test 2

Question 1

the fluorescence intensity is proportional to ______

Answer 1

the concentration of the utilized fluorescent conjugate at a certain time and/or location

Question 2

an absolute determination of fluorescence intensities depends on…

Answer 2

sample and instrument characteristics

Question 3

fluorescence photobleaching

Answer 3

the presence of other light-absorbing molecules

Question 4

the measurement of fluorescence intensity and spectrum is often used for…

Answer 4

qualitative not quantitative

Question 5

for quantitative information…

Answer 5

ratiometric measurement methods are often necessary

Question 6

ratiometric methods (definition)

Answer 6

based on the measurement of at least two parameters which are influenced by possible artefacts in the same or at least very similar way

comparison of these two parameters then allows us to determine the pure information of interest independent from the artefacts

Question 7

ratiometric fluorescence dyes (definition)

Answer 7

designed so that the parameter of interest can be deduced directly from the measured intensity of these two bands

Question 8

fluorescence polarization assays are based on…

Answer 8

simultaneous measurement and comparison of two photophysical parameters of fluorescence, the horizontal and vertical component of the fluorescence polarization

Question 9

fluorescence polarization measurements allow the determination of…

Answer 9

the time constant of the rotational diffusion of fluorescently labelled biomolecules or complexes

Question 10

since the rotational diffusion depends very much on the size of these objects, it can be used for…

Answer 10

quantitative determination of receptor-ligand binding, proteolysis, protein-DNA interactions, and membrane fluidity when the corresponding components are fluorescently labelled

Question 11

the only fluorescence dyes that are excited are those…

Answer 11

that are aligned with their transition dipole moment for absorption are the same as or similar to the polarization vector of the exciting light

Question 12

photoselection (definition)

Answer 12

the excitation of only this subpopulation of fluorescence dyes

Question 13

for large particles, which is bigger: I(ii) or I (i)?

Answer 13

I(ii)

Question 14

for small particles, I(ii) and I(i) are what?

Answer 14

approximately equal

Question 15

I(ii) and I(i) can be used for…

Answer 15

calculating the parameters of fluorescence polarization and fluorescence anisotropy

Question 16

I(ii) and I(i) both increase with…

Answer 16

increasing rotational diffusion time and molecular size of the labelled species

Question 17

P = (equation)

Answer 17

P = (I(ii) - I(i)) / (I(ii) + I(i))

Question 18

r = (equation)

Answer 18

r = (I(ii) - I(i)) / (I(ii) + 2I(i))

Question 19

r and P increase with…

Answer 19

binding

Question 20

r and P decrease with…

Answer 20

dissociation

Question 21

I(ii) bound _____ I(ii) unbound

Answer 21

>

Question 22

I(i) unbound ______ I(i) bound

Answer 22

>

Question 23

mixtures of different fluorescently labelled species…

Answer 23

exhibit anisotropies that can be linearly calculated from the fractions of the individual fluorescently labelled components

Question 24

r prime

Answer 24

average anisotropy measured for the mixture

Question 25

fi

Answer 25

the fraction of the individually fluorescently labelled component i in relation to all components labelled with the same fluorescence dye

Question 26

ri

Answer 26

the corresponding fluorescence anisotropy that would be measured if only the individual component i were present

Question 27

r equals ...

Answer 27

f(1)r(1) + f(2)r(2

Question 28

f(1), f(2),... are...

Answer 28

fractions of the free and bound ligand

Question 29

r(1) and r(2) are...

Answer 29

anisotropies of the free and bound ligand

Question 30

fret is the transfer of...

Answer 30

excitation energy from an electronically excited molecule, called a donor (D), to an acceptor (A) molecule in the electronic ground state

Question 31

if donor and acceptor have a large separation...

Answer 31

little energy transfer occurs after selective donor excitation fluorescence of the donor molecule will dominate

Question 32

after selective excitation of the donor...

Answer 32

vibrational relaxation occurs in the donor

Question 33

donor-acceptor transitions can be estimated from...

Answer 33

the spectral overlap, J, of the donor fluorescence with the acceptor absorption

Question 34

fret efficiency is calculated by...

Answer 34

R(0) ^6 / (R(0)^6 + r^6)

Question 35

R(0)

Answer 35

forster distance

Question 36

forster distance

Answer 36

defines the donor-acceptor distance, r, for which a transfer efficiency of 50% is observed

Question 37

the transfer efficiency measured in a fret experiment allows us to estimate...

Answer 37

the distance between donor and acceptor fluorescence dyes under different biological conditions

Question 38

fluorescence kinetics of a fluorescence dye depends on...

Answer 38

environmental conditions such as solvent polarity

Question 39

the rate of recovery of fluorescence is an indicator of...

Answer 39

the mobility of the fluorescing molecules adjacent to the photobleached volume and relates to their diffusion coefficient

Question 40

chiroptical methods are based on...

Answer 40

the use of circular-polarized light and the differences obtained in experiments using left circular polarized or right circular polarized light

Question 41

circular dichroism (CD)

Answer 41

based on the differences in the absorption or extinction coefficient of biomolecules for left and right circular polarized light

Question 42

the observed difference (CD) is quantified by...

Answer 42

ellipticity

Question 43

O(lambda) =

Answer 43

(2.303[ODL(lambda) - ODR(lambda)] * 180) / 4 pi

Question 44

molar ellipticity equation

Answer 44

(100 * O(lambda)) / CL

Question 45

alpha helix CD graph

Answer 45

high above 0 to low below 0 to 0

Question 46

beta sheet CD graph

Answer 46

slightly above 0 to slightly below 0 to slightly above 0

Question 47

CD equation that's with the graph (idk)

Answer 47

O(lambda) = f * each O of each protein shape

Question 48

CD graph b form DNA

Answer 48

kind of negative to very negative to kind of positive to 0

Question 49

CD graph z form DNA

Answer 49

kind of positive to very positive to very negative to 0

Question 50

optical rotatory dispersion (ORD) is based on

Answer 50

differences in the refractive index, n, of a sample for left and right circular polarized light

Question 51

wavelength-dependent optical rotation equation

Answer 51

(180 l [n1 - nr])/ wavelength

Question 52

circular dichromism is based on differences in...

Answer 52

absorptions measured with right or left handed circular polarized light

Question 53

optical rotatory dispersion is based on differences in...

Answer 53

the refractive index with right or left handed circular polarized light

Question 54

circular birefringence

Answer 54

n1 - nr

Question 55

in order for a molecule to exhibit circular birefringence and circular dichroism, it must be...

Answer 55

chiral

Question 56

why is the measurement of light scattered at biomolecules important?

Answer 56

used to determine particle size, shape, aggregations, and diffusional processes

Question 57

the electric field of light interacts with...

Answer 57

electron clouds to induce transitions

Question 58

elastic light scattering

Answer 58

if the scattered light has the same frequency and energy has incident photons but different propagation vectors

Question 59

infrared spectral range (IR)

Answer 59

caused by the interaction between the IR electric field vector and the molecular dipole transition moments related to the molecular vibrations

Question 60

major disadvantage for IR

Answer 60

high absorption of IR radiation by water

Question 61

raman spectroscopy

Answer 61

based on inelastic scattering of photons at the biomolecules (photons change their frequency)

Question 62

in raman spectroscopy, the frequency change is caused by...

Answer 62

a loss or gain in the photon energy corresponding to transitions between vibrational levels of the molecules at which the scattering occurred

Question 63

hv = hv1 (raman)

Answer 63

elastic scattering

Question 64

hv doesn't equal hv1

Answer 64

inelastic scattering

Question 65

alpha helix vibrational spectra

Answer 65

1650

Question 66

beta sheet vibrational spectra

Answer 66

1630

Question 67

nmr spectroscopy is used for the investigation of...

Answer 67

structural, mechanistic, and dynamical properties of biomolecules under physiological conditions

Question 68

alpha spin

Answer 68

the magnetic moment is oriented with the external magnetic field

Question 69

beta spin

Answer 69

the magnetic moment is oriented against the external magnetic field

Question 70

nmr spectroscopy is based on the measurement of

Answer 70

the energy difference between these two states by absorption or emission of electromagnetic radiation on the radiowave scale