If a Codon Is Mutated, Say from GGU to CGU, Is the Same Amino Acid Specified? ______

RNA Lab Report

If a codon is mutated, say from GGU to CGU, is the same amino acid specified? ______

Using information from the course and online research, answer the questions.

Searching Websites:

Conduct a keyword search to find websites. To begin a keyword search, start by searching broad terms such as RNA, transcription, translation, or the scientist’s name. The resulting list of websites can give you a lot of information, but how do you know if it is reliable? Some basic guidelines can help you when you open a website and try to determine its reliability.

Always consider a site's:

Objectivity - Excessive expressions of emotion, opinions, and stereotyping are tip-offs that the information on a site may be biased.
Ownership and contributors - Go to the Home or About page of the website and find out who sponsors and writes for the site. Look for contributors who have reliable credentials, such as "Harvey Jones, Professor, University of Wisconsin—Madison."
Writing style and mechanics - Check the grammar, spelling, and writing style on the site. Errors and awkwardness are signs of a nonprofessional website.
Currency - Look for publication or copyright dates associated with the site; the more current the better.
Links - What links does the site contain? A reliable website will offer links to other reliable websites, not to "junk" sites.

Keyword Search: RNA, transcription, translation, or the scientist’s name.

Scientific Analysis:

1. Scientists use observations and inferences for many discoveries and conclusions in genetics. What is the difference between an observation and an inference? Give an example of each.

2. If DNA from a cell is placed in a test tube containing the enzyme DNA polymerase and nucleotides, the result is new copies of the original DNA. This evidence was used to understand DNA replication (DNA passing information from one generation to the next). Write an explanation detailing why this clue represents solid data and is not an opinion or an inference.

3. In your own words, describe Crick's Central Dogma. Explain why this is an inference.

Scientific Contributions

There were many scientists that contributed to decoding the genetic code. Explore the contributions of some scientists.

4. Describe Marshall Nirenberg's contribution to determining the role of RNA in genetics.

5. Describe how Seymour Benzer's phage experiments contributed to deciphering the genetic code.

6. Describe Seymour Brenner's contribution to cracking the genetic code with respect to translation.

Replication, Transcription, and Translation

Place an x in the box for which process each item is a characteristic.

Characteristic / Replication / Transcription / Translation
1. RNA polymerase unwinds the DNA double helix.
2.This is the first part of protein synthesis.
3. After the stop codon is reached, the protein is separated from the ribosome.
4. Amino acids sequences are made from RNA sequences.
5. A copy of RNA is made from DNA.
6. Peptide bonds form between amino acids.
7. Uracil hydrogen bonds with adenine.
8. tRNA brings amino acids to the ribosome.
9. Copies of the original DNA are made.
10.Thymine hydrogen bonds with adenine.

7. Use the table and your research to compare and contrast transcription and translation.

8. In your own words, explain the function of mRNA, tRNA, and rRNA.

9. Use the codon chart to convert this sequence into an amino acid:

UCU-CGA-GCC-GUU-GGG-UGA

10. Explain why an mRNA strand composed of only uracil nucleotides (UUUUUUUUUU) did conclusively prove that the DNA code was a triplet code.

11. How could this mRNA sequence support a triplet code? ACACACACACAC

12. Listthe steps involved in protein synthesis, beginning with the DNA code in the nucleus and ending with a polypeptide. Try to explain it in 10 steps.

13. A mutation in a codon may not result in a change of an amino acid in the protein sequence. Explain why, using the genetic code chart to give an example.