What Is DNA?

Contributor: Hannah Brooks. Lesson ID: 12206

When a builder builds a building, he or she is supplied with instructions or blueprints. When cells are created, they follow instructions as well! Learn about these amazing molecules that build life!

3To4Hour
categories

Life Science

subject
Science
learning style
Visual
personality style
Lion
Grade Level
High School (9-12)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

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DNA groove animation

  • Do you know what this structure is?
  • Did you know it is responsible for sustaining all life on the earth?

You have an extraordinary molecule in every cell in your body. It is constantly replicating and being used to create proteins that help support cellular processes.

The molecule is called Deoxyribose Nucleic Acid or DNA. It is one of the most important molecules in your body because it instructs your cells on how to function.

cellular DNA

DNA is made up of nucleotides. The structure is similar to building bricks connected to make a tall tower.

Each nucleotide comprises three components: a sugar backbone, a phosphate group, and a nitrogen base.

DNA nucleotides

The sugar and phosphate groups work to provide structure for the DNA molecule, while the nitrogen bases are responsible for bonding two strands of DNA.

There are four nitrogen bases in DNA: Adenine, Cytosine, Guanine, and Thymine.

  • Can you find the bonds between molecules of adenine and thymine in the image above?

These are weak bonds that can break apart so that DNA can replicate. Adenine always bonds with thymine, and cytosine always bonds with guanine.

The strict bonding rules in DNA cause the molecule to twist, taking on the traditional double helix shape.

DNA strand

James Watson and Francis Crick are cited as discovering DNA, but they used the work of many scientists to develop a working theory for the molecule's structure.

One notable contributor to their research was Rosalind Franklin, a female chemist who created X-ray images of DNA that helped Watson and Crick visualize the molecule.

If you want to read more about the structure and discovery of DNA, check out DNA Is a Structure That Encodes Biological Information.

DNA is essential because it can pass genetic information from parent to offspring and holds the blueprint for cell directions. Remember that it comprises nucleotides containing a phosphate group and sugar to provide structure to the molecule and a base for bonding to another DNA strand.

Review what you have learned with the following video.

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Keep going in the Got It? section to explore more about the function of DNA in a cell!

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