DNA+and+Protein+Synthesis+8th


 * DNA - The Molecule of Life**

From your studies in cell division and genetics, you should have a general idea of the structure and function of the DNA molecule.

**Activity One**

First, let's [|review replication.] Answer the questions on this page as you review.

Remember that a chromosome is a long strand of DNA wrapped with proteins that allow it to coil and uncoil. All along the length of the chromosome, there are segments of DNA called genes. Each gene (and there are thousands and thousands of them) is a recipe for a particular protein. Each of these proteins is an expression of one of our many traits. For example. we have genes for hair color, eye color, height, freckles, finger length, head shape, nose shape, eye shape, body type, and all sorts of hormones and enzymes. Each of these traits is expressed through a combination of amino acids that form specific proteins.

Activity Two In the above review, you were able to see long strands of DNA being unwound and copied during S-phase. This is called replication. However, sometimes the cell only needs a specific gene to be copied so that a specific protein can be produced. In this case, only part of the molecule will "unzip" -- the part of the molecule that contains the instructions for making this one protein. Let's begin by [|building a molecule of DNA.] Solve the [|Backpack Mystery.] Now solve the [|Canadian Mystery.]
 * Which nucleotide bonds with T?
 * Which bonds with A?
 * Which bonds with C?
 * Which bonds with G?

**Activity Three** **DNA Biography** **The process of discovering the structure and function of DNA was a long one, with each scientist building upon the work of those who came before. The following are scientists who made significant contributions to our understanding of the molecule of life.** 1. Friedrich Miescher 2. Frederick Griffith 3. Oswald Avery 4. Alfred Hershey 5. Martha Chase 6. James Watson 7. Francis Crick 8. Erwin Chargaff 9. Rosalind Franklin 10. Maurice Wilkins 11. Barbara McClintock 12. Ian Wilmut 13. Alec J. Jeffreys 14. Craig Venter 15. John Sulston 16. Michael M. Baden 17. Henry C. Lee 18. Barry Scheck 19. Peter Neufeld 20. Dr. Margaret Pericak-Vance a. When and where was this person born? b. Where was this person educated? What was his/her field of study? What degrees did he/she obtain? c. What is this person's contribution to our knowledge of DNA? d. What works, if any, were published by this individual? e. If this person is deceased, when did he/she die? f. If this person is still living, what is he/she doing now?
 * You will research the work and life of one of the above scientists who will be assigned to you and write a one-page report that includes, but is not limited to, the following information:**
 * **__I//f there are interesting pieces of information about this person, beyond the information you collected above, you may include them in your report.//__**
 * **View the [|rubric.]**

**Activity Four**
 * Who are you really? Let's determine your [|DNA Alias.] Your teacher will give you a worksheet for this activity.**




 * Now embark on this [|DNA Webquest.] Answer the questions on your own paper.**
 * Click on Explore the Evidence.
 * What makes you YOU?
 * Describe the shape of a strand of DNA.
 * What is a gene?
 * What are the four bases of DNA?
 * Click on The Science Scoop.
 * What is a genome?
 * Are the genomes of all the organisms alike? Explain.
 * What two scientists received a Nobel Prize for discovering the structure of DNA?
 * Describe the structure of DNA.
 * Of how many bases is the average gene composed?
 * How many base pairs make up the entire human genome?
 * Are all human genomes identical? Explain.
 * How does our knowledge about the human genome help us?
 * Click on Scientist at Work.
 * Why was Dr. Amato upset to learn the shoes and handbags might have come from Yacare Caiman?
 * How did the importer of the shoes explain himself?
 * How did Dr. Amato determine whether the reptile skins were protected or not?
 * What did Dr. Amato discover?
 * What happened to the importer?
 * Explain how our knowledge of DNA is important in solving crimes.
 * Click on See for Yourself. What did you learn?
 * Check out all the other icons. Write down one really interesting thing that you learned today.

**Activity Five**


 * Explore and manipulate [|this model] of DNA.

Go through this [|tutorial] of protein synthesis.**

Once you understand the bonding rules of DNA, you are ready for the next step: transcribing DNA into RNA. Here are the basics:
 * Transcription begins in the nucleus. **Why is this?**
 * In transcription, a molecule of RNA is built from a DNA template.
 * RNA can escape the nucleus, but DNA cannot. **Why is this?**
 * RNA is different from DNA in three main ways:
 * It contains only a single strand (rather than two strands in DNA)
 * It does not contain thymine, but contains uracil instead
 * It contains a different sugar: ribose (instead of deoxyribose)
 * When a strand of DNA is used to construct a strand of RNA, the RNA contains a message that will be carried to the cytoplasm outside the nucleus. For this reason, we call this particular strand of RNA **messenger RNA**, or mRNA.
 * When the mRNA finds the ribosome in the cytoplasm, it is **translated** into a protein:
 * The two subunits of a ribosome come together to "read" the mRNA message.
 * The ribosome reads the message in units called codons, which are triplets of nuceotides.
 * Molecules of tRNA (transfer RNA) match the codons to amino acids that are found in the cytoplasm.
 * The tRNA begins to build a chain of amino acids at the ribosome, **thus translating the mRNA message into a protein.**
 * Now let's [|try a little TnT] (transcription and translation) on our own.

**Your teacher will give you a practice worksheet entitled BREAKING THE CODE. **
 * Now you are ready to [|synthesize a protein] on your own!**

And now...........Solve the [|Baffling Baby Mystery!]

After you have finished your DNA Extraction lab, log on to [|this site] to complete the lab analysis. **Activity Six**

**And now, class, are you ready to play Codon Bingo?**

Turn your name into a DNA sequence and then click on the [|Mighty Mutations Maker.]**
 * More with codons:

**Activity Seven Review for Test ** 1. Describe 3 differences between a DNA molecule and an RNA molecule. 2. What is a nucleotide? 3. What is a base? 4. What are the four bases of which DNA is comprised? 5. Explain what happens to the DNA molecule during replication. 6. Where does replication take place? 7. Under what circumstances does replication take place? 8. Describe what happens to the DNA molecule during transcription. 9. Why does transcription take place? 10.Where does transcription take place? 11.Why is it necessary for the DNA molecule to make a messenger molecule? 12.Outline the process of translation. 13.Where does translation take place? 14.Of what is a protein constructed? 15.How are the amino acids linked into a chain? 16.What is a codon? How many bases comprise a codon? 17.What is an anticodon? 18.Given the DNA sequence TACTTAAGCCTACCGGATTTAACT 19.If the 9th base in the mRNA sequence is changed to a U, what will be the result? 20.If the 9th base in the mRNA sequence is changed to an A, what will be the result? 21.If a G is added after the 4th codon, what will be the result? 22.If the 5th base is removed from the sequence, what will be the result? 23.If given the amino acid tryptophan, 24.What is the purpose of the start and stop codons? 25.What is the average number of bases in a protein?
 * Divide the sequence into codons.
 * Build the complementary strand of DNA
 * Transcribe a strand of mRNA using the original DNA template.
 * Translate the mRNA into tRNA.
 * Using the mRNA, find the appropriate amino acids
 * give the mRNA codon
 * give the tRNA anticodon
 * give the original DNA codon

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