Presentation on theme: "Changes to the Genetic Code"— Presentation transcript:
1Changes to the Genetic Code Reporting Category 2Mechanisms of GeneticsStation 8Changes to the Genetic Code
2Essential Question-Bell Ringer Humans have approximately 75,000 to 100,000 genes in a typical cell. A single gene contains about 10,000 nitrogen base pairs. How is it possible for a single mutation to one of these base pairs to cause a life-threatening condition?Journal
3Essential Question answer: Nitrogen base combinations code for amino acids, which produce proteins. If a mutation to one of the base pairs affected a protein that was vital to the functioning of a crucial organ or system, this mutation would cause the organ or system to fail.Journal
4Pre-Review QuestionDuring the process of protein synthesis, a section of the DNA molecule is copied into which other molecule?Nucleic acidCytoplasmic DNAMessenger RNATransfer RNA
5Pre-Review QuestionIn messenger RNA, each codon specifies a particular:NucleotidePurineAmino acidPyrimidine
6Pre-Review Question True True or False Any change in the genetic sequence (DNA) that affects the genetic information is referred to as a mutation.True
7Pre-Review QuestionType of mutation that takes place when a base codon is changed but both code for the same amino acid:Silent mutationTransition mutationTransversionDeletion
8Lab ActivitiesYou will now go to the lab and complete the activities for todays topics…
10AUG CCA ACA GUG AGA UUA CAG AAA UCG UAA Write and answer the question in your journal (Include the DNA sequences)1. Using the mRNA Genetic Code chart, determine the name of the amino acid each codon represents.AUG CCA ACA GUG AGA UUA CAG AAA UCG UAAStart, proline, theorine, valine, arganine, leucine, glutamine, lysine, serine, stop.This will serve as your original strand.2. What does this chain of amino acids represent?A polypeptide chain or a protein strand.
11AUG CCA ACA GCG AGA UUA CAG AAA UCG UAA Write and answer the question in your journal (Include the DNA sequences)3. Some genetic mutations are caused by changes in the bases of some codons. Compare the two sequences below and compare them to the original sequence. Can you identify which codon was changed and what the new amino acid will be?AUG CCA ACA GCG AGA UUA CAG AAA UCG UAAAUG CCA ACA GUG AGA UUG CAG AAA UCG UAA11
12AUG CCA ACA GCG AGA UUA CAG AAA UCG UAA AnswerAUG CCA ACA GCG AGA UUA CAG AAA UCG UAAUracil has been replaced with cytosineThis will change the amino acid from valine to alanine.AUG CCA ACA GUG AGA UUG CAG AAA UCG UAAAlanine has been replaced with guanine.However, this still codes for the same amino acide.This is known as a silent mutation.12
13AUG CCA ACA UGU GAG AUU ACA GAA AUC GUA A Write and answer the question in your journal (Include the DNA sequences)4. If an additional base is added it it called a frameshift. Compare the original strand to the strand below and find the insertion. How many amino acids would be affected?AUG CCA ACA UGU GAG AUU ACA GAA AUC GUA A13
14AUG CCA ACA UGU GAG AUU ACA GAA AUC GUA A Write and answer the question in your journal (Include the DNA sequences)4. If an additional base is added it it called a frameshift. Compare the original strand to the strand below and find the insertion. How many amino acids would be affected?AUG CCA ACA UGU GAG AUU ACA GAA AUC GUA AStart, proline, theorine, cysteine, glutamic acid, isoleucine, threonine, glutamic acid, isoleucine, valine, nothing.14
155. What is the significance of this frame-shift mutation for the structure of the protein? After the mutation, 7 of the 10 codons now code for a different amino acid than the original sequence did. In addition, a single adenine (A) base ends the strand. This frame-shift mutation will cause massive changes in the types of protein produced by the new strand.
16What I need to remember…. • Mutations are changes in DNA that can beinherited.• Certain codons are responsible for starting theproduction of a protein, and other codons stop theprocess.• Mutations occur when bases are added or deletedand when segments of DNA are missing.• Not all mutations are harmful—some are verybeneficial.
17Post Review QuestionWhat type of point mutation is illustrated in the table below?SubstitutionSilentDeletionInsertionOriginal StrandMutated StrandDNATAC GTA CGG TAATGC GTA CGG TAAmRNAAUG CUA GCC AUUACG CAU GCC AUUAmino acidMet His Ala IsoThr His Ala Iso
18Post Review Question Identify the following mutation: Translocation DeletionInversionDuplication
19Post Review Question Identify the following mutation: Translocation DeletionInversionDuplication