GIZMOS UC SCOUT

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Name: Lilyth Lerma Date: 2/7/2025


Student Exploration: DNA Analysis
Directions: Follow the instructions to go through the simulation. Respond to the questions and
prompts in the orange boxes.

Vocabulary: allele, codon, DNA, DNA sequence, gene, genotype, identical twins, nitrogenous base,
phenotype, trait

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1.​ The two navy officers shown at left are identical twins.
Why do you think identical twins look so similar?

Identical twins look so similar because identical twins
have the same genetic makeup, meaning, the same
DNA (same nitrogenous bases). This is because they
are fertilized by the same egg, making them identical.

2.​ Most brothers and sisters don’t look exactly the same.
What causes most siblings to have different appearances?
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brothers and sisters don't look exactly alike because
everyone (including parents) actually has two copies
of most of their genes. And these copies can be
different. Parents pass one of their two copies of each
of their genes to their kids.
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Gizmo Warm-up
Most of an organism’s traits, or characteristics, are determined
by genes encoded in DNA. Traits are determined by the
sequence of the four nitrogenous bases in the DNA molecule:
adenine, thymine, cytosine, and guanine.

Except for identical twins, the DNA sequence of every
individual is unique. In the DNA Analysis Gizmo, you
will analyze partial DNA sequences of frogs.

1.​ Select the POPULATION tab. What are the three main traits that vary between the frogs?




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, The three main traits that differ between the frogs are the spots on their body, the color of the
eyes and the color of the skin
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2.​ Which frog would you expect to have the most similar DNA sequence to frog A? Why?

The three main traits that differ between the frogs are the spots on their body, the color of the
eyes and the color of the skin




Activity A: Get the Gizmo ready:

Identical twins ●​ Select the FIND THE TWINS tab.

Question: How are DNA sequences used to analyze relationships?​

1.​ Observe: Look at the three frogs on the TWINS tab. How does their appearance compare?

The three frogs have the same traits. They are all colored orange, have pink eyes, and
contain black spots on their body.
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2.​ Predict: What do you expect the DNA sequences of the three frogs to look like? ​ ​
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I expect them to look different.
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3.​ Identify: Drag frog A to the scanning station and click SCAN. Drag the resulting DNA sequence to
the bin at the upper right of the Gizmo. Each band on the sequence represents a single nitrogenous
base of DNA. The band is dark if that base is present and pink if that base is absent.

Scan frogs B and C. Drag their DNA sequences into the bin. If two frogs are identical twins, they will
have exactly the same DNA sequence. Compare the three sequences.

Could any of these frogs be identical twins? If so, which frogs? ​ ​ ​ ​

Yes because frogs with similar characteristics can contain the same DNA. The frogs that are
identical twins are frog A and frog B.

4.​ Analyze: DNA is composed of four different nitrogenous bases. For the type of DNA sequence used
by the Gizmo, a complete DNA sequence would have scan readouts for all four nitrogenous bases.
Knowing this, why can you not be entirely certain the frogs are identical twins using the simplified
sequences on the Gizmo?
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Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved​