Introduction to Translation - Online Tutor, Practice Problems & Exam Prep

Introduction to Translation Concept 1

Hey, everyone. So in this video, we're going to take an introductory look at translation. Now we're calling that in translation, a ribosome reads the genetic information in mRNA to synthesize proteins. And we're going to say this process requires tRNA, amino acids, and enzymes to translate mRNA into protein. Now, tRNAs are responsible for transporting our amino acids, which we represent by this blue sphere, to the ribosomes. So, here if we have our image, we have our mRNA. It wants to undergo translation to become protein. And, again, to utilize this, we need our tRNA. Remember, here's our tRNA structure with its anticodons down here. Remember that we are attaching our amino acid at the acceptor stem, which is on the 3\' prime end. And remember, these two structures here represent the complete ribosome. So mRNA with the assistance of tRNA, our ribosome here, and enzymes, through translation, we can make our given protein. Now, tRNA molecules must first be activated before they enter the translation process. So, right now, we're just peeking in trying to look at the introductory look at what translation is and how it does things. So just remember, it's essentially mRNA going to protein, the utilization of tRNA, amino acids, enzymes, ribosomes in order to get it done. Right? So now that we've talked about this introductory thing, we continue onwards with talking further about translation.

Introduction to Translation Concept 2

In this video, we're going to take a look at the activation of tRNA. Now, during activation, an amino acid is attached to the acceptor stem which is on the 3 prime end of tRNA. Now, here we're going to say an ester bond is formed between the c terminus end of the amino acid and the free OH at the 3 prime end of tRNA. If we take a look here at this image, we could say that where the OH is located is the 3 prime end of tRNA and this will be the 5 prime end. Remember that tRNA, it looks like a cloverleaf in terms of its structure. Here we have our Amino Acid. This is its C Terminus end. This C Terminus end, this carboxylate anion interacts with the OH here. Remember, a Carboxylic Acid or a carboxylate with an alcohol is what helps to create an Ester. Here goes our Ester linkage right here. Again, this is still the 3 prime and this is still the 5 prime. Now, in order to do this, we use an aminoacyl tRNA synthetase that catalyzes the ester bond formation. Now, each amino acid has a different synthetase. Here, we're just using a generic amino acid because our R group is unknown. Because of this, the enzyme name which is our substrate followed by synthetase would be aminoacyl tRNA synthetase. And, because we're using this generic name, this newly created ester bond for this structure would just be our aminoacyl tRNA. Now, here, for the one on the right, we're using a specific amino acid. We're using alanine because now the R group is a methyl. That is a specific R group, so this is talking about the amino acid alanine. Because of this, it has its specific name. So this is alanyl tRNA synthetase. And we would depict this as just our alanine here, helping to make the ester linkage. And then here, we'd say that this is our Alanyl tRNA. Again, we're going to use this generic name for all the 20 Amino Acids in general, but if we're given a specific one, the name changes a bit, we drop the INE here of this amino acid and change it to YL. You're expected to know this generic name for this enzyme that's used to activate tRNA. We're just showing you this specific amino acid in this case so you can see how does the name change for a specific amino acid. Right? So just keep that in mind when looking at the activation of a tRNA molecule.

Introduction to Translation Example 1

Which of the following statements is incorrect about translation?

• A: Translation is a part of gene expression. This is true. Remember that transcription and translation together encompass gene expression. So translation is indeed a part of gene expression.
• B: Translation requires tRNA molecules as carriers of amino acids. That's true. Remember, our mRNA brings in our codon and tRNA brings in the anticodon so that it can carry an amino acid in for protein synthesis.
• C: A ribosome reads the genetic information from a DNA strand and synthesizes a protein. This is incorrect. The ribosome doesn't read the genetic information from a DNA strand, it does it from an mRNA strand.
• D: Ribosomes, the sites of protein synthesis, are located outside the nucleus in the cytosol. This is true. Remember when mRNA has been made and processed and after it's processed it leaves the nucleus of the cell to go into the cytosol so that it can connect with the ribosomes, which are also the sites of protein synthesis.

So here, the only option that is incorrect is option C. Ribosomes don't read DNA to synthesize protein. They read mRNA in order to synthesize protein.

During activation, an amino acid bonds to the ___ end of tRNA through its ___-terminus.

• A. 5’, C
• B. 3’, N
• C. 5’, N
• D. 3’, C

Here’s what students ask on this topic:

What is the role of tRNA in the translation process?

tRNA, or transfer RNA, plays a crucial role in the translation process by transporting amino acids to the ribosome, where proteins are synthesized. Each tRNA molecule has an anticodon that pairs with a specific codon on the mRNA strand, ensuring that the correct amino acid is added to the growing polypeptide chain. The amino acid is attached to the 3' end of the tRNA through an ester bond, formed by the enzyme aminoacyl tRNA synthetase. This process ensures that the genetic code in the mRNA is accurately translated into a functional protein.

How does aminoacyl tRNA synthetase activate tRNA?

Aminoacyl tRNA synthetase activates tRNA by attaching an amino acid to the tRNA's 3' end. This enzyme catalyzes the formation of an ester bond between the carboxyl group of the amino acid and the hydroxyl group at the 3' end of the tRNA. Each amino acid has a specific synthetase, ensuring that the correct amino acid is attached to its corresponding tRNA. For example, the enzyme alanyl tRNA synthetase attaches alanine to its tRNA, forming alanyl tRNA. This activation is essential for the tRNA to participate in the translation process, where it delivers the amino acid to the ribosome for protein synthesis.

What is the significance of the 3' end of tRNA in translation?

The 3' end of tRNA is significant in translation because it is the site where the amino acid is attached. This attachment is facilitated by the enzyme aminoacyl tRNA synthetase, which forms an ester bond between the amino acid's carboxyl group and the hydroxyl group at the 3' end of the tRNA. This activated tRNA, now called aminoacyl tRNA, is essential for delivering the correct amino acid to the ribosome during protein synthesis. The 3' end's role ensures that the genetic code in the mRNA is accurately translated into a functional protein, maintaining the fidelity of the translation process.

What is the function of ribosomes in the translation process?

Ribosomes are the molecular machines that facilitate the translation process by reading the genetic information encoded in mRNA and synthesizing proteins. They consist of two subunits, which come together during translation. The ribosome moves along the mRNA strand, reading codons and coordinating the binding of tRNA molecules that carry specific amino acids. The ribosome catalyzes the formation of peptide bonds between amino acids, creating a growing polypeptide chain. This process continues until a stop codon is reached, signaling the end of translation and the release of the newly synthesized protein.

How does the structure of tRNA contribute to its function in translation?

The structure of tRNA is crucial for its function in translation. tRNA molecules have a cloverleaf structure with an anticodon loop that pairs with the mRNA codon and an acceptor stem at the 3' end where the amino acid is attached. The anticodon ensures that the tRNA delivers the correct amino acid corresponding to the mRNA codon. The acceptor stem's 3' end is where the amino acid is esterified by aminoacyl tRNA synthetase. This structure allows tRNA to accurately translate the genetic code in mRNA into a specific sequence of amino acids, forming a functional protein.