Protein Synthesis and Mutation Review

Size: px

Start display at page:

Download "Protein Synthesis and Mutation Review"

Bonnie Baldwin
5 years ago
Views:

Protein Synthesis and Mutation Review 1. Using the diagram of RNA below, identify at least three things different from a DNA molecule. Additionally, circle a nucleotide.

1 Protein Synthesis and Mutation Review 1. Using the diagram of RNA below, identify at least three things different from a DNA molecule. Additionally, circle a nucleotide. 1) RNA is single stranded; DNA is double stranded 2) RNA contains the sugar ribose; DNA contains the sugar deoxyribose 3) RNA contains the base Uracil (U); DNA contains the base Thymine (T) 2. Label the diagram of protein synthesis below using the following terms: Amino acid, anticodon, codon, cytoplasm, DNA, nucleus, ribosome, trna AMINO ACID trna ANTI- DNA 10 mrna RIBOSOME CYTOPLASM 3. Using the same vocabulary as above, explain the process of protein synthesis. This should be a detailed description of what happens during transcription in the nucleus, and what happens during translation on the ribosome.

2 Protein synthesis is the process of making proteins. The DNA contains the codes to make the proteins, but it CANNOT leave the nucleus. As a result, it must deliver the message in a different way. STEP 1 OF PROTEIN SYNTEHSIS-TRANSCRIPTION. The section of the DNA that contains the code for the needed protein temporarily unwinds. Using this section, an mrna strand is created (transcribed) from the DNA. It does this by matching the base pairs. Remember, DNA contains the base Thymine (T), while RNA contains Uracil (U). This means that A will now pair with U in transcription. For example, if you transcribed the sequence ATCG, you would get UAGC. At the end of transcription, the mrna is now ready to deliver the message (instructions for the protein) to the ribosome (rrna). STEP 2 OF PROTEIN SYNTHESIS-TRANSLATION. The mrna lands on the ribosome with the directions to create a protein. Every 3 letters on the mrna strand is called a codon, and codes for 1 amino acid, the building blocks of a protein. The amino acids will always begin with the start codon (MET) and end when a stop codon is reached. The amino acid that corresponds to the codon on the mrna is carried over on a trna molecule, which knows where to land because of its anti-codon that pairs with the codon on the mrna. It is important to remember that although the trna carries the amino acid, the mrna CODES for that amino acid. You will always use mrna and the codon chart to determine the right amino acids. Once the trna arrives, it drops off the amino acid. The next codon is read, and the next trna molecule will drop off its amino acid. This continues until a stop codon is read. At this point, the amino acid chain (protein) is complete, and the protein is ready to be used. 4. Using your codon chart, transcribe the mrna into amino acids using the codon chart provided below. SER LEU ALA THR ARG SER SER LEU ALA THR SER SER SER LEU ALA THR ARG SER

3 5. Using the DNA strand below, transcribe it to mrna. Then, use the mrna strand to find the amino acids. Finally, fill in the corresponding anticodons on the trna. A codon chart is provided for you below. A G G C G C G U C U C G A U C U C C G C G C A G A G C U A G Arginine Arginine Valine Serine Isoleucine

6. Use the diagram below to answer the following questions. AMINO ACID trna ANTI- a. Label the following in the diagram above: amino acid, codon, anticodon, trna b.

4 6. Use the diagram below to answer the following questions. AMINO ACID trna ANTI- a. Label the following in the diagram above: amino acid, codon, anticodon, trna b. Which of the two trna molecules above will attach to the mrna? The trna on the right will attach to the codon shown on the mrna. c. How did you know which trna molecule would attach to the codon shown? The trna on the left has the matching anti-codon to the codon on the mrna. Remember, the anti-codon only indicates where the trna should land. It is the codon on the mrna that codes for the amino acid that the trna carries. d. Suppose one of the bases on the mrna was changed. Would the same trna molecule still attach to the strand? Explain your answer. No; the trna anti-codon would no longer match the codon on the mrna. e. Use the codon chart to determine what amino acid is being coded for by the mrna codon. The mrna codon is GCA. This codes for the amino acid alanine.

7. The trna molecules below use the anticodons to match the messenger RNA codons. Each amino acid carried by the trna corresponds to the mrna codon.

List the amino acids in the order that they would appear on the protein chain. 2 4 3 1 Coded amino acids in correct order: MET (start) PHE ASP LEU 8. Define the term mutation in relation to DNA.

5 7. The trna molecules below use the anticodons to match the messenger RNA codons. Each amino acid carried by the trna corresponds to the mrna codon. Complete the steps below using the following two diagrams. a. Number the trna anticodons in the order in which they should appear to match the codons in the mrna strand. b. Determine the amino acids that are being coded for on the mrna and carried on the trna. List the amino acids in the order that they would appear on the protein chain Coded amino acids in correct order: MET (start) PHE ASP LEU 8. Define the term mutation in relation to DNA. A mutation is a change in the DNA sequence. This may result in a change to the mrna sequence, which could cause a change in the protein and trait. 9. Describe a point mutation. Does it always result in a change in the amino acid sequence? A point mutation means 1 letter is changed on the sequence. This does not always change the amino acid sequence. For example, let s say that a point mutation occurred, and AGU was changed to AGC. Even though a C was added where there should have been a U, AGU and AGC both code for the amino acid serine, meaning there would not be a change in the amino acid sequence. 10. Describe a frameshift mutation. Why do these cause such large changes to the amino acid chain? A frameshift mutation means there is an addition or deletion of a letter in the sequence. This causes large changes because codons are read in 3 s. By shifting the sequence by 1 letter, you change the way the codons are read from the point of the mutation, changing the protein.

6 11. Transcribe and translate the original DNA sequence. Then, do the same for each mutated DNA sequence. Then, determine the consequence, if any, for each mutation, by circling your choice for each question. You will need the codon chart above. AUG UGG AAC CGC UGC UGA Start TRY ASP ARG CYS STOP AUG UAG AAC CGC UGC UGA Start STOP AUG CUG GAA CCG CUG CUG A Start LEU GLU PRO LEU LEU AUG UGG AAU CGC UGC UGA Start TRY ASP ARG CYS STOP

RNA and Protein Synthesis Guided Notes

RNA and Protein Synthesis Guided Notes is responsible for controlling the production of in the cell, which is essential to life! o DNARNAProteins contain several thousand, each with directions to make