DNA Review Mr. Hefti – Pulaski Biology We can think about the DNA sequence of a gene as a sentence made up entirely of three-letter words. In the sequence, each three-letter word is a codon, specifying a single amino acid in a protein. Have a look at this sentence: Thesunwashotbuttheoldmandidnotgethishat. If you were to split this sentence into individual three-letter words, you would probably read it like this: The sun was hot but the old man did not get his hat. This sentence represents a gene. Each letter corresponds to a nucleotide base, and each word represents a codon. What if you shifted the three-letter "reading frame?" You would end up with T hes unw ash otb utt heo ldm and idn otg eth ish at. As you can see, it is no longer an understandable sentence. In the same way, only one three-letter reading frame within a gene codes for the correct protein. Across 2. the two sides of DNA held together by weak ____ bonds 5. always pairs with cytosine 6. where protein is assembled from the message on the RNA 7. the shape of DNA, double ____ 9. process of copying DNA 13. composed of a sugar, a base, and a phosphate 14. sections of DNA that code for a trait 15. replaces thymine in RNA The following DNA sample was taken from a volunteer snork. The DNA was then transcribed to its complimentary RNA strand. Your job is to analyze the RNA sample and determine the phenotype (how the organism looks) based on the sequence. AUG is a start codon, it signifies the beginning of a new gene. UAA is a stop codon and signifies the end of a gene. The genes are in order from gene 1 to gene 9. Use the codon chart above. Snuffle Snork AUG | GUA UCU AAA | GUU CCU ACU GAA AAG | CUU CUC CUC CCC | GUU GCG GCU | CAU CAC| GUA UUU UAU | GUA AUU CUU CUG CCC ACA | GUU GAC GAC GCA | UUC UCG GGU | AGA UAU UGU | UAA ☺What is this type of diagram called? ☺What are the ☺What it the name of this structures called? ☺What are the lab technique? markings called? ☺ What causes the DNA to ☺What are they made out of? separate? ☺Is this person a ☺ What moves faster: boy or a girl? small fragments or large ☺Do you see any mutations? fragments of DNA? ☺If so, circle it. ☺ Whodunit? ☺What kind of mutation is it?