OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What role do amino acids play during the protein synthesis process?

1. They form triple bonds with mRNA

2. They create a protective layer for the cell

3. They join together in a chain to form proteins

4. They bind with DNA to initiate transcription

The correct answer is: They join together in a chain to form proteins

Amino acids play a crucial role in the protein synthesis process by joining together in a specific sequence to form proteins. This process takes place in two main stages: transcription and translation. During transcription, the DNA sequence is copied into messenger RNA (mRNA), which then carries the genetic information to the ribosomes, the sites of protein synthesis. In the translation phase, ribosomes read the mRNA sequence in sets of three nucleotides, known as codons. Each codon corresponds to a specific amino acid. Transfer RNA (tRNA) molecules bring the appropriate amino acids to the ribosome, where they are linked together in the order specified by the mRNA sequence. As these amino acids bond together with peptide bonds, they create a growing polypeptide chain, which eventually folds into a functional protein. Understanding this process highlights the importance of amino acids as the building blocks of proteins, which carry out a vast array of functions within living organisms, from structural roles to enzymatic activity and beyond.