What is causing different proteins to migrate at different rates?

Question

BlackTom AI · Accepted Answer

When considering why different proteins move at different speeds during gel electrophoresis, the key factor is the ability of the molecule to navigate the porous gel matrix. 
Option 1: 'depending on their charge some proteins are attracted to the electrode and some are repelled by the electrode' This describes how charge can influence movement direction in an electric field, but in typical SDS-PAGE experiments proteins are coated with SDS to give a uniform negative charge, making charge differences less about rate and more about direction. The statement overstates the role of intrinsic charge variations in determining rate, so it is not the primary reason for rate differences. 
Option 2: 'large proteins can quickly pass through gaps in the gel while small proteins are delayed as they become caught in the gel' This reverses the actual relationship. Large proteins have more difficulty navigating the gel pores and therefore migrate more slowly, not quickly. The claim contradicts the physical barrier nature of the gel matrix. 
Option 3: 'small proteins are able to quickly pass through the gel polymer while large proteins are more impeded' This aligns with the fundamental principle of polyacrylamide or agarose gels: pore size restricts larger molecules more, so smaller proteins move faster through the network. It directly explains the observed difference in migration rates. 
Option 4: 'charged proteins are attracted to the electrode while uncharged proteins are not attracted' In the context where SDS is used, most proteins carry uniform charge, and even when charge differences exist, uncharged proteins would still be affected by the electric field or rely on other interactions; this statement does not accurately capture why migration rates differ, and it misrepresents the essential mechanism of separation under standard conditions. 
Overall, the most plausible and scientifically accurate explanation among the choices is that size disparity leads to different migration rates because smaller proteins traverse the gel matrix more readily, whereas larger ones are hindered by the pore structure.

What is causing different proteins to migrate at different rates?

View Explanation

Log in for full answers

Similar Questions

Which of the following is NOT true regarding DNA gel electrophoresis?

Why is agarose gel electrophoresis commonly used to analyse DNA fragments for verifying gene insertion?

What is the purpose of a DNA ladder or molecular weight marker in gel electrophoresis?

Which of the following factors can affect the resolution of bands in a gel electrophoresis experiment?

Which of the following statements about loading dyes is wrong?

Ammonium persulfate is added to an SDS-PAGE setup because:

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler