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WorksheetsDownstream #3
Total questions: 20
Worksheet time: 10mins
One spot on a 2D ( 2 Dimensional) PAGE represents one protein form.
True
False
A Dot blot is useful in determining the_.
optimal pH of the antibody.
optimal antibody concentration.
charge of the antibody.
estimate molecular weight (size) of the antibody.
The aim of proteomics is
to remove disease causing genes from humans.
to introduce new genes to human beings.
to identify and sequence of all the genes present in the human body.
to compare expression profiles between a healthy cell vs. a diseased cell.
What can be added to prevent gel swelling during the western blot transfer?
SDS
Methanol
Heat
Blotting paper
What do the heights of the peaks represent in the mass spectrum?
charge: mass ratio
average atomic mass
relative abundance of each isotope
number of isotopes
What is plotted along the x-axis of a mass spectrum?
Relative Abundance
Mass/charge
Abundance /charge
Mass
Which statement about PVDF membranes is True ( correct)?
PVDF membrane produce a lower background due to its less sensitivity.
PVDF membranes are difficult to strip and reprobe.
PVDF is used for lower molecular weight proteins and cost less than nitrocellulose.
PVDF membranes should be used when SDS is added to the buffer.
In a mass spectrometer, molecules are bombarded with high-speed electrons and are ionized before broken into smaller fragments. Which species will be detected by the mass spectrometer?
Neutrons
Cations
Anions
Protons
What is the main characteristic of an isocratic compared to a gradient elution method?
The mobile phase composition remains constant.
The mobile phase condition starts with a high proportion of organic solvent.
Isocratic elution is more powerful than gradient elution.
The organic solvent proportion is more rapidly increased.
What is the purpose of adding SDS to the western blot transfer buffer?
Maintains the pH during transfer
Increases the ability of proteins to bind to the support membranes.
Allows for rapid transfer of small molecular weight proteins from the gel to Nitrocellulose membranes.
Elutes large proteins out of the gel
Hard ionization (source) refers to the processes which impart little residual energy onto the subject molecule and as such result in little fragmentation.
True
False
Which statement is correct about 2D DIGE .
There is no need for the bioelectrical focusing of protein samples
Can analyze differences in protein abundance between samples.
Labels protein sample with fluorescent dyes after 2-D electrophoresis.
Because DiGE uses dyes the gels cannot be used for mass spectrometry
One can perform carbon dating with a mass spectrophotometer.
True
False
Which of the following statements is true (correct) about ionization methods?
MALDI -TOF samples are solvated and usually come from HPLC.
ESI( Electrospray) uses a laser energy absorbing matrix to create ions from large molecules with maximal fragmentation.
EI ( Electron Impact) shatters chemical bonds producing many charged ions resulting in too many signals to analyze from a single protein.
MAlDI-TOF is particularly useful for non-polar peptides whereas ESI is preferred for polar/charged peptides.
What is the correct order of the basic components inside a mass spectrometer?
introduce sample---ion transfer---mass analyzer--- detector
Introduce sample---mass analyzer---ion transfer---detector
Ion source---mass analyzer---ion transfer—recorder
Ion source---detector---mass analyzer----recorder
Which statement is correct about FPLC?
FPLC Systems that operate at pressures at very high pressures — up to 5,000 psi (34 MPa).
FPLC system can only use FPLC column material but in HPLC systems, both types of columns materials can be used.
FPLC is primarily an analytical technique used primarily for quantitative and qualitative analysis of liquid samples.
FPLC columns (hardware) are typically stainless steel.
Which statement is false about gravity chromatography?
Typically used for small scale, rapid preparative chromatography of nucleic acids and proteins.
Appropriate for laboratory-scale separations and involves minimal instrumentation.
Suited for single-step purifications like desalting and affinity applications.
Unlike other forms of liquid chromatography, not suitable for affinity chromatography.
If your primary antibody is raised rat , then your secondary antibody should be?
Goat anti-rabbit
Goat anti-rat
Rat anti-mouse
Rat anti-goat
After proteins run on an SDS-PAGE gel, a transfer is executed. What is the purpose of the transfer in Western blot protocol
Probe the gel with an antibody to detect a protein of interest
Visualize the proteins run on the gel
Denature the proteins in the sample
Move proteins from the SDS-PAGE gel to a nitrocellulose membrane
The non-specific sites on the nitrocellulose membrane can be blocked by:
Sodium dodecyl sulfate
Whole liquid milk
Non fat powdered milk
Sodium chloride
