Engage: Cause and Effect

Have you ever made an unexpected change? What kind of effect did it have? Did it cause a misunderstanding? Did it affect one of your grades in class? Have you ever made a change that turned out to be all right?

Watch the following video to get an idea about changes and the effects they can have.

Explore 1: Analyze and Identify

This next activity is your opportunity to analyze point mutations in a DNA nucleotide sequence and determine the type of mutation. It may help you keep track of the mutations and the possible effects by taking notes in a table similar to the one below.

Sequence Number Type of Mutation Description of Problem Consequence


Explain 1: Types of Mutations

DNA base mutations may not affect a gene's protein, or they may have a serious effect. It depends on the mutation and the function of the protein coded by the gene. There are other types of mutations to consider. Watch the following video to find out more about mutations. To help you keep track of the information in the video and the rest of the lesson, create a note-taking tool such as the one pictured on the page or download and print a copy. The file, Mutations Notes Sheet, is available in Related Items.




Explore 2: Disease, Variation, or Both?

Now it is time for you to explore mutations from a slightly different perspective. Try your hand at the following activity that asks you to guess if a mutation leads to variation within a species, disease within a species, or both. Click the following image to begin the activity. Remember to use your favorite note-taking system to track the information. 

Note: This activity opens in a new window. Simply close the window to return to this resource.

Cite Source
Activity image and link courtesy of http://learngenetics.utah.edu

Explain 2: It's Not All Bad

Do you still think of the word mutation in a negative way? Variations of traits within a species are sometimes caused by one or more mutations. Click the following image, and find out how color perception in our eyes developed due to a deletion mutation.

Note: This activity opens in a new window. Simply close the window to return to this resource.


Cite Source
Activity image and link courtesy of PBS LearningMedia (www.pbslearningmedia.org); retrieved from http://d3tt741pwxqwm0.cloudfront.net/pbslm/Your_Inner_Fish_sa/index.html

Elaborate 1: Disease-Causing Mutations

You've seen how mutations in DNA have a variety of effects. Some changes are harmful and some are not. Some changes lead to variation within a species. What about the diseases that are caused by gene and chromosomal mutations? To get started, let's take a look at the following molecules. 







Sickle Cell Hemoglobin
Normal Hemoglobin


Image Credit: David Goodsell, retrieved from RCSB PDB; //creativecommons.org/licenses/by/3.0/us/

The molecule to the left represents the protein structure of hemoglobin. Hemoglobin is the oxygen carrier in our red blood cells. The molecule to the right is also hemoglobin, but its structure is different due to a point mutation in the DNA code. Sickle cell hemoglobin causes red blood cells to change from a rounded shape to a shape similar to the letter C, impeding their ability to travel through smaller blood vessels and also to transport oxygen to the body's cells. This type of mutation leads not only to disease but also to a variation in the human species that could be advantageous in countries where malaria is prevalent. 

Click the following image to read about a variety of diseases caused by various types of mutations.

Note: Clicking the image opens a new tab. Simply close the tab when finished with the text to return to this resource.



normal and sickled red blood cells


Cite Source
National Human Genome Research Institute

The focus of this section is on conditions caused by chromosomal mutations. Click the image of the chromosomes to engage in an interactive where you'll learn about conditions caused by too few or too many chromosomes and those caused by chromosomes with missing or extra genes. You can even practice building a chromosome map known as a karyotype.

Note: Clicking the image opens a new tab. Simply close the tab when finished with the interactive to return to this resource.

Image Credit: Jane Ades, NHGRI www.genome.gov

Cite Source

Elaborate 2: An Interesting Hypothesis

Could a chromosomal mutation ever be beneficial? After all, it is such a huge change. Click the picture to learn how one such mutation may have contributed to human evolution.

Note: Clicking the picture opens a new tab in your browser. After you have finished watching the video, close the new tab to return to this resource.



Cite Source
Screen capture of graphic courtesy of PBS LearningMedia (www.pbslearningmedia.org); retrieved from http://www.pbslearningmedia.org/resource/evol07.sci.life.evo.genconnect/human-chromosome-2/

Teacher Notes

The resource focus is TEKS (B)(6)(E) where students are expected to identify and illustrate changes in DNA and evaluate the significance of the changes. The resource is for use during Tier 1 instruction. However, it can be assigned as a tutorial, a review, homework, or as an introduction to the unit of study. It is up to you, the teacher, to review the components and use them as you see fit to provide additional support for student learning.

It is recommended that students use an interactive journal or science notebook to track their thoughts, ideas, questions, and "ahas" as they navigate through the content. A note-taking tool is provided as an option in the Related Items section at the bottom of the web page. You will also find additional resources to differentiate instruction in Related Items.

The following is a short description of each lesson component. Note that there are no assessments within the resource.

Engage: Video Segment

Professor Finestein, a fictitious character, introduces the concept of genetic mutations by using mistakes in the English language as a metaphor.

Explore 1: Interactive Animation

Students take on the role of quality control supervisor in a protein production factory. They analyze amino acid sequences for mistakes, identify the mutations, and approve or recycle the amino sequence.

Explain 1: Video

This section includes a video that helps students understand more detailed information about mutations. A note-taking tool is available in Related Items. It is designed for students to use throughout the resource.

Explore 2: Interactive Weblink

Students are introduced to the idea that mutations can lead to disease, variation within a species, or sometimes both.

Explain 2: Interactive Weblink

The focus of this section is on variation in a species as it relates to the evolutionary development of color perception in human eyes.

Elaborate 1: Web Text and Interactive Weblink

Students are first introduced to the effects of the point mutation that causes sickle cell anemia. Then they explore web text that provides information on a variety of diseases caused by mutations and the environment. The third part of the section is focused on chromosomal mutations and nondisjunction during meiosis.

Elaborate 2: Web Interactive

Students view information that suggests the translocation of one chromosome to another led to the development of the human species.