Step 3c: Protein Function

How a Firefly's Tail Makes Light (optional)

This video gives a quick overview of protein synthesis, from gene to functional protein, using firefly luciferase as an example.

If your students are not familiar with fireflies, first show them the Nature's Fireworks video (Look for the "What are fireflies?" box on the web page linked below).

Project video to the whole class.

• Through proteins, the information in genes shape characteristics at the cellular, tissue, and organismal levels.
• Cells make specific proteins by reading the genetic code in specific genes.

Students see a real-life example highlighting the relationship between a gene, the protein it codes for, and its function in an organism.

5 minutes

How a Firefly's Tail Makes Light (video)

What are Proteins?

This video introduces the structure and diversity of proteins.

Project video to the whole class.

• Proteins are made from amino acids.
• Different combinations of amino acids make different proteins.

5-10 minutes

Test a Protein's Activity

In this online interactive, students drag and drop to learn how a protein’s shape can affect its function in a cell.

Have students explore individually or in pairs.

• To do their work, proteins physically interact with each other and with other molecules.
• A proteins shape impacts its function.

Students see a real-life example of a protein, learn about the job it does in a cell, and see how differences in a protein’s structure affect its function.

20 - 30 minutes

Computers with internet access

Test a Protein's Activity

Classical vs. Molecular Genetics

This online interactive brings together the classical and molecular perspectives of genetics. By exploring familiar terms and examples, it describes how the two views are different, and also how they are connected.

20 minutes

Computers with internet access

Classical vs. Molecular Genetics (Interactive)

What Really Makes a Trait Dominant or Recessive?

From the perspective of molecular genetics, both alleles of a gene contribute to a phenotype, making the terms "dominant" and "recessive" problematic. A more complete understanding of inheritance patterns can come through understanding what is happening at the protein level. Learn more in this short video.

Project video to the whole class.

• All alleles of a gene contribute to phenotype.

10-20 minutes

Outcome of Mutation

How does a difference in a gene’s DNA sequence lead to a difference in an observable trait? This piece explores 8 real examples of changes in protein structure and/or function that lead to remarkably different traits.

Project to the whole class. Walk through and discuss a few examples.

• Variations in DNA sequences lead to variations in proteins, which lead to variations in traits.

This piece explores the remarkable variations in traits (effect) that are caused by small differences in DNA.

10-15 minutes