29 Questions
What is the primary advantage of capillary electrophoresis over gel electrophoresis?
All of the above
What is the purpose of a buffer system in electrophoresis?
All of the above
Which of the following is a characteristic of a buffered solution?
The pH remains constant as the buffer molecules take up or release protons
What is the main disadvantage of capillary electrophoresis?
Requirement for fluorescent labeling of samples
How does a buffer maintain the pH of a solution near its pKa?
By providing sufficient acidic and basic forms to buffer the solution
What is the role of buffer ions in the electrophoresis process?
To carry the current through the gel and prevent pH fluctuations
What is the purpose of inserting a comb into the gel in gel electrophoresis?
To create holes for loading the sample
Why is it crucial to keep the thickness of the gel and the volume of the buffer constant in gel electrophoresis?
To ensure consistent results by maintaining current flow
What will happen if contact is made with the gel buffer while the current is on in gel electrophoresis?
There will be a significant shock hazard
How does the charge/mass ratio of sample molecules affect their migration in gel electrophoresis?
It determines the speed at which samples migrate through the gel matrix
What happens to the gel after the comb is removed and it is placed into the gel box in gel electrophoresis?
The gel is allowed to cool and solidify
Why are gel baths designed to stop the current when a protective cover is removed from the gel bath?
To prevent shock hazards when handling the gel bath
What is the role of methanol and acetic acid after electrophoresis on the sample?
Fix the sample
How does silver staining work under optimal pH conditions?
Deposits metallic silver on the target
What is the main difference between silver diamine and silver nitrate procedures?
Silver nitrate precipitates black silver salt upon introduction of formaldehyde
Which dye sits on the minor groove of the double helix for double-stranded DNA staining?
SYBR green I
What is a disadvantage of SYBR gold dye?
Stains both DNA and RNA
How does SYBR green differ from EtBr in terms of binding to DNA bases?
SYBR green intercalates between bases
What is the impact of raising the buffer concentration on gel stability?
Lessens gel stability
Which ions move more quickly through the gel?
+2, -2, +3
Why are Tris base and Borate preferred for maintaining constant pH during electrophoresis?
They remain partly uncharged at desired pH
Which buffer is prone to precipitation and could result in localized distortions in DNA electrophoresis?
TBE
What other characteristics, besides pKa and charge, should be considered when choosing a buffer?
Toxicity, interaction with other components
How does an increase in buffer concentration impact the conductivity of the electrophoresis system?
Increases conductivity
What is the main reason that the nucleic acid should be completely denatured (single stranded) before separation?
To allow the nucleic acid to migrate according to its size rather than its secondary structure
What is the primary purpose of using fluorescent labels on the nucleic acids?
To allow the nucleic acids to be detected during the capillary electrophoresis process
What is the main advantage of using a capillary in the electrophoresis process?
Improved heat dissipation properties
Which of the following is NOT a common forensic application of the capillary electrophoresis technique described in the text?
Protein structure analysis
How does the electrokinetic injection process work to draw the sample into the capillary?
A transient high-positive charge is applied to the platinum electrode close to the end of the capillary
Learn about the process of separating nucleic acids based on size and charge using electrophoresis. Understand the importance of denaturing nucleic acids to ensure accurate separation.
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