Nucleic Acid Electrophoresis Process

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What is the primary advantage of capillary electrophoresis over gel electrophoresis?

Increased sensitivity and immediate detection

Decreased runtime and preparation time

Automatic analysis of results by software

All of the above (correct)

What is the purpose of a buffer system in electrophoresis?

To carry the current and protect the samples

To maintain the pH of the solution

To prevent severe fluctuations in the pH of the gel

All of the above (correct)

Which of the following is a characteristic of a buffered solution?

The buffer concentration must be low to provide sufficient acidic and basic forms

The addition of acid or base will significantly affect the pH

The buffer does not protect sample molecules from damage

The pH remains constant as the buffer molecules take up or release protons (correct)

What is the main disadvantage of capillary electrophoresis?

Requirement for fluorescent labeling of samples Signup and view all the answers

How does a buffer maintain the pH of a solution near its pKa?

By providing sufficient acidic and basic forms to buffer the solution Signup and view all the answers

What is the role of buffer ions in the electrophoresis process?

To carry the current through the gel and prevent pH fluctuations Signup and view all the answers

What is the purpose of inserting a comb into the gel in gel electrophoresis?

To create holes for loading the sample Signup and view all the answers

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 Signup and view all the answers

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 Signup and view all the answers

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 Signup and view all the answers

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 Signup and view all the answers

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 Signup and view all the answers

What is the role of methanol and acetic acid after electrophoresis on the sample?

Fix the sample Signup and view all the answers

How does silver staining work under optimal pH conditions?

Deposits metallic silver on the target Signup and view all the answers

What is the main difference between silver diamine and silver nitrate procedures?

Silver nitrate precipitates black silver salt upon introduction of formaldehyde Signup and view all the answers

Which dye sits on the minor groove of the double helix for double-stranded DNA staining?

SYBR green I Signup and view all the answers

What is a disadvantage of SYBR gold dye?

Stains both DNA and RNA Signup and view all the answers

How does SYBR green differ from EtBr in terms of binding to DNA bases?

SYBR green intercalates between bases Signup and view all the answers

What is the impact of raising the buffer concentration on gel stability?

Lessens gel stability Signup and view all the answers

Which ions move more quickly through the gel?

+2, -2, +3 Signup and view all the answers

Why are Tris base and Borate preferred for maintaining constant pH during electrophoresis?

They remain partly uncharged at desired pH Signup and view all the answers

Which buffer is prone to precipitation and could result in localized distortions in DNA electrophoresis?

TBE Signup and view all the answers

What other characteristics, besides pKa and charge, should be considered when choosing a buffer?

Toxicity, interaction with other components Signup and view all the answers

How does an increase in buffer concentration impact the conductivity of the electrophoresis system?

Increases conductivity Signup and view all the answers

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 Signup and view all the answers

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 Signup and view all the answers

What is the main advantage of using a capillary in the electrophoresis process?

Improved heat dissipation properties Signup and view all the answers

Which of the following is NOT a common forensic application of the capillary electrophoresis technique described in the text?

Protein structure analysis Signup and view all the answers

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 Signup and view all the answers