Your lab partner Shirley took an extract from bovine liver and diluted it by a factor of 10 before running an absorbance assay at 340nm (as done in lab) to identify the activity concentration of your extract. What (if anything) should you change about your experiment to get better results?

Question

Your lab partner Shirley took an extract from bovine liver and diluted it by a factor of 10 before running an absorbance assay at 340nm (as done in lab) to identify the activity concentration of your extract.  What (if anything) should you change about your experiment to get better results?

BlackTom AI · Accepted Answer

The question describes Shirleys dilution of bovine liver extract by a factor of 10 and then running an absorbance assay at 340 nm to determine activity concentration. The single provided answer choice is: You need to further dilute your extract, attempt again using a lower concentration of extract.

Consider the core idea behind absorbance measurements in enzyme assays: Beer's Law relates absorbance (A) to concentration (c) through A = εlc. When the extract is too concentrated, the absorbance can be outside the linear range of the instrument or approach saturation, leading to inaccurate activity readings. If Shirley already diluted by a factor of 10 and the signal is still too high or non-linear, further dilution helps bring the absorbance into the instrument’s optimal linear range (typically A ~ 0.2–1.0 for many spectrophotometers), improving accuracy and precision.

Why this option makes sense: Diluting to a lower concentration reduces the slope of the absorbance versus concentration, decreasing the risk of detector saturation and non-linearity, and allows more reliable extrapolation to activity concentrations. It also helps when the assay has a high background or when the extinction coefficient at 340 nm yields large absorbance for the given amount of analyte.

Why other potential choices (if they existed) might be wrong: If one were to assume you should concentrate the sample, you would push the absorbance higher, increasing risk of detector saturation and non-linearity, which would degrade data quality. If an option suggested using a different wavelength not appropriate for the assay, the absorbance signal could be weaker or uninformative for the activity being measured. If an option proposed not changing anything, the existing high absorbance could still be outside the linear range, producing unreliable results. If an option recommended running without a blank or improper baseline correction, systematic error could distort the measurement.

In summary, since the current condition after a 10x dilution may still yield too high or non-linear absorbance at 340 nm for accurate quantification, the prudent adjustment is to dilute further and re-measure to obtain data within the spectrophotometer’s linear range, enabling a more reliable determination of activity concentration.

类似问题

Which of the following parameters is used to determine the concentration of protein in a spectrophotometer?

What was the world's first widely adopted biodiversity policy?

The aim of the Paris Agreement is to ensure that the earth’s preindustrial temperature is not exceeded by more than º Celsius.

The IPCC's mission is to Blank ______.

Why have most international agreements for environmental protection been based on the honor system?

As was exhibited with the Montreal Protocol and the encouragement of reduced CFC production, trade can be an effective tool to compel compliance with international treaties.

The Stockholm Declaration and UNEP were the result of the Blank ______ first conference on the Human Environment in 1972.

In addition to the direct mission of the Convention on International Trade in Endangered Species (CITES), why was CITES so important?

更多留学生实用工具

智能学习助手

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