Standard 7: Protein Synthesis Team: Science!

Protein Synthesis (How proteins are made!) Objectives: Proficency: Summarize the processes of transcription and translation and explain the importance of each process in the production of proteins. Determine the order of amino acids in a protein given a strand of DNA. Relates that a change in the order of amino acids in a protein will change the shape and function of the protein as a result of a mutation Basic: compare the structure of DNA and RNA identify a picture/diagram of the processes of transcription translation, and label the steps

Overall this is how proteins are made(Protein synthesis) Flow of Information DNA RNA Proteins (Transcription) (Translation)

But 1st……What are Proteins? Proteins come from the genetic code found on the DNA strand. So what is a gene? Let’s find out: John Perry answers…. What is a gene? Examples of different shapes of proteins 

Before we cover how a protein is made, let’s conquer: DNA vs RNA

DNA vs RNA DNA <------Type of molecule-----> RNA <------ Type of Helix-----> <------ Type of Sugar-----> <------ Types of Bases----->

So now you know what RNA is, let’s discuss the 3 Types of RNA Messenger RNA(mRNA) - RNA molecules that carry copies of genetic instructions Transfer RNA (tRNA) - transfers each amino acid to the ribosome as it is specified by “messages” of mRNA Ribosomal RNA (rRNA) - part of the ribosome structure

3 types of RNA Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal (rRNA)

Before we move on…can you tell the difference between DNA and RNA Before we move on…can you tell the difference between DNA and RNA? Now Let’s discuss PROTEIN SYNTHESIS: There are two main steps: Transcription and Translation Question: Why do you think mRNA is made? Why can’t the cell just use DNA to make proteins?

Transcription and Translation Video Why it's important that we talk about making proteins.....

1st…..Transcription Transcription video clip

Transcription is when mRNA is produced by copying part of the sequence of DNA into a complementary sequence of mRNA RNA Polymerase binds to DNA and separates strands. RNA polymerase then uses one strand of DNA as a template from which (mRNA) messenger RNA is made Transcription

DNA begins to unwind at a promoter region DNA begins to unwind at a promoter region. This is a specific sequence of bases that signal where the region should start. Signals in DNA that tell RNA Polymerase where to start copying- like the beginning of a sentence! Similar regions tell RNA Polymerase where to stop- like a period.

Genetic Code Proteins are made by joining amino acids into long chains (called polypeptides). There are 20 different amino acids that combine in different ways to make up different proteins (like the alphabet) “language” of mRNA instructions (order of nucleotides) is called the genetic code

Remember…. RNA has the four bases: What bases does DNA have? Adenine and Uracil Guanine and Cytosine What bases does DNA have?

Now that the mRNA is written (transcription), it now needs to be read (translation). Reading the Genetic Code: The Genetic code is read 3 letters (bases) at a time; each “word” is 3 letters long= codon UCG-CAC-GGU Each codon represents different amino acids

Transcription and Genetic Code Discussion Questions   1. What is made during transcription and why? 2. What is the genetic code? 3. What is the three letter “word” that represents an amino acid? _______________ 4. What base is found in RNA that is not found in DNA? 5. What makes up a protein? _______________ _________________

Translation Translation video clip

2nd….Translation–Reading the Genetic Code Reading the code from the mRNA is done in the ribosome. Here the information from mRNA allows the protein to be put together.

Remember the mRNA was first transcribed in the nucleus and then it was released into the cytoplasm. Translation begins when a mRNA molecule attaches to a ribosome.

Each codon of the mRNA molecule moves through ribosome. tRNAs bring the correct amino acid to the ribosome. In order to read the codons on the mRNA strand, the tRNA has an anticodon.

As the mRNA moves through the ribosome and the tRNAs bring in the correct amino acids, the protein builds on top of the ribosome. There’s actually a stop codon on the mRNA strand that signals that the protein does not need anymore amino acids. The mRNA breaks up and goes back into the cytoplasm.

Practice Protein Synthesis DNA strand: A T G G T A G C T mRNA : tRNA: Amino acids: (protein)

Why are Proteins Important? Proteins are often enzymes, which catalyze and regulate chemical reactions Flower color Blood type Regulate rate and pattern of growth throughout organism Proteins are EVERYTHING!!!

Translation and Protein Discussion Questions 1. In a nutshell, what does translation do? 2. Where does translation take place? 3. As the codons are being read, what do they represent? 4. Why are proteins important?

There are 2 main steps to how a protein is made: Transcription and Translation (use the word bank on your notes to fill in the blanks) Class Activity: Baking a Cake Analogy for Protein Synthesis

Lets Bake a Cake What all do you need to do or gather before you can bake a cake? Recipe Book Kitchen Pantry Recipe Index Card Kitchen Counter Ingredients Keebler Elves Cake!

Let’s use an analogy of baking a cake to understand it: = -DNA is a large book of recipes(___________________) that is too large to leave the pantry(_____________) in the kitchen(________________________). -So a copy of the DNA strand, so therefore a copy of the recipe (___________) is written from the DNA strand. This process of copying and writing the recipe on an index card would be (________________). -The copied recipe on the index card (_____________), must now leave the pantry (_____________) and go to the countertop(_______________) where it can be read(_________________)and the cake (_____________) can be assembled. The process of assembling the cake would be (____________________________).

Well how is the cake(_______________) assembled Well how is the cake(_______________) assembled? Ingredients (_________________) are needed! So all of the ingredients—the flour, oil, eggs, sugar, water, baking soda, icing------ (______________________________), are transferred to the countertop(_______________) from your helpers the Keebler Elves (____________). One by one the Keebler Elves(____________) bring the correct ingredient(_______________________) to the countertop(__________________) according to what is written on the recipe index card (_____________). So as the recipe card is read (_______________________), the cake (____________) is being made! Later that cake (_____________) is baked in the oven (______________________________) that needs that cake (_____________).