Test 2

Question 1

what ion parameter is measured in mass spectrometry

Answer 1

mass/charge

Question 2

what is the source of charge of protein ions in the electrospray ionization method

Answer 2

external power supply

Question 3

the role of trypsin used in peptide mass fingerprint measurements is to

Answer 3

digest each protein into a defined set of fragments

Question 4

what is measured in nanopore sequencing

Answer 4

current flowing through the nanopore

Question 5

sequencing nanopores produced from graphene are typically

Answer 5

too wide

Question 6

currently the best sequencing nanopore is made from

Answer 6

MspA channel

Question 7

the advantage of nanopore sequencing over 1st and 2nd generation sequencing methods is

Answer 7

longer read length

Question 8

voltage difference applied across a membrane containing a sequencing nanopore causes flow of the following substances through the nanopore

Answer 8

all of the above ( pos ions, neg ions, and DNA)`

Question 9

if the pressure driving the sheath stream in a flow cytometer is decreased the diameter of the sample stream at the interrogation point will

Answer 9

increase

Question 10

measurements of light scattering in the forward direction reflect cell

Answer 10

size

Question 11

measurements of light scattering in the side direction reflect cell

Answer 11

granularity

Question 12

what dichroic mirror is required to combine 2 laser beams as shown in the figure(633 nm and 488 nm)

Answer 12

LP 600 nm

Question 13

in FACS drops are formed because of

Answer 13

nozzle vibration

Question 14

the role of the ion mirror in time-of-flight mass analyzer

Answer 14

increase differences in path lengths traveled by ions

Question 15

if accelerating voltage in the time-of-flight mass analyzer is 30kV what should be the voltage in the ion mirror

Answer 15

32kV

Question 16

the diameter of a sequencing nanopore has to be approximately equal to

Answer 16

diameter of a single-stranded DNA molecule

Question 17

the length of a sequencing nanopore has to be approximately equal to

Answer 17

distance between nucleotides in a single-stranded DNA

Question 18

the most important limitation of the approach that employs a native membrane channel as a sequencing nanopore is

Answer 18

DNA translocation is too fast

Question 19

deflection of drops in FACS is caused by

Answer 19

electrical force

Question 20

photon energy is proportional to the light wave

Answer 20

frequency

Question 21

fluorophore molecules

Answer 21

absorb and emit light of a longer wavelength

Question 22

the diagram shows energy levels(jablonski diagrams) of two fluorophores which fluorophore has longer peak emission wavelength

Answer 22

A bc lines are closer

Question 23

in a flow cytometer the transmission band of the emission filter should overlap with

Answer 23

fluorophore emission spectrum

Question 24

non-specific dna dyes are used to stain cell

Answer 24

nucleus

Question 25

the diagram shows energy levels (jablonski diagrams) for two organic fluorophores which fluorophore has larger dimensions of the fluorescent part of the molecule

Answer 25

A bc lines are closer

Question 26

the plot shows spectra of voltage sensitive dye di-4-anepps what is the approximate value of the dye stokes shift (peak one at 450 nm and 650 nm peak)

Answer 26

200 nm

Question 27

what should be the approximate transmission range of an optical filter suitable for measurement of fluorescent emission of di-4-anepps

Answer 27

650/50 nm

Question 28

what is the cause of fluorophore photobleaching

Answer 28

interaction of excited fluorophore with surrounding molecules

Question 29

what methods can potentially help reduce phototoxicity of organic fluorophores

Answer 29

remove oxygen and change excitation filter

Question 30

both graphene sequencing nanopores and alpha hemolysin channel sequencing nanopores are limited by

Answer 30

DNA translocation is too fast

Question 31

which ion parameter is measured in mass spectrometry

Answer 31

none of the above( momentum, mass, charge, energy)

Question 32

which parameter is measured by mass spectrometry

Answer 32

the mass/charge ratio

Question 33

what is the source of charge of protein molecules in the MALDI ionization method

Answer 33

Matrix

Question 34

in a time of flight mass analyzer

Answer 34

lighter ions will arrive to the detector first

Question 35

what is the purpose of the first mass spectrometer in the tandem mass spectrometry

Answer 35

select a peptide

Question 36

what is the purpose of the second mass spectrometer in the tandem mass spectrometry

Answer 36

measure mass of peptide fragments

Question 37

trypsin is used in mass spectrometry because

Answer 37

it digests each protein into fragments

Question 38

photon energy is proportional to the light wave

Answer 38

frequency

Question 39

the frequency of the emitted fluorescent light in comparison to the absorbed light is

Answer 39

smaller

Question 40

which ion parameter is changed when an ion mirror is added to a time of flight mass analyzer

Answer 40

ion path length

Question 41

fluorescent dye molecules for staining mitochondria are electrically

Answer 41

positive

Question 42

generic (non-specific) DNA fluorescent dye molecules are electrically

Answer 42

positive

Question 43

DNA staining with generic fluorescent dyes can be performed

Answer 43

in live or dead cells

Question 44

non specific fluorescent DNA dyres are typically used to stain

Answer 44

Nucleus

Question 45

immunoflourescent probes may include

Answer 45

small organic fluorophores, quantum dots, proteins

Question 46

in comparison to organic fluorophores quantum dots are likely to have

Answer 46

stronger long-term chemical toxicity

Question 47

the emission spectrum of a quantum dot in comparison to a typical organic fluorophore is

Answer 47

narrower

Question 48

the absorption spectrum of a quantum dot in comparison to a typical organic fluorophore is

Answer 48

wider

Question 49

a decrease of quantum dot diameter will have the following effect on the wavelength of it fluorescence emission

Answer 49

decrease

Question 50

which fluorophores are membrane permeable(may diffuse passively through membrane)

Answer 50

none (all fluorophores can be used on fixed cells that have been made permeable)

Question 51

what happens when quantum dot diameter increases

Answer 51

the energy levels get smaller meaning the wavelength gets bigger with increasing diameter of the quantum do