The Secret Code of Life

Codes and Ciphers: The Pigpen code - knows the key Codes were made as : a means of sending information easily such as the Morse code, or to send secret information – short and secret A code replaces words, phrases or sentences with numbers or letters while a cipher rearranges the letters to further disguise the message The Pigpen code will work to encode secret messages only if the other person receiving the message knows the key Codes were made as a means of sending information easily such as the Morse code, or to send secret information – short and secret A code replaces words, phrases or sentences with numbers or letters while a cipher rearranges the letters to further disguise the message

Can you decipher this? Can you decode this message? There are no secrets better kept than the secrets that everybody guesses." This is the pigpen cipher, an original French cipher, that was used by groups such as Napolean’s spies to send secret messages

Why does the human body need a code? The nucleus has an amazing design of sending information quickly to the rest of the cell (function is to control the cells functions) The stored information in the DNA needs to transfer it’s information quickly and reliably into a product. The information is stored in packets or “files” called genes. Genes are places or locations on a chromosome that contain a specific piece of information for the creation of a protein. The transfer of this information is called PROTEIN SYNTHESIS.

The Central Dogma The central dogma or “idea” of the transmission of information in the cell is Transcription Translation DNA  RNA  PROTEIN Where, DNA is read and transfers the information of the blueprint of the protein to RNA, and RNA transfers this information to be created in the cytoplasm Transcription + Translation = Protein Synthesis

The Genetic Code The DNA has a triplet code using only the 4 nucleotides, A,C,G and T. Only 3 nucleotides form a triplet which, when in a gene, codes for a part of a protein. There are 34 total different triplets that can be created but only 20 different amino acids. (Would a doublet code work just as well?? i.e. only 2 nucleotides to represent 20 amino acids. Why are there a lot of codes that mean the same amino acid?) Many triplets in a specific order will generate a specific protein (this is based on the order of the bases in the DNA) The bottom line is that the genes we have in our DNA create PROTEINS which we need. These proteins are made up of amino acids joined together in a specific manner to create the protein needed. There are 3 stop codons which tell the machinery not to continue the protein synthesis process.

Example DNA STRANDS mRNA Protein TAC GCT TAA CGG ACT TTA ATG CGA ATT GCC TGA AAT AUG CGA AUU GCC UGA Met – Arg – Ile – Ala – stop

MUTATIONS – When the code is changed! A mutation is a change in the DNA from its original form (mutatio = change, alteration in Latin) When just one base is changed in the DNA, it is considered a mutation. It would also create a new allele for the gene. Not all mutations are harmful.

Types of Mutations i) Insertion: 1 or 2 bases are added to DNA at one place (not in multiples of 3 – why is that?) ii) Deletion: 1 or 2 bases are added to DNA at one place (not in multiples of 3 – why is that?) Iii) Substitution: of 1 base for another base e.g. A  T or G  C i)TAC GCT AGG ATG TAC GGC TAG GAT G ii) TAC GCT AGG ATG TAC CTA GGA TG iii)TAC GCT AGG ATG TAC ACT AGG ATG

Effects of mutations on Proteins Positive – causes the protein to be have an even better function Negative – causes the protein to have little or no function OR disrupts another protein’s function e.g. Sickle cell anemia Neutral – causes the protein to have no significant change in function

Effects of DNA changes on Proteins B. Neutral mutation A. Normal protein No change in the active site C. Negative mutation D. Positive mutation No active sites 2 active sites now, more effective protein