If three glycine molecules (relative molecular mass 75) react together to form a tripeptide, the relative molecular mass of the product would be
A - VCE - SSCE Chemistry - Question 17 - 2003 - Paper 1
Question 17
If three glycine molecules (relative molecular mass 75) react together to form a tripeptide, the relative molecular mass of the product would be
A. 171
B. 189
C. 20... show full transcript
Worked Solution & Example Answer:If three glycine molecules (relative molecular mass 75) react together to form a tripeptide, the relative molecular mass of the product would be
A - VCE - SSCE Chemistry - Question 17 - 2003 - Paper 1
Step 1
Calculate the total mass of glycine molecules
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Answer
To find the total mass of three glycine molecules, we multiply the relative molecular mass of one glycine molecule by three:
3imes75=225.
This gives a total initial mass of 225.
Step 2
Account for the formation of the tripeptide
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Answer
During the formation of a tripeptide from three amino acids, two molecules of water are released (one for each peptide bond formed). Each water molecule has a relative molecular mass of about 18. Therefore, the total mass lost is:
2imes18=36.
To calculate the relative molecular mass of the tripeptide, we subtract the mass lost from the total mass of glycine:
225−36=189.
Step 3
Conclusion
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Answer
The relative molecular mass of the product, the tripeptide, is therefore 189.
