CAIE A Level Biology 9700 · Nucleic acids and protein synthesis
The following is the sequence of a mature mRNA molecule from a eukaryotic cell:
5' – AUG GCA UUU GAU UGA – 3'
The table below shows the amino acids coded for by some mRNA codons.
| mRNA Codon | Amino Acid |
|---|---|
| AUG | Met (start) |
| GCA | Ala |
| GCU | Ala |
| UUU | Phe |
| UUC | Phe |
| GAU | Asp |
| GAC | Asp |
| UGA | Stop |
Describe how this mRNA sequence is used to direct the synthesis of a polypeptide during translation.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.