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DNA Replication and Protein Synthesis

Overview

Students explore two of the most fundamental processes in molecular biology — DNA replication and protein synthesis — connecting the structure of DNA to how genetic information is expressed.

Learning Objective
Students understand how DNA is copied before cell division and how the genetic code is translated into proteins.

Resources needed

  • None

Lesson stages

0 / 7 done
  1. 1 Recap: DNA is a double helix made of nucleotides, each with a base (A, T, C, G). Complementary base pairing: A-T and C-G.
  2. 2 Introduce DNA replication: before a cell divides, the entire DNA must be copied.
  3. 3 The process: the double helix unzips, each strand acts as a template, complementary nucleotides are added, two identical double helices are formed.
  4. 4 Introduce transcription: the DNA code is copied into messenger RNA (mRNA) in the nucleus.
  5. 5 Introduce translation: the mRNA moves to a ribosome, where it is read in triplets (codons). Each codon codes for one amino acid.
  6. 6 Transfer RNA (tRNA) brings amino acids to the ribosome in the correct order. Amino acids join to form a polypeptide chain (protein).
  7. 7 Ask: why is a mutation in one base potentially serious? (Changes one codon, which may change one amino acid, which may change the protein's shape and function).

Tap a step to mark it as done.

Variations

  • Model replication using complementary base pair cards.
  • Decode a short mRNA sequence to identify amino acids using a codon table.
  • Discuss how mutations can be harmful, neutral, or occasionally beneficial.
More information

Teach: replication, transcription, translation, mRNA, tRNA, codon, amino acid, polypeptide, ribosome. The central dogma — DNA to RNA to protein — is the core framework of molecular biology.

Focus on replication and transcription before introducing translation. The concept of the genetic code as a triplet system is the key challenge.

Can students describe the steps of DNA replication? Can they explain how a sequence of DNA bases leads to a specific sequence of amino acids in a protein?

Model base pairing using differently coloured stones or clay balls labelled A, T, C, G. Draw the double helix structure in soil. No specialist materials needed.

Students often think proteins are made directly from DNA. The two-step process — transcription (DNA to mRNA) and translation (mRNA to protein) — is the essential correction. DNA never leaves the nucleus.

DNA replication and protein synthesis are the molecular foundation of all life. Understanding them is essential for genetics, evolution, medicine, and biotechnology including genetic engineering and CRISPR.

Activity details
Secondary Challenging 30 minutes no prep Whole Class, Small Group Indoor & Outdoor
Topics
DNA Replication Protein Synthesis Molecular Biology