Lesson Plan - Get It!
What if the blueprints for a skyscraper were inside the head of the designer, and he couldn't tell anyone what they were? Kiss that building goodbye! Even worse, what if cells couldn't access their DNA instructions?
What do you think would happen if a construction worker didn't have blueprints from which to build?
It would make it really hard to build skyscrapers and bridges! DNA is the blueprint for all living organisms, but you learned in the previous Related Lesson that DNA cannot leave the nucleus! In order to be able to instruct other parts of the cell on how to function, DNA must be able to send the directions out into the cell. It uses a special molecule, called, "Ribonucleic acid," or RNA, to send instructions out of the nucleus and into the cell.
Before continuing, if you missed or would like to review the first lessons in our What Is DNA? series, please go to Related Lessons in the right-hand sidebar.
Compare the images of DNA and RNA above.
- What differences do you notice?
If you saw that RNA only had one strand, you made a good observation! Discuss this with a parent or teacher. RNA is much smaller than DNA because it is single-stranded. You might notice that there is a new base listed, called, "uracil." While DNA uses guanine, adenine, thymine, and cytosine to bond strands, RNA replaces thymine with uracil. Uracil bonds with adenine only!
There are two types of RNA you will need to know in this lesson:
Messenger RNA, or mRNA, is responsible for moving genetic code from the nucleus to the cellular environment. Observe how it moves through a nuclear pore to the cellular space inside the membrane.
Transfer RNA, or tRNA, is responsible for bringing amino acids, or proteins, to meet the mRNA. mRNA and tRNA match much like two strands of DNA, base-to-base.
Turning DNA into mRNA in the nucleus is called "transcription," because the genetic code is being copied to a similar code on mRNA that is able to move out of the nucleus.
As you watch From DNA to protein - 3D, from yourgenome, for an overview of the process of transcription, answer the following questions:
- Where does transcription take place?
- What is the role of mRNA?
- Where does translation take place?
- How are the mRNA and tRNA related?
- How are proteins made in the cell?
This video will also introduce you to the next part of our learning: translation.
- Where did the process of translation occur in the video?
Ribosomes floating in the cytoplasm help aid the process of translation, which takes genetic information in code and translates it into protein chains.
During transcription, the mRNA is matched with tRNA molecules carrying different amino acids. They are bonded using the bonding rule: adenine with uracil and cytosine with guanine. This leads to amino acids forming a chain structure called a "polypeptide."
Notice how the protein is made up of individual beads. These beads represent amino acids that are bonded together. Proteins carry out a lot of cellular functions and help keep cells healthy!
Watch an overview of the whole process from the Amoeba Sisters, and write down the steps you observe. Consider adding sketches to each step once you have completed Protein Synthesis and the Lean, Mean Ribosome Machines:
There are a lot of steps to take DNA and make proteins, but it is a process required to keep the cell functioning. Remember that it starts out in the nucleus with DNA being transcribed into mRNA. mRNA is able to leave the nucleus and meet up with tRNA at the ribosome. Here, the code is used to bond different amino acids together into a long chain.
- How would the process change if DNA could leave the nucleus?
- Why do you think there are multiple kinds of RNA working together?
Discuss what you have learned with a parent or teacher.
In the Got It? section, you will review the entire process online!