Basic Genetics

This hands-on activity reinforces the processes of transcription and translation. Usingpaper cut-outs, students follow the rules of complementary base pairing to build an mRNAmolecule, then translate the mRNA codons to assemble amino acids, building a protein. At theend, they learn which of 5 actual proteins they’ve built. (DNA and amino acid sequences havebeen abbreviated.)

Learning Objectives

• The arrangement of DNA building blocks in a gene specifies the order of amino acids in theprotein it codes for.
• Amino acids are the building blocks of proteins.
• The sequence of amino acids in a protein determines its structure and function.
• Living things make proteins the same way.

Estimated time
60-90 minutes

Materials
Copies, scissors, tape, paper clips

Instructions
Have students work individually or in pairs.

Review with the class how the structure and function of proteins is dictated by the DNA sequence of genes (structure and function of DNA).

See Teacher Guide for further instructions.

Using a paper model, students make a mutation of their choice (substitution, insertion, or deletion) in a gene during DNA replication. Then they transcribe and translate the mutated sequence to reveal the resulting amino acid sequence.

After completing the activity, students learn about the example gene and protein—Human Leukocyte Antigen (HLA-B)—including known variants.

Learning Objectives

• During DNA replication, occasional errors change DNA sequences. This process is called mutation.
• Changes in DNA sequences can lead to changes in proteins.

Estimated time
45 minutes

Materials
Copies, scissors, tape

Instructions

1. Begin this activity by reviewing the following:
   • DNA replication follows base-paring rules: A-T, C-G
   • Sometimes during DNA replication, a base is inserted, deleted, or substituted with a different one, changing the DNA sequence of a gene.
   • Changes in the DNA sequence of a gene can lead to changes in the protein it codes for.
2. Give each student or pair of students one copy of the instructions and cut-outs.
3. After students finish building their protein, give them a copy of the Protein and variant information handout.

This paper model of sexual reproduction uses real pigeon traits to demonstrate how two parents can produce highly varied offspring. Students recombine parental chromosomes, make gametes, then randomly combine two gametes. Finally, they decode the resulting allele combinations to draw the traits of a pigeon offspring.

Learning Objectives

• Variations in the DNA sequences of genes are called alleles.
• Alleles are shuffled during sexual reproduction (recombination, independent assortment, and random fertilization).
• Allele shuffling during sexual reproduction contributes to genetic variation in a population.

Estimated time
30 minutes

Materials
Copies, colored paper, scissors, tape, colored pencils

Instructions

1. Give each student a copy of the instructions and chromosome cut-outs.
2. After students complete their pigeons, hang them (along with the gametes they used to make them) all on a large wall space or white board.
3. Discuss the following:
   • How allele “shuffling” during sexual reproduction contributes to genetic and phenotypic variation in offspring
   • The amount of genetic and phenotypic variation you see in the offspring from just two pigeons

In this laboratory experiment students explore how effectively different sunscreens protect yeast cells from damage caused by ultraviolet (UV) radiation.

Students build an edible model of DNA while learning basic DNA structure and the rules of base pairing.

Students use edible models of the DNA molecule to transcribe an mRNA sequence, then translate it into a protein.

Compare sexual and asexual reproduction in several organisms.

Learning Objectives

• There are two modes of reproduction; sexual and asexual.
• There are advantages and disadvantages to both sexual and asexual reproduction.

Investigating Reproductive Strategies (PDF)