light microscopes provide only enough magnification to view objects larger than _________ nm

Answer 42

200 nm

Question 43

physicist who experimented with the magnetics lenses for focusing electron beams and realized that it was possible to take advantage of smaller wavelength of electrons to create a imaging device theoretically capable of greater magnification than a light microscope

Answer 43

ernst ruska

Question 44

who built the first electron microscope

Answer 44

ruska and knoll

Question 45

2 most common types electron microscope

Answer 45

1. transmission electron microscopy (tem) 2. scanning electron microscopy (sem)

Question 46

similar to light microscopy in that beam passes through a very thinly sliced sample to provide an image on the other side

Answer 46

transmission electron microscopy (TEM)

Question 47

the image is made by focusing the electro beam onto a view screen coated with some material that fluoresces in response to the incoming electrons

Answer 47

transmission electron microscopy (TEM)

Question 48

the electron beam is gradually scanned across the surface of the specimen

Answer 48

scanning electron microscopy (SEM)

Question 49

provides more three dimensional image instead of a cross sectional slice of the specimen

Answer 49

scanning electron microscopy

Question 50

provides magnified images similar to those of SEM but with resolution similar to those of TEM

Answer 50

atomic force microscopy (AFM)

Question 51

works by moving a mechanical probe across the surface of the object being scanned

Answer 51

AFM

Question 52

all are part of the more general class of techniques called

Answer 52

scanning probe microscopy (SPM)

Question 53

an instrument that uses focuses laser beams to create piconewton (10^-12N) size forces that can be used to hold and manipulate microscopic particles, even as small as single molecule or atom.

Answer 53

optical tweezers

Question 54

the phenomenon of focused laser beams holding a single particle in place in three dimensions is called an

Answer 54

optical traps

Question 55

can be used tot hold and manipulate particles anywhere from 0.1nm to 10,000nm in size and have been used to trap single viruses, DNA molecules, bacteria, living cells, and organelles

Answer 55

optical tweezers

Question 56

particularly useful for investigating the mechanics of and forces associated with molecular motors

Answer 56

optical traps

Question 57

a technique used in electrophysiology to measure and characterize electric currents in cells, particularly in excitable tissue cells such as neurons

Answer 57

voltage clamp

Question 58

the value of the voltage that is held constant is called

Answer 58

command voltage

Question 59

how is voltage clamp technique held constant

Answer 59

through a feedback mechanism

Question 60

what detects event the slightest change in the voltage and immediately pumps current across the membrane through the electrode to keep the voltage at the command voltage

Answer 60

feedback mechanism

Question 61

allows us to measure the cell's electric current under a variety of conditions

Answer 61

voltage clamp

Question 62

a technique that the electrode feedback mechanism is used tot keep the current constant while allowing the voltage to vary

Answer 62

current clamp

Question 63

an alternative technique for applying the electrode to the cell.

Answer 63

patch clamp

Question 64

allows us to investigate the behavior of a single ion channel within the membrane

Answer 64

patch clamp

Question 65

measurement of energy changes in form of heat

Answer 65

calorimetry

Question 66

instrument designed to measure heat energy

Answer 66

calorimeter

Question 67

can be used to determine the amount of energy necessary to unwind a piece of DNA helix

Answer 67

calorimetry

Question 68

can be also used to measure the binding strength of various drugs to a particular protein

Answer 68

calorimetry

Question 69

useful for measuring the very small amounts of energy associated with many biophysical processes

Answer 69

microcalorimeter

Question 70

remember Patch clamp measures the flow of ions through individual ion channels, voltage clamp maintains a constant membrane potential to record the resulting currents, and current clamp injects current to measure the resulting changes in membrane potential in a neuron.

Answer 70

glhf