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

Question

BlackTom AI · Accepted Answer

When considering the purpose of a DNA ladder or molecular weight marker in gel electrophoresis, we first look at how size estimation is performed in this technique.
Option 1: 'To amplify DNA samples' This is incorrect because ladders are not involved in amplification; PCR uses primers and polymerases, not a DNA ladder as a reference. The ladder itself does not boost or replicate DNA.
Option 2: 'To provide a reference for estimating the sizes of DNA fragments' This is the core role of a ladder. It contains fragments of known lengths, which run alongside samples so you can compare bands and deduce approximate sizes.
Option 3: 'To color the gel' While some gels use dyes for visualization, the ladder's primary function is not coloring; dyes used for loading or visualization do not define fragment sizes.
Option 4: 'To improve gel resolution' The ladder does not inherently improve resolution; resolution depends on gel composition, electrophoresis conditions, and sample quality. The ladder’s job is reference sizing, not sharpening separation.

In summary, the ladder serves as a calibration tool that allows researchers to translate the distance migrated in the gel into an estimated fragment size by comparing to the known standards, making option 2 the correct description of its purpose.

BIOL2309.13196.202610 Exam - Multiple Choice Part- Requires Respondus LockDown Browser

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

查看解析

登录即可查看完整答案

类似问题

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 causing different proteins to migrate at different rates?

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:

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单