RNA & Protein Synthesis 2014 Putting all the pieces together!

By the end of class today… Explain what RNA is and why we need it Describe the differences between DNA and RNA Identify the 3 types of RNA Be able to transcribe RNA from DNA

Let’s Review DNA stores our…… DNA is found in the… DNA stands for Genetic information DNA is found in the… Nucleus DNA stands for DeoxyriboNucleic Acid The sugar found in DNA is Deoxyribose The 4 N-Bases of DNA are Adenine, Thymine, Cytosine, & Guanine DNA is composed this many strands… 2

What is RNA? Ribonucleic Acid “Decodes” instructions from DNA codes

RNA Structure Made of nucleotides Sugar (ribose) Phosphate group (phosphate + oxygen) Nitrogen base (A, U, C, G)

Sounds a lot like DNA? How it’s different: Sugar is ribose Single stranded Contains uracil instead of thymine

Let’s Practice DNA sequence RNA sequence T A C G A T A A C G G T A U G C U A U U G C C A

3 Types of RNA Messenger RNA (mRNA) Single strand attaches to DNA Carry copies of DNA instructions for assembling proteins -Starts in the Nucleus -Leaves to Cytoplasm to meet up with Ribosome

3 Types of RNA Ribosomal RNA (rRNA) Make up ribosomes, where proteins are assembled Reads mRNA’s code

3 Types of RNA Transfer RNA (tRNA) Transfers amino acid to the ribosome as coded by the mRNA

Makin Proteins DNA contains the instructions to make all the proteins needed for your body Ribosomes take these instructions and manufacture the proteins for the cells/body Well if DNA is in the nucleus….how do the instructions get to the ribosomes? We need a MESSENGER…..

Transcription Since DNA is stuck in the nucleus, we must use mRNA to relay the information to the ribosomes Process by which mRNA is formed from DNA is called Transcription This occurs in the Nucleus And is a similar procedure like when DNA replicates. Instead of making new DNA we make a single strand of mRNA Once mRNA is formed, it leaves the nucleus and heads for the ribosomes

Steps of Transcription DNA Strand T A C G G A C T A G T C C T G C T T A G A C C G A T T A T G C C T G A T C A G G A C G A A T C T G G C T A A

Steps of Transcription Enzyme T A C G G A C T A G T C C T G C T T A G A C C G A T T G G A C G A A T C T G G C T A A A C T A A T G C C T G

Steps of Transcription RNA Nucleotides Enzyme T A C G G A C T A G T C C T G C T T A G A A U G C C G A T T G G C T A A T C T A A T G C C T G A T C A G G A C G A

Steps of Transcription mRNA Strand Forming T A C G G A C T A G T C C T G C T T A G A C C G A T T A U G C C U G A U A T G C C T G A T C A G G A C G A A T C T G G C T A A

Steps of Transcription G G A C T A G T C C T G C T T A G A C C G A T T C C U G A U C A G G A C G A A U G U A A T G C C T G A T C A G G A C G A A T C T G G C T A A

Steps of Transcription G G A C T A G T C C T G C T T A G A C C G A T T G A A U C U G G C U A A C A A U G C C U G A U C A G G A T G C C T G A T C A G G A C G A A T C T G G C T A A

Steps of Transcription 1 new strand of mRNA A U G C C U G A U C A G G A C G A A U C U G G C U A A T A C G G A C T A G T C C T G C T T A G A C C G A T T A T G C C T G A T C A G G A C G A A T C T G G C T G A

Continuing the Protein Process Once mRNA leaves the nucleus it finds a ribosome to begin production Ribosomes (rRNA) are made of 2 parts or subunits During this next process the mRNA lies in between the two subunits mRNA A U G C C U G A U

Translation Once mRNA and the ribosomes have formed a complex, the next step of protein synthesis occurs….Translation The ribosome begins to read or “translate” the code on the mRNA Every 3 letters/bases on a mRNA makes a “word” called a codon

Translation continued… Transfer RNAs (tRNA) carry amino acids to the ribosomes to create the protein There are 3 letters/bases on a tRNA that correspond to a mRNA, this 3 base sequence is called an anti-codon. Amino Acid tRNA anticodon U A C G G A C U A A U G C C U G A U mRNA codon

Translation cont… Once the correct tRNA matches with the mRNA, the amino acid is released to start the protein The ribosome will move along reading the mRNA The tRNA’s will continue to drop off their amino acids These amino acids are linked to each other with a peptide bond

Translation …. Once the amino acids are linked with a peptide bond, the tRNA is released back into the cytoplasm to grab another amino acid and continue the process

Ribsome surrounds mRNA Steps of Translation A U G C C U G A U C A G G A C G A A U C U G G C U A A Ribsome surrounds mRNA

tRNA matches with the corresponding sequence of mRNA Steps of Translation U A C A U G C C U G A U C A G G A C G A A U C U G G C U A A tRNA matches with the corresponding sequence of mRNA

The ribosome shifts and anther tRNA pairs with the mRNA codon Steps of Translation U A C G G A A U G C C U G A U C A G G A C G A A U C U G G C U A A The ribosome shifts and anther tRNA pairs with the mRNA codon

between the amino acids Steps of Translation Peptide Bond U A C G G A A U G C C U G A U C A G G A C G A A U C U G G C U A A A peptide bond forms between the amino acids

Steps of Translation U A C G G A C U A A U G C C U G A U C A G G A C G A A U C U G G C U A A Ribosome shifts again. The 1st tRNA is released without the amino acid & and new tRNA joins.

This process continues until the ribosome reaches a ‘stop’ codon Steps of Translation A G A C C G A U G C C U G A U C A G G A C G A A U C U G G C U A A This process continues until the ribosome reaches a ‘stop’ codon

At the stop codon, the ribosome detaches and releases the new protein Steps of Translation New Protein A U G C C U G A U C A G G A C G A A U C U G G C U A A At the stop codon, the ribosome detaches and releases the new protein

Odds & Ends There are only 20 amino acids But 64 possible codons of mRNA This means that some codons code for the same amino acid There is one Universal ‘Start’ codon that ALL proteins must start with AUG = Methionine There are a few different ‘stop’ codons that all proteins end in

Mutations Causes of Mutations A permanent change that occurs in a cell’s DNA is called a mutation Causes of Mutations Random and spontaneously Chemicals and Radiation change DNA High-energy forms of radiation, such as X rays and gamma rays

So let’s review…. What does RNA stand for? What sugar is found in RNA? Ribonucleic Acid What sugar is found in RNA? Ribose What N-base is in RNA but not DNA? Uracil How many strands are in RNA? One What are the 3 types of RNA? mRNA, tRNA, rRNA

Some more review  Where does Transcription take place? Nucleus And what is formed during this process? mRNA Where does the mRNA travel to after leaving the nucleus? Ribosome What is the next step for protein synthesis? Translation What is the Universal Start Codon? AUG What type of bond links the amino acids together? Peptide Bond

Any questions? Aloha