EQ How does a cell make proteins with the information from DNA? Protein Synthesis: Get Started Get Started Think of a corn cell that is genetically modified to contain the Bt gene and a corn cell that is not modified. In what ways are the cells similar? In what ways are the cells different? What is the relationship between DNA and proteins in a cell? Introduction Read the introduction. Protein synthesis is the process in which a cell makes a protein. It has two phases. Transcription is the first phase, where DNA is used to make mrna. Translation is the second phase, where the mrna is used to make a protein. 1
As you view the simulation, be sure to correct the order of the Transcription and Translation cards, as needed. The correct card order is: D, F, E, J, A, H, B, G, C, I Tape/staple/glue the copies of the cards into your journal and follow procedure step #9. This is a cell with DNA in its nucleus. The mrna molecule leaves the nucleus and travels to a ribosome in the cytoplasm of the cell, where it will begin the translation process. 2
trna molecules bind to the mrna-ribosome complex according to the information on contained in the codons in the mrna molecule. Specific trnas bind to each codon, and carry an amino acid. The amino acid chain continues to grow as the mrna continues to move along the ribosome, matching the trna molecule and bringing new amino acids. Transcription Complementary RNA nucleotides match with the DNA bases. The nitrogenous base uracil replaces thymine. Translation Central Dogma 3
Video Mismatch Repair Part B: Mutations Codon - Set of 3 nucleotides on mrna that codes for an amino acid Mutations changes in the sequence of nucleotides in the DNA. Key Vocabulary Step #10 Types of Mutations Insertion add a nucleotide Deletion remove a nucleotide Substitution change a nucleotide Three base insertion 3 nucleotides are added or deleted. Codon Chart Codon Chart The Codon Chart at the right shows you how to determine which amino acid goes with which m-rna codon sequence. To decode a codon, start with the First Base, then the Second Base, and finally the Third Base. 4
Codon Chart Sickle Cell Anemia is caused by a substitution mutation Discuss and Respond in your Journal Why is it possible for mutations to be neutral? Gene Therapy Scientists fix genes so they produce the correct protein 5
Gene Therapy Restores Boy s Sight Hemophilia Gene Therapy Breakthrough Analysis 1 Analysis 2 Define protein synthesis and describe how it works. 5 TACTCGGCATTGTGA 3 Analysis 3 Analysis 4 Predict the results of a two-base insertion or deletion to a strand of DNA that codes for a protein. How is this different from a three-base insertion or deletion? One night while watching TV you hear a newscaster say, DNA mutations cause damaged proteins. Based on your work in Part B, how would you respond to this claim? 6
Summary Analysis 5 Describe the relationship between gene therapy and protein synthesis. Check In 3 molecules in central dogma flowchart 2 processes involved in protein synthesis 1 reason why mutations may not change a protein Key Vocabulary amino acid DNA mrna mutation protein protein synthesis replication RNA transcription translation 7