Types of RNA - Online Tutor, Practice Problems & Exam Prep

RNA is shorter and single-stranded compared to DNA, with three main types: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries genetic information from DNA in the form of codons, which are sequences of three nucleotides that correspond to specific amino acids. rRNA is a structural component of ribosomes, the sites of protein synthesis. tRNA, the smallest RNA type, transports amino acids to ribosomes and contains anticodons that pair with mRNA codons, facilitating protein assembly. Understanding these RNA types is crucial for grasping protein synthesis and genetic expression.

Types of RNA Concept 1

Now, when it comes to RNA, just remember that RNA itself is shorter and it's single-stranded when compared to DNA strands. Remember, DNA has so many genes, so many nucleotides, and when it comes to RNA, we're only taking a small portion of this genetic information. And because of that, RNA is shorter. Now, even though it's shorter and it's single-stranded, it can have complex shapes.

Now, let's talk about the different types of RNA. Here we're going to talk about the first two. We're going to say that in total there are 3 types of RNA that differ in their size and their functions, but here we're going to pay attention to the first two. The first one is called messenger RNA which is mRNA. It acts as a messenger carrying DNA-encoded information and is translated to protein. It contains codons, which are 3 nucleotides that correspond to a specific amino acid. They are formed in the nucleus and transported to the ribosomes. Remember these are special organelles within a given cell.

Next, we have our ribosomal RNA, but before we do that, we have our messenger RNA (mRNA), we have our DNA strand up here, and we're going to copy a portion of that DNA to create our mRNA. This mRNA and these three nucleotides together help to form our codon. These codons can correspond to a specific amino acid which we'll see later on.

Now, moving over to ribosomal RNA (rRNA), this is the largest RNA of the three. It forms part of the structure of ribosomes, and this is the site of protein synthesis. Our rRNA is this yellow line in here. We're going to say that our ribosomes are these two structures, this top larger structure and this smaller bottom blue structure. Together, these two pieces are our ribosomes. Later on, we'll talk about how they work together in terms of reacting with ribosomal RNA and how this creates proteins. But for right now, just remember ribosomal RNA is a basically important aspect of ribosomes and the site of protein synthesis. So remember, we've discussed the first two types of RNA, there's still a third one left to talk about.

Types of RNA Concept 2

Now our 3rd RNA is called tRNA or transfer RNA. Here it's the smallest RNA of the 3. It carries amino acids to the ribosome during protein synthesis. Now, here it's going to contain what we call an anticodon. These are just our 3 nucleotides complementary to the mRNA codon. So remember, mRNA has codons, which are our 3 nucleotides. tRNA has anticodons, which are complementary to it. Now, here it's going to contain what we call an acceptor stem and it's at the 3' prime end where amino acids bind. And, we're going to say here that tRNA itself can form a complex 3D cloverleaf-shaped structure. So, if we take a look here, we're going to say that our amino acid is attaching to the 3' prime end here, this blue sphere, and, remember, we have 20 amino acids that we learned previously in our earlier chapters. tRNA is just this entire structure. Now if we were to expand a little bit further, we can see that this structure that's tRNA has these things here on the bottom. These represent our anticodon. Remember, when we copied a portion of DNA to make our mRNA, we created a codon. This codon of our 3 nucleotides here. These 3 nucleotides are complementary to the anticodon of our tRNA. Remember, G links up with C, A links up with U, it's U because remember, RNA deals with uracil not thymine and then again G with C. So these 3 link up with these 3, the codon with the anticodon. So, just remember tRNA may be the smallest RNA but we can see that in its shape it's pretty complex looking. We have our 3' prime end here which the acceptor stem adds or which acts as the acceptor stem where we have the amino acid that can bind. We have our 5' prime end over here. This structure, if you really look at it, kind of resembles a clover leaf. Okay. So that's why they call it that particular shape, because it kind of resembles this, cloverleaf that we have in the right-hand corner. Right? So just remember, this represents our 3rd RNA, which is our smallest RNA.

Types of RNA Example 1

Here it says, match each statement with mRNA, rRNA, or tRNA. The first one says, "transfers amino acids to ribosomes for polypeptide synthesis." Well, this represents near the end where we're talking about protein synthesis itself. Transferring amino acids is accomplished by tRNA. Next, "created in the nucleus of the cell and carries genetic information to the ribosomes." Remember, we have DNA acting as our genetic information. It's copied to help create our mRNA. This happens within the nucleus and then eventually leaves the nucleus to go towards the ribosomes. So here, we're talking about mRNA. "Forms the structure of ribosomes," which is ribosomal RNA, or rRNA. "It contains anticodons complementary to the codons of mRNA." Remember, our codons come from mRNA, and our anticodons come from tRNA. This is how we are able to bring in our designated amino acid for protein synthesis. Finally, "acts as a template for protein synthesis." So our template strand that's helping with all of this protein synthesis is originally DNA, but we copy it into mRNA. That mRNA sequence of nucleotides acts as our template for eventual protein synthesis. So here, this is mRNA as our answer. So, this is what we'd say for each one of the given terms when we have to match them with mRNA, rRNA, or tRNA.

Which type of RNA contains groups of 3 nucleotides that code for a specific amino acid?

• A. tRNA
• B. rRNA
• C. mRNA
• D. none of the above

Rank RNAs in order of smallest to largest.

• A. tRNA, rRNA, mRNA
• B. tRNA, mRNA, rRNA
• C. rRNA, mRNA, tRNA
• D. mRNA, rRNA, tRNA

If tRNA has an anticodon 3’ UCG 5’, which of the following is the complementary mRNA codon?

• A. 5’ AGC 3’
• B. 5’ CGA 3’
• C. 3’ AGC 5’
• D. 3’ CGA 5’

Here’s what students ask on this topic:

What are the main types of RNA and their functions?

The main types of RNA are messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries genetic information from DNA in the form of codons, which are sequences of three nucleotides that correspond to specific amino acids. This information is used to synthesize proteins. rRNA is a structural component of ribosomes, which are the sites of protein synthesis. It helps form the ribosome's structure and facilitates the translation of mRNA into proteins. tRNA, the smallest RNA type, transports amino acids to the ribosome during protein synthesis. It contains anticodons that pair with mRNA codons, ensuring the correct amino acids are added to the growing protein chain.

How does mRNA differ from DNA?

mRNA differs from DNA in several ways. Firstly, mRNA is single-stranded, whereas DNA is double-stranded. Secondly, mRNA is shorter because it only carries a portion of the genetic information from DNA. Thirdly, mRNA contains the nucleotide uracil (U) instead of thymine (T), which is found in DNA. Additionally, mRNA is synthesized in the nucleus and then transported to the ribosomes in the cytoplasm, where it serves as a template for protein synthesis. In contrast, DNA remains in the nucleus and serves as the long-term storage of genetic information.

What is the role of tRNA in protein synthesis?

tRNA plays a crucial role in protein synthesis by transporting amino acids to the ribosome. Each tRNA molecule has an anticodon, a sequence of three nucleotides that is complementary to an mRNA codon. This ensures that the correct amino acid is added to the growing polypeptide chain. The amino acid binds to the 3' end of the tRNA, known as the acceptor stem. During translation, the tRNA anticodon pairs with the mRNA codon, allowing the ribosome to link the amino acids together in the correct order to form a protein.

What is the structure and function of rRNA?

rRNA, or ribosomal RNA, is the largest type of RNA and forms a key structural component of ribosomes, which are the sites of protein synthesis. Ribosomes consist of two subunits, a larger one and a smaller one, both of which contain rRNA and proteins. rRNA helps maintain the ribosome's structure and facilitates the translation of mRNA into proteins by ensuring the proper alignment of mRNA and tRNA. It also catalyzes the formation of peptide bonds between amino acids, a critical step in protein synthesis.

How do codons and anticodons interact during protein synthesis?

During protein synthesis, codons and anticodons interact to ensure the correct sequence of amino acids in a protein. Codons are sequences of three nucleotides on mRNA that correspond to specific amino acids. Anticodons are complementary sequences of three nucleotides on tRNA. When a tRNA molecule with the correct anticodon pairs with an mRNA codon, it brings the corresponding amino acid to the ribosome. This interaction ensures that amino acids are added in the correct order, allowing the ribosome to synthesize a protein according to the genetic instructions carried by the mRNA.