Presentation on theme: "RNA Review RNA is just like DNA, except that it is only one strand, instead of two. The other difference is that RNA replaces all of the THYMINE with."— Presentation transcript:
RNA Review RNA is just like DNA, except that it is only one strand, instead of two. The other difference is that RNA replaces all of the THYMINE with URACIL. So, C still pairs with G. Cytosine with Gaunine But now, A pairs with U. Adenine with Uracil
RNA Review RNA is like a photocopy of the DNA. It is what actually gets sent out to the ribosomes for building proteins. The CEO (the nucleus) does not want to let the DNA out of his reach. It is way way too long and the CEO needs it to replicate! It is needed to replicate new DNA, if the cell ever needs to make a new cell or reproduce. Plus, it contains instructions for everything So, the CEO (nucleus) decides to make a photocopy of the DNA to send out to the WORKERS (ribosomes). The RNA is specific to one protein. For example, it could just build protein, or hemoglobin. This is the RNA! We call it mRNA for MESSENGER RNA!
Transcription Review mRNA is created through the process of TRANSCRIPTION! Just like DNA replication, transcription occurs by splitting the DNA apart. However, in transcription it is only temporary. Then, the mRNA strand pairs up with one strand of DNA and base pairs come together. The only difference is mRNA pairs A with U (it still pairs T with A). Finally, the DNA molecule comes back together and the mRNA head off for the ribosomes (workers) to build proteins.
Transcription and Translation Transcription is the process that creates a photocopy of the instructions. The instructions are the DNA. The photocopy is the mRNA Translation is the process in which the workers read the photocopy to create proteins. The workers are the ribosomes Let’s read a story about it… But first, what is an analogy? A comparison between two things
Translation Translation starts with the mRNA leaving the nucleus for the cytoplasm A ribosome grabs hold of a strand of mRNA and starts to read it, three letters at a time. Each 3 letter section of mRNA is called a CODON. Each codon represents an amino acid that will be added to the chain.
What is a codon? Remember, a GENE is like a sentence in the genetic code ACGUUGCCAAGCAAUCG (or HASBROWNHAIR) Then, A CODON is like a word Each codon tells the ribosome which AMINO ACID to use A codon is 3 letters Ex. CAG means glutamine Some codons mean “Start” or “Stop” A BASE is like a letter A, U, G, C
Building Proteins As the ribosome reads the mRNA, transfer molecules (tRNA) fetch amino acids and bring them back to the ribosome. The transfer molecules line up with the correct codon and add their amino acid to the growing chain. Eventually, the rib0some reads “stop” and the protein chain is complete! Let’s try translating some proteins!
Let’s see it in action… eature=channel eature=channel nscribe/ nscribe/
Let’s Try it! TRANSCRIPTION: First, translate the DNA into mRNA. DNA: TAAGCTACCTTCGCATGGCATGCATC mRNA: AUUCGAUGGAAGCGUACCGUACGUAG TRANSLATION: Next, read the mRNA from left to right, looking for the “start” codon AUG. TRANSLATION: Now, read one codon at a time and use your codon chart to find the correct AMINO ACID TRANSLATION: Once you get to the stop codon, you’re chain of amino acids is complete and you have created a protein!
Now, try it on your own.
Exit Slip 1) What is a codon? 2) Describe the process of translation in your own words: