The protein fibronin can be broken down into amino acids using an enzyme - AQA - A-Level Chemistry - Question 2 - 2021 - Paper 3
Question 2
The protein fibronin can be broken down into amino acids using an enzyme.
A student uses thin-layer chromatography (TLC) to identify these amino acids.
The student i... show full transcript
Worked Solution & Example Answer:The protein fibronin can be broken down into amino acids using an enzyme - AQA - A-Level Chemistry - Question 2 - 2021 - Paper 3
Step 1
Calculate the Rf value of the unknown amino acid
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Answer
To calculate the Rf value, we use the formula:
Rf=Distance traveled by the solventDistance traveled by the amino acid
From Figure 3, let’s assume the distance traveled by the unknown amino acid is 0.34 cm and the distance traveled by the solvent front is 1.0 cm.
Substituting these values into the formula gives:
Rf=1.00.34=0.34
Step 2
Identify the unknown amino acid
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Answer
Referring to Table 1, the amino acid with an Rf value of 0.34 is glycine.
Step 3
State how the amino acids can be made visible at the end of the experiment.
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Answer
The amino acids can be made visible at the end of the experiment using a UV lamp or ninhydrin, which reveals the spots on the TLC plate.
Step 4
State why each amino acid has a different Rf value.
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Answer
Each amino acid has a different Rf value because they possess different relative affinities and solubilities in the solvent and stationary phases.
