Question

Which of the following is the name of the threebase sequence in the mRNA that binds to a tRNA molecule? a. \(\mathrm{P}\) site b. codon c. anticodon d. CCA binding site

Short answer

b. codon

Step-by-step solution

Understand the Question

Determine what the question is asking. It wants to identify the name of the three-base sequence in mRNA that binds to a tRNA molecule.

Recall Key Concepts

Remember that mRNA (messenger RNA) contains sequences called codons, while tRNA (transfer RNA) has anticodons. These sequences pair together during protein synthesis.

Review the Options

Evaluate the options given: a. P site b. codon c. anticodon d. CCA binding site

Eliminate Incorrect Options

Option a (P site) refers to a site within the ribosome. Option d (CCA binding site) refers to the binding site of an amino acid on tRNA.

Identify the Correct Answer

Option b, codon, refers to the sequence in mRNA that pairs with the anticodon in tRNA. Therefore, the correct answer to the question is 'codon'.

Key concepts

mRNA codon

Understanding mRNA codons is crucial for grasping how genetic information is translated into proteins. Messenger RNA (mRNA) carries the genetic code from DNA to the ribosome, where proteins are synthesized. The genetic code in mRNA is organized into codons, which are sequences of three nucleotide bases. Each codon corresponds to a specific amino acid or a stop signal during the process of protein synthesis.

Here are some key points about mRNA codons:

• There are 64 possible codons, each representing one of the 20 different amino acids or a stop signal.
• Codons are read in the 5' to 3' direction along the mRNA strand.
• The start codon, AUG, signals the beginning of protein synthesis and codes for the amino acid methionine.
• Stop codons (UAA, UAG, UGA) signal the end of protein synthesis.

Understanding codons helps in comprehending how genetic instructions are translated into the sequences of amino acids that make up proteins.

tRNA anticodon

The role of tRNA anticodons is to ensure that the correct amino acids are incorporated into the growing polypeptide chain during protein synthesis. Transfer RNA (tRNA) is the molecule responsible for transporting amino acids to the ribosome. Each tRNA has a specific three-nucleotide sequence called an anticodon, which is complementary to an mRNA codon.

Some critical aspects of tRNA anticodons include:

• Anticodons are read in the 3' to 5' direction on the tRNA molecule.
• The anticodon sequence pairs with the mRNA codon via complementary base pairing (A-U, G-C).
• Each tRNA molecule carries an amino acid that corresponds to its specific anticodon.
• This complementary pairing is key to ensuring the correct sequence of amino acids in the resulting protein.

The tRNA anticodon's specificity ensures that the mRNA's genetic code is accurately translated into a functional protein. This match between codon and anticodon is a critical step in the fidelity of protein synthesis.

Protein Synthesis

Protein synthesis is the fundamental process by which cells manufacture proteins, vital for countless cellular functions. The process occurs in two main stages: transcription and translation.

Here's a breakdown of protein synthesis:

• Transcription: This initial stage involves copying the genetic information from DNA into mRNA. During transcription, RNA polymerase binds to the DNA and synthesizes a complementary mRNA strand.


• Translation: The mRNA is then transported to the ribosome, where it directs the assembly of the protein. During translation, mRNA codons are read by the ribosome in sets of three bases at a time.


• tRNAs bring the appropriate amino acids to the ribosome based on their anticodon sequences that match the mRNA codons.
• The ribosome links the amino acids together to form a polypeptide chain, which then folds into a functional protein.

Understanding protein synthesis helps explain how genetic information is transformed into the proteins vital for life processes. It highlights the importance of mRNA codons and tRNA anticodons in accurately translating genetic instructions into functional products.