Main Types of Electrophoresis Explained with Examples
Types of Electrophoresis is essential in chemistry and helps students understand various practical and theoretical applications related to this topic. This concept is widely used for separating biological molecules like DNA, RNA, and proteins in labs and research.
Let’s learn its principle, major types, step-by-step examples, and real-life application, all in a simple, student-friendly way.
What is Types of Electrophoresis in Chemistry?
A type of electrophoresis refers to a specific method used to separate charged particles or molecules under the influence of an electric field. This concept appears in chapters related to gel electrophoresis, separation techniques, and analytical chemistry.
It is a foundational part of your chemistry syllabus and is important for understanding how scientists analyze complex mixtures using electricity and gels or papers.
Molecular Formula and Composition
Electrophoresis is not a chemical compound, so it does not have a molecular formula. Instead, it is a process involving a sample (like DNA or proteins) in a supporting medium (such as agarose gel, polyacrylamide gel, paper, or capillary) and an electrolyte buffer. Its components vary depending on the type of electrophoresis performed.
Preparation and Synthesis Methods
To perform electrophoresis, first prepare the gel or paper, then mix your biological sample with a loading dye. Place the prepared medium in an electrophoresis chamber filled with buffer solution.
Load the sample in wells and apply a voltage. The procedure changes slightly depending on the type—gel electrophoresis (agarose or polyacrylamide), paper electrophoresis, or capillary-based methods.
Physical Properties of Types of Electrophoresis
Physical properties depend on the medium used:
- Agarose gels are semi-solid, porous, and transparent.
- Polyacrylamide gels are clear, can be soft or firm, and allow fine separation.
- Paper is flat, absorbent, and used for simple separations.
- Capillaries are thin tubes, usually made of glass or plastic.
Chemical Properties and Reactions
Electrophoresis does not cause chemical changes but analyzes molecules based on their physical — not chemical — properties. However, buffer may maintain pH or react with sample ends to stabilize molecules during migration. Sometimes, special stains are used after separation to visualize the bands.
Frequent Related Errors
- Confusing movement direction: cations move toward the cathode, anions toward the anode.
- Forgetting that different gels separate by different properties (size, charge, shape).
- Not choosing the correct buffer for the molecule studied.
- Running electrophoresis too long, causing samples to migrate out of the gel.
Uses of Types of Electrophoresis in Real Life
Types of electrophoresis are widely used in biotechnology labs for DNA fingerprinting, paternity testing, protein analysis, medical diagnostics, and quality control in drug manufacturing.
For example, agarose gel electrophoresis is crucial in molecular biology for checking DNA purity, while SDS-PAGE (a gel electrophoresis type) is used to separate proteins by size.
Relation with Other Chemistry Concepts
Electrophoresis is closely related to chromatography and electrolysis. Both are separation techniques but use different physical principles (chromatography separates by affinity, electrophoresis by charge/size). Understanding these methods helps students build strong analytical skills.
Step-by-Step Reaction Example
- Prepare an agarose gel with wells for sample loading.
Mix agarose powder with buffer, heat until dissolved, pour into tray, let it set. - Load DNA samples mixed with tracking dye into wells.
Use a micropipette for accuracy. - Connect chamber to power supply and switch on.
DNA migrates towards the positive (anode) as it is negatively charged. - Watch for blue dye movement to monitor progress.
- Stop power when bands are well separated. Remove gel and stain (e.g., with ethidium bromide).
- Visualize bands under UV light and compare to a DNA ladder marker.
Lab or Experimental Tips
Remember, always use fresh buffer and ensure gel thickness is even for best results. Place wells close to the negative terminal for nucleic acid runs, as nucleic acids migrate toward the positive end. Vedantu educators suggest drawing a simple set-up diagram to remember orientation and current flow.
Try This Yourself
- Name the three main types of electrophoresis based on support medium.
- Why is agarose preferred for DNA, but polyacrylamide for proteins?
- Write two real-life examples where electrophoresis is applied outside biology.
Final Wrap-Up
We explored Types of Electrophoresis—their principles, types, procedures, and significance in chemistry and biology. With clear steps and real-life examples, you’ll find this topic easier to remember for exams and lab work.
FAQs on Types of Electrophoresis in Chemistry: Principles and Methods
1. What is the basic principle of electrophoresis?
The basic principle of electrophoresis is that charged molecules will move through a solution or gel when an electric field is applied. Since opposite charges attract, negatively charged molecules move towards the positive electrode (anode), and positively charged molecules move towards the negative electrode (cathode). The speed of this movement depends on the molecule's size, shape, and overall charge, allowing for effective separation.
2. What are the main types of electrophoresis explained simply?
The most common types of electrophoresis are distinguished by the material used to separate molecules. The main types include:
- Gel Electrophoresis: Uses a gel (like agarose or polyacrylamide) as a molecular sieve to separate molecules, usually DNA, RNA, or proteins, based on size.
- Paper Electrophoresis: Uses a strip of filter paper. It is simpler but less precise and is typically used for separating smaller molecules like amino acids.
- Capillary Electrophoresis: Uses a very thin glass capillary tube, offering extremely high speed and resolution for separating tiny amounts of a sample.
3. What are the general steps to perform gel electrophoresis in a lab?
A typical gel electrophoresis experiment involves four main steps:
- Preparation: A gel, usually made of agarose, is cast in a tray, and a comb is used to create small wells for the samples.
- Sample Loading: The DNA, RNA, or protein samples are carefully loaded into the wells of the gel.
- Running the Gel: The gel tray is placed in a buffer-filled tank, and a power supply is connected to create an electric field, causing the samples to move through the gel.
- Visualisation: After the run, the gel is stained with a dye that binds to the separated molecules, making them visible as distinct bands under UV light.
4. How is electrophoresis used for DNA fingerprinting?
In DNA fingerprinting, electrophoresis is used to create a unique pattern of DNA bands for an individual. First, a DNA sample is cut into smaller fragments using specific enzymes. These fragments are then separated by size using gel electrophoresis. Since every person's DNA sequence is slightly different, the cutting enzymes produce a unique set of fragment sizes, resulting in a distinctive banding pattern—the DNA fingerprint—which can be used for identification in forensics or paternity tests.
5. Why is gel electrophoresis preferred over paper electrophoresis for DNA analysis?
Gel electrophoresis is preferred for DNA analysis because the gel matrix acts like a molecular sieve. The pores in the agarose or polyacrylamide gel are small enough to physically obstruct the movement of large molecules like DNA, causing them to separate very effectively based on size. Paper electrophoresis lacks this sieving effect and offers much lower resolution, making it unsuitable for distinguishing between DNA fragments of different lengths.
6. What is the importance of the buffer solution in an electrophoresis experiment?
The buffer solution is crucial for two main reasons. First, it conducts the electric current from one end of the gel to the other. Without it, the molecules wouldn't move. Second, it maintains a stable pH during the experiment. This is important because the pH can affect the charge of the molecules being separated, and a stable pH ensures that the separation is consistent and reliable.
7. What happens if the voltage is set too high during electrophoresis?
If the voltage is too high, it can cause significant problems. The high electric current will generate excess heat, which can cause the gel to melt or deform. This heat can also damage the sample molecules (like DNA). As a result, the separation becomes very poor, leading to smeared or distorted bands instead of sharp, clear ones, making the results difficult or impossible to interpret.
8. How does electrophoresis separate molecules that have the same size but a different charge?
When molecules have the same size, their separation depends entirely on their charge density (the overall charge-to-mass ratio). A molecule with a higher net charge will experience a stronger pull from the electric field. This stronger electric force causes it to migrate through the gel or solution much faster than a molecule of the same size with a lower net charge.
