DNA Replication Transcription Translation Lab Worksheet

DNA Replication/Transcription/Translation Lab Worksheet Understanding DNA Replication Directions: Using model materials to demonstrate DNA replication: 1. On a separate Word document, present a detailed analysis of DNA replication at one replication fork. Use drawing, descriptions, and/or captions detailing the process. 2. In the analysis include the following: a. Show how the leading and lagging strands are synthesized b. Show the proteins (enzymes) involved in DNA replication and what their functions are Understanding DNA Transcription and Translation Directions: Complete the following questions. Questions 1- 3 can be submitted on the same document as the Understanding DNA Replication assignment. Refer to Figure 1 as it illustrates the process of DNA transcription, translation, and protein synthesis. 1. The stages of transcription are initiation, elongation, and termination. Draw a representation of each of these stages in a separate Word document. Be sure to include the names of important enzymes and locations. 2. Once mRNA is created through transcription, it is often processed. Explain how mRNA can be processed. Include the names of important enzymes or structures. 3. Translation is how mRNA gets used to create a peptide sequence. Draw what is going on inside a ribosome. Be sure to include the locations of mRNA, tRNA, each subunit of the ribosome, and where the amino acid sequence forms. Figure 1. The Central Dogma of Molecular Genetics: DNA Codes for RNA, and RNA Codes for Protein. DNA Transcription and Translation Exercises (Converting DNA template Sequences and Identifying types of Mutation Name: Directions: Now that you have gone through the steps on how to convert you will be in charge of converting a DNA template sequence into an amino acid produce. In the figure below the template strand is labeled. The DNA template is what is used to create a representative mRNA strand. You can see its complementary DNA strand as well as the mRNA strand. Take care to note the direction of the strands (3’ends and 5’ ends). Once an mRNA strand is created then the mRNA can be used to code for an amino acid sequence. The table below shows how the mRNA strand was converted into a peptide. Table 1. mRNA Strand Converted into a Peptide DNA Template Strand 3' T A C T T C A A A C C G A T T 5' DNA 5' A T G A A G T mRNA 5' A U G A A G U U U G G C U A A 3' Amino Acid Met Lys Phe T T G G C T Gly A A 3' - The conversion of the mRNA sequence to amino acid can be done from the genetic code for protein synthesis (see Figure 17.5 in the text or Figure 2 below). Figure 2. The standard Genetic Code for Protein Synthesis (Reprinted from Campbell Biology (9th ed) (p. 330), by Reece, Urry, Cain, Wasserman, Minorsky & Jackson, 2011, San Francisco, Calif: Pearson Benjamin Cummings) 1. Using the example above determine the following peptide strands. DNA Template Strand 3' T A C A A A C A T T T A A T T 5' DNA 5' A T G T T T G T A A A T T A A 3' mRNA 5' A U G U U U G U A A A U U A A 3' Met Asn Amino Acid Phe Val - DNA Template Strand 3' 5 T C A G T G G A C C A A A T T ' DNA 5' A G T C A C C T G G T T T A A 3' mRNA 5' A G U C A C C U G G U U U A A 3' Amino Acid Ser His Leu Val - 2. Mutations in DNA can affect the peptide product that is being coded. Below is a wild type gene along with a series of mutations of that same gene. Determine the type of mutation as well as how it affects the final peptide sequence. Wild type: DNA Template Strand 3' 5 T A C T T C A A A C C G A T T ' DNA 5' A T G A A G T T T G G C T A A 3' mRNA 5' A U G A A G U U U G G C U A A 3' Amino Acid Met Mutation: Substitution DNA Template Lys Phe Gly - Effect: Change in 3' T A C T T C A A A C C A A T T 5 Strand ' DNA 5' A T G A A G T T T G G T T A A 3' mRNA 5' A U G A A G U U U G G U U A A 3' Amino Acid Met Mutation: Substitution Lys Phe Ala Leu Effect: Different protein was made DNA Template Strand 3' 5 T A C T T C A A A T C G A T T ' DNA 5' A T G A A G T T T A G C T A A 3' mRNA 5' A U G A A G U U U A G C U A A 3' Amino Acid Met Mutation: Frameshift Lys Phe Ser Leu Effect: Different protein was made DNA Template Strand 3' T A C T T C A A C C G A T T 5 ' DNA 5' A T G A A G T T G G C T A A 3' mRNA 5’ A U G A A G U U G G C U A A 3' Amino Acid Met Mutation: Deletion proteins function Lys Leu Ala - Effect: An A was removed in the DNA strand may alter the DNA Template Strand 3' 5 T A C A T C A A A C C G A T T ' DNA 5' A T G T A G T T T G G C T A A 3' mRNA 5' A U G U A G U U U G G C U A A 3' Amino Acid Mutation: substitution Met - Phe Gly Leu Effect: signals the cell to stop building a protein DNA Template Strand 3' T A C A T T C A A A C C G A T T DNA 5' A T G T A A G T T T G G C T A A 3' mRNA 5' A U G U A A G U U U G G C Amino Acid Mutation: substitution properly Met - Val Trp 5 ' U A A 3' Leu - Effect: One A is left over, and protein may not function 3. What mutations would have the greatest effect on peptide sequence? Which would have the least effect? Why? Deletion of a nucleotide will lead to frameshift mutation, causing the greatest change in protein structure. Substitution will have the least effect because, most of the time the shape of the protein is not affected by this mutation.