Question

Use of a colorimetric assay to determine protein concentration may be subject to all of the following EXCEPT: (A) the use of standards. (B) measurement error (C) the Hawthorne effect. (D) systematic error

Short answer

C. The Hawthorne effect.

Step-by-step solution

- Understand Each Option

First, examine each provided option to understand how it relates to a colorimetric assay. Options are: (A) the use of standards, (B) measurement error, (C) the Hawthorne effect, and (D) systematic error.

- Analyze Option A

A colorimetric assay often uses standards to calibrate measurements and ensure accuracy. Therefore, this option is typically relevant to the process.

- Analyze Option B

Measurement error refers to inaccuracies that occur during data collection. This is a common concern in colorimetric assays and other scientific measurements.

- Analyze Option C

The Hawthorne effect is a change in behavior when subjects know they are being observed. This effect is generally associated with human behavior studies, not with laboratory assays.

- Analyze Option D

Systematic error refers to consistent and repeatable errors associated with faulty equipment or flawed experimental design. This type of error can affect colorimetric assays.

- Identify the Correct Answer

Among the options, the Hawthorne effect (C) is unrelated to the process of determining protein concentration using a colorimetric assay, as it pertains to human observation.

Key concepts

Measurement Error

Measurement error happens when we collect data and it’s not totally accurate. Think of it as small mistakes that can happen during an experiment. In the context of a colorimetric assay for determining protein concentration, measurement errors might occur due to:

• Incorrect calibration of the equipment.
• Imperfectly prepared reagents.
• Human mistakes while reading results.

It’s important to minimize these errors to get reliable data. Remember, no measurement can be perfect, but reducing measurement error helps improve the overall accuracy and trustworthiness of the results.

Hawthorne Effect

The Hawthorne effect happens when people change their behavior because they know they are being watched. This concept originated from studies on worker productivity but is not limited to that. In scientific experiments, especially those involving human subjects, this can be a significant concern. However, in the case of a colorimetric assay, which is used to measure protein concentration in a lab setting without human subjects being observed, the Hawthorne effect is not applicable. It’s more about how awareness of observation can influence human actions, not the accuracy of chemical or biological assays.

Systematic Error

Systematic errors are consistent, repeatable errors that are present in an experiment due to faulty equipment or flawed procedures. Unlike random errors, which vary and can be reduced by averaging multiple measurements, systematic errors will skew all measurements in the same direction. In a colorimetric assay, systematic errors might stem from:

• Consistency in faulty reagent batches.
• Errors in the measurements due to the wrong calibration settings.
• Bias in the experimental design that causes all results to be off by a certain amount.

To identify and correct systematic errors, scientists often use control samples and repeat experiments to ensure that their data is as accurate as possible. Understanding and mitigating systematic errors are crucial for reliable scientific studies.